lifetime deliverable d3.1 - vttlifetime.vtt.fi/lifetime_deliverable_3_1.pdf · 3.5.2 condition...
TRANSCRIPT
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Thematic Network LIFETIME
Lifetime Engineering of Buildings and Civil Infrastructures
Deliverable 3.1: Generic description of lifetime engineering of buildings, civil and industrial infrastructures
Second draft 26. 08. 2005
Author:
Professor, Dr. Asko Sarja Technical Research Centre of Finland, VTT
VTT Building and Transport Finland
Contributors:
Chapter 2: Dr. Hyvel Davies
Hywel Davies Consultancy United Kingdom
Chapter 3.6:
Professor, Dr. Frank Schultmann Chair for Construction Management and Economics,
University of Siegen Germany
Espoo, August 2005 VTT Building and Transport
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ACRONYM : LIFETIME TITLE : Lifetime Engineering of Buildings and Civil Infrastructures CONTRACT N° : G1RT-CT-2002-05082 PARTNERS : PROJECT CO-ORDINATOR : Technical Research Centre of Finland (VTT), VTT Building Technology Professor, Dr. Asko Sarja PRINCIPAL CONTRACTORS
Taylor Woodrow Construction ltd UK Centre Scientifique et Technique du Batiment, F Imperial College of Science Technology and Medicine, (T H Huxley School of Environment, Earth Sciences and Engineering)
UK
Universitaet Karlsruhe (University of Karlsruhe) Facility Management and Institut f. Maschinenwesen im Betrieb
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Members: Totally 89 Members Observers: Totally 4 Observers PROJECT START DATE : 01. 06. 2002 DURATION : 38 Months
Project funded by the European Community under the ‘Competitive and Sustainable Growth’ Programme (1998-2002)
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CONTENTS
PROJECT CO-ORDINATOR : Technical Research Centre of Finland (VTT),................... 2 VTT Building Technology ......................................................................................................... 2 1. Framework of Lifetime Engineering...................................................................................... 6
1.1 Background ...................................................................................................................... 6 1.2 Definition and sectors of Lifetime Engineering............................................................... 7 1.3 Process towards the practice of Lifetime Engineering................................................... 10
1.3.1 Societal needs in Europe ......................................................................................... 10 1.3.2 Lifetime Project Cluster of EU GROWTH Program .............................................. 11 1.3.3 References ............................................................................................................... 13
1.4 Generic requirements and criteria of lifetime quality .................................................... 14 2 Current International and European State of the Art............................................................. 17
2.1 Introduction .................................................................................................................... 17 2.2 Key aspects and definitions of Lifetime Engineering .................................................... 17 2.3 Life Cycle Costing ......................................................................................................... 21
2.3.1 General .................................................................................................................... 21 2.3.2 Government Guidance............................................................................................. 21 2.3.3 Practical Considerations of Life Cycle Costing ...................................................... 22 2.3.4 Eurolifeform Project................................................................................................ 23
2.4 Lifetime Responsibility Procurement or Lifetime Contracting...................................... 23 2.4.1 EU Public Procurement Directives ......................................................................... 23 2.4.2 Further Guidance..................................................................................................... 24
2.5 Life Cycle Analysis........................................................................................................ 25 2.5.1 Energy ..................................................................................................................... 26 2.5.2 Pollution Emissions................................................................................................. 26 2.5.3 Health and Wellbeing.............................................................................................. 26 2.5.4 Water ....................................................................................................................... 27 2.5.5 Materials Specification............................................................................................ 27
2.6 Condition Assessment and Monitoring of Structures .................................................... 28 2.7 Service Life Planning and Design.................................................................................. 28 2.8 The hieracrchy of available knowledge ......................................................................... 29
2.8.1 Key directives.......................................................................................................... 30 2.8.2 Mandate 350............................................................................................................ 31
2.9 International and European Standards........................................................................... 33 2.9.1 ISO/TC207 “Environmental Management” ............................................................ 33 2.9.2 ISO/TC59 “Buildings” ............................................................................................ 33 2.9.3 International and European standards in response to energy performance of buildings and directive 2002/91/EC and health&Comfort perforformance..................... 34 2.9.4 International and European standards on test methods for indoor air pollutants and health& comforth performance of buildings and EC Mandate M/XXX (Dangerous Substances)....................................................................................................................... 35
2.10 References to Chapter 2 ............................................................................................... 37 2.11 Further reading ............................................................................................................. 39
3. A model of Lifetime Engineering Process ........................................................................... 41 3.1 Principles........................................................................................................................ 41 3.2 Integrated Lifetime Design (ILD) .................................................................................. 45
3.2.1 Principles, methodology and methods .................................................................... 45
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3.2.2 Tasks and methods of the design process................................................................ 48 3.2.3 Descriptions of the design phases ........................................................................... 51
3.3 Reliability and extended limit states design................................................................... 61 3.3.1 Generalised limit states ........................................................................................... 61 3.3.2 Design life ............................................................................................................... 61 3.3.3 Limit states .............................................................................................................. 62 3.3.4 Extended reliability of structures ........................................................................... 65 3.3.5 Statistical methods for integrated lifetime reliability control................................. 66 3.3.6 Safety factor method for static, fatique and dynamic loading................................. 67 3.3.7 Reliability under obsolescence................................................................................ 74 References to chapter 3.3 ................................................................................................. 75
3.4 Lifetime Procurement and Construction (LPC) ............................................................. 76 3.4.1 Procurements and contracting types........................................................................ 76 3.4.2 EU Public Procurement Directives ......................................................................... 76
3.5 Lifetime Facility Management ....................................................................................... 77 3.5.1 MR&R Strategy, Optimisation and Decision-Making [Lifecon D1.1] ................... 77 3.5.2 Condition Assessment Protocol (CAP) [Lifecon D3.1] .......................................... 79 3.5.3 Service Life Prediction............................................................................................ 80 3.5.4 Environmental Degradation Loads.......................................................................... 83 3.5.5 Quantitative classification of environmental loads [Lifecon D4.2] ........................ 83 3.5.6 MR&R Planning...................................................................................................... 85 3.5.7 IT- Prototype [Lifecon D1.2, D1.3] ........................................................................ 90
3.6 End-of-Life Management of Buildings .......................................................................... 91 3.6.1. Introduction ............................................................................................................ 91 3.6.2. Classification and Composition of Demolition Waste........................................... 92 3.6.3. Techniques for the Recovery and the Reuse of Construction and Demolition Waste.......................................................................................................................................... 94 3.6.4. Economics of Deconstruction and Marketing of used Building Materials .......... 100 3.6.5. End-of-Life Management: case studies................................................................ 106
4. Development of building concepts..................................................................................... 114 4.1 Some principles for increasing the productivity and life cycle quality........................ 114 4.2 Basic principle for achieving competitiveness in life cycle quality............................. 115 4.3 Tools for productivity development............................................................................. 118
4.3.1 Integrated information........................................................................................... 118 4.3.2 Site automation...................................................................................................... 119 4.3.3 Networking............................................................................................................ 120 4.3.4 Advanced materials and structural engineering .................................................... 120
4.4 Building concept development..................................................................................... 121 4.5 References to Chapter 4 ............................................................................................... 122
5. Central methods of lifetime engineering............................................................................ 124 5.1 Life cycle costing ......................................................................................................... 124
5.1.1 The discount rate ................................................................................................... 137 5.1.2 Present Value......................................................................................................... 138 5.1.3 Profitability index.................................................................................................. 138 5.1.4 The annuity method. ‘Annual cost’...................................................................... 138 5.1.5 Internal rate of return............................................................................................. 139 5.1.6 Simple payback ..................................................................................................... 139 5.1.7 Value or cost of a building at the end of the life cycle.......................................... 139 5.1.8 LCC calculation procedure.................................................................................... 140 5.1.9 References to Chapter 5.1 ..................................................................................... 140
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5.2 Risk and reliability principles, analysis and control .................................................... 141 5.2.1 Aim and role of risk assessment and control in LMS ........................................... 141 5.2.2 Quantitative approach ........................................................................................... 143 5.2.3 Risk analysis methods ........................................................................................... 144 5.2.4 Fault tree analysis (FTA)....................................................................................... 145 5.2.5 Risk assessment and control procedure................................................................. 151 References to Chapter 5.2 .............................................................................................. 156
5.3 Service life planning and obsolescence........................................................................ 157 5.3.4 Elements of obsolescence analysis....................................................................... 159 5.3.5 Limit states ........................................................................................................... 161 5.3.6 Methods for obsolescence analysis and decision making .................................... 163 5.3.5 QFD in obsolescence analysis and decision making............................................ 164 5.3.7 LCC in obsolescence analysis and decision making............................................ 165 5.3.8 MADA in obsolescence analysis and decision making ....................................... 165 5.3.9 FTA in obsolescence analysis and decision making ............................................ 166
5.4 Modelling of performance and service life .................................................................. 173 5.5 Service life design ........................................................................................................ 173 5.6 Ecological analysis and calculations (economy of the nature) .................................... 176 References to Chapter 5.6 .................................................................................................. 177 5.7 Cultural acceptance criteria and analysis ..................................................................... 177 5.8 Multiple Criteria Optimisation and Decision making (MADA, QFD) ........................ 177
5.8.1 Analytical Hierarchy Process (AHP) as a set of Multi-Attribute Decision Analysis (MADA) ......................................................................................................................... 177 5.8.2 Principles of Quality Function Deployment Method (QFD) ................................ 178 5.8.3 General Use of QFD Method ................................................................................ 180 5.8.4 Alternative applications of QFD in Life Cycle Management System (LMS)....... 186
5.9 MR&R (Maintenance, Repair and Rehabilitation) Planning ....................................... 187 5.9.1 Concepts ................................................................................................................ 187 5.9.2 Necessary planning elements ................................................................................ 188 5.9.3 Survey and condition assessment.......................................................................... 189 5.9.4 RAMS (Reliability, Availability, Maintainability, and Safety). ........................... 190
6. Future trends and research, development and education needs ......................................... 196 6.1 Knowledge development.............................................................................................. 196 6.2 Development of processes and organisations.............................................................. 197 6.3 Development of building technology........................................................................... 197 References to Chapter 6 ..................................................................................................... 198
7. Conclusions ........................................................................................................................ 199 APPENDIX 1. Terms and Definitions of Lifetime Engineering ........................................... 200 APPENDIX 2. EU Directives relating to Lifetime Engineering............................................ 205 APPENDIX 3. State of the Art Summary of International laws, norms, regulations, guides and rules ................................................................................................................................. 215
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1. Framework of Lifetime Engineering
1.1 Background
The civil engineering (buildings, civil and industrial infrastructures and environmental engineering), even more than other branches of technique, is strongly tied into the surrounding society [13] (Figure 1.1).
ENVIRONMENT
Natural Built
SOCIOLOGY
POLITICS
ECONOMY
Building Building Productsdesign production and product
development
ARCHITECTURE
Natural Engineering Generalsciences sciences technology
ARTS
CULTURAL MILIEU OFSOCIETY
Market
Figure 1.1 Development environment of building technology [13].
The objectives and targets of construction are defined in general politics of each society in connection to the environmental, sociological and economic objectives. At the background of the development there exist the heritage of general culture, arts and architecture of each region and society. Knowledge push is served by natural sciences, engineering sciences and general technology. This knowledge is transferred into technology through design, building production and building products. The entire evolution is strongly controlled by market forces and business of the companies. All over the world societies have identified and accepted the goal of sustainable development in order to reach a stable social and economic development in harmony with nature. Against all these aspects: social, economic, cultural and ecological, the construction branch is a major player. In ecological aspects most dictating is energy efficiency. Building sector is responsible for a major share of all the influences mentioned above. This is why the goal of a sustainable building branch is a big challenge for civil engineering. These changes are creating for the construction new challenges, which can be fulfilled successfully only through active and innovative changes in the design, products, manufacturing methods and management. Introducing into the solving of the challenges the latest advancements of the new technologies, a drastic development can be achieved. In the time period of 10 to 15 years we can talk on an entirely new generation of building technology. The new solutions will be developed, or in fact already are partly existing, in prototypes and in limited applications. The advanced technology will then penetrate into more wide applications until it is the common practice. This evolution phase has started in the second part of 1980’s and will be implemented into the common practice until 2010-2015 [11]. Sustainable development is aimed to reach a stable social and economic development in harmony with nature and cultural heritage. Against all these aspects: social, economic, ecological and cultural, the construction branch is a major player. The construction branch includes building and civil engineering and all their life cycle phases: construction, operation, maintenance, repair, renewal, demolition and recycling. As an example, in Europe the construction branch share is: 11 % of GNP, 15 % of
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employment, and 40 % of raw materials consumption, energy consumption and waste production. Building and civil engineering structures are responsible for a major share of all the influences mentioned above. Building and civil engineering structures are the longest lasting products in societies. Typically the real service life of structures lies between 50 years and several hundreds of years. We know, and this is especially known here in Greece, that some of the most valued historic structures currently, have even reached an age of several thousand years. This is the reason why sustainable engineering in the field of buildings and civil infrastructures is especially challenging in comparison to all other areas of technology. In order to reach these objectives we have to make changes even into paradigm, and especially the frameworks, processes and methods of engineering in all phases of the life cycle: investment planning and decisions, design, construction, use and facility management, demolition, reuse, recycling and wasting. This is the reason for starting to speak on lifetime engineering. The lifetime (also called: "whole life" or "life cycle") principle has been started to introduce into design and management of structures during last years, and this development process is getting increasing interest in practice of structural engineers.
1.2 Definition and sectors of Lifetime Engineering
Lifetime engineering is a theory and practice of predictive, optimising and integrated long-term investment planning, design, construction, management in use, MR&R&M (Maintenance, Repair, Rehabilitation and Modernisation) end-of-life management of assets. With the aid of lifetime engineering we can control and optimise the lifetime properties of of built assets with design and management corresponding to the objectives of owners, users and society. Lifetime engineering includes:
- Lifetime investment planning and decision-making - Integrated lifetime design - Lifetime Procurement and Contracting: Integrated lifetime construction - Integrated lifetime management and maintenance, repair, rehabilitation and Moderniastion
(MRR&M) planning and actions - End of Life management: Recovery, reuse, recycling and disposal
The integrated lifetime engineering methodology concerns the development and use of technical performance parameters to optimise and guarantee the lifetime quality of the structures in relation to the requirements arising from human conditions, economy, cultural and ecological considerations. The lifetime quality is the capability of the whole network or an object to fulfil the requirements of users, owners and society over its entire life, which means in the practice the planning period (usually 50 to 100 years). Lifetime investment planning and decision-making is a basic issue in starting the construction, but also in lifetime asset management. Generally the investment planning and decision making is used in evaluating project alternatives, either in planning of a construction project or in MR&R planning. The procedure includes consideration of characteristics or attributes which decision makers regard as important, but which are not readily expressed in monetary terms. Examples of such attributes in case of buildings are: location, accessibility, site security, maintainability, and imago. Integrated lifetime design includes a framework, a description of the design process and its phases, special lifetime design methods with regard to different aspects: human conditions, economy, cultural
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compatibility and ecology. These aspects will be treated with parameters of technical performance and economy, in harmony with cultural and social requirements, and with relevant calculation models and methods. Lifetime Procurement and Contracting: Integrated lifetime construction means procurements, where the contractor takes usually responsibility on technical design, construction, operation and maintenance of the facility over a defined life period of the the facility. This contract period can vary, and is usually between 15 and 30 years. Integrated lifetime management and maintenance planning includes continuous condition assessment, predictive modelling of performance, durability and reliability of the facility, maintenance and repair planning and decision-making procedure regarding alternative maintenance and repair actions. Modernisation includes actions for modification and improvements to an existing asset or structure to bring it up to an acceptable condition, which meets the changed generic and specific requirements. End-of Life Mangement: Dismantling, reuse, recycling and disposal includes comprehensive recycling system together with logistic principles and solutions, consisting of selective demolition, the selection of site wastes, treatment and quality control of treated wastes for use as raw materials in buildings, roads and trafficked areas. The system is operated by several partners: cities as client and firms involved in the construction process as technical actors. The role of Lifetime Engineering as a link between normative praxis and the targets of sustainable building is presented in Figure 1.2.
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Figure 1.2 Generic Lifetime Engineering as a link between normative praxis and the targets and requirements of sustainable building.
The entire context of Lifetime Engineering is presented in Figure 1.3.
Resistance against mechanical loads
Sustainable Society - Sustainable Building
Normative and traditional theory and methods of building and
civil engineering
Generic Lifetime Engineering
Generic Requirements for sustainable building
Durability against degradation
Usability against obsolescence
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Figure 1.3 Context of the praxis of Lifetime Engineering. 1.3 Process towards the practice of Lifetime Engineering
1.3.1 Societal needs in Europe
There is a clear need for a uniform European approach for assessing, validating and operating Civil Infrastructures, Buildings and Industrial facilities with full consideration of all generic requirements, which are presented in Figure 1.2:
- The economic values embedded in buildings, civil and industrial infrastructures are utmost significant and the safe, reliable and economically and ecologically sound operation of these structures are at great need. Also huge number of buildings in Eastern Central Europe will urgently need effective maintenance and repair, which has to be planned for a long time span.
- Infrastructures, especially the production and transport structures, will be of major importance within current and future enlarged European Union, when a great amount of civil infrastructures of doubtful quality will be assimilated within the Union’s transport system. This creates a need for adaptation of existing infrastructure and of construction of new infrastructure for along time span.
- European extractive industries provide the raw materials that are the essential components of civil and other industrial infrastructures. In order to maintain its competitiveness, the European extractive industries need to remain at the forefront of technology and adopt an integrated design and environmental management procedure throughout their operational lifetime.
- Considering the fragmented European construction industry it is of vital importance that a network addressing these issues is operating on a European and international level with full participation of the important key actors in the sector. The international networking is bounding together a large number of currently ongoing and planned national R&D programs and projects.
The building and civil engineering market is reactionary and new knowledge only spreads slowly. Solutions are often not up to date, repair work is done too late, and construction and repair costs are high. Very great action has to be taken to systematically combine together information on solutions and results that are known to different national markets. The actors in different countries can then make comparison of own experience with the “Global wisdom”.
Integrated Life- Cycle Design (ILCD) Integrated Life- Cycle Design (ILCD)
Ownership, Planning and Management of InvestmentsOwnership, Planning and Management of Investments
Life Time Managementsystems (LMS)
Life Time Managementsystems (LMS)
Management
Data for Lifetime Design and Management
Data for Lifetime Design, Construction and Management
Norms, Standards andGuidelines for Lifetime
Design, Management andMaintenance Planning
Norms, Standards andGuidelines for Lifetime
Design, Construction andManagement
Practices ofDesign andManagement ofBuildings andInfrastructures
Practice ofLifetime Engineering ofBuildings andInfrastructures
Integration of Design, Construction and Management
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The minerals and energy production industry, on the other end, is an important source of raw materials, revenue and employment in Europe, particularly in areas where other employment options are limited. It also generates growth and stimulates other trade activities in the surrounding areas. Therefore, any projects that would improve the competitiveness of this industrial sector would also have a positive effect on the community as a whole. The ageing population in Europe is going to have special requirements for comfortable and autonomous living. Furthermore buildings need to adapt to changes in the nature of work. This demand of multi-functionality, due to the changing needs of users, is opening up totally new markets, which can create new jobs. Efficient maintenance, repair and modernisation of infrastructures means investing more work for saving of natural resources and energy, and for avoiding environmental burdens and waste. Because maintenance and repair are work intensive areas of production, this means in EU movement of several hundred thousands actual low skill jobs of new construction to high skill jobs in maintenance and repair. Maintenance and repair works require a high level of skill from the workers, which rise needs for additional training of the workers. The lifetime engineering (life cycle design, maintenance and management planning) is a new challenge for engineers, which also must be educated and trained for that skill. Our intellectual resources must be increasingly directed through renewed education and training into the work towards economically, culturally and ecologically sustainable, healthy, safe and convenient infrastructure [11], [5]. Working conditions and working safety will be an important aspect at the development of construction, maintenance and repair of infrastructures. Indirectly the well performing, healthy and safe infrastructures are increasing working safety especially at traffic, industrial production and power plants as well as on their neighbourhood areas. Most recent regulations, such as the Construction, Design and Management Regulations, require the designer to consider not only how the building can be constructed safely but also, and equally importantly, how it should be maintained safely. Understanding what needs maintaining and replacing over the life of the building and allowing safe access or designing out elements that will be difficult, expensive or risky to access will reduce the risk of accidents and improve safety at work for those responsible for ensuring the performance and maintenance of the building [5]. Building owners, users and designers need to be aware of the implications of premature failure of performance of part of the building on the business or process that the building contains. This approach has been used for some time in other industries, such as military engineering, but is not well understood and seldom used by the construction industry. Loss of reduction in the performance of building services, weather-tightness and finishes lead to unhealthy buildings and poor working conditions and poor productivity. The methodology to be developed through the project will mean that designers will be better able to understand and articulate to the client and user the risks of loss of performance and propose means of minimising the occurrence. 1.3.2 Lifetime Project Cluster of EU GROWTH Program
Cluster "LIFETIME: Life time design and management of civil infrastructures and buildings”, is working with integration and systemasing the development of the lifetime engineering idea. This cluster started the work in 2001, and will continue until 2004. The cluster is consisting of five ongoing projects of the EU Growth program: 1. INVESTIMMO: A Decision Making Tool for Long-Term Efficient Investment Strategies in Housing
Maintenance and Refurbishment. Co-ordinator: Dr. Dominique Caccavelli, CSTB, France 2. EUROLIFEFORM: A probabilistic approach for predicting the life cycle cost and performance of
buildings and civil infrastructure. Co-ordinator: Prof. Phil Bamforth, Taylor Woodrow, UK
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3. LIFECON: Life Cycle Management of Concrete Infrastructures for improved sustainability. Co-ordinator: Prof. Dr. Asko Sarja, VTT Building and Transport, Finland
4. LICYMIN: Life Cycle Environmental Impact in Mining. Co-ordinatoor: Prof. Dr. Sevket Durucan, ICSTM, UK
5. CONLIFE: Life-time prediction of high performance concrete with respect to durability. Co-ordinator: Prof. Dr. Max J. Setzer, Universität Essen (DE)
The objectives of the Cluster “LIFETIME” are:
- to integrate the knowledge of partners of these three projects for advancing the work and results of all projects
- to co-operate in similar tasks in order to avoid parallel overlapping work and parallel results - to integrate the Information Networks through linking between these three projects - to create and deliver a continuously updated database of produced models for later European
exploitation and - to produce an integrated and generic “European Guide for Life Time Design and Management of
Civil Infrastructures and Buildings” in order to contribute the development process in practical application of Life Time Design and Management on different sub areas and by different owners.
The Cluster has a common management, which is carried out by Management Group. The Management Group is consisting of Co-ordinators of the five projects. Each project will produce own results and deliverables on their focus areas. From these results, an editorial group under the guidance and control of Cluster management Group will produce a generic integrated report: “European Guide for Life Time Design and Management of Civil Infrastructures and Buildings”. A Thematic Network "Lifetime: Lifetime Engineering of Buildings and Civil Infrastructures" is supporting the dissemination and exploitation of the results of the Cluster "Lifetime". This Network is consisting of 93 partners from 29 countries and is planned to work in the years 2002-2005. The overall objective of the LIFETIME Thematic Network is to contribute to European and world-wide development of a more sustainable built environment. The Network involves all key stakeholders of buildings and civil infrastructures , including mining, whose activities concern investment planning, design, facility management and maintenance, reuse and recycling. The aim is to help to activate on this issue national, European and even world-wide development processes, which will continue in a long perspective still after the Network. The objectives will be reached with world-wide discussions, information exchange and Workshop meetings between stakeholders. Moving into lifetime technology means that all processes must be renewed. Furthermore, new methodologies and calculation methods must be adopted, e.g., from mathematics, physics, systems engineering, environmental science/engineering and other natural and engineering sciences. However, we have to keep in mind the need for strong systematics, transparency and simplicity of the design process and its methods in order to keep the multiple issues under control and to avoid excessive design work. The adoption of the new methods and processes will necessitate renewal of education and training of all stakeholders. New investmen planning and optimisation systems, methodologies and methods are serving as first phase of lifetime engineering. This issue is especially dealth with in the cluster project "INVESTIMMO" A new model of integrated life cycle design includes a framework for integrated structural life cycle design, a description of the design process and its phases, special lifetime design methods with regard to different aspects discussed above. The main phases in the model of integrated life cycle design process are: Analysis of the actual requirements, interpretation of the requirements into technical performance specifications of structures, creation of alternative structural solutions, life cycle analysis and preliminary optimisation of the alternatives, selection of the optimal solution between the alternatives and finally the detailed design of the selected structural system and its modules and components. The
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conceptual, creative design phase is very decisive in order to utilise the potential benefits of integrated design process effectively. Controlled and rational decision making when optimising multiple requirements with different metrics is possible through the application of systematics of multiple attribute optimisation and decision making. In detailed design phase, life cycle aspects rise needs for total performance over the life cycle, including durability design and design for mechanical and hygro-thermal long term performance. Lifetime oriented construction includes consideration of lifetime issues in all procurement models. Especially central role of lifetime engineering is included in specific lifetime procurement. This means, that the contractor is taking a responsibility on the construction phase, and on operation and maintenance of the building or infrastructural object for a certain time period, usually 15 to 30 years. This procurement type is used during last years increasingly especially in cases of large infrastructural objects like roads and airports, but is increasing also on the building sector, for example in case of communal buildings like schools etc.. The lifetime oriented construction rise needs also for long term partnerships between stakeholders, especially between contractors, designers and deliverers. This partnership allows long term development in business activities and in technical issues of product and production development. A predictive life time maintenance and management system called “LIFECON” will make it possible to change the facility maintenance, management and operation of civil infrastructures and buildings from a reactive approach into a predictive and performance based life cycle approach. This objective is concretised through an open and generic model of “Integrated and Predictive Life cycle Maintenance and management planning System (LMS)”. This system description includes the framework, process, performance and service life models, condition assessment protocol model, as well as optimising and decision making methods for lifetime optimising MR&R (Maintenance, Repair, Rehabilitation) planning. Both Network (entire stock of objects) and object level are dealt with. This system is open, generic and predictive in its character; thus it can be applied for different kinds of structures and objects, and with different technical specifications [ http://www.vtt.fi/rte/strat/projects/lifecon/ ].
1.3.3 References
[1] Sarja, Asko, Bamforth, Phil, Caccavelli, Dominique, Durucan, Sevket. Cluster "Lifetime" Description. 2001-01-05. [2] Life-time prediction of high performance concrete with respect to durability (CONLIFE). Project Co-ordinator: Prof. Dr. Max J. Setzer/ Ms. Susanne Palecki - Universität Essen (DE) [3] Probabilistic approach for prodicting life cycle costs and performancer of buildings and civil infrastructure (EUROLIFEFORM). C co-ordinated by Taylor Woodrow Construction Ltdo-ordinator: Prof. Phil Bamforth, Taylor Woodrow Construction Ltd [4] A decision-making tool for long-term efficient investment strategies in housing maintenance and refurbishment ( INVESTIMMO). Co-ordinator: Dr. Dominique Caccavelli, Centre Scientifique et Technique du Bâtiment (CSTB) , France. [5] Life cycle assessment of mining projects for waste minimisation and long term control of rehabilitated sites (LICYMIN). Co-ordinator: Professor Sevket Durucan, Imperial College of Science, Technology and Medicine, UK. [6] Life Cycle Management of Concrete Infrastructures for improved sustainability LIFECON. Co-ordinator: Professor Asko Sarja, Technical Research Centre of Finland (VTT). [7] Lifetime Engineering of Buildings and Civil Infrastructures (LIFETIME). Co-ordinator: Professor Asko Sarja, Technical Research Centre of Finland (VTT). [8] The Sixth Framework Programme. Work Programme.
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1.4 Generic requirements and criteria of lifetime quality
Current goal and trend in all areas of mechanical industry as well as in building and civil engineering is the Lifetime Engineering (also called "Life Cycle Engineering"). The integrated lifetime engineering methodology is aiming at regulating optimisation and guaranteeing the life cycle requirements with technical performance parameters. With the aid of lifetime engineering we can thus control and optimise the human conditions (functionality, safety, health and comfort), the monetary (financial) economy and the economy of the nature (ecology), taking into consideration also local cultural compatibility (Figure 1.?). The integrated lifetime engineering methodology concerns the development and use of technical performance parameters to guarantee, that the structures fulfil through the life cycle the requirements arising from human conditions, economy, cultural and ecological considerations (Figure 1.?). With the aid of lifetime engineering we thus can control and optimise the human conditions (safety, health and comfort), the monetary (financial) economy and the economy of the nature (ecology), and taking into account cultural and social needs. For the life cycle design, the analysis and design are expanded into two economical levels: monetary economy and ecology, which means the economy of nature. The life cycle expenses are calculated into the present value or into annual costs by discounting the expenses from manufacture, construction, maintenance, repair, changes, modernisation, reuse, recycling and disposal. The monetary costs are treated as usual in current value calculations. The expenses of nature are the use of non-renewable natural resources: materials and energy, the production pollutants into air, water or soil, and production of solid waste. Consequences of air pollution are health problems, inconvenience for people, ozone depletion and the global climatic change. The goal is to limit the natural expenses under the allowed values and to minimise them. Table 1.1 Generic requirements as components of the criteria for a sustainable lifetime quality
1. Human requirements - functionality in use - safety - health - comfort
2. Economic requirements - investment economy - construction economy - lifetime economy in:
operation maintenance repair rehabilitation renewal demolition recovery and reuse recycling of materials disposal
3. Cultural requirements - building traditions - life style - business culture - aesthetics - architectural styles and trends - image
4. Ecological requirements - raw materials economy - energy economy - environmental burdens economy - waste economy - biodiversity - geodiversity
In the level of practical engineering the generic requirements can be treated with a number of technical factors which are presented in Table 1.1. These can be used in analysing the indicators of the lifetime quality. The central life cycle quality indicators of a structural system are:
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- functional usability in the targeted use - adaptability in use - changeability during use - reliable safety - healthy - durability, which means resistance against degratation loads - resistance against obsolescence - ecological efficiency.
In buildings, the compatibility and easy changeability between load-bearing structures, partition structures and building service systems is important. Regarding the life cycle ecology of buildings, the energy efficiency of the building is a dictating factor. Envelope structures are responsible for most of the energy consumption, and therefore the envelope must be durable and have an effective thermal insulation and safe static and hygro-thermal behaviour. The internal walls have a more moderate length of service life length, but they have the requirement of coping with relatively high degrees of change, and must therefore possess good changeability and re-useability. In the production phase it is important to ensure the effective recycling of the production wastes in factories and on site. Finally, the requirement is to recycle the components and materials after demolition. Obsolescence of buildings is either technical or functional, sometimes even aesthetic in nature. Technical and functional obsolescence is usually related to the primary life time quality factors of structures. Aesthetic obsolescence is usually architectural in nature.
Civil engineering structures like harbours, bridges, dams, off shore structures, towers, cooling towers etc. are often very massive and their target service life is long. Their repair works under use are difficult. Therefore their life cycle quality is tied to high durability and easy maintainability during use, saving of materials and selection of environmentally friendly raw materials, minimising and recycling of construction wastes, and finally recycling of the materials and components after demolition. Some parts of the civil engineering structures like waterproof membranes and railings have a short or moderate service life and therefore the aspects of easy re-assembly and recycling are most important. Technical or performance related obsolescence is the dominant reason for demolition of civil engineering structures, which raise the need for careful planning of the whole civil engineering system, e. g. the traffic system, and for selection of relevant and future oriented design criteria.
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Figure 1.4 Transforming the generic requirements into technical factors.
Economy and performance:
- Investment economy - Life cycle economy - Energy economy - Static and dynamic
safety and reliability in use
- Service life - Hygro-thermal
performance Internal air quality
- Acoustical performance - Changeability of
structures and building services
- Operation in service - Reuse - Recycling - Waste management
ECONOMY - Investment
economy - Building costs - Life cycle costs
HUMAN CONDITIONS
- Functionality - Health - Safety - Convenience
CULTURE - Building traditions - Life style - Business culture - Aesthetics - Architectural styles
and trends - Image
ECOLOGY - Raw materials
economy - Energy economy - Environmental burdens
economy - Waste economy - Biodiversity
Usability: - Function spaces - Health and internal
air quality - Functional
connections - Accessibility - Aesthetics - Flexibility in use - Maintainability - Refurbishment-
ability
Reuse and disposal:
- Recycling of wastes in manufacture
- Selective dismantling
- Reuse of components
- Recycling of dismantling materials
- Waste management of manufacture and dismantling
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2 Current International and European State of the Art Contributer: Dr. Hywel Davies, Hywel Davies Consultancy
2.1 Introduction
This chapter includes a review of standards and associated literature on technology and lifetime economy of the design, construction, operation and management of assets (buildings and civil infrastructures). This State of the Art report seeks to identify the primary sources of information currently available on lifetime engineering. The key distinction between lifetime engineering and the traditional approach adopted in many contracts and projects is that the lifetime approach seeks to work to the time horizon of the building or asset, whereas the traditional approach tends to adopt the timeframe of the specific contract to which the participant is working, Lifetime engineering requires information about the whole life performance of the building or asset, whether in structural, ecological, economic or social.terms. This review seeks to identify the currently available knowledge as it is incorporated into Standards, formal guidance documents and Codes of Practice, and to categorise it according to the technical field to which it applies and the authoritative or informative nature of the knowledge. Since the scope of is defined in this way, it provides a boundary for the references included. There are many hundreds of other relevant references to papers, journals and conferences. Some of the most recent and relevant are identified either in the text, or in the appendices. The Review also seeks to identify the key EU policy drivers and Directives which are currently influencing the development of Lifetime thinking within Europe, and globally, and to highlight the specific initiatives which are developing in response. These are categorised according to the legal status of the relevant documents, as described in section 4. A summary of other sources is given in the bibliography and further references section. 2.2 Key aspects and definitions of Lifetime Engineering
This review of “Lifetime Engineering” has considered the following six areas of interest to construction in particular. These are the same areas that are addressed elsewhere in the Lifetime network and also in related projects, such as LifeCon and Eurolifeform.
1. Life Cycle Costing (LCC)
2. Lifetime responsibility procurement (Lifetime Contracting), where the contractor takes a responsibility for maintenance and even operation of the asset for some time period (usually 15-30 years). This can be known by a variety of names, of which “PFI”, or Private Finance Initiative is the most common generic description, but can take a number of forms.
3. Life Cycle Analysis (LCA) or Environmental Impact Analysis
4. Condition assessment and monitoring of structures
5. Service life planning and design
6. Selective demolition, reuse and recycling
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It will be helpful to clarify the meaning of the terms used in the list above. Terminology in this area is still evolving, and so a number of terms are used to describe similar things. Life cycle cost. The brief for this review was to address life cycle cost. For the purposes of this review, the term life cycle cost, as defined below in ISO 15686, Buildings and constructed assets — Service life planning — Part 1: General principles, is used as the preferred term.
life cycle cost - total cost of a building or its parts throughout its life, including the costs of planning, design, acquisition, operations, maintenance and disposal, less any residual value (15686-1, Clause 3.7.5).
This definition is also used in ISO DIS 15686-5, Buildings and constructed assets — Service life planning — Part 1: Whole Life Costing, which is the nearest to an international statement of consensus on the definition. It is also very similar to definitions used by the Office of Government Commerce in the UK, and by the U.S. General Services Administration, and is the definition adopted in the Final Report of an EU expert task group on Life Cycle Costs in Construction, 29 October 2003. ISO DIS 15686-5 defines life cycle as follows:
life cycle - the period of time between a selected date and the cut-off year or last year, over which the criteria (e.g. costs) relating to a decision or alternative under study is assessed. This period may be determined by the client for the analysis (e.g. to match the period of ownership) or on the basis of the probable physical life-cycle of the asset itself (15686-5, Clause 4.33).
However, it is important to be aware that other terms are in common use in some countries, with similar, but not identical, meanings. Other terms which may be in use to mean essentially the same as life cycle cost include:
- Total Life Cycle Cost - Whole Life Cycle Cost - Life Cycle Cost Analysis - Through Life Cost - Working Life Cost - Lifetime Cost
ISO DIS 15686-5, Buildings and constructed assets — Service life planning — Part 1: Whole Life Costing, defines the term whole life cost as follows:
whole life cost - an economic assessment considering all agreed projected significant and relevant cost flows over a period of analysis expressed in monetary value. Where the term uses initial capital letters it can be defined as the present value of the total cost of an asset over the period of analysis. It is implicit that the projected costs are to achieve defined levels of performance, including reliability, safety and availability. (15686-5, Clause 4.33).
All these various terms are considered under the one heading of Life Cycle Cost (section 3). The table below attempts to illustrate the variations between the three most commonly used terms: Life Cycle Cost (LCC), Whole Life Cost (WLC) and Through Life Cost (TLC).
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Table 2.1 Relationship between different stages in the life of an asset that are included within various terms WLC LCC TLC Stage in the overall life cycle
OPTIONAL Investment including – planning – design – purchase – installation Energy Maintenance, operation and management
INCLUDED INCLUDED
INCLUDED
Replacements Salvage value, net disposal Customer impacts and intangibles
OPTIONAL
Externalities The EU Guide to Green Procurement (see section 3.2.2) contains the following observation:
“A distinction is sometimes made between “whole-life costs” (or “total cost of ownership”) and “life cycle cost”, the latter often being a somewhat more narrow concept that does not always include such costs as end of life and waste removal costs. It would be up to the contracting authorities to apply the concept that is most appropriate on a case-by-case basis (on the basis of available information for instance)” Footnote 49, page 30
Lifetime responsibility procurement or Lifetime Contracting There is no standard definition for this concept, which encompasses procurement in which the asset is designed, constructed and operated for a fixed period, usually by a private sector body, usually on behalf of a public sector service provider. There are a variety of forms which this can take, of which the most common is the Private Finance Initiative (PFI) or the Public Private Partnership (PPP). Life Cycle Analysis According to ISO 14040 life cycle assessment (LCA) is:
“A systematic set of procedures for compiling and examining the inputs and outputs of materials and energy and the associated environmental impacts directly attributable to the functioning of a product or service system throughout its life cycle.” (ISO 14040: Life cycle assessment – principles and framework, 1998)
The Society of Environmental Toxicology and Chemistry, SETAC defines LCA as "Life Cycle Assessment is a process to evaluate the environmental burdens associated with a product, process, or activity by identifying and quantifying energy and materials used and wastes released to the environment; to assess the impact of those energy and materials used and releases to the environment; and to identify and evaluate opportunities to affect environmental improvements. The assessment includes the entire life cycle of the product, process or activity, encompassing, extracting and processing raw materials; manufacturing, transportation and distribution; use, re-use, maintenance; recycling, and final disposal". (Guidelines for Life-Cycle Assessment: A 'Code of Practice', SETAC, Brussels, 1993).
Condition assessment and monitoring of structures
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This describes the process of assessing the performance of a building or a constructed asset and comparing the present condition either against data from previous assessments, or against objective performance requirements. It is the subject of ISO 15686: Buildings and constructed assets — Service life planning — Part 7: Performance evaluation for feedback of service life data from practice. Service life planning and design ISO 15686, Buildings and constructed assets — Service life planning — Part 1: General principles, defines service life planning as follows:
service life planning - preparation of the brief and design for the building and its parts to achieve the desired design life e.g., in order to reduce the costs of building ownership and facilitate maintenance and refurbishment (15686-1, Clause 3.1.7).
Service life planning is a design process which seeks to ensure, as far as possible, that the service life of a building will equal or exceed its design life, ideally whilst optimising the life cycle cost of the building. ISO 15686-1 provides a methodology for forecasting the service life and estimating the timing of necessary maintenance and replacement of components, and so provides a means of comparing different building options. Selective demolition, reuse and recycling This aspect of the building life cycle, whilst it is discussed within standards making bodies, has not yet become the subject of explicit standards guidance or definitions.
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2.3 Life Cycle Costing
2.3.1 General
The construction industry has been slow to embrace the concept of Life Cycle Costing (LCC). This has been well documented by reports written in 1999 (Clift and Bourke) and 2000 (Robinson and Kosky). In the UK whole life costing can be traced back to the early 1970’s when the Department of Industry introduced the concept of "terotechnology". In Canada the concept dates back at least to July 1980, when Canadian Building Digest CBC 212, Buildings and Life-Cycle Costing, (Rakhra) was first published. In the US the Department of Defence introduced the concept during the 1980s. “The Performance and Cost Managed Building” was published in 1993, reporting a UK funded development of a computer based cost in use database. In spite of these early developments progress towards a comprehensive and robust method of assessing long-term costs of ownership of constructed assets has been slow and arduous. Work to develop British and International standards began in the early 1990s. A draft International Standard for life cycle costing, ISO 15686-5, has now been developed, and is likely to be published before the end of 2006. As noted above in section 2.2.1, there are differences in the detailed definitions of Life Cycle Costs or Whole Life Costs. Ideally, life cycle costing should address the entire product cycle from raw materials extraction to end of life and recycling, as shown in Figure 2.1.
Figure 2.1 The Life Cycle of Building Products (from Life-Cycle Cost Analysis (LCCA) by Sieglinde Fuller, National Institute of Standards and Technology (NIST)). 2.3.2 Government Guidance
On both sides of the Atlantic government property agencies have adopted life cycle costing. In the UK, the Office of Government Commerce has published guidance: “Achieving Excellence in Construction Procurement Guidance 07: Whole-life costing and cost management”. This specifies clearly that UK
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public procurement of construction works should be based on life cycle cost estimates, and not initial costs. The guide particularly focuses on the need to base decisions on a whole-life approach rather than initial capital cost. It gives advice on producing whole-life cost models and explains what needs to be done to keep costs under control at key stages in the project. The U.S. General Services Administration has also adopted life cycle costing for its building programme, and has recently published a major review of the life cycle cost impact of procurement to the US LEED standards, which shows that in most cases the additional cost of procuring a LEED certified building is less than 5%, and in some cases may not result in any additional costs. Indeed, as an integrated approach to environmental performance of buildings becomes more common, the case for cost premiums will become weaker. As a result of this study, the GSAs Facilities Standards for the Public Buildings Service, now requires all new construction and major modernisation projects to be certified through the LEED programme. In Canada “The Environmentally Responsible Green Office at a Glance” has been developed by Architectural and Engineering Services, part of the Real Property Services (RPS) Branch of Public Works and Government Services Canada (PWGSC). It provides guidance for Canadian public sector developments. At the same time, some, such as Robinson and Kosky, have argued that the techniques of whole life cost have been well developed within the property and construction industry for many years. Several texts have been published explaining the use and application of whole life costing in construction. However, Robinson and Kosky argue that these have generally ignored the financial barriers to the successful use of whole life costing. At the same time, some have argued that LCC fails to account for all relevant costs, as the analyses often only cover specified period only, and not the whole life of the asset from conception to demolition or removal. It has also been noted that LCC methods may not adequately address durability, service life and environmental issues. The development of life cycle costing, in tandem with life cycle analysis to address the environmental aspects, is now being taken forward to address the whole of asset life. This is likely to be further assisted by the European initiatives to develop standards for the integrated environmental assessment of buildings. These, along with the ISO 15686 series of standards addressing service life planning, including Life Cycle Costing, are likely to push the integrated approach into mainstream use. 2.3.3 Practical Considerations of Life Cycle Costing
It has been noted that the Public Procurement Directives permit tenders that are assessed on the “most economically advantageous” basis to take account of life cycle and environmental aspects. But at the award stage of a procurement procedure the price of a tender is always one of the most influential factors. How is price defined? Initial purchase price is just one of the cost elements in the whole process of procuring, owning and disposing. To assess the overall cost of a contract over the whole life involves including in the purchasing decision all the costs that will be occurred during the lifetime of the product or service. This need not be difficult or time consuming. Although there are many special techniques for making elaborate life cycle costing calculations on the market, a simple comparison of obvious and measurable costs should cover: — purchase and all associated costs (delivery, installation, commissioning, etc). — operating costs, including energy, spares, and maintenance. — end of life costs, such as disposal, decommissioning and removal.
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(Source: UK Chartered Institute of Purchasing)
These costs should be factored in at the contract award stage to ensure that they are taken into account when determining the most economically advantageous tender. This will also contribute to obtaining a product or service with a better environmental performance, as the process will reveal costs of resource use and disposal that may not otherwise have received proper attention. 2.3.4 Eurolifeform Project
This project developed a probabilistic approach for predicting life cycle costs and performance of buildings and civil infrastructure, and was known by the project title EuroLifeForm (ELF). The project set out to develop a design methodology and supporting data, using a probabilistic approach. Although primarily addressing technological and cost issues environmental impact and other factors were also considered in the project. For further references to recent European work on life cycle costing, the published outputs of the EuroLifeForm project are recommended, although it is worth noting that they have preferred the term Whole Life Cost to Life Cycle Cost. Relevant Eurolifeform papers are listed in the references in a separate section. 2.4 Lifetime Responsibility Procurement or Lifetime Contracting
The two most significant recent innovations in public sector project finance are the Private Finance Initiative (PFI) and the subsequent evolution of Public Private Partnerships (PPP). Governments all over Europe and elsewhere are turning to the PFI/PPP as an effecient and effective way of delivering services to the public. PFI involves the public and private sectors working together. Traditionally the public sector procured capital assets by paying for them up front and in full. In a typical PFI/PPP project a single, stand-alone, special purpose business, the Project Company, is created by the private sector. This will build a facility, which may be a school, hospital, road, bridge or other asset, which is then operated for a fixed period, known as a concession. The public sector pays for this through a service charge, which will be conditional on the level of service provided. Variations on this are known as “Design, Build and Operate” (DBO), “Design, Build, Finance and Operate” (DBFO), “Build, Own, Operate, Transfer” (BOOT). Whilst the contractual arrangements vary, they all adopt the PFI/PPP concept. Because the asset is being built by the operator, who is paid an agreed service charge for providing an asset with a specified functional performance, and usually incurs penalties if the functions are not available as, when and to the quality prescribed, the operator has to take a whole life view of the asset. However, what has happened in practice is that the “whole life” view has turned out to be the life of the concession plus the time, usually five years, for which the asset must still be serviceable after transfer. Whilst there are no published international standards, there are various other guidance documents relating to lifetime procurement. 2.4.1 EU Public Procurement Directives
The EU is updating its rules on procurement procedures for public works contracts, public supply contracts and public service contracts (Directive 2004/18), and also for the water, energy, transport and postal services sectors (Directive 2004/17). The revision, based on internal market principles, aims to simplify, harmonise and modernise the rules. It introduces a new procedure - called competitive dialogue
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- and promotes the development of electronic procedures. Recourse to social and environmental criteria is authorised for the selection of economic operators, based on European Court of Justice case-law. As part of this review, the Directives allow contracting authorities to award contracts based on what is deemed “the most economically advantageous” basis. Under this provision, Article 53 of Directive 2004/18 allows the contracting authority to assess bids against “various criteria linked to the subject-matter of the public contract in question, for example, quality, price, technical merit, aesthetic and functional characteristics, environmental characteristics, running costs, cost�effectiveness, after�sales service and technical assistance, delivery date and delivery period or period of completion”. This means that lifetime performance aspects can, as long as they are clearly quantified and the weighting applied to them as against other criteria in the contract awards process is stated in the call for tenders, form a part of the procurement requirements of public bodies specifying under the new public procurement directives. 2.4.2 Further Guidance
A major criticism of PFI/PPP in the UK has been the lack of standard forms of contract, requiring many projects to re-invent significant amounts of contract documents. This is now being addressed by the Treasury, which is responsible for the management of the PFI/PPP in the UK public sector. They have published a set of standard guidance, “Standardisation of PFI Contracts, Version 3, April 2004”. Almost everything published to date has been written from the point of view of the public sector client. There is very little which sets out the key issues for bidding consortia and lenders. However, the European Construction Institute has published a guide intended for private sector participants, Public Private Partnerships - A Review of the Key Issues, which is applicable to the whole European PFI/PPP market. The European Commission has developed a staff working document giving guidance on environmental aspects of procurement. Published in August 2004, “Buying green! A handbook on environmental public procurement” is a guidance document for the Commission services. Although it is not a binding commitment for the Commission, it does set out how the Commission wants to see its business handled from an environmental perspective. It addresses areas such as the purchase of energy efficient computers and buildings, office equipment made of environmentally sustainable timber, recyclable paper, electric cars, environmental friendly public transport, organic food in canteens, electricity stemming from renewable energy sources and air conditioning systems complying with state of the art environmental solutions. The Commission acknowledges that “green purchasing” can set an example and influence the market-place. By promoting green procurement, public authorities can provide industry with real incentives for developing green technologies. In some product, works and service sectors the impact can be particularly significant, as public purchasers command a large share of the market (in computers, energy efficient buildings, public transport, and so on.). If life cycle costs of a contract are considered, green public procurement may save money and protect the environment at the same time, by saving materials and energy, reducing waste and pollution, and encouraging sustainable patterns of behaviour. The handbook is available on the EUROPA website of the Commission, which also contains further practical information, useful links and contact information for contracting authorities who want to make their purchases greener (http://europa.eu.int/comm/environment/gpp/).
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2.5 Life Cycle Analysis
Life cycle analysis is strictly a process for application to products. However, it has been extended from specific building and construction products and components and is applied to whole buildings and constructed works. Strict LCA activity is covered by the ISO 14000 series of international environmental management system standards, which provide generic guidance on how to manage the environmental impacts of activities, products, and services, (see section 5.1 for further details). A growing body of schemes cover the wider field of environmental impact combined with energy assessment of buildings in the UK, US, Canada, Australia and elsewhere. It includes:
- the Natural Resources Canada tool, GBtool, for environmental assessment of buildings. It can be used anywhere, but must be normalised for a specific country to be comparable. See http://www.iisbe.org/iisbe/gbc2k5/gbc2k5-start.htm for details.
- the Building Research Establishment Environmental Assessment Method (BREEAM)(BRE) - BREEAM Canada, Canadian Standards Association publication 1132 (1st ed. 1996). - BREEAM/Green Leaf combines the BREEAM set of environmental issues with the Green Leaf
Eco-Rating procedure. - Green Globes, a web-enabled self-assessment based on BREEAM/Green Leaf - the latest draft ICE guidance, Civil Engineering Environmental Quality and Assessment Scheme
(CEEQUAL) - “Environmental Code of Practice for Building Services” and Case Studies (BSRIA) - “Environmental Rules of thumb” (BSRIA) - the Green Building Handbook (in two volumes) (Spons 1997 and 2000)(SPON) - the Green Guide to Specification (Building Research Establishment 2002)(BRE) - “A Guide to Sustainable Engineering Specification”, a report into the incorporation of
environmental issues in the National Engineering Specification (NES) - “Constructing for Sustainability”, the Construction Industry Council’s guidance to clients (CIC) - “Environmental Impacts of Materials”, Volumes A-F (CIRIA 1995) - “Leadership in Energy and Environmental Design” (US Green Building Council) see
www.usgbc.org . Leed covers a range of new and existing buildings, and there is also a Canadian version of LEED.
- Energy Star scheme, developed by the US Environment Protection Agency – see www.energystar.gov .
- Australia has adopted its own version of Energy Star – see www.energystar.gov.au . - The Association of Environmentally Conscious Builders in the UK runs a website which lists its
own product assessments – see www.newbuilder.co.uk/greenpro . - The BRE runs a scheme for environmental profiling of products, ENVEST, as a subscription
based assessment product. Similar schemes operate in other countries. There is a particular interest in, and a number of schemes for, construction in Canada. For specific information on these see the papers presented by Skopek at Sustainable Building 2002, for which details are given in the references under “conference proceedings”.
The key environmental and energy impacts of buildings described below are identified in most or all of the listed schemes. The issues are considered under five major headings:
- Energy Conservation - Pollution Emissions - Health and Wellbeing - Water conservation - Materials Specification
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2.5.1 Energy
Energy use by buildings and the processes within them is responsible for almost half of UK CO2 emissions. Nearly 20% results from commercial and industrial buildings and about 27% from housing. Energy use also results in sulphur and nitrogen oxide emissions from electricity generating plant which contribute both to acid deposition and poor air quality in urban areas.
While the cost of energy use is a small part of a company’s overall costs, compared to items such as salaries and rent, it is a cost that a company can control. Energy costs currently represent approximately 20% of the service charge paid by occupants of multi-tenanted buildings and thus reducing energy use is likely to have both an economic benefit as well as reducing environmental impacts. It is becoming clear that the fiscal and regulatory regime in the UK and the wider EU will increase the pressure on the commercial sector to tighten its control of energy use.
This has consequences both for new build and for refurbishment work, where the building services form a significant element of many projects, offering opportunities for improvements in a much shorter timescale than the overall building replacement cycle would suggest. Building energy performance is primarily a design issue, but it must be appreciated that good design can be totally compromised by inappropriate specification or poor installation and site practice. Energy consumption in the production of materials and components is addressed under the materials specification heading. Energy consumption during transport and construction should also be considered for larger projects. 2.5.2 Pollution Emissions
Pollution emissions can occur both during construction and in operation. It is important that both are minimised. This requires attention to the design, to minimise the potential for pollution; to specification of materials and components to reduce their potential to release pollutants in use, and to construction and installation activity. Whilst there are ongoing debates about the long term issues of such materials as PVC and urea formaldehyde, more significant issues for consideration in this project relate to releases from the building to groundwater or drainage and releases to atmosphere.
Refrigeration systems are a particular area of concern. As well as the not inconsiderable issues of the forecast increase in energy consumption due to air conditioning, which is set to rise fourfold over the next 20 years, there is the issue of greenhouse and ozone depleting gases within such systems. Given the ozone depleting potential of some refrigerants, the environmental impact of the energy used to run the system can be dwarfed by the potential impact of accidental release of such gases to atmosphere. Design, specification and workmanship issues need to be addressed in relation to pollution from buildings during construction and use.
2.5.3 Health and Wellbeing
Since most Western Europeans spend about 90% of their lives in buildings, creating comfortable and satisfying environments appropriate to the activities within a building is important. In office buildings a poor working environment will cost more than poor energy or water consumption through reduced staff satisfaction, higher absenteeism and reduced productivity. However, a pleasant, well designed working environment can attract and retain staff and increase productivity.
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An integrated approach to building design is essential to create the best working environments. However, there are also key opportunities to influence the comfort and performance of a building at the specification stage. These may include providing appropriate lighting for the tasks to be performed or zoning heating and cooling controls to provide more effective and direct control of thermal comfort. As with everything else, the best designed and specified building has to be delivered to the original design and specification during the construction phase.
2.5.4 Water
UK water consumption has risen by 70% since 1970. To meet increasing demand, new sources of supply are needed, but they are costly and may damage the environment. The alternative is to reduce demand for water.
Offices use, on average, 43% of water for WC flushing, 20% for urinal flushing, 27% for washing and 9% in canteens. Industrial buildings have a similar profile, although additional water may be used for manufacturing processes. Some buildings include external planting requiring irrigation. It has been estimated that water savings of 70% or more can be achieved by using water efficient appliances and sanitary ware. However, the economic case for this is probably more marginal than for energy conservation. 2.5.5 Materials Specification
There is often a choice of materials and products available for a given function, for example windows can have metal, wood or plastics frames, with further choices within each category. Each of these choices will have a variety of impacts on the environment over its lifecycle, including manufacture, use and disposal. They will also have different financial costs. Choosing the most appropriate, or “best”, option for a given use is a complex process of balancing many different issues, for which there is usually no standard means of comparison. One product may require less energy to produce and fit on site, but it may produce a potentially carcinogenic by product as part of its manufacture. Different population groups have different views on the relative importance of the various issues. While it can be difficult to reach an overall view on a product’s impacts or benefits the issues to be considered will generally include the following:
- Embodied Energy: the primary energy needed to win the raw materials, process them into the product, deliver it to site and install it in the building.
- Embodied Emissions: the pollution emissions that occur in manufacture, including, CO2, NOx, SOx, and Volatile Organic Compounds (VOCs).
- Toxicity: potentially toxic compounds that may be released into the environment as part of the manufacturing process, in use or on disposal (for example by combustion).
- Resources: overall use of resources in manufacture, particularly use of any potentially scarce resources.
- Waste: the quantity of waste material that is created and requires disposal. - Recycling: the potential to reuse or recycle the product at the end of its life or use of recycled or
reclaimed materials as part of the manufacturing process.
Such life cycle analysis has been carried out for many products, as detailed in the references. It is a complex procedure that is still developing and subject to considerable debate, for example between proponents of steel and concrete frames for buildings. Each has developed arguments to “demonstrate” that their favoured material uses less embodied energy. However, there may be many other factors,
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including site or project specific issues, that influence the overall impact of a given material in a given location for a given use. 2.6 Condition Assessment and Monitoring of Structures
Data from the practical on site application of building products, components, and elements provides the most useful data for service life design and life cycle costing. Yet there is a requirement for this data to be produced in a comparable and usable format. To address this concern ISO FDIS 15686 Buildings and constructed assets — Service life planning — Part 7: Performance evaluation for feedback of service life data from practice has been developed. This is currently the only standard available in the field.
For further details see the Conference Proceedings referred to in the Further Reading section, which include several papers on this concept.
2.7 Service Life Planning and Design
Service Life Planning is the systematic organisation of the design process to seek to ensure, as far as it is possible, that the design that is delivered is capable of delivering the specified service life. This is the basic objective of all the work on service life planning. It also underpins the work on costing and life cycle assessment, which introduce cost and environmental performance aspects into the specified service life.
ISO 15686 Buildings and constructed assets — Service life planning — Part 1: General principles (2000) is the basic document underpinning this work. It is widely discussed in a number of papers included in the conference proceedings section of further reading. For those unfamiliar with the concept, it is strongly recommended to review the papers from these conferences.
The concept of service life planning has also been adopted by specific matrials sectors, in particular the concrete industry. Several examples of service life planning codes have been developed in the Asia Pacific region, in particular to address known concrete durability issues. Known examples of standards which have been developed are listed under the “Concrete Structures” section of the references.
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2.8 The hieracrchy of available knowledge
There is a significant body of technical information available which addresses whole life performance. As well as the standards literature, there have been a number of international scientific conferences addressing the theme over the last 10 years (or more). More recently, the EU has begun to address environmental and sustainability issues through a number of EU Communications and Directives. As well as covering a wide range of technical areas, the available information on lifetime performance comes in a variety of forms. These range in importance and legal standing, as is illustrated in the generic knowledge hierarchy presented in Figure 2.2.
Figure 2.2 The hierarchy of technical information The Lifetime project has reviewed available knowledge at all these levels, using a variety of techniques, including questionnaires of network participants and literature reviews. This review focuses in particular on EU legislative requirements and the supporting standardisation activity. This focus is important, because of the connection between EU Directives and Regulations and standards, primarily standards developed by CEN, the European Standards Body, but also on occasion international standards developed by ISO. Under the New Approach standards play a key role in support of EU Directives. The Single European Act, 1985, agreed by European Community Heads of State, began a programme of actions to complete the European Single Market. One action was the development of a series of “New Approach” Directives, designed to provide a framework for a single market in goods and services, based on a series of supporting technical specifications, or standards. Under the Construction Products Directive (CPD) the supporting harmonised standards number well over 500, with a much larger number of common test method standards. This requirement has led to a substantial programme of standards development within CEN. When complete, the programme will provide a single set of performance specification based standards covering the whole of the construction market and applying across the European Community. This set of standards will in effect be mandatory
EU Directives
National Regulations and Technical Requirements
International and European Standards
National Standards and recognised professional guidance documents
Published Scientific Literature and Conference proceedings
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for many specifiers and purchasers because of the effect of the European Public Purchasing Directives, and they are therefore highly relevant to specifiers and engineers as well as to materials suppliers. The CPD has generated a large number of standards, but many are test methods or are product specific. The CPD is almost exclusively about specific products, and about demonstrating that they are fit to be placed on the single market. Whilst the CPD talks about the suitability of products, when incorporated into construction works, to enable the works to achieve and economically reasonable working life, the thrust of the Directive is product performance at manufacture, and not the life cycle of the product. There are initiatives to address life cycle issue on a horizontal basis across construction, through the Dangerous and Regulated Substances mandate and through initiatives arising from the Drinking Water Directive. Other Directives, such as the Energy Performance in Buildings Directive (EPBD), Water Framework Directive, Landfill Directive and related waste and pollution control directives, are all horizontal directives, giving rise to requirements that apply across industrial sectors. However, they tend to take a whole life approach. As such they will be increasingly relevant to construction as the sector moves from a shorter term approach to a more sustainability oriented, whole life approach to the delivery of buildings and other constructed assets. 2.8.1 Key directives
The key Directives considered are listed in Table 2.2. Summary statements, based on information from the European Union website, are included in Appendix A to this report. Table 2.2 Key European Union Directives relating to Lifetime Engineering
Directive Act
Date of entry
into force
Final date for implementation in the Member States
Directive 89/106/EEC 27.12.1998 27.06.1991 Construction Products Directive 93/68/EEC 02.08.1993 02.08.1993
Energy Performance of Buildings Directive 2002/91/EC 04.01.2003 04.01.2006
Directive 2000/60/EC 22.12.2000 22.12.2003 Framework Directive in the field of water policy
Decision No 2455/2001/EC 16.12.2001 -
Decision 96/350/EC 28.05.1996 Framework Directive on waste disposal
Directive 96/59/EC 16.09.1996
Integrated pollution prevention and control: IPPC Directive Directive 96/61/EC 30.10.1996 30.10.1999
Public works contracts, public supply contracts and public
service contracts Directive 2004/18/EC 31.04.2004 31.01.2006
Public procurement in the water, energy, transport and
postal services sectors Directive 2004/17/EC 31.4.2004 31.01.2006
Of these Directives, the first two are quite specific to construction and have stimulated a wide ranging set of mandates from the European Commission to CEN to develop technical standards to underpin implementation. The remaining three Directives introduce requirements affecting the operation of the construction process (and demolition) as well as the operation of the building or constructed asset.
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Since 1998 the EU has been developing its overall strategy for integrating the environment into EU policies. This is required under Article 6 of the Amsterdam Treaty, which requires that environmental protection is integrated into the definition and implementation of all Community activities and policies. The so called “Cardiff process” was adopted with the aim of introducing a horizontal approach to environment policy across the EU by incorporating it into all Community policies. It was supported by the “Communication from the Commission to the European Council of 27 May 1998 on a partnership for integration: a strategy for integrating the environment into EU policies (Cardiff- June 1998) [COM(1998) 333]. The previous Community strategy was based on a vertical approach and consisted of adopting environmental regulations by sector. This produced good results but only partly solved the environmental problems facing the EU. A Communication from the Commission to the European Parliament and the Council on the Single market and environment in June 1999 set out proposals to extend the integrated approach to the internal market, industry and development. It acknowledged that environmental standards are often perceived as barriers to market access (strict technical standards), just as open markets are frequently seen as a threat to the quality of the environment. The Communication set out proposals to pursue the objectives of the Treaty on both the single market and the environment, whilst also honouring international obligations. To this end the action plan set targets to deliver a single market for the benefit of all citizens, in which environmental protection would play an important role, reinforcing the synergies between the single market and environment policies, with the aid of a series of measures on public procurement, State aid, standardisation, financial reporting and eco-labelling. As a specific measure it was decided to adopt, together with the European standardisation bodies, a programme to progressively integrate environmental considerations into their activities and explore the possibility of promoting participation by environmental NGOs in the standardisation process. 2.8.2 Mandate 350
In March 2004 the European Commission through DG Enterprise issued Mandate M/350, which set out requirements for European Standards in the field of Integrated Environmental Performance. These requirements take the form of a Standardisation Mandate to CEN dated 29 March 2004, which directs CEN to address the “Development of Horizontal Standardised Methods for the Assessment of the Integrated Environmental Performance of Buildings”. The mandate states that “further independent development of whole building (works) models and environmental product declarations on the national level leads to divergence and the risk that barriers to trade will develop will increase.” It goes on to add that “national regulations regarding environmental product information are expected to emerge. At the moment no formal mandatory regulations exist. Industry however is already facing demand for information from the market place, based on different methods within the EU Member States. The net result of this is mounting costs for industry and a mutual non-acceptance of environmental product information. To ensure that comparable environmental information is generated and used, without creating barriers to trade, national schemes need to be based on a common European programme founded upon European or International standards for Environmental labels and declarations - type III environmental declarations.” The mandated work is to address the following subjects with standards or technical reports:
- a framework standard for integrated environmental building performance - a horizontal standard on the aggregation of LCA results of individual materials into the building
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- a horizontal standard on the LCA methodology for building products/materials- including data quality of LCA data
- a horizontal standard on the communication format/EPD Business-to-business - a horizontal standard on the communication format/EPD Business-to-consumer - a Technical Report on generic data A technical report on the assessment of the environmental
performance of the construction process of a building - a technical report on the assessment of the environmental performance of the end of life phase
process (demolition, recycling, waste treatment processes) of a building and products The work is to be completed by the end of 2007. CEN has established a Working Group of the CEN Technical Board to develop a business plan for the new TC which will be established to develop the standards. This is likely to be led by AFNOR. The mandate directs CEN to base its work on the existing ISO documents, with some additional material to be added. There are a number of CEN standards either published or in draft, and these are summarised below.
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2.9 International and European Standards
2.9.1 ISO/TC207 “Environmental Management”
Standards written by ISO/TC207 “Environmental management” are the basis for assessment of environmental performance of buildings. The basic tool for assessing environmental performance is the Life Cycle Assessment (LCA). The Environmental Product Declaration (EPD) is the basic tool for communicating environmental information. ISO/TC207 standards are generic in nature because they can be applied to all materials, products and services. Relevant standards
- ISO/CD14025 Environmental labels and declarations – Type III environmental declarations – Principles and Procedures (ISO TC207/SC3)
- BS EN ISO 14040:1997 Environmental management. Life cycle assessment. Principles and framework (ISO TC207/SC5)
- BS EN ISO 14041:1998 Environmental management. Life cycle assessment. Goal and scope definition and inventory analysis (ISO TC207/SC5)
- BS EN ISO 14042:2000 Environmental management. Life cycle management. Life cycle impact (ISO TC207/SC5)
- BS EN ISO 14043:2000 Environmental management. Life cycle assessment. Life Cycle Interpretation (ISO TC207/SC5)
- PD ISO/TR 14047:2003 Environmental management. Life cycle impact assessment. Examples of application of ISO 14042
- DD ISO/TS 14048:2002 Environmental management. Life cycle assessment. Data documentation format
- PD ISO/TR 14049:2000 Environmental management. Life cycle assessment. Examples of application of ISO 14041 to goal and scope definition and inventory analysis
2.9.2 ISO/TC59 “Buildings”
ISO/TC59 is developing standards to assess sustainability in the building sector and for service life planning of buildings. The draft ISO technical specification for the assessment of environmental performance of buildings forms a good framework for a European horizontal standard for the assessment of environmental performance of buildings. The basic tool for assessment of economic performance in terms of sustainability is Life Cycle Costing, and this is the subject of a Draft ISO. Relevant standards
- ISO 15686-1 Buildings and constructed assets – Service life planning – General principles (ISO/TC59/SC15)
- ISO 15686-2 Buildings and constructed assets – Service life planning – Service life prediction procedures (ISO/TC59/SC15)
- ISO/DIS 15686-5 Buildings and constructed assets – Service life planning – Whole life costing (ISO/TC59/SC15)
- ISO 15686-6 Buildings and constructed assets – Service life planning – Guidelines for considering environmental impacts (ISO/TC59/SC15)
- ISO/DIS 15686-8 Buildings and constructed assets – Service life planning – Reference service life and service life estimation (ISO/TC59/SC15)
- ISO/AWI 15686-9 Buildings and constructed assets – Service life planning – Service life declarations (ISO/TC59/SC15)
- ISO/DIS 21930 Building construction - Sustainability in building construction – Environmental declaration of building products (ISO/TC59/SC17)
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- ISO/TR 21932 Building construction - Sustainability in building construction – Terminology (ISO/TC59/SC17)
- ISO/TS 21931 Building construction - Sustainability in building construction – Framework for environmental performance of buildings (ISO/TC59/SC17)
- ISO/WD 15392 Building Construction – Sustainability in building construction – General Principles (ISO/TC59/SC17)
- ISO 6707-1 Building and civil engineering – Vocabulary – General terms (ISO/TC59/SC2) (a further 9 parts are currently out for ballot as ISO DIS.)
2.9.3 International and European standards in response to energy performance of buildings and directive 2002/91/EC and health&Comfort perforformance
The future standards for the framework for assessment of integrated building performance and environmental performance of buildings, health & comfort performance of buildings and life cycle cost performance of buildings should apply the standards under development for assessment of energy performance of buildings. According to the EC standardisation mandate M/330 EN based on the Directive 2002/91/EC on the energy performance of buildings, CEN is developing an integrated and interacting methodology for the calculation of the energy uses and losses for heating and cooling, ventilation, domestic hot water, lighting, natural lighting, passive solar systems, passive cooling, position and orientation, automation and controls of buildings, and auxiliary installations necessary for maintaining a comfortable indoor environment of buildings. The standards under the mandate M/330 shall be prepared by the CEN/TC89 “Thermal performance of buildings and building components”, CEN/TC156 “Ventilation for buildings”, CEN/TC169 “Light and lighting”, CEN/TC228 “Heating systems for buildings” and CEN/TC 247 “Building automation and building management”. Relevant standards by CEN/TC89:
- EN ISO 13790 Thermal performance of buildings – Calculation of energy use for space heating - EN ISO 13791 Thermal performance of buildings - Calculation of internal temperatures of a
room in summer without mechanical cooling - General criteria and validation - EN ISO 13792 Thermal performance of buildings - Calculation of internal temperatures of a
room in summer without mechanical cooling - Simplified methods - EN 13829 Thermal performance of buildings - Determination of air permeability of buildings -
Fan pressurization method - Energy performance of buildings – Methods of assessment to be used for the energy certification
of buildings - Energy performance of buildings – Overall energy use, primary energy and CO2 emissions - Energy performance of buildings – Ways of expressing energy performance of buildings - Energy performance of buildings – Application of calculation of energy use to existing buildings - Energy performance of buildings – Additional applications of calculations for the inclusion of
the positive influences of daylighting, solar shading, passive cooling, position and orientation, renewables, quality district heating and cooling, quality CHP (including on-site) and for modular inclusion of future technologies
- Thermal performance of buildings – Calculation of energy use for space heating and cooling – Simplified method with extension of scope of EN ISO 13790
Relevant standards by CEN/TC156:
- CR 1752 Ventilation for buildings - Design criteria for the indoor environment - Criteria for the Indoor Environment including thermal, indoor air quality (ventilation), light and
noise - Ventilation for buildings - Terminals - Comfort criteria
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- EN 13465 Ventilation for buildings - Calculation methods for the determination of air flow rates in dwellings
- Ventilation for buildings – Calculation methods for the determination of air flow rates in buildings
- Ventilation for buildings – Calculation methods for energy requirements due to ventilation and infiltration in buildings
- EN 13779 Ventilation for non residential buildings - Performance requirements for ventilation and room conditioning systems
Relevant standards by CEN/TC169:
- Energy performance of buildings – Energy requirements for lighting (including daylighting) - EN 12665 Light and lighting - Basic terms and criteria for specifying lighting requirements
Relevant standards by CEN/TC247:
- Building Management Services - Building Management Services - Part 1: General Terms and Definitions
ISO/TC 205 “Building environment design” is developing standards for design of new buildings and retrofit of existing buildings for acceptable indoor environment and practicable energy conservation and efficiency. In the scope of ISO/TC205 the indoor environment includes air quality, and thermal, acoustic, and visual factors. Relevant standards by ISO/TC205:
- ISO/CD 16813 Building environment design - Indoor environment - General principles - ISO/CD 16814 Building environment design - Indoor environment - Methods of expressing the
quality of indoor air for human occupancy 2.9.4 International and European standards on test methods for indoor air pollutants and health&
comforth performance of buildings and EC Mandate M/XXX (Dangerous Substances)
According to the EC standardisation mandate M/XXX EN based on the Construction Product Directive 89/106/EEC, CEN will develop horizontal test standards dedicated to the emission of specified regulated dangerous substances from construction products into indoor air. ISO/TC146/SC6 “Air quality – Indoor air” and CEN/TC264 “Air quality” are developing emission test methods for indoor air pollutants. The future standards relating to the assessment of health & comfort performance of buildings and EPD of building products should refer to the relevant existing and draft standards for emission test methods for indoor air pollutants from building products. Relevant standards by ISO/TC146/SC6 and CEN/TC264:
- ISO 16000-3 Indoor air -- Part 3: Determination of formaldehyde and other carbonyl compounds -- Active sampling method
- ISO 16000-4 Indoor air -- Part 4: Determination of formaldehyde -- Diffusive sampling method - ISO 16000-6 Indoor air -- Part 6: Determination of volatile organic compounds in indoor and test
chamber air by active sampling on Tenax TA sorbent, thermal desorption and gas chromatography using MS/FID
- EN ISO 16000-9 Indoor air -- Part 9: Determination of the emission of volatile organic compounds -- Emission test chamber method
- EN ISO 16000-10 Indoor air -- Part 10: Determination of the emission of volatile organic compounds -- Emission test cell method Circulated for Information - B/500/-/2.0080/04Page 8
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- EN ISO 16000-11 Indoor air -- Part 11: Determination of the emission of volatile organic compounds -- Procedure for sampling, storage of samples and preparation of test specimens
- ISO 16000-13 Indoor air -- Part 13: Measurement of polychlorinated dioxins/furans and polychlorinated biphenyls (PCBs)
- ISO 16000-15 Indoor air -- Part 15: Measurement of nitrogen dioxide (NO2) - ISO 16000-17 Indoor air -- Part 17: Measurement of the concentration of airborne mould spores -
- Sampling with gelatine/polycarbonate filters followed by a culture-based
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2.10 References to Chapter 2
DEFINITIONS ISO 15686 Buildings and constructed assets — Service life planning — Part 1: General principles (2000) ISO DIS 15686 Buildings and constructed assets — Service life planning — Part 5: Whole life costing (2004) ISO FDIS15686 Buildings and constructed assets — Service life planning — Part 7: Performance evaluation for feedback of service life data from practice (2005) Commission for the European Communities “Buying green! A handbook on environmental public procurement”, (August 2004) (http://europa.eu.int/comm/environment/gpp/). LIFETIME ENGINEERING CONCEPTS BRE “Building Research Establishment Environmental Assessment Method” (BREEAM) “BREAM 98 for New Offices; An Environmental Assessment Method for Office Buildings”; BRE; (Garston) (1998) “BREEAM 5/93 An Environmental Assessment for New Industrial; Warehousing and Non-food retail units”; BRE; (Garston) (1993) “BREEAM 2/91; An Environmental Assessment for New Superstores”; BRE (Garston) (1991) BRE Anderson J, Shiers D, with Sinclair M; Green Guide to Specification (Garston) (2002) BSRIA “Environmental Code of Practice for Buildings and their Services; (Code of Practice & Case Studies Volume 1”; (Bracknell) (1996) BSRIA Rawlings R “Environmental Rules of thumb”; Technical Note 12/99 (Bracknell) (1999) CEEQUAL “Civil Engineering Environmental Quality and Assessment Scheme” Report at the ICE Sustainability Sector Strategy Launch; (London, 24 April 2002) CIC “Constructing for Sustainability, a client’s guide to sustainable construction. Construction Industry Council (London) (2003) CIRIA “Environmental Impacts of Materials”, Volumes A-F (1995) Clift, M. & Bourke, K. (1999) Study on whole life costing. BRE, Watford Commission for the European Communities “Buying green! A handbook on environmental public procurement”, (August 2004) (http://europa.eu.int/comm/environment/gpp/). Directive 2004/17/EC of the European Parliament and of the Council of 31 March 2004, coordinating the procurement procedures of entities operating in the water, energy, transport and postal services sectors Directive 2004/18/EC of the European Parliament and of the Council of 31 March 2004, on the coordination of procedures for the award of public works contracts, public supply contracts and public service contracts Fuller, S.K. & Petersen S.R. Life-Cycle Costing Manual for the Federal Energy Management Program, NIST Handbook 135, available for download as a PDF file from http://www.bfrl.nist.gov/oae/publications/handbooks/135.pdf (1995) HM Treasury “Standardisation of PFI Contracts, Version 3, April 2004”. See http://www.hm-treasury.gov.uk/documents/public_private_partnerships/key_documents/standardised_contracts/ppp_keydocsstand_index.cfm ISO DIS 15686 Buildings and constructed assets — Service life planning — Part 5: Whole life costing (2004) ISO FDIS 15686 Buildings and constructed assets — Service life planning — Part 7: Performance evaluation for feedback of service life data from practice (2005) NES A Guide to Sustainable Engineering Specification, (a report into the incorporation of environmental issues in the National Engineering Specification) (London) (2001) Office of Government Commerce “Achieving Excellence in Construction Procurement Guidance 07: Whole-life costing and cost management”. http://www.ogc.gov.uk/sdtoolkit/reference/achieving/index.html Public Private Partnerships - A Review of the Key Issues. European Construction Institute, Loughborough, June 2003. ISBN 187 3844522
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Public Works and Government Services Canada, “The Environmentally Responsible Green Office http://www.pwgsc.gc.ca/rps/aes/content/ercr_guidebook_toc-e.html Rakhra, A.S. Canadian Building Digest 212. Buildings and Life-Cycle Costing, Originally published July 1980. Robinson, G.D. and Kosky, M. Financial Barriers & Recommendations to the Successful Use of Whole Life Costing in Property & Construction, Report for the Construction Research & Innovation Strategy Panel, CRISP London, 2000. SPON E&FN Woolley T, Kimmins S, Harrison P and Harrison R; Green Building Handbook Volume 1; (London) (1997) SPON E&FN Woolley T and Kimmins S; Green Building Handbook Volume 2; (reprinted London) (2000) Steven Winter Associates, Inc. “LEED® Cost Study - Final Report to U.S. General Services Administration (October 2004). The Performance and Cost Managed Building Vol 2 of A Report on the Outcome of Research leading to the development of Building & Performance & Costs-in-Use Databases and related support in a Performance & Cost Management System for use in the Property & Construction Industries, LINK/CMR Research Project No 4, Nov 1993 Eurolifeform Project "Rethinking Whole Life Cycle Cost Based Decision Making". The Association of Researchers in Construction Management ARCOM 20th Annual Conference and Annual General Meeting - The Heriot-Watt University, Edinburgh, UK, 1-3 September 2004. "Eurolifeform: An Integrated Probabilistic Whole Life Cycle Cost and Performance Model for Buildings and Civil Infrastructure". The International Construction and Building Research Conference of the Royal Institution of Chartered Surveyors, Leeds, UK, 7-8 September 2004. “Methodology for the Value Quantification of Industrial Building Sustainable Projects”, Losada R. San-José T. Rojí E. Jesús C. Ormazabal G, 2nd International Symposium: Integrated Lifetime Engineering of Buildings and Civil Infrastructures, Kuopio, Finland, December 1-3, 2003 Conference Proceedings Integrated Lifetime Engineering of Buildings and Civil Infrastructures Proceedings of 1st International Symposium ILCDES 2000, Helsinki, Finland Integrated Lifetime Engineering of Buildings and Civil Infrastructures Proceedings of 2nd International Symposium ILCDES 2003, Kuopio, Finland Sustainable Building 2002 Petterson, Dr T. D., (Editor) 3rd International Conference on Sustainable Building, Oslo 2002 9DBMC – Proceedings of the 9th International Conference on the Durability of Building Materials and Components, Brisbane, 17-20 March 2002. Proceedings published by CSIRO BCE, PO Box 56, Highett, Victoria. Concrete Structures Standard Specification for Concrete Structures, 2001 “Maintenance” International Joint Seminar of the KSCE and JSCE presented at the 2003 KSCE Annual Conference, Daegu, Korea, pg 59–70. Asian Concrete Model Code, Level 1 & 2 Documents International Committee on Concrete Model Code for Asian, 2001 Takewaka, K., Yokota, H., Hida, K., Sugiyama, T., Yokota, H., Sato, Y. (2004) Maintenance for Chloride Attack, Guidelines for maintenance and rehabilitation of concrete structures against chloride induced deterioration Level 3 Document Asian Concrete Model Code 2001, Japan Concrete Institute Concrete and Reinforced Concrete Structures, Guide to Maintenance, (2004) TCXDVN 318, Vietnam Institute for Building Science & Technology, Construction Publishing House, Hanoi
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2.11 Further reading
LIFETIME ENGINEERING CONCEPTS Boussabaine, A. & Kirkham, R. (2004) Whole Life-cycle Costing Risk & Risk Responses. Blackwell Publishing, Oxford Breitenbuchner, R., Gehlen, C., Schiessl, P.,Van den Hoonard, J., Siemes, T. (1999) Service life design of the Western Scheldt tunnel 8DBMC, pp3-15 DuraCrete Manual (2000) The European Union, Brite EuRam III, contract BRPR-CT95-0132, Project BE95-1347, Report no. BE95-1347/R17, May 2000 Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis – April 2002 [Annual Supplement to NST Handbook 135 and NBS Special Publication 709], available for download as a PDF file from http://fire.nist.gov/bfrlpubs/build02/PDF/b02017.pdf (2002) Hovde, P.J. & Moser K. (2004) Performance Based Methods for Service Life Prediction, State of the Art Reports. CIB Report: Publication 294 Hovde, P.J. & Moser K. (2004) Performance Based Methods for Service Life Prediction, State of the Art Reports. CIB Report: Publication 294 Jernberg, P.,Lacasse, M. A., Haagenrud, S.E., Sjöström, C. (Editors) ( 2004) Guide and Bibliography to Service Life and Durability Research for Building Materials and Components CIB Report: Publication 295 Marteinsson, B. (2003) Assessment of Service Lives in the Design of Buildings - Development of the Factor Method Centre for Built Environment, Gävle, Sweden DURABILITY RELATED STANDARDS FOR BUILDING ELEMENTS AND COMPONENTS ISO STANDARDS & Draft INTERNATIONAL STANDARDS ISO 12543-4:1998 Glass in building - Laminated glass and laminated safety glass - Part 4: Test methods for durability (ISO TC160 SC1) ISO/TR 13434:1998 Geotextiles and geotextile-related products - Guidelines on durability (available in English only) (ISO TC 221) ISO/WD 13823 General principles on the design of structures for durability (ISO TC98 SC2) ISO 14615:1997 Adhesives - Durability of structural adhesive joints - Exposure to humidity and temperature under load (ISO TC61 SC11) ISO/DIS 21887 Durability of wood and wood-based products - Definition of use classes (ISO TC165 SC1) ISO/DIS 21892 International framework for classifying wood products durability based on use classes (ISO TC165 SC1) ISO 20340:2003 Paints and varnishes - Performance requirements for protective paint systems for offshore and related structures (ISO TC35 SC14) ISO/DIS 21887 Durability of wood and wood-based products - Definition of use classes (ISO TC165 SC1) ISO/DIS 21892 International framework for classifying wood products durability based on use classes (ISO TC165 SC1) ISO 22156:2004 Bamboo -Structural design (available in English only) (ISO TC165 SC1) ISO 22762-1 Elastomeric seismic-protection isolators - Part 1: Test methods (available in English only) (ISO TC45 SC4) ASTM STANDARDS Volume 04.12 BUILDING CONSTRUCTIONS (II): E 1671 — LATEST; PROPERTY MANAGEMENT SYSTEMS; TECHNOLOGY and UNDERGROUND UTILITIES 1,274 Pages; 148 Standards Available November 2005 Volumes 04.11 and 04.12 contain 270 tests and practices that set down standard procedures for measuring the performance of buildings, including: air leakage and ventilation performance; building economics; building preservation; durability performance of building constructions; structural
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performance; exterior insulation and finish systems; lead hazards associated with buildings; and performance of roof systems, windows, and doors. Volume 04.12 also includes standards that address property management systems. The latest standard practice for establishing the guiding principles of property management provides property managers with the means to examine the quality, quantity, and substance of a current or proposed system, as well as the context to determine how each element contributes to an efficient and cost-effective operation. Other standards cover the assessment of loss, damage, and destruction of property, assets, or material; physical inventory of durable, moveable property; administrative control of property, and traditional property management definitions and terms. Committee E06.22 on Durability Performance of Building Constructions Published Standards E773-01 Standard Test Method for Accelerated Weathering of Sealed Insulating Glass Units E774-97 Standard Specification for the Classification of the Durability of Sealed Insulating Glass Units E2094-02 Standard Practice for Evaluating the Service Life of Chromogenic Glazings E2141-02 Standard Test Methods for Assessing the Durability of Absorptive Electrochromic Coatings on Sealed Insulating Glass Units E2188-02 Standard Test Method for Insulating Glass Unit Performance E2190-02 Standard Specification for Insulating Glass Unit Performance and Evaluation E2354-04 Standard Guide for Assessing the Durability of Absorptive Electrochromic Coatings within Sealed Insulating Glass Units Committee E06.71 on Sustainability Published Standards E1991-98 Standard Guide for Environmental Life Cycle Assessment of Building Materials/Products E2114-04 Standard Termninology for Sustainability Relative to the Performance of Buildings E2129-03 Standard Practice for Data Collection for Sustainability Assessment of Building Products Work Items WK574 Standard Practice for Data Collection for Sustainability Assessment of Building Products WK575 Practice for Assessment of Green Roofs WK3161 Standard Guide for the Use of Data for Building Product Sustainability Assessment WK4235 Standard Guide for Selection, Installation, and Maintenance of Plants for Green Roofs WK4236 Standard Practice for Determination of Dead Load s and Live Loads f or Green Roof Systems WK4237 Standard Test Method for Water and Media Retention of Synthetic Drain Boards for Green Roofs WK4238 Standard Test Method for Maximum Substrate Density for Dead Load Analysis of Green Roofs WK4239 Standard Test Method for Saturated Hydraulic Conductivity of Granular Drainage Media [Falling-Head Method] for Green Roofs WK5566 Standard Guide for General Principles of Sustainability Relative to Buildings US Department of Defence Standards for Life Cycle Cost MIL-HDBK-259, Military Handbook, Life Cycle Cost in Navy Acquisitions, available from Global Engineering Documents, (1 April 1983) MIL-HDBK-276-1, Military Handbook, Life Cycle Cost Model for Defense Material Systems, Data Collection Workbook, Global Engineering Documents, (3 February 1984) MIL-HDBK-276-2, Military Handbook, Life Cycle cost Model for Defense Material Systems Operating Instructions, Global Engineering Documents, (3 February 1984)
3. A model of Lifetime Engineering Process
3.1 Principles
Lifetime engineering differs from traditional engineering through the following properties:
1. All classes of the multiple requirements and properties of lifetime quality are taken into account 2. Time over the actual time period is always included in analysis, optimisation and decision
making calculations and considerations 3. All requirements and properties are predicted into the actual time period of lifetime 4. Requirements and properties are weighted for optimisation and decision making
The praxis of the lifetime engineering includes:
- systems - processes and - methods,
which are applied for systematic working at all phases of the life cycle during the lifetime. A key issue of the lifetime engineering is the optimised lifetime quality, including all generic requirement classes (Table 3.?). These quality criteria are applied at all phases of the life cycle (Figure 3.?):
1. Lifetime revenue and investment planning 2. Lifetime design 3. Lifetime procurement and construction 4. Lifetime management, maintenance, retrofitting and modernisation 5. End-of-Life Management: selective demolition, reuse, recycling, wasting
The conceptual, creative design phase is very decisive in order to utilise the potential benefits of integrated design process effectively. Controlled and rational decision making when optimising multiple requirements with different metrics is possible through the application of systematics of multiple attribute optimisation and decision making. In detailed design phase, life cycle aspects rise needs for total performance over the life cycle, including durability design and design for mechanical and hygro-thermal long term performance.
As an example, the effect of optimising the lifetime costs is presented in Figure 3.1. The potential for optimising the lifetime costs is highest at the first phases of investment planning and building project planning, and decreases gradually until the construction phase, where most of the lifetime costs are already fixed. Another important phase follows in optimising maintenance, repair and rehabilitation (MR&R) planning, where still many important factors of operation and maintenance costs will be gradually optimised and fixed.
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REAL PROPERTY LIFE CYCLE
LANDLAND
DEVELOP-MENT
DEVELOP-MENT
UTILIZATIONUTILIZATION
VACANTVACANTREDEVELOP-MENT
REDEVELOP-MENT
UTILIZATIONUTILIZATION
DEMOLITIONDEMOLITION
Figure 3.1 Life cycle of a real estate (Ref.: Koskelo, Taina, 2000; adapted from Halder 1999, p. 4; see also Schulte 2000b, p. 143). Because the applications of lifetime engineering on different fields of building and civil engineering differ from each others, all the phases and viewpoints are described here first generally, and the in more details separately for buildings and civil iunfrastructures, including the following sections:
- Apartment buildings and houses - Office and commercial buildings - Industrial buildings - Industrial infrastructures - Civil infrastructures
Lifetime engineering serves the following benefits for different stateholders:
- Investors and owners are aiming to optimise the lifetime benefit/cost ratio of facilities. This means the objective to optimising the lifetime quality (value in use) in relation to lifetime costs. In the integrated lifetime design, especially in the phases of pre-briefing and briefing, will be optimised and decided major part of the potential lifetime quality and lifetime costs (Figure 3.2).
- Designers (architects, structural designers and designers of building service systems) are in a central role in concretising the lifetime targets of owners, users and society in their designs. They are also important partners in the education and training on practice. The integrated lifetime design serves possibilities for new and enlarget services of designers for the benefit and added value of owners their clients: owners, users, contractors, subcontractors, manufacturesr and the society.
- The possibilities and the responsibility of contractors in optimising the lifetime quality in a co-operation with other stakeholders have been increased in comparison to traditional production. This is the case in spite of the contracting model, but the contractor has especially high potential of optimisation in the lifetime responsibility contract. The benefits of predictive and optimising lifetime engineering can be concretised most effectively in development of entire buildsing concepts.
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- The manufacturers of building modules, components and materials have a responsibility in optimising the lifetime properties of their products as a part of alternative building concepts of clints or contractors. Their clients and other stakeholders need also data on the lifetime quality properties of the modules, components and products. Central properties of the products are: service life, mechanical and physical performance properties, needs of maintenance and repair in use, health properties and ecological efficiency.
Figure 3.2 A small increase in planning and design costs increase the chance that lifetime costs are at their minimum.
Maximum
Maximum
Optimum
Design cost Construction cost Use and MR&R (maintenace, repair and rehabilitation) costs
Declining influence on costs
Unnecessary costs
Necessary extra cost
Minimum or optimum
Modified from: John Kelly and Steven Male, Value Management in Design and Construction. E&FN SPON London. 1993.
Minimum or optimum
High influence Low
Low influence High expenditure
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Figure 3.3 Characteristics of the optimisation and decision making in different phases of the planning and design process [John Kelly and Steven Male, Value Management in Design and Construction. E&FN SPON London. 1993.].
Quantity of information
Value management
and cost
management opportunities
Unstructured information Concept information
Design information
a b A B C D E F G H
Project awareness
Client development
Inception Feasibility Outline proposal
Scheme design
Detail design
Production information
Bills of quantiti
Tender action
Pre-brief Briefing Sketch plans Working drawings
Value management
Cost management
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Figure 3.4 Interaction between databases, optimising and decision making, and general managerial, planning and design programs.
3.2 Integrated Lifetime Design (ILD)
3.2.1 Principles, methodology and methods
The current objectives towards sustainable society and construction sector can be iterpreted into generic requirements for construction as presented in Table 3.1.
General databases Databases of stakeholders
Value managementlevel 5: Investment planning
Value and cost management programs
General databases Databases of stakeholders
Value managementlevel 4: Spaces
Architectural design programs Product data modelling
General databases Databases of stakeholders
Value managementlevel 3: Technical Systems
Architectural and technical design programs Product data modelling
Architectural and technical design programs Product data modelling
General databases Databases of stakeholders
Value management level 1: Components
Architectural and technical design programs Product data modelling
General databases Databases of stakeholders
Value managementlevel 2: Modules
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Table 3.1 Generic classified requirements of structures and buildings [1,3].
1. Human requirements
• functionality in use • safety • health • comfort
2. Economic requirements
• investment economy • construction economy • lifetime economy in:
o operation o maintenance o repair o rehabilitation o renewal o demolition o recovery and reuse o recycling of materials o disposal
3. Cultural requirements
• building traditions • life style • business culture • aesthetics • architectural styles and trends • imago
4. Ecological requirements
• raw materials economy • energy economy • environmental burdens economy • waste economy • biodiversity and geodiversity
The role of Lifetime Engineering as a link between normative praxis and the targets of sustainable building is presented in Figure 3.5.
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Fig. 3.5 Generic Lifetime Engineering as a link between normative praxis and the targets and requirements of sustainable building. The objective of the integrated Lifetime Engineering is to achieve optimised and controlled lifetime quality of buildings or civil infrastructures in relation to the generic requirements.
- The lifetime quality means the capability of an asset to fulfil the requirements of users, owners and society on an optimised way during the entire design life of the asset.
- This objective can be achieved with a performance-based methodology, applying generic limit state approach.
- This means, that the generic requirements have to be modelled with technical and economic numerical parameters into quantitative models and procedures, and with semi-numerical or non-numerical ranking lists, classifications and descriptions into qualitative procedures. This methodology can be described in a schedule, which is presented in figure 2.4 [1].
Sustainable Society - Sustainable Building
Normative and traditional theory and methods of building and
civil engineering
Generic Lifetime Engineering
Generic Requirements for sustainable building
Resistance against mechanical loads
Durability against degradation
Usability against obsolescence
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LIMIT STATES IN TERMS OF GENERIC REQUIREMENTS• Serviceability limit states• Ultimate limit states
LIMIT STATES IN TERMS OF QUANTITATIVE MODELS ANDQUALITATIVE CLASSIFICATIONS, RANKINGS AND DESCRIPTIONS
• Serviceability limit states• Ultimate limit states
OPTIMISATION AND DECISION PROCEDURES• choices between MR&R alternatives
GENERIC REQUIREMENTS• Human requirements• Economic requirements• Ecological requirements• Cultural requirements
QUANTITATIVE MODELS OF• Functionality in use (partly)• Human health• Human comfort (partly)• Economy• Ecology (partly)
QUALITATIVE CLASSIFICATIONS,RANKINGS and DESCRIPTIONS OF
• Functionality in use (partly)• Human health• Human comfort (partly)• Ecology (partly)• Cultural acceptability
Figure 3.6 Schedule of the generic procedure of reliability management.
3.2.2 Tasks and methods of the design process
The tasks and methods are presented in Table 3.2.
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Table 3.2 Design phases, tasks and methods of integrated life cycle design. Design phase Tasks
Life Cycle Design Methods
1. Investment planning Set objectives of the building project. Define the study time period. Create alternative investment plans. Calculate life cycle costs (monetary economy and ecology). Calculate cash flows of alternatives. Evaluate benefits of the alternatives. Compare LCC:s and make final decision. Define final objectives.
Multiple criteria analysis, optimisation and decision making. Life cycle (monetary and natural) economy Risk analysis
2. Analysis of client`s and user`s needs
Identify relevant attributes (customer`s requirements). Estimate the rate of importance of each attribute as weight.
Modular design methodology. Quality Function Deployment Method (QFD)
3. Functional specifications of the buildings
Transfer the results of needs analysis to demands. Identify relevant functional properties. Define weight of each property.
Modular design methodology. Quality Function Deployment Method (QFD)
4. Technical performance specifications
Transfer functional properties and their weights from previous task to demands. Identify technical performance properties. Identify weight of each property.
Modular design methodology. Quality Function Deployment Method (QFD) Risk analysis
5. Creation and sketching of alternative structural solutions
Create and sketch alternative solutions for building, its structural systems and building services in co-operation with other designers and project partners.
Modular design methodology.
6. Modular life cycle planning and service life optimisation of each alternative
Define the requirement for design service life of the building. Modulate the building into service life modules of different servece life classes.
Modular design methodology. Modular service life planning. Life cycle (monetary and
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Identify the number of life cycles of each module during the design service life of the building. Identify the design life cycle costs (monetary and ecology) of the modules. Sketch alternative service lifes for the modules. Define optimal service lifes of the modules, basing on minimum total costs (monetary cost and ecology).
natural) economy calculations.
7. Multiple criteria ranking and selection between alternative solutions and products
Transfer the optimised service life cost of each alternative building concept fro previous task. Define multiple attributes from anlysed omner`s and user`s requirements. Evaluate the performance properties of each alternative. Select the alternative for concretisation between the alternatives.
Modular design methodology. Quality Function Deployment Method (QFD). Multiple Criteria Analysis, optimisation and decision making Risk analysis
8. Detailed design of the selected solution
Design the structural modules for different performance requirements. Make the synthetic design.
Design for future changes Design for durability Design for health Design for safety Design for hygro-thermal performance. User`s manual. Design for reuse and recycling
The introducing of the integrated design principles into practical design is a quite wide process, where not only the working of the structural engineers is changing, but where also the co-operation between structural engineers, architects, building service system designers and other partners of construction and use have to be developed. Especially the co-operation with clients and architects is important in order to effectively utilise the expertise of the structural engineers in the most decisive creative and conceptual phases of design. This kind of co-operation also helps the clients to realise the benefits of investing slightly more into the structural design. Another important change in the design will be some kind of modulation of the design, it means the separation of the designing of the functions, spaces and performance specifications from the designing of technical systems and modules. The first part of the design, which is performance oriented, will be made by architect and technical designers in close co-operation between each others as well as with the client and users. The second part, which is a concretising phase, is made in a close teams of technical designers and manufacturers. The concretising phase is often connected to specific building concepts of contractors and their suppliers. In this way the current problem of diversified design and manufacturing processes can be avoided without compromising the functional and performance requirements and other requirements for the life cycle use of the building, which are discussed above.
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3.2.3 Descriptions of the design phases
Several new aspects are widening the scope of the structural design and construction in that amount, that the entire working processes must be re-engineered. In design, we can start to establish a new design process, which can be called integrated structural design, which will be scheduled and described in the following. Starting from investment planning and analysis of owner`s and user`s needs and requirements the structural engineer must be ready to work together with architect and other partners of the building process. The controlled and rational decision making when optimising between the multiple requirements with different metrics is possible through the application of systematics of multiple requirements decision making. The ecology and heath aspects are increasing in weight. The service life principles are introducing the time as a variable in economics and design. Close co-operation with clients and architects is needed.
3.2.3.1 Investment planning Lifetime investment planning and decision making is also called “Value Management”, which is a service which maximises the functional value of a project by managing its development from concept to completion and commissioning through the audit (examination) of all decisions against a value system determined by the client. In this phase the client, transmits a clear statement of the value requirements of that project to the project designers [John Kelly and Steven Male, Value Management in Design and Construction. E&F SPON, London, 1996. 181 p. ISBN 0 419 15120 6]. The investment planning and decision making applies value management to audit and optimise:
- The client`s use of a facility in relation to its corporate strategy - The project brief - The emerging design - The production method
Typical features of value management in lifetime engineering are:
- A proactive and predicting lifetime approach through the use of multi-disciplinary (economy, architecture, structural engineering, building service systems engineering) team-oriented creative process to generate alternatives to investment solution
- The use of structured systems method - The relationship of function with value
The owner/client defines life cycle objectives like area and functional requirements of building and its spaces, economy, requirements for use, service life, aesthetic objectives and ecological objectives. Designers in co-operation with the owner create alternative investment plans, make a multiple criteria analysis and decision making between alternatives.
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Figure 3.7 presents a summary of analyses and other important issues from the viewpoint of technical life cycle cost-effectiveness, related to investment analysis of real estates [Koskelo, Taina, 2005].
Investment analysis
Risk analysis
Risks return and investment
value
Marketresearch
Technical evaluation
Cash flow expectations/analysis
Different risk analyses Location
Services: Needed/ available
Technical risksLeaseanalyses
Suitability for use
Technical condition
Usage
Technical characteristics
Technicalquality
Aesthetical quality
Income
Investment value and price
Maintenance and life cycle
costs
Residual and salvage values
Functionalquality
Financing, tax and legal environments
Different value concepts
Figure 3.7 Analyzing real estates from the viewpoint of the technical life cycle. [Koskelo, Taina, 2005].
3.2.3.2 Analysis of client`s and user`s needs The analysis of client`s needs is a phase, which is belonging to the preparative phase of the building project. This phase deals mainly with the functions in use and spatial requirements of the buildings, and it lays on the responsibility of client, architect and contractor. Usually the structural designer is not included in this analysis, but he serves technical support for architect and uses the results as a starting information for his work. The role of detailed design phase is to guarantee, that the targets and specifications, which are defined in conceptual design, can be realised in construction and all over the life cycle. This means the buildability, the serviceability, the durability, the maintainability, the reapairability and finally the demolishability, recyclability and wasteability of structures. The methods used at this phase are: Structural mechanics, Building Physics (moisture and thermal calculation methods, and methods of acoustics and fire resistance) and durability design.
3.2.3.3 Interpretation of the client`s and user`s needs into functional life cycle requirements of the buildings
As an analysis method QFD method (Chapter 5.2) can be applied when ranking the function properties of draft design alternatives in comparison to owner`s and user`s needs. The architect has main responsibility of this phase, and structural engineer is serving technical support in knowledge and possibly in calculations connected to the analysis.
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3.2.3.4 Interpretation of the functional life cycle requirements into technical performance specifications The results of the functional analysis and planning will be converted into structural requirements in co-operation between architect and structural designer. The result is a set of technical specifications, including mechanical, physical, aesthetic, environmental, energy and health specifications. The performance specifications are presented in details in ISO 6240-1980: “Performance standards in building - Contents and presentation” and ISO 6241-1984: “Performance standards in building - Principles for their preparation and factors to be considered”.
Once the client´s needs have been properly defined and transferred into functional requirements they must be expressed as performance specifications. They should as far as possible be quantitative and preferably related to well established (standardised) test methods. However, such methods are available only to a limited extent and therefore the performance requirements must be given in other forms. Often the requirements are described only in qualitative terms. Requirements or ”target figures” for heating and cooling energy needs are given in some cases as well as economical figures like annual costs for the building or sub-systems. The modular scheduling and allocation at the conceptual design phase includes the specification of the alternative structural solutions regarding to the target service life and technical performance requirements of each structural module. Based on the specifications the estimates of life time monetary and environmental costs as current values or annual costs are calculated. The model of the modular specification of the technical performance properties is presented in Table 3.3. The specification work must be interactive with life cycle optimisation of the central properties in order to reach the target of optimal design [13],[7].
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Table 3.3 Specification of performance properties for the alternative structural solutions on a module levels; as an example a multi-storey apartment building.
Structural module Central performance properties in specifications 1. Foundations
- bearing capacity - target service life - limits and targets of environmental impact profiles
2. Bearing frame
- bearing capacity - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles.
3. Envelop/Walls
- target values of thermal insulation - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles
4. Envelop/Roof
- target values of thermal insulation - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles
5. Envelop/Ground Floor
- target values of thermal insulation - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles
6. Envelop/Windows
- target values of thermal insulation - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles
7. Envelop/Doors
- target values of thermal insulation - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles
8. Partition Floors
- target values of sound insulation - target service life - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles - estimated intervals of the renewal of connected
installations 9. Partition walls (incl. doors)
- target values of sound insulation - target service life - estimated intervals of spatial changes in the building - estimated repair intervals - estimated maintenance costs - limits and targets of environmental impact profiles - estimated intervals of the renewal of connected installations
10. Bathroom and kitchen
- target values of sound and moisture insulation - target service life - estimated repair intervals
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- estimated maintenance costs - limits and targets of environmental impact profiles - estimated intervals of the renewal of connected installations
3.2.3.5 Creation and sketching of alternative structural solutions The phase of conceptual design regarding to the result is decisive, because the decisions made in these phases have large influence on the economic, environmental, aesthetic, functional and technical quality of the structures. The role of structural designer in this phase is to support the decision making, which will be done by owner and user. The main tools in this work are the methods of creative the structural drafting, the analysis, the optimisation, the multiple criteria decision making, which are described above. The role of architect is manly the same as that of structural designer, but the tools are more weighted into creative functional and aesthetic points. A close co-operation between structural designer, architect and building services designers is needed. Today and in the future the demands of living and working for spaces and other functional requirements are changing more and more rapidly. The future value of buildings is largely depending on their flexibility for changes. Structural system and it`s compatibility with building service system are decisive factors for changeability of the building. Starting already in sketch design the design for changes is one of central tasks. Important issues at the conceptual design are:
- Definition of storey height to be enough for installations - Long spans of floorings in order not to prevent changes with too many vertical bearing structures - Location of openings at facades - Spaces of staircases (connection modules) for traffic and for horizontal and vertical connections
of building service systems - Space for horizontal piping and wiring - Room size enough for alternative uses - Easy movable and reusable partition walls - Easy changeable electrical and communication wiring systems
3.2.3.6 Modular life cycle planning and service life optimisation At the life cycle planning, a modular systematic is preferred. This allows the systematic allocation and optimisation of the target service life as well as life cycle economy and ecology of different parts of the building [13],[7]. A suited modularization at the highest level of hierarchy is the following: Bearing frame, envelop, foundations, partitions, heating and ventilating services, information, water and sewage system, control services and waste management system. All of these assemblies are specified during the development or design process on continuously increasing precision starting from general performance specifications and ending into detailed designs. The tasks for each design alternative are the following:
- Classification of building modules into target service life classes, following a suited classification system.
- Stating the number of renewals of each module during the design service life of the building. - Calculation of total life cycle monetary costs and costs of the nature (ecology) during the design
life cycle of the building. - Preliminary optimisation of the total life cycle cost varying the value of service life of key
modules in each alternative between the allowed values.
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The division of the building into modules can be the same as presented in chapter 2.2.5. After calculations the life cycle monetary and natural costs of alternatives are transferred into multiple criteria ranking and selection between alternatives.
3.2.3.7 Ranking and selection between design alternatives and products Ranking between design alternatives ends the sketch design phase resulting the draft designs. Partly already at the phase of sketch design also some key products which are connected to solution of the structural system are selected even if the selection of products are mainly done at later phases of the design. When applying integrated design procedure all classes of requirements are systematically taken into account at the ranking. As a ranking method Multiattribute Decision Analysis (MADA) is applied [14],[16]. The core properties are mainly calculated quantitatively with numerical equations, but some of added properties are evaluated qualitatively only. The properties are normalised through comparison with reference alternative. This phase of design is usually made under responsibility of architect who is supported with structural designer and designers of building service systems.
3.2.3.8 Detailed design of the selected solution
The detailed design includes generally the following phases:
1. Ordinary mechanical design 2. Durability design 3. Final design
Ordinary mechanical design is performed using conventional design methods. Its purpose is to determine the preliminary dimensions for the structure. The durability design procedure is different for structures consisting of different materials. Regarding to concrete structures, the basic procedure most often can be applied. Often the procedure of durability design of steel structures follows the general procedure, as well. The durability of wooden structures is connected to moisture and temperature and thus leads to the moisture control of structures in order to eliminate the danger of rotting in wood. When using deterioration calculation models, also the design procedure of wooden structures is following the general procedure. A flow chart of the design procedure, as an example the design of concrete structures, is presented in Figure 3.7.
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PROCEDURE 1
REQUIREMENTS OF EACH DESIGN OBJECT for:- Length of the design life time (50 y, 100 y etc)- technical performance specifications- economy, safety, health, comfort, ecology, culture- other specifications when needed- limit values of specified properties, and- weighting factors for MADEM
PROCEDURE 3CALCULATE THE NUMERICAL LIFE TIME VALUES
(OR CLASSES OR DESCRIPTIONS) OF:
- Initial cost- Life time cost- Secondary savings
Environ-mentallife timeimpact
Service lifeplanning
Life timeperformanceevaluations
PROCEDURE 4MULTIPLE REQUIREMENTS DECISION MAKING AND
OPTIMISATION
PROCEDURE 2DEFINE TECHNICAL SPECIFICATIONS OF DESIGN ALTERNATIVES
ALT. 1 ALT 2 ALT. 3 ALT. N
Figure 3.7 Multi-attribute decision making procedure.
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Static, dynamic and seismic design Mechanical design includes the static, fatigue and dynamic design aspects. This design is traditional and there are a lot of manuals, guides, norms and standards existing. Therefore this phase is not discussed more in this context. Durability design and obsolescence design for service life The role of durability design is important in life cycle design. The objective of durability design is to guarantee, that the specified target service life can be achieved in each working environment of the structures. In ordinary design the durability for ordinary service life, generally for 50 years, is taken into account with structural detailing rules of norms, standards and design manuals. When using a target service life other than 50 years separate service life design calculations are needed. For these specific purposes the statistically based service life design methods can be used for producing specific detailing rules and model designs which then can be applied for similar specific cases. Statistically based life cycle design can be applied also in product development of prefabricated structural units. The detailed durability design procedure is the following [4],[8]:
1. Specification of the target service life and design service life 2. Analysis of environmental effects 3. Identification of durability factors and degradation mechanisms 4. Selection of a durability calculation model for each degradation mechanism 5. Calculation of durability parameters using available calculation models 6. Possible updating of the calculations of the ordinary mechanical design (e.g. own weight of
structures) 7. Transfer of the durability parameters into the final design
The lifetime safety factor design procedure is somehow different for structures consisting of different materials, although the basic design procedure is the same for all kinds of materials and structures. The lifetime safety factor method is analogous with the statical safety factor method, also called limit state design. Hygro-thermal design In many countries, modern building has demonstrated significant problems associated to the indoor climate. The expression SBS (Sick Building Syndrom) is used to characterise the problem. Much research has been performed in order to clarify the mechanisms but the final answer is still lacking. Drastically increased thermal insulation and air tightness of buildings following the first so called oil crisis in 1973 when the energy prices increased rapidly is often blamed for the problems. However, it seems obvious that moisture content and transport in the materials and in the building components play an important role. The well known problems in connection with foundation systems using concrete slabs directly on the ground and crawl space foundations could exemplify this. As the moisture dynamic is closely related, and very often impossible to separate from the thermal mechanisms it is obvious that the hygrothermal analysis of the building comes into focus. Design methods are available today for the most important performance requirements but it must be stated that they are not at all so accurate as those used in strength and deformation analysis. One reason for this is that the measurement of material properties is in many respect much more difficult, specially concerning moisture transport. There is also a lot of basic physics which is not fully clarified.
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Important material properties in the hygrothermal analysis are - heat conductivity - specific heat - thermal diffusivity - vapour resistance - moisture diffusivity - capillarity - sorption curves (relative humidity vs moisture content at equilibrium)
The hygrothermal design of a building contains the following major steps,
- Definition of building context - Clarification of thermal and moisture environment (boundary conditions) - Analysis of temperatures and moisture status in different parts of the structure. Account should
be taken to non-steady state conditions. - Definition of critical temperature and moisture levels - Comparison of actual and critical values - Accepting/rejecting the proposed solution
Acoustic design Acoustic design usually includes air born sound insulation, impact noise level control between spaces and control of vibrations of structures during use. The sound insulation is usually controlled through standards on sound insulation and on vibrations, but also special rules and calculation methods e.g. for floorings are existing. In special cases, e. g. in concert halls and in theatres, the internal sound acoustics is a primary demand. This is a job of specialised experts and is not treated here in details. Design for safety The static and dynamical safety as well as fire safety are defined in international and national regualtions, norms and standards treated with traditional methods of mechanical design. Because these design methods are very traditional, they are not treated in this document. A new viewpoint of Integrated Life Cycle Design into the safety is a systematic consideration and optimisation of long term safety, taking into account the degradation effects. Design for health and convenience The healthy checking can follow the guidelines of SETAC [18] and other national and international codes and standards and guides. The main issues are to avoid moisture in structures and on finishing surfaces, and to check, that all materials used do not cause emissions or radiation, which are dangerous for health and comfort of the users. On some regions also the radiation from ground must be eliminated though insulation and ventilation of the foundation. Thus main tools for health design are: selection of materials, especially finishing materials, eliminating risks of moisture in structures through water proofing drying under construction and ventilation, and elimination of possible radioactive earth radiation with air proofing and ventilation of ground structures [17]. Design for reuse and recycling The components of the environmental profile of the basic materials already include the recycling efficiency, which means the environmental expenses in recycling. It is important to recognise that the
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recycling possibilities of the building components, modules and even technical systems shall be reconsidered in connection with design. The higher the hierarchical level of recycling, the higher also the ecological and economical efficiency of recycling [11],[12]. The designers can influence reuseability and recycleability with choise of structural system, component types and their connections, and with choice of materials. Referring to the performance and service life based modular systematics, the modules and comnponents can be devided into different classes of reuseability and recycleability. Typically the modules and components with short service life or high need of changes should have a good ability for reuse and recycling. Modules and components, which have a long service life, typically the bearing frame, must allow good changeability of spaces, and they must have a long service life and a good maintainability. Special issues to be treated in design of structures and materials for reuse and recycling are:
- Modular structural system with autonomous modules with a dimensional and modulation and clear tolerance system
- Separability of the structural components or materials during demolition of building e. g. with the use of demountable structural components using suited connections and joints
- Constructive separation of technical systems (e. g. structures and building service systems) with different service lives and different recycling techniques.
- Reduction of the variety of materials - Ability of separation for materials, which can not be recycled together - Avoiding of insoluble composite substances and/or composite substances that are either only
slightly soluble or soluble only within a high expenditure or energy input
3.2.3.9 User’s manual and maintenance plan The building like a car or other equipment needs a user`s manual. The manual will be produced gradually at the design process in co-operation between partners in design, manufacture and construction. Ordinary tasks of structural designer are:
- Collecting list of maintenance tasks of structural system - Collecting and applying instructions for operation, control and maintenance procedures and
works - Checking and co-ordination of operation, control and maintenance instructions of product
suppliers and of contractor - Preparing the relevant chapters for user’s guidebook - Checking relevant parts of the final user’s guidebook
Main information sources for the User`s manuala are product declarations of producers, which have to include relevant information on all classes of technical performance, service life, maintenance actions and frequency, and health aspects. Also information on environmental impact profile, resue and recycling should be included in product declaration.
3.2.3.10 Final integrated design specifications Design specifications which are produced at different phases of the design process are during the design collected together, co-ordinated and checked in order to avoid differences in details and specifications. This co-ordination is a continuing task over the design period, and it finally produces also documentation for building control and maintenance during the use. References to Chapter 3.2
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1. Asko Sarja, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002. ISBN 0-415-25235-0.
2. Mats Öberg, Integrated life cycle design, application to Swedish concrete multi-dwelling buildings. Doctor Thesis, Lund University of Technology, Division of Building Materials, Report TVBM-1022, Lund 2005. 262 p. + Annexes.
3.3 Reliability and extended limit states design
3.3.1 Generalised limit states
The lifetime performance modelling and the limit state approach, which are based on the integrated and generic requirements of Table 3.?, are working as an essential core of the lifetime design and management of structures. Performance based modelling includes the following three classes:
1. Static and dynamic (mechanical) modelling and design 2. Degradation based durability and service life modelling and design 3. Obsolescence based performance and service life modelling and design
When looking at the statistics of demolitions of buildings and structures we can notice the following reasons for demolition:
- Obsolescence is the cause of demolition of buildings or infrastructures in about 50% of all demolition cases. In the case of modules or component renewals the share of obsolescence is still higher. This means that the obsolescence is the dominating reason for demolitions in cases, where structures are working in non-degrading environment.
- Degradation is a dominating reason for demolition of the structures, which are working in highly degrading environment. This is most often the case in demolition of civil some infrastructures. Even in case of civil however, also obsolescence is an important reason for demolition.
A conclusion of this, and a challenge for structural designers is, that we have to include the durability and obsolescence criteria into the design, as well as into the MR&R (Maintenance, Repair and Rehabilitation) planning of structures. The mechanical modelling has been traditionally developed on the limit state principles already starting in 1930`s, and introduced into common practice in 1970`s. Therefore it is not treated in this report, which is focused on durability limit state design and obsolescence limit state design. 3.3.2 Design life
Design life is a specified time period, which is used in calculations. Ordinary design life is 50 years (EN 1990) for buildings and 100 years for civil engineering structures. In special cases even longer design life cycles can be used. However, after 50 years the effect of increased design life cycle is quite small and it can be estimated as the residual value at the end of the calculation life cycle. Temporary structures are designed for a shorter design life, which will be specified in each individual case. The classification of design life of EN1990: 2002 is presented in Table 3.4.
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Table 3.4 Classification of EN 1990: 2002 for design life of structures [2]. Class 1: 1–5 years Special case temporary buildings Class 2: 25 years Temporary buildings, e. g. stores
buildings, accommodation barracks Class 3: 50 years Ordinary buildings Class 4: 100 years Special buildings, bridges and other
infrastructure buildings or where more accurate calculations are needed, for example, for safety reasons
Class 5: over 100 years Special buildings e. g. monuments, very important infrastructure buildings
3.3.3 Limit states
The origination classes of limit states are as follows:
- Static and dynamic - Degradations - Obsolescence
The serviceability limit states and ultimate limit states of concrete structures in relation to this classification are presented in Table 3.5 [1].
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Table 3.5 Generic mechanical, degradation and obsolescence limit states of concrete structures [1].
Limit states Classes of the limit states Mechanical (static
and dynamic) limit states
Degradation limit states Obsolescence limit states
1. Serviceability limit states 1.1 Deflection
limit state
1.2 Cracking limit state
1.3 Surface faults causing aesthetic harm (colour faults, pollution, splitting, minor spalling)
1.4 Surface faults causing reduced service life (cracking, major spalling, major splitting)
1.5 Carbonation of the concrete cover (grade 1: one third of the cover carbonated, grade 2: half of the cover carbonated, grade3: entire cover carbonated)
1.6 Reduced usability and functionality, but still usable
1.7 The safety level does not allow the requested increased loads
1.8 Reduced healthy, but still usable
1.9 Reduced comfort, but still usable
2. Ultimate limit states
2.1. Insufficient safety against failure under loading
2.2. Insufficient safety due to indirect effects of degradation:
- heavy spalling
- heavy cracking causing insufficient anchorage of reinforcement
- corrosion of the reinforcement causing insufficient safety.
2.3. Serious obsolescence causing total loss of usability through:
- loss of functionality in use (use of building, traffic transmittance of a road or bridge etc.)
- safety of use
- health
- comfort
- economy in use
- MR&R costs
- ecology
- cultural acceptance
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Table 3.6 Comparison of static and dynamic (mechanical) limit state method,
Mechanical limit state design
Durability limit state design
Obsolescence limit state design
1. Strength class 2. Target strength 3. Characteristic strength ( 5 % fractile) 4. Design strength 5. Partial safety factors of materials strength 6. Static or dynamic loading onto structure 7. Partial safety factors of static loads 8. Service limit state (SLS) and ultimate limit state (ULS)
1. Service life class 2. Target service life 3. Characteristic service life (5% fractile) 4. Design life 5. Partial safety factors of service life 6. Environmental degradating loads onto structure 7. Partial safety factors of environmental loads 8. Serviceability and ultimate limit states, related to the basic requirements: Human requirements, lifetime economy, cultural aspects and lifetime ecology
1. Service life class 2. Target service life 3. Characteristic service life (5%fractile) 4. Design life 5. (Partial safety factors of service life) 6. Obsolescence loading onto structure 7. Partial safety factors of obsolescence loading 8. Serviceability and ultimate limit states related to obsolescence in relation to the basic requirements: Human requirements, lifetime economy, cultural aspects and lifetime ecology
Table 3.7 Summary of performance and functionality limit states.
A. Performance limit states Serviceability limit states Ultimate limit states 1. Surface cracking 2. Surface scaling 3. Deflection 4. Carbonatisation until reinforcement 5. Corrosion of reinforcement 1. Failure under static, dynamic or
fatigue loading
B. Functionality limit states 1. Weakened functionality 1. Total loss of functionality 2. Weakened economy of operation 2. Total loss of economy of
operation 3. Weakened economy of MR&R 3. Total loss of economy of MR&R 4. Minor health problems in use 4. Severe health problems in use 5. Aesthetic change of surface (abrasion, colour changes)
6. Cultural ineligibility 5. Total loss of cultural eligibility 7. Weakened ecology 5. Severe ecological problems or
hazards The generic durability limit states and their application in specific cases can be described with numerical models and treated with numerical methodology, which are quite analogous to the models and methodologies of the mechanical (static and dynamic) limit states design. A schedule of the development of the degradation based durability modelling is presented in figure 3.? [1].
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The limit states of obsolescence differ form the mechanical and degradation limit states. There are no international or national normative standards concerning the obsolescence, and no exactly defined limit states of obsolescence. Some remarks have been presented e. g. in ISO standards [5], and in American standards [6], but real analysis methods have not been presented. Therefore a deep expertise is required in obsolescence risk analysis. The obsolescence loading can be defined as the changes of the use, business, technology and working environment, or even as the development of the society around the still-standing structure. All these changes can induce obsolescence loading through individual, local, national, regional or global changes of generic human, economic, ecological and cultural requirements. The limit states of obsolescence often can not be described in quantitative means. Therefore we often have to apply qualitative descriptions, criteria and methods [4,1]. Even with these quite inexact means we can reach a level of rational selection and decisions between the alternatives. There is still much potential to develop the methodology, models and tools into more detailed and precise level. The final objective of the obsolescence analysis is to reduce demolishing of facilities that have not reached their mechanical or durability limit states, and thus promote the sustainable development. 3.3.4 Extended reliability of structures
The statistical reliability methodology and requirements are defined in the European standard EN 1990. This standard is based on partial safety factor method, but the reliability requirements are expressed also in terms of statistical reliability index β The general definition of the reliability index β of standard normal distribution is defined as a factor, which fulfils the equation: Pf = Ф(-β) (1) where Ф is the cumulative distribution function of the standardised Normal distribution. The requirements of the standard EN 1990 for the reliability index are shown in Table 3.8 for the design of new structures, as well as for the safety of existing structures [2] . Table 3.8 Recommended minimum values for reliability index β in ultimate limit states and in serviceability limit states, according to EN 1990: 2002[2].
Minimum values for � 1 year period 50 years period
Reliability Class
Ultimate limit states
Serviceabilility limit states
Ultimate limit states
Serviceabilility limit states
RC3/CC3: High consequence for loss of human life, or economic, social or environmental consequences very great
5,2
No general
recommendation
4,3
No general
recommendation
4,7
RC2/CC2: Medium consequence for loss of human life, or economic, social or environmental consequences considerable
4,7
2,9
Fatigue: 1,5 to 3,8 1)
1,5
RC1/CC1: Low
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consequence for loss of human life, or economic, social or environmental consequences small or negligible
4,2 No general recommendation
3,3 No general recommendation
3.3.5 Statistical methods for integrated lifetime reliability control
The simplest mathematical model for describing the 'failure' event comprises a load variable S(t) and a response variable R(t) [8,4,3]. This means, that both the resistance R and the load S are time dependent, and the same equations can be used for static reliability and durability. Usually the time is neglected as a variable in static and dynamic calculations; they are included only in fatigue reliability. In durability related limit states and service life calculations the time is always included as a variable of R(t) and S(t). In principle the variables S(t) and R(t) can be any quantities and expressed in any units. The only requirement is that they are commensurable. Thus, for example, S can be a weathering effect and R the capability of the surface to resist the weathering effect. If R and S are independent of time, the 'failure' event can be expressed as follows
{failure} = {R(t) < S(t)} (2a)
The failure probability Pf is now defined as the probability of that 'failure':
Pf = P{R<S} (2b)
Either the resistance R or the load S or both can be time-dependent quantities. Thus the failure probability is also a time dependent quantity. Considering R(�) and S(�) are instantaneous physical values of the resistance and the load at the moment � the failure probability in a lifetime t could be defined as (Sarja and Vesikari1996): Pf(t) = P{R(�)<S(�)} for all � < t (3a)
The determination of the function Pf(t) according to the Equation 3a is mathematically difficult. That is why R and S are considered to be stochastic quantities with time-dependent or constant density distributions. By this means the failure probability can usually be defined as:
Pf(t) = P{R(t)<S(t)} (3b) According to the equation 3b the failure probability increases continuously with time as schematically presented in Figure 3.7. [8].
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Figure 3.7 The increase of failure probability. Illustrative presentation [8]. Considering continuous distributions, the failure probability Pf at a certain moment of time can be determined using the convolution integral: Pf (t) = ∫ FR(s,t)fS(s,t)ds (4)
where FR(s) is the cumulative distribution function of R, fS(s) the probability density function of S, and s the common quantity or measure of R and S. The integral can be approximately solved by numerical methods. In static and dynamic calculations the time is not a variable, but the reliability is calculated at the moment t=0. In durability calculations the time is a variable of the resistance R(t), but usually the environmental degradation load S(t) is considered to be constant. The value of S is depending on the environmental exposure conditions and actual design life of the structure. The environmental loads are classified in the standards, for concrete structures the standard EN 206 can be used [9]. Mathematical formulation for applied statistical degradation methods are presented in the Model Code of JCSS (Joint Committee for Structural Safety) [10]. The statistical reliability calculations are serving as important basis for applied safety factor methods, which are now in common use. The statistical method is used in special cases, when the reliability has to be analysed in very individual terms. In such a case the material parameters and dimensions have to be determined in so high number of samples, that statistical values (mean value and standard deviation) can be calculated. In ordinary design or condition assessment this is not possible, and the safety factor method is then applied. The reliability index and the corresponding probability of failure can be calculated analytically only in some special cases. Usually the equations are solved with suited numerical methods of partial differential equations, or with simulations. 3.3.6 Safety factor method for static, fatique and dynamic loading
Partial safety factor method for mechanical loading The partial safety factor has already been in common European codes and use already about three decades. The latest updating of this methodology is presented in EN 1990 [2], and there is no need to present this methodology in this report. Lifetime safety factor method for durability
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1. Principle
In practice it is reasonable to apply the lifetime safety factor method in the design procedure for durability, which was first time presented in the report of RILEM TC 130 CSL [8,11]. The lifetime safety factor method is analogous with the static limit state design. The durability design using the lifetime safety factor method is related to controlling the risk of falling below the target service, while static limit state design is related to controlling the reliability of the structure against failure under external mechanical loading. The durability design with lifetime safety factor method is always combined with static or dynamic design and aims to control the serviceability and service life of a new or existing structure, while static and dynamic design controls the loading capacity.
2. Lifetime safety factors in the durability limit states design The lifetime safety factor design procedure is somewhat different for structures consisting of different materials, although the basic design procedure is the same for all kinds of materials and structures. Limit states can be the same as in static design, but some generalised limit states, including e. g. visual or functional limit states, can be defined. In this way the principle of multiple requirements, which is essential for integrated life cycle design, can be introduced. Limit states are divided into two main categories:
1. Performance limit states 2. Functionality limit states
The performance limit states affect the technical serviceability or safety of structures, and the functional limit states affect the usability of structures. Both of these, but especially the latter is often connected to obsolescence. The performance limit states can be handled numerically, but the functional limit states can not always be handled numerically but only qualitatively. Investigations in practice have shown, that about 50% of all demolished buildings or civil infrastructures have been demolished because of obsolescence, and the same amount because of insufficient technical performance or safety. A short summary of the parameters of durability limit states is presented above in table 5. The design service life is determined by formula (Sarja and Vesikari 1996 [8,11], modified:Sarja 2001 [12] and Sarja 2002[4]): tLd·γtk >= tg (6)
where tLd is the design service life, tLk the characteristic service life γtk the lifetime safety factor, and tg the target service life.
Using the lifetime safety factor, the requirement of target service life (corresponding to a maximum allowable failure probability) is converted to the requirement of mean service life. The mean service life is approximated by service life models which show the crossing point of the degradation curve with the limit state of durability (figure 2.). The mean service life evaluated by the service life model divided by the central lifetime safety factor is design life, which must be greater than or equal to the requirement for the design life (also called target service life).
tLd = tLk /γt0 (7a)
69
tLd ≥ tg (7b)
where
tLd is the design service life.
γt0 central safety factor When using ordinary characteristic values the equations get the following formulations:
tLd = tLk / γtk ≥ required service life (target service life) (Table3) (8a)
t Ld = tL k / γtk≥ required design life (=target service life) (Table3) (8b)
Figure 3.8 The meaning of lifetime safety factor in a performance problem.
The lifetime safety factor depends on the maximum allowable failure probability. The lifetime safety factor also depends on the form of service life distribution. Figure 3.8 illustrates the meaning of lifetime safety factor when the design is done according to the performance principle. The function R(t) – S is called the safety margin. Performance behaviour can always be translated into degradation behaviour. By definition, degradation is a decrease in performance. The transformation is performed by the following substitutions: R(0) – R(t) = D(t) (9) R(0) – S = Dmax or R(0) – Rmin = Dmax
R, S
Time µ tγt0t =Ld L
µ t L
S k
R µ
Safety margin
Failure probability
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Let us consider that the degradation function is of the following form: ∆ D(t) = a.tn (10) where ∆ D(t) is the mean value of degradation, a the constant coefficient, t time, and n degradation mode coefficient .
The exponent n may in principle vary between -∞ and +∞. The values of n are defined as follows: - Accelerating degradation process: n > 1 - Decelerating degradation process: n<1 - Linear degradation process: n=1
The coefficient a is fixed when the mean service life is known:
α = Dmax / µtL (11) Degradation is assumed to be normally distributed around the mean. It is also assumed that the standard deviation of D is proportional to the mean degradation, the coefficient of variation being constant, VD. Figure 3.9 shows the degradation as a function of time
Figure 3.9 The meaning of lifetime safety factor in a degradation process. The safety index β of standard normal distribution can be expressed as a function of mean values of R and S, and standard deviation of the difference R0 - S0 , as follows: β = (µR - µS) / SQR (VR
2 + VS2) (12a)
µ
γLdt = Lt
t0µ t L
Time
D
µ D
Safety margin
Failure probability
max D
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In the degradation models we apply the statistical bases only for the capacity, because the environmental load is defined only as classified magnitudes. Applying into the degradation, and assuming S to be constant we get an estimate
D
g
gD
g
V
D
D
DV
DD ⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛−
=−
=
1max
maxβ (12b)
where Dmax is the maximum allowable degradation, Dg the mean degradation at tg, and VD the coefficient of variation of degradation. From Figure 3.9 and from equation 12b we get:
ntn
g
n
gt
g t
t
D
D0
0max γγ
=
⎟⎠⎞⎜
⎝⎛
⎟⎠⎞⎜
⎝⎛
= (13)
By assigning this to equation (12) we obtain the central lifetime safety factor and mean value of the design life:
t0 = (β .VD +1)1/n
(14) tLd = µ tL / γt0
where tLd is the design life µ tL mean value of the service life β the safety index V D the coefficient of variation of the degradation The lifetime safety factor depends on statistical safety index β (respective to the maximum allowable failure probability at tg), the coefficient of variation of D (=VD) and the exponent n. Thus the lifetime safety factor is not directly dependent on design life (target service life) tg itself. If the degradation process is accelerating, n<1. In the case of decelerating degradation n>1. In the case of linear degradation process n=1. The selection of the value of n can be done when knowing the degradation model. Often the degradation process in the degradation models is assumed to be linear. In these cases, or always when no exact information on the degradation process is known, the value n=1 can be used. The mean design life can be transformed into characteristic design life with the form: tk = t0 (1 – k V t )
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(15)
tLd = tLk / γtk = µ tL /γ t0
where tLk is the characteristic service life µ tL the mean value of the service life tLd design life k a statistical factor depending on the statistical reliability level
expressed as a fractile of the cases under the characteristic value (usually the fractile is 5%, and
Vt coefficient of variation of the service life ( if not known, an estimate v D = 0,15-0,30 can usually be used). The characteristic lifetime safety factor γtk can be calculated with the equation
tLd = tLk / γtk = µ tL / γt0 γtk = γt0* tLk / µ tL= (β⋅VD + 1)1/n* (1−1,645⋅ V tLd ) (16) where β is the safety index V D the coefficient of variation of the degradation (usually. 0,2-0,4 ) V tLd the coefficient of variation of the design life (usually 0,15-0,30 ) Looking at the equations 14 and 16 we can see, that there is a correlation between ν D and ν t. In equation 14 we obtain, that the standard deviation of �(td) = � (V D). This means that V td = V D / γt0 = V D / (β.VD +1)1/n (17) Assuming again, that n=1 we get the values of central and characteristic lifetime safety factors. Examples of central and characteristic safety factors for different limit states and reliability classes are presented in Table 3.8 for the cases ν D = 0,3 and ν D = 0,4 . In practice it is recommended to use the characteristic values of the parameters, because they are used also in the static and dynamic calculations.
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Table 3.8 Central and characteristic safety factors in the cases V D = 0,3 and V D = 0,4. An application of EN1990: 2002.
Lifetime safety factor 1 year reference period 50 years reference
period
Reliability
Class/ Consequence
Class
Safety index β Central safety factor
γ0
Characteristic safety
factor γk
Central safety factor γ0
Characteristic safety
factor γk
Ultimate limit states 1 year
reference period
50 years reference period
V D =
0,3
V D =
0,4
V D
= 0,3
V D =
0,4
V D =
0,3
V D =
0,4
V D =
0,3
V D =
0,4 RC3/CC3: High consequence for loss of human life, or economic, social or environmental consequences very great
5,2
4,3
2,56
3,08
2,07
2,42
2,29
2,72
1,80
2,06
RC2/CC2: Medium consequence for loss of human life, or economic, social or environmental consequences considerable
4,7
3,8
2,41
2,88
1,92
2,22
2,14
2,52
1,65
1,86
RC1/CC1: Low consequence for loss of human life, or economic, social or environmental consequences small or negligible
4,2
3,3
2,26
2,68
1,77
2,02
1,99
2,32
1,50
1,66
Serviceability limit states RC3/CC3 No general recommendations. Will be evaluated in each case separately RC2/CC2 2,9 1,5 1,87 2,16 1,38 1,50 1,45 1,60 1 1 RC1/CC1 1,5 1,5 1,45 1,60 1 1 1,45 1,60 1 1
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3.3.7 Reliability under obsolescence
3.3.7.1 Principles Obsolescence means the inability to satisfy changing functional (human), economic, cultural or ecological requirements. Obsolescence can affect to the entire building or civil infrastructural facility, or just some of its modules or components. The obsolescence analysis and control is aiming to guarantee the ability of the buildings and civil infrastructures to maintain an ability to meet all current and changing requirements with minor changes of the facilities. Lifetime design aims at minimising the need of early renewal or demolition. Examples of the obsolescence are as follows:
- Functional obsolescence is due to changes in functions and use of the building or its modules. This can even be when the location of the building becomes unsuitable. More common are changes in use which require changes in functional spaces or building services systems. This rises need for flexible structural systems, usually requiring long spans and minimum numbers of vertical load bearing structures. Partition walls and building services systems which are easy to change are also required.
- Technological obsolescence is typical for building service systems, but also the structure can be a cause when new products providing better performance become available. Typical examples are more efficient heating and ventilation systems and their control systems, new information and communication systems such as computer networks, better sound and impact insulation for floorings, and more accurate and efficient thermal insulation of windows or walls. Health and comfort of internal climate is the requirement which is increased in importance. The risk of technological obsolescence can be avoided or reduced by estimating future technical development when selecting products. The effects of technical obsolescence can also be reduced through proper design of structural and building service systems to allow easy change, renewal and recycling.
- Economic obsolescence means that operation and maintenance costs are too high in comparison to new systems and products. This can partly be avoided in design by minimising the lifetime costs by selecting materials, structures and equipment which need minimum costs for maintenance and operation. Often this means simple and safe products which are not sensitive to defects and or their effects. For example, monolith external walls are safer than layered walls.
- Cultural obsolescence is related to the local cultural traditions, ways of living and working, aesthetic and architectural styles and trends, and imago of the owners and users.
- Ecological obsolescence happens often in a case of large infrastructural projects. In large projects this is often related to high waste and pollution production or loss of biodiversity. In case of buildings we can foresee in the future problems especially in the use of heating and cooling energy, because heating and cooling is producing for example in Northern and Central Europe about 80 to 90 % of all CO2 pollution and acid substances into air. From the viewpoint of technical potential and lifetime economy there is a clear chance to reduce the consumption of the heating energy into 1/3 ... 1/5 from the current standard level.
For each alternative of design or MR&R solution, the following obsolescence procedure will be made: 1. identifying the relevant obsolescence factors 2. analysing relevant obsolescence limit states 3. selecting evaluation methods for the relevant potential obsolescence cases 4. evaluating the characteristic service life against the actual modes of the obsolescence 5. evaluating the required lifetime safety factors for each mode of obsolescence 6. listing the modes of the obsolescence, and the corresponding values of the design service life 7. moving the results into the general design or MR&R planning procedure
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3.3.7.2 Methods for obsolescence limit states design Although obsolescence is increasing in importance, no standards addressing obsolescence of civil infrastructure or building facilities have been enacted so far. Principled strategies and guidelines for dealing with obsolescence have been presented [5, 12] but the real analysis methods have not been applied. As obsolescence progress of a facility depends on the development of local conditions, as well as on the general development of society during the service life (or residual service life) of a facility, there is lot of uncertainty involved in obsolescence analyses. Like in any uncertainty-filled problem, also in obsolescence situation the case must be structured down to smaller parts, which can be consistently handled. It must be noted that he obsolescence avoidance thought should be present in all life cycles of the facility: planning and programming; design; construction; operations, maintenance and renewal; retrofitting and reuse. The obsolescence analysis should be performed before the onset of obsolescence, as a part of the facility owning and management strategy. The following methods can be applied in obsolescence analysis:
- Quality Function Deployment method (QFD) [Lifecon Deliverables D2.3 and D5.1]
- Life Cycle Costing method (LCC) [Lifecon Deliverable D5.3]
- Multiple Attribute Decision Aid (MADA) [Lifecon Deliverable D2.3]
- Risk Analysis (RA) [Lifecon Deliverable D2.3]
References to chapter 3.3
[1] Sarja, Asko, Lifetime performance modelling of structures with limit state principles. Proceedings of 2nd International SymposiumILCDES2003, Lifetime Engineering of Buildings and Civil Infrastructures, Kuopio, Finland, December1-3, 2003. pp. ??. Association of Finnish Civil Engineers, Helsinki 2003. [2] EN 1990: 2002: Eurocode - Basis of structural design. CEN: European Committee for Standardisation. Ref. No. EN 1990:2002 E. 87 pp. [3] Sarja, Asko, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002. ISBN 0-415-25235-0. [4] Sarja, Asko, Reliability based life cycle design and maintenance planning. Workshop on Reliability Based Code Calibration, Swiss Federal Institute of Technology, ETH Zurich, Switzerland , March 21-22, 2002. http://www.jcss.ethz.c [5] ISO/DIS 15686-1, Buildings-Service life planning-Part 1 General Principles. Draft 1998. [6] Pihlajavaara, S.E. Contributions for the development of the estimation of long-term performance and service life of concrete. Espoo 1994. Helsinki University of Technology. Faculty of Civil Engineering and Surveying, Report 3, 26p. + articles 49p. [7] Sarja, Asko, Sarja, Asko (ed). Open and industrialised building. London. E & FN Spon, 1998. 228 p. [8] Sarja, Asko & Vesikari, Erkki (Editors). Durability design of concrete structures. RILEM Report of TC 130-CSL. RILEM Report Series 14. E&FN Spon, Chapman & Hall, 1996. 165 pp. [9] EN 206-1 Concrete-Part1: Specification, performance, production and conformity. CEN European Committee for Standardisation, December 2000. REf. No EN 206-1:2000 E. 72 pp. [10] JCSS Model Code. Joint Committee of Structural Safety. http://www.jcss.ethz.ch , [11] Sarja, Asko, Sarja, Asko, Environmental Design Methods in Materials and Structural Engineering. RILEM Journal: Materials and structures, Vol. 32, December 1999, pp 699-707 [12] Iselin, D.G., Lemer, A.C., (Eds), The Fourth Dimension In Building: Strategies For Minimizing Obsolescence. National Research Council, Building Research Board. National Academy Press, Washington, D.C. 1993. 59 pp. + Appendix 42 pp.
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[13] Sarja, Asko, Development towards practical instructions of life cycle design in Finland. RILEM Proceedings PRO 14, Proceedings of the RILEM/CIB/ISO International Symposium: Integrated Life-Cycle Design of Materials and Structures, ILCDES 2000. pp. 57-62. 3.4 Lifetime Procurement and Construction (LPC)
3.4.1 Procurements and contracting types
The two most significant recent innovations in public sector project finance are the Private Finance Initiative (PFI) and the subsequent evolution of Public Private Partnerships (PPP). Governments all over Europe and elsewhere are turning to the PFI/PPP as an efficient and effective way of delivering services to the public. PFI involves the public and private sectors working together. Traditionally the public sector procured capital assets by paying for them up front and in full. In a typical PFI/PPP project a single, stand-alone, special purpose business, the Project Company, is created by the private sector. This will build a facility, which may be a school, hospital, road, bridge or other asset, which is then operated for a fixed period, known as a concession. The public sector pays for this through a service charge, which will be conditional on the level of service provided. Variations on this are known as “Design, Build and Operate” (DBO), “Design, Build, Finance and Operate” (DBFO), “Build, Own, Operate, Transfer” (BOOT). Whilst the contractual arrangements vary, they all adopt the PFI/PPP concept. Because the asset is being built by the operator, who is paid an agreed service charge for providing an asset with a specified functional performance, and usually incurs penalties if the functions are not available as, when and to the quality prescribed, the operator has to take a whole life view of the asset. However, what has happened in practice is that the “whole life” view has turned out to be the life of the concession plus the time, usually five years, for which the asset must still be serviceable after transfer. Whilst there are no published international standards, there are various other guidance documents relating to lifetime procurement. 3.4.2 EU Public Procurement Directives
The EU is updating its rules on procurement procedures for public works contracts, public supply contracts and public service contracts (Directive 2004/18), and also for the water, energy, transport and postal services sectors (Directive 2004/17). The revision, based on internal market principles, aims to simplify, harmonise and modernise the rules. It introduces a new procedure - called competitive dialogue - and promotes the development of electronic procedures. Recourse to social and environmental criteria is authorised for the selection of economic operators, based on European Court of Justice case-law. As part of this review, the Directives allow contracting authorities to award contracts based on what is deemed “the most economically advantageous” basis. Under this provision, Article 53 of Directive 2004/18 allows the contracting authority to assess bids against “various criteria linked to the subject-matter of the public contract in question, for example, quality, price, technical merit, aesthetic and functional characteristics, environmental characteristics, running costs, cost-effectiveness, after-sales service and technical assistance, delivery date and delivery period or period of completion”. This means that lifetime performance aspects can, as long as they are clearly quantified and the weighting applied to them as against other criteria in the contract awards process is stated in the call for tenders, form a part of the procurement requirements of public bodies specifying under the new public procurement directives.
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3.5 Lifetime Facility Management
3.5.1 MR&R Strategy, Optimisation and Decision-Making [Lifecon D1.1]
Typical needs and requirements of governmental organisations for a computer aided management system are the following. For the administration of the organisation:
- Need for economic justification of decisions - Objective basis for decisions, based on engineering, economic and ecological grounds - Strategic guidelines for preservation of assets - Determination of medium and long-term objectives, and need for definition of appropriate
maintenance strategies to achieve this - Optimising MR&R strategies based on engineering and economic grounds - Need for selection of justificable maintenance decisions within budget constraints - Need for showing value for money in infrastructure provision and maintenance - Need for integration of allocation of funds - Evaluation of whole life costing, including user costs
For the maintenance engineers and repair designers the needs are:
- Well organised condition assessment and inventory for the structures - Optimisation of MR&R actions for specific components, modules and objects - Guaranteed safety - Safeguarded investments - Correct timing of MR&R actions - Evaluation of MR&R costs - Combination of optimised actions into MR&R projects - Prioritisation of projects - Producing annual repair and reconstruction programmes - Budget control
The ultimate objective of a management process is to make the necessary decisions between the inspection of structures and the execution MR&R projects. In other words a life cycle (LC) management process should be able to answer the strategic questions: which structures should be repaired? which MR&R methods should be used? when to do the MR&R actions? how to combine the actions into projects? All these questions should be answered taking into account technical demands, functional performance, safety, economy, ecology and other necessary viewpoints. The MR&R projects are then executed according to the system assisted decisions. Lifecon LMS is a predictive and integrated life cycle management system. The system makes it possible to organise and implement all the activities related to planning, constructing, maintaining, repairing, rehabilitating and replacing structures in an optimised way taking into account safety, serviceability, economy, ecology and other aspects of life cycle planning. The following activities are included in the LIFECON management process:
1. Assistance in inspection and condition assessment of structures, 2. Determination of the network level condition statistics of a building stock, 3. Assessment of MR&R needs, 4. LC analysis and optimisation for determination of optimal MR&R methods and life cycle action
profiles (LCAP's) for structures 5. Definition of the optimal timing for MR&R actions 6. Evaluation of MR&R costs, 7. Combination of MR&R actions into projects 8. Sorting and prioritising of projects, 9. Allocating funds for MR&R activity 10. Performing budget check,
78
11. Preparation of annual project and resources plans 12. Updating degradation and cost models using inspection and feed back data
The decision making process is performed at three levels of structural hierarchy (3.?):
1. Component/module 2. Object 3. Network level.
The component/module level addresses structural components such as beams and columns and their combinations, i.e. modules. The object level refers to complete structures or buildings such as bridges and nuclear power plant units. The network level addresses networks of objects such as stocks of bridges or buildings.
Network level
Updated degradationand cost models
Optimised MR&Rmethods and life cycle actionprofiles
Annual project andresources plans
Timing and costevaluation of projects
System Database
Object level
Component specific data
Component/module level
Conditionassessment
Definition, timing andcost evaluation of MR&R actions
Planning and prioritisation of MR&R projects
Structural andfunctional analysis
Predicted actions,damage observationsand functionaldeficiencies
Definition of strategical targetsLC + risk analyses Budget share and check
Checking of work programmes
Executed MR&Rprojects
Applicationof degradationand cost models
Figure 3.10 Three levels of decision making in Lifecon LMS.
The object level process is designed for companies and organisations which own only a limited amount of concrete infrastructures. It is a practically oriented process which helps the maintainers to plan and execute the MR&R projects based on the inspection and condition assessment data. It provides maintainers with proposals for MR&R actions with optimised timing, composition of actions (project planning) and annual project programmes of infrastructure networks. The network level process is designed for national road administrations and other organisations which are responsible for the upkeep of a large network of concrete infrastructures. The network level process can be applied administration level operative planning and decision-making. It makes it possible for the administration of an organisation to evaluate the necessary funding for MR&R activity and optional maintenance strategies.
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The network + object level process is an integrated network and object level process. By a special interface the optimised work programmes produced of the object level can be compared and harmonised with the network level optimum before returning back to the object level and implementation. 3.5.2 Condition Assessment Protocol (CAP) [Lifecon D3.1]
The repeated assessment of the structure condition is a decision process, which serves to identify necessary actions which lead to the most effective fulfilment of all defined requirements. One option is to “buy” additional information by inspection to obtain more reliable information on the current condition. This knowledge can be used to update models with the intention of improving the precision of future predictions. In summary the following aims were pursued:
- Integration of existing probabilistic service life models and reliability theory in the framework for condition assessment of concrete structures
- Provision of an organized system for collecting, rating and storing of data - Ensure that information is only collected if necessary and information is suitable for the defined
purpose - The approach has to be applicable to users managing small to very large assessment projects,
with or without a) large sampling effort and b) experience on and capacities for reliability analysis.
The main idea is to start with a low inspection volume and with basic investigation methods which will be increased or become more sophisticated if intermediate results suggest so. The scheme of this ideology can be found in Figure , where the basic framework of condition assessment is presented. The flowcharts concerning planning of condition assessment, visual inspection as well as general inspection are presented in detail in Lifecon deliverable D3.1. Eventhough Lifecon LMS focuses on the management of concrete structures, such objects are never built solely of concrete. The CAP is meant for the assessment of concrete, protective measures for concrete and imbedded re-bars and pre-stressing steel. Those materials (e.g. sealers) whose failure due to deterioration leads to concrete deterioration are included. Other materials are out of the scope. The developed framework can nevertheless be adopted to every type of material.
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Newly builtStructure?yes no
Repairrequired?yes no
Birthcertificate
RepairInspection
Visual Inspection(regular intervals)
General Inspection(Date according to
Service Life Models)
Structural Assessment(on demand)
Calibratedparameters
DataIn-Use Inspection
DataRepair Inspection
Calibrated Models(data after repair)
As built data
Design Models
Database
Calibrated Models(after Inspection)
Date + Extentof next Inspection
In-Use-Inspection(continous parameter calibration):
Figure 3.11 Basic framework for the condition assessment.
3.5.3 Service Life Prediction
3.5.3.1 Alternative models Three types of degradation models are described in detail, including some examples of application. These models are:
- Statistical degradation models - RILEM TC130 CSL models - Reference Structure model
Characteristic properties of these models are as follows:
- Statistical degradation models are based on physical and chemical laws of thermodynamics, and thus have a strong theoretical base. They include parameters, which have to be determined with specific laboratory or field tests. Therefore some equipment and personnel requirements exist for the users. The application of statistical "Duracrete" method raises need for a statistically sufficient number of tests. Statistical reliability method can be directly applied with these models.
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- RILEM TC 130 CLS models are based on parameters, which are available from the mix design of concrete. The asset of these models is the availability of the values from the documentation of the concrete mix design and of the structural design.
- Reference structure model is based on statistical treatment of the degradation process and condition of real reference structures, which are in similar conditions and own similar durability properties with the actual objects. This method is suited in the case of a large network of objects, for example bridges. It can be combined with Markovian Chain method in the classification and statistical control of the condition of structures.
Because of the openness principle of Lifecon LMS, each user can select the best suited models for their use. It is sure, that there exist also a lot of other suited models, and new models are under development. They can be used in Lifecon LMS after careful validation of the suitability and reliability. Special attention has to be paid to the compatibility of entire chain of the procedure of reliability calculations.
3.5.3.2 Statistical degradation models [Lifecon D3.2] Statistical degradation models include the mathematical modelling of corrosion induction due to carbonation and chloride ingress, corrosion propagation, frost (internal damage and surface scaling) and alkali-aggregate reaction. Models are presented on a semi-probabilistic and a full-probabilistic level. Semi-probabilistic models only include parameters obtainable throughout structure investigations, without making use of default material and environmental data. Full-probabilistic models are applicable for service life design purposes and for existing objects, including the effect of environmental parameters. For each full-probabilistic model a parameter study was performed in order to classify environmental data. The application of the models for real structures is outlined. The objects of the case studies have been assessed in order to obtain input data for calculations on residual service life. Each degradation mechanism will be treated separately hereby demonstrating:
- possible methods to assess concrete structures - the sources for necessary input data - approach used in durability design - application of models for existing structures - the precision of the applied models - necessary assumptions due to lack of available data - possible method to update data gained from investigations throughout condition assessment - default values for input data - output of the calculations
The use of full-probabilistic models for the calibration of the Markov Chain approach is described.
3.5.3.3 RILEM TC 130 CSL models [Lifecon D2.1] RILEM TC 130 CSL degradation models include a set of selected calculation models consisting of parameters, which are known from mix design and other material properties and ordinary tests. Therefore these models are usually easy to apply also in cases when no advanced laboratories and equipment are available. The following degradation processes are included in the RILEM TC 130 CSL models:
- Corrosion due to chloride penetration - Corrosion due to carbonation - Mechanical abrasion - Salt weathering - Surface deterioration - Frost attack
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Degradation affect either the concrete or the steel or both. Usually degradation takes place on the surface zone of concrete or steel, gradually destroying the material. The main structural effects of degradation in concrete and steel are the following:
- Loss of concrete leading to reduced cross-sectional area of the concrete. - Corrosion of reinforcement leading to reduced cross-sectional area of steel bars. Corrosion may
occur a) at cracks b) at all steel surfaces, assuming that the corrosion products are able to leach out through
the pores of the concrete (general corrosion in wet conditions). - Splitting and spalling of the concrete cover due to general corrosion of reinforcement, leading to
a reduced cross-sectional area of the concrete, to a reduced bond between concrete and reinforcement and to visual unfitness.
3.5.3.4 Reference structure models [Lifecon D2.2] Reference structure degradation prediction is aimed for the use in cases, when the network of objects (e.g. bridges) is so large in number that a sample of them can be selected for a follow-up testing, and these experiences can be used for describing the degradation process of the entire population. The reference structure models are of two types: 1) surface damage and 2) crack damage models. Degradation factors such as frost damage, corrosion of reinforcement, carbonation and chloride penetration may have combined effects that may be of great importance to the service life of a structure. By traditional prediction methods of service life these combined effects are usually ignored. However in computer simulation they can be considered without great theoretical problems. The progress of the depth of carbonation or the depth of critical chloride content is promoted by both the frost-salt scaling of a concrete surface and the internal frost damage of concrete. The internal frost damage is evaluated using the theory of critical degree of saturation. The internal damage is evaluated as the reduction of the dynamic E-modulus of concrete. The condition state (or damage index) of a structure is evaluated using the scale 0, 1, 2, 3, 4. This scale is also used throughout the bridge management system. The degradation models for both surface damage and crack damage have been programmed on Excel worksheets. The surface damage models describe normal degradation processes on the surfaces of reinforced concrete structures combining the effects of frost-salt attack, internal frost damage attack, carbonation, chloride ingress and corrosion of reinforcement. The crack damage models emulate the processes of depassivation and corrosion at a crack of a concrete structure. All management systems that include a prediction module, such as Lifecon LMS, need reliable environmental load data. In Lifecon deliverable D4.2 the relevant systematic and requirements for quantitative classification of environmental loading onto structures, as well as sources of environmental exposure data are given. Lifecon D4.2, chapter 6 contains instructions and guidelines for how to characterise the environmental loads on concrete structures on object and network level. However, these guidelines have to be validated (and possibly adjusted) before they finally can be used in the LMS. In this report the results from the practical validation are summarised. The EN 206-1 system and the standard prEN 13013 have been tested out on the chosen objects and compared with detailed environmental characterisation of the same objects using the available data and methods for environmental characterisation. Such studies have been undertaken in five countries (Norway, Sweden, Germany, Finland and United Kingdom) to develop the needed national annexes for a proper implementation of EN206-1 across Europe. Strategies and methodologies for developing the quantitative environmental classification system for concrete are given. Those are, firstly, comparative case studies using the new European standard -“EN 206-1 Concrete” and detailed environmental characterisation of the same objects, and secondly, a more theoretical classification based upon parametric sensitivity analysis of the complex Duracrete damage functions under various set conditions. In this way the determining factors are singled out and classified. Such classification systematic is needed to enable sound prediction of service lives and maintenance intervals both on object and network level. This in turn is a necessary prerequisite for change of current reactive practise into a pro-active life-cycle based maintenance management.
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3.5.4 Environmental Degradation Loads
3.5.4.1 Environmental load parameters [Lifecon D4.1] The first and general approach to generate data on the degradation agents affecting concrete infrastructures ought to be through utilisation of the climate and weather data normally measured at meteorological sites. This data has to be processed, adapted and modelled to fit into the degradation models. A summary of the needed environmental data is presented in Table 3.?. Table 3.8 Environmental data for degradation modelling.
Deterioration mechanism
RH Temp. CO2 Precipi-tation
Wind Radia-tion
Chloride Conc.
Freeze-thaw cycles
[SO2] [O3]
Reinforced concrete
Carbonation induced corrosion X (X) X X X
Chloride induced corrosion X X X X
Propagation of corrosion X X X X
Alkali-aggregate reaction No model
Frost attack internal/scaling (X) X X (X) (X) (X) X
Supplementary materials (Dose-response functions)
Galvanised steel/zink coating X X X X X
Coil coated steel X X X X
Sealants/bitumen No function
Polymers No function
Aluminium X X X X 3.5.5 Quantitative classification of environmental loads [Lifecon D4.2]
Object level The different components are exposed in different ways and different amounts, due to orientation, sheltering, sun/shadow, distance from “source” for exposure, and more, and all this have to be taken into account. A step-wise characterisation of the environmental parameters onto the surface of the structure is as follows:
1. Choose object
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2. Divide the structure/construction into components with different expected Categories of Location (due to orientation, sheltering...). Use either the EOTA system [D4.2 Annexes] or the height classification system [Table 5 in D4.2].
3. Attain EN206-1 exposure classes to the various components/parts of the construction 4. Adjust for the effect of sheltering, etc. on driving rain and deposition on other agents to the
structure by calculation of CR, CT, O and W [Chapter 5.6.1 in D4.2]. 5. Find climatic information from nearby meteorological stations. Necessary information:
a. Temperature. Preferably, if available, time series for a long period (>10 years). Main information is average temperature for summer and winter conditions, max/min and average monthly temperature. Surface temperature can be calculated from the following equation:
b. Moisture. Preferably, if available, time series for a long period (>10 years). Main information is average annual precipitation and monthly number of days with rain > 0.1mm and rain >2.5mm. Monthly or seasonal relative humidity.
c. Wind. Preferably, if available, time series for a long period (>10 years). Main information is wind rose showing frequencies of wind speed and direction.
6. Check correlation or relevance for meteorological data for the object. a. From some (2-4) nearby stations – any significant difference in meteorological data? b. Distance from meteorological station. c. Height above sea level. Normally the average temperature decreases 0.6-0.7º C per 100 m. d. Sunny/shadowed areas (for instance of valleys). A difference of 0.5-1º C in air temperature
may be expected. e. Topography – differences in wind speed and direction.
7. Calculation of spell index and wall spell index and driving rain [D4.2 annexes]. For the various EN206-1 classified parts of the structure:
8. Characterisation of RH 9. Characterisation of moisture: Total time with moisture comes from: time with rain +
condensation + high RH 10. Characterisation of temperature profiles on construction 11. Characterisation of chloride, either from sea-salt from Cole models/mapping authorities for land
transported sea-salt, ref example from Germany, or from deicing salts-formula Cr = 1000(-9.56+0.52SF +0.38SL+0.14FD-0.20ID)/w (Average amount of de-icing salt for each application incident [g/m²]).
12. Characterisation of pollutants like SO2, O3, H+ and CO2. Contact national (and local) ICP Modelling and Mapping groups concerning already mapped information. Contact points for all European countries are given on web-page http://www.rivm.nl/cce/. Find available environmental data from national or local authorities.
Network level - regional level On regional level the mapping and classification is related to the objects location. Necessary input is meteorological and other environmental information. These guidelines will await the proper characterisation on object level and choice of appropriate parameters for network level.
3.5.4.3 GIS-based quantification of environmental load parameters [Lifecon D4.3] All countries have extensive meteorological networks that can provide the necessary meteorological data
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on all levels, either as point measurements or as models on network level for the area in question. Meteorological data can be shown as maps showing the common meteorological parameters (i.e. average temperature and precipitation), or specifically derived parameters may be generated from the time series of the basic parameter. The measuring, testing and evaluation of air quality are assuming growing importance in developed countries as elements of a comprehensive clean air policy and geared to sustainable development. A huge bulk of data is therefore generated on the various geographical levels. In 1995 EEA (European Environment Agency) summarised the state of the air pollution-monitoring situation in Europe. The report provides detailed country-wise tables on networks, sites, compounds, reporting etc., summarised into country reports, and again summarised into summary tables covering all the 29 countries from which data were available. The costs for climatic and pollution data varies between the different countries. In most cases it is quite expensive to get these data, especially if they have to be adjusted in some extent. The guideline given in Lifecon D4.2 is possible to adopt, which have been shown by the Norwegian and the Swedish contributions. However, the work effort is quite large, which possibly will be a problem in the future. The standard prEN 13013 (driving rain) is possible to use in most cases, but some difficulties arise when assessing other constructions than buildings.
3.5.6 MR&R Planning
3.5.6.1 RAMS Analysis Supported with QFD Method [Lifecon D5.1] The purpose is to offer an assisting decision making tool, which takes into account LIFECON generic requirements, when considering best choices between different repair methods, systems and materials. The combination of RAMS-analysis (Reliability, Availability, Maintainability, Safety) and QFD (Quality Function Deployment) method consists in principle of 3 phases, as presented in Figure 3.11.
1. Determiningweighting factors of
RAMS
2. Evaluation ofdifferent methods,
systems and materials
3. Sensitivity analysis
Figure 3.11 The phases of combined RAMS and QFD mehods in the optimising MR&R planning. In maintenance and repair planning QFD is serving as a quantitative method and RAMS as a qualitative method. The merging of the two methods (phase 2) is presented in Figure 3.12.
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Figure 3.12 Combination of QFD and RAMS, phase 2. QFD can be used for interpreting any requirements into specifications, which can be either performance properties or technical specifications. In this connection QFD serves as an optimising and selective linking tool between alternative repair methods and products and their performance properties (RAMS). Fundamental objectives in the combination of QFD and RAMS are:
- Identification of the functional requirements of the owners, the users and the society (generic Lifecon requirements)
- Interpreting and aggregating generic Lifecon requirements first into Performance Properties (RAMS) and then into alternative repair methods and products of structures
- Optimising the alternative repair methods or products in relation to Performance Properties (RAMS)
- Selection from different design and repair alternatives Full description of the merging of QFD and RAMS, as well as application of the combination to four different cases (bridge, wharf, building, tunnel) is presented in Lifecon deliverable D5.1.
3.5.6.2 Life Cycle Costing (LCC) of MR&R [Lifecon D5.2] The real challenge of successful LCC analysis lies in making unbiased assumptions, which produce fair comparisons of alternate designs or maintenance policies. As with any evaluation process, it is always easier to assess or evaluate smaller entities. That is why it is recommendable to build a Cost Breakdown Structure (CBS) for the different MR&R methods, using commensurate subtitles and units to compare the costs of the different methods. Life cycle cost is the total discounted monetary cost of owning, operating, maintaining, and disposing of a building, building system or infrastructure over a period of time. LCC analysis can be used to evaluate and compare different MR&R methods, the calculations are made over the whole service life of a building or a structure and the relevant costs are converted to their equivalent present value. The alternative with the lowest total present value is the most economical choice.
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Lifecon D5.2 gives guidelines to the decision maker how to select MR&R methods on LCC basis. Preliminary selection of applicable MR&R methods can be made when the degradation mechanism is known. When the applicable MR&R methods are chosen, the equations of LCC are relatively straightforward and simple. As is the case with most evaluation techniques, the real challenge lies in making unbiased assumptions, which produce fair comparisons of alternate designs.
3.5.6.4 Life Cycle Ecology (LCE) of MR&R [Lifecon D5.3] The generic life cycle ecology (LCE) includes the following components [Lifecon D2.1].
- raw materials economy - energy economy - environmental burdens economy - waste economy - biodiversity
These components are weighted differently in different areas and places of the world, because the critical components are varying. Therefore we have to treat LCE on different levels:
- global level (e. g. the green house gas production and energy consumption) - regional level (e. g. water consumption and biodiversity) - local level (e. g. wastes, biodiversity, raw materials)
LCE should ideally include assessment of environmental impacts caused by all human activities throughout the whole life cycle of a structure. This is, however, a very difficult process since the relationship between the external environment and the category endpoint can be very complex. Normally, the Life Cycle Ecology (LCE), will stop at the step before category endpoint, showing only the impact categories, which is fairly easy to do, and then interpret the results from the various category indicators. The methodological framework for the assessment of environmental impacts from rehabilitation and maintenance of concrete structures is based on the ISO-standards 14040 - 14043. From the condition survey of a concrete structure, the method of maintenance and type of maintenance are first selected. The selections depend on type and extent of damage and type of external environmental conditions as well as type of equipment and materials to be used for the repair. The next step in the process is to determine the functional unit. The functional unit is the reference unit used in a life cycle study. All emission, energy and flow of materials occurring during the repair process are related to this unit. The functional unit shall be measurable and will depend on the goal and scope of the analysis. The goal of the Life Cycle Ecology (LCE) shall unambiguously state the intended application and indicate to whom the results will be communicated. Thus, the functional unit for a paint system may be defined as the unit surface (m²) protected for a specified time period. The maintenance/life cycle inventory (LCI) phase will consist of:
1. Quantifying the amount of all raw materials, chemicals and equipment, which are necessary to fulfil the maintenance function. This quantification gives the reference flow, for which all inputs and outputs are referred to and are closely connected to the functional unit.
2. Providing environmental data of consumed raw materials, chemicals and equipment from the suppliers (specific data) or from databases (generic data) or from a life cycle inventory (LCI) carried out at supplier level. All materials used are recommended to have an environmental declaration with scope “Cradle to port”. The environmental declaration shall include use of resources such as energy (renewable, non renewable), materials (renewable, non renewable), water and waste as well as emissions to air and water.
3. Quantifying and classifying the waste from the process as recycling, disposal or hazardous waste. The framework for application of the LCE into MR&R projects is presented in Figure 3.12. In order to demonstrate how the methodological framework for the assessment of environmental impacts can be applied to various types of repair and maintenance systems for concrete structures, two examples of commonly used systems have been selected for analysis. The one system is a patch repair with shotcreting, where the damage has been caused by a chlorideinduced corrosion of embedded steel.
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The other system is a preventive measure based on a hydrophobic surface treatment, which is commonly used as a general protection of the concrete surface both against moisture and chloride penetration.
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Figure 3.12 Methodological framework for assessment of environmental impacts from rehabilitation and maintenance of concrete structures
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3.5.7 IT- Prototype [Lifecon D1.2, D1.3]
A demonstrative prototype includes the main modules of generic user requirements, and some modules of the object structuring and MR&R algorithms. The prototype is aimed at demonstration of the Lifecon LMS, and as a core for development of more focused software tools. The user documentation will give a brief overview on how to use the system. It will not go into detail on the Lifecon LMS methods or how to apply them in the Lifecon LMS IT system. Figure 3.13 shows the workflow and dataflow for the IT prototype and the interactions between the main components.
MMS-library-assets
-assessments-damage atlas
Sigma-network analysis-predictive results
MMS db
Sigma DB
Maps
Reports
Input data
Predictiveforecastresults
Workflow
Dataflow
LMS prototype: Simplified workflow and dataflow structure
Figure 3.13 Lifecon LMS: Simplified workflow and dataflow structure
The Lifecon IT system consists of three modules:
1. The Norgit Cafe Application Platform This platform is based on standard, third party and Norgit developed Windows components and add ins with rich functionality. Included in Norgit Cafe is a Data Explorer, a License manager, a Lookup manager, a Photo manager, a Document manager, a Drawing manager, a Graph manager, a Report Generator, a 3D visualizer and a Data Access Class Layer. The Norgit Cafe is extensible with additional modules and functionality by providing a set of standard Windows "com" interfaces for this purpose. The Visual Basic, Visual C++ and the Java programming languages can be used for this purpose. The Norgit Cafe Application Platform with its add ins and components are the building blocks for the Maintenance Management System (MMS). MMS Assets and Condition Assessment are built on top of the Norgit Cafe Data Explorer GUI addin. The Assets and Condition Assessment add ins are integrated with Norgit Cafe standard functionality: Photos, maps, documents and drawings. The Kompas system is based on the Norgit Cafe Component Data Access Class Layer.
2. Maintenance Management IT system prototype (MMS). Two modules/addins named Assets and Condition Assessment is made for the Maintenance Management System prototype. Condition
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Assessment contains Inspection Plans and Inspection Programs. Most of the content in Assets and Condition Assessment may have photos, maps, documents and drawings assigned.
3. The Material Upgrade/Degrade Kompas system model for Maintenance Analysis and Planning. This model requires Maintenance Groups and Degrade matrixes as input. The percent amount of upgrade/degrade from year to year for each maintenance group is user defined. The results are Life Cycle Condition profiles for each Maintenance group and also values and Life Cycle Costs for each Maintenance group is calculated.
References to Chapter 3.5
3. Asko Sarja, A process towards lifetime engineering in the 5th and 6th Framework Program of EU. Proceedings of ILCDES 2003 Symposium, Kuopio, December 2003, pp. 7-15. Association of Finnish Civil Engineers, Helsinki 2003. Symposium Proceedings. ISSN 0356-9403, ISBN 951-758-436-9. Association of Finnish Civil Engineers, RIL, http://www.ril.fi.
4. Life Cycle Management of Concrete Infrastructures for improved sustainability LIFECON.EU
GROWTH Program, G1RD-CT-2000-00378. Deliverables D1-D15. Co- ordinator: Professor Asko Sarja, Technical Research Centre of Finland (VTT). http://www.vtt.fi/rte/strat/projects/lifecon/
5. Taina Koskelo, A Method for Strategic Technical Life Cycle Management of Real Estates.
Doctor Thesis. Helsinki University of Technology, Doctor dissertation Series 2005/1. Espoo 2005. 230 p. + Appendixes. htpp://www.tuta.hut.fi/ URL: http://lib.hut.fi/Diss/2005/isbn9512275066
6. John Kelly and Steven Male, Value Management in Design and Construction. E&F SPON,
London, 1996. 181 p. ISBN 0 419 15120
7. Markus Krüger and Christian U. Grosse, Structural health monitoring with wireless sensor networks. Otto Graf Journal, Vol. 15. 2004. Materialprüfungsanstalt Universität Stuttgart, Otto Graf Institut (FMPA), MPA Stuttgart, pp. 77-89.
8. Ayaho Miyamoto, Japanese Strategy of Life Cycle Management in Civil Infrastructures Systems.
2nd International Symposium ILCDES 2003, Integrated Life-Time Engineering of Buildings and Civil Infrastructures, December 1-3, 2003, Kuopio, Finland, Symposium Proceedings. ISSN 0356-9403, ISBN 951-758-436-9. Association of Finnish Civil Engineers, RIL, http://www.ril.fi.
3.6 End-of-Life Management of Buildings
Contributor: Prof. Dr. Frank Schultmann Chair for Construction Management and Economics, University of Siegen
3.6.1. Introduction
Although recycling of construction materials has a long tradition in Europe the use of recycled materials is still mainly focused on low-grade applications. One of the main obstacles to the use of recycled construction materials in high-grade applications is the heterogeneity of the composition and the contamination of construction and demolition waste (C&D waste) resulting from demolition of buildings. As an improvement in the quality of recycled materials in processing is technically limited, efforts have been made to improve the quality of the waste arising on demolition sites. While demolition often leads to a mixing of various materials and
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contamination of non-hazardous components, deconstruction or selective dismantling of buildings instead of demolition help to preserve and reuse material. The latest developments in the European law on waste management encourage the efforts of deconstruction. In recent years several projects have been conducted to analyse the technical and economical feasibility of various deconstruction strategies. Even though, in most cases the information published on these projects is not very detailed and the results of most of the projects conducted by private companies have not even been published, some projects are well documented and allow deriving valuable information for future activities. In the following, the framework for the End-of-Life Management of buildings is presented, underlined by some case studies. Moreover, a sophisticated planning approach and a computer tool for decision support and optimisation of deconstruction work will be introduced.
3.6.2. Classification and Composition of Demolition Waste
In general, figures about the amount and composition of demolition waste are found together with construction waste. The term construction and demolition waste covers a wide range of materials, for instance: - Waste arising from the total or partial demolition of buildings and/or civil infrastructure; - Waste arising from the construction of buildings and/or civil infrastructure; - Soil, rocks and vegetation arising from land levelling, civil works and/or general foundations; - Road planning and associated materials arising from road maintenance activities. One characteristic of construction and demolition waste arising from demolition (and construction) is the heterogeneity of its composition depending on the different construction types, as well as the multitude of materials, elements, and aids used in the construction area. Cross-contamination and general mixing of materials have to be avoided according to the regulations mentioned above. Nevertheless, demolition still often results in a mixture of materials. In Germany, construction and demolition waste was classified according to a waste catalogue issued by the Länder Working Group Waste (LAGA Katalog) which distinguishes between the main groups shown in Table 3.9. Table 3.9 Construction and demolition waste according to LAGA-classification
Waste Code Description31409 demolition debris31410 road construction debris31411 excavation debris31441 contaminated demolition waste and excavation debris91206 waste from construction sites
31407 ceramic and stone wastes31408 glass waste31423; 31424 contaminated soil31436 asbestos waste31438 gypsum waste54912 bitumen, asphalt waste55508 painting materials57 various plastic and rubber waste58 textile waste
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The former LAGA catalogue was not compatible with the European Waste Catalogue (EWC) due to the different approaches adapted to the structuring. Since 1st January 1999 EWC came into force in Germany enforced by the corresponding national ordinance (Verordnung zur Einführung des Europäischen Abfallkataloges (EAKV)) [52]. For an intermediate period a combined catalogue [16] gives references as far as possible in order to facilitate the introduction of the EWC. According to the EWC, construction and demolition waste is grouped in Section 17 00 00 comprising the materials listed in Table 3.10. Table 3.10 Construction and demolition waste in the European Waste Catalogue
Waste Code Description17 Construction and Demolition Waste17 01 concrete, bricks, tiles, ceramics and gypsum based materials17 01 01 concrete17 01 02 bricks17 01 03 tiles and ceramics17 01 04 gypsum based construction materials17 01 05 asbestos based construction materials17 02 wood, glass and plastic17 02 01 wood17 02 02 glass17 02 03 plastic17 03 asphalt, tar and tarred products17 03 01 asphalt (containing tar)17 03 02 asphalt (not containing tar)17 03 03 tar and tar products17 04 metals (including their alloys)17 04 01 copper, bronze, brass17 04 02 aluminium17 04 03 lead17 04 04 zinc17 04 05 iron and steel17 04 06 tin17 04 07 mixed metals17 04 08 cables17 05 soil and dredging spoil17 05 01 soil and stones17 05 02 dredging spoil17 06 insulation materials17 06 01 insulation materials containing asbestos17 06 02 other insulation materials17 07 mixed construction and demolition waste17 07 01 mixed construction and demolition waste Up to now, no official statistics are available about the arising and composition of waste resulting from the demolition or deconstruction of buildings. Some hints about the composition and amount of demolition waste are given in [53,34]. It can be assumed that demolition waste arising from the demolition of buildings in Germany sums up to 45 Mio. tonnes per year [15]. In order to obtain reliable data about the amount and composition of demolition waste resulting (only) from the demolition or deconstruction of buildings, studies had been carried out studies to determine using a model where existing buildings were first classified by the criterion size, age and building type [50]. Based on detailed bills of materials for the predominant buildings the average composition of demolition waste from buildings can be determined. A validation of this model for the Upper-Rhine Region (Baden (D) - Alsace (F)) shows that the major shares of the components are minerals (cf. Figure 1).
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Plastics0.6 %
Bricks and Stones50.2 %
Wood13.4 %
Steel0.9 %
Concrete25.5 %Metals
0.2 %
Gypsum and Mortar9.2 %
Figure 3.14 Composition of demolition waste from residential buildings
3.6.3. Techniques for the Recovery and the Reuse of Construction and Demolition Waste
3.6.3.1 Separation Techniques for the Building waste The separation of building materials can be achieved by different techniques. The most efficient among them is the selective dismantling of buildings. Due to the fact that every single building element can be separated from the others, the achievable separation of the building materials is extremely high. But on the other hand an extensive dismantling leads to high personnel costs. Depending on the prices for disposal and recycling in the region the building is situated in these personnel costs can be higher than the savings caused by less expansive disposal. More frequently than by selective dismantling different building materials are separated by manual sorting after a demolition. The material separation achieved by manual sorting is not as exact as if the building were dismantled. In many cases sorting takes less time, which makes it cheaper compared to dismantling. That means, that if the requirements regarding the purity of the recycling material are not very strict, sorting is probably preferred. Some building elements such as water pipes and cables, located under the plaster or iron radiators can rather be better sorted afterwards rather than being dismantled, at least from an economic point of view. A further possibility to separate the foreign matter from the genuine mineral building waste is the use of separating devices in recycling plants. The main principles and techniques of separation devices will be explained more closely in the following (cf. [47]). In Germany, most stationary recycling plants possess either an air flow based or a water based separation device, whereby the majority of German recycling plants use air flow based separation devices, although the water based technique provides the better quality [11], [4]. Wet separation techniques use water to separate lighter and heavier materials. In some cases other substances are added to the water to increase the specific weight of the water and to change the point light materials flow up. Some water based separating devices use supplementary water jets or air to support the separation by density differences. Figure 2 gives a general overview of the different kinds of water based separating techniques, which can be differentiated by the four categories: thin film separation, jig separation, up current separation, float and sink separation. Within these four categories several different devices are available.
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density based separation
jig separation
thin film separation
up current separation
float and sink separation
Figure 3.15 Overview of water based separating techniques Air flow based separating devices use the air flow to "blow away" light materials and to isolate the lighter non mineral materials from the heavier material materials. In general the airflow-based techniques are characterised by lower operating costs. But, on the other hand, the resulting material separation is not as exact as under the use of the wet techniques. Figure 3.16 shows the functionality of frequently applied airflow based separating devices. The "reverse air flow sorting technique" and the "cross air flow sorting technique" are the fundamental systems in the field of airflow based separating devices. Cross airflow sorting has the advantage that the materials remain in the device for a much shorter time which increases performance. In addition the geometric form of materials to be separated is much more important than with reverse airflow sorting. As a consequence, modern cross air flow sorting devices use the correlation of geometric form and the quality of material separation to achieve a better sorting [8]. The "exhaust of foreign matter" is a modification of the cross airflow sorting technique. Instead of using a free fall system, the materials to be sorted lie on a vibrating conveyor belt that preseparates the light materials from the mineral fraction. Zig-zag separation devices use the reverse air flow sorting technique which is modified by the zig-zag form of the mechanism. Thus the effectiveness of sorting can be increased, because the zig-zag form has the same effect as a succession of several single cross air flow sorting devices [51].
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foeignmatter
air flow
air filter
airproduct
input
foreignmatter
air filter
air flow
air flow
input
product
foreign matter
air flow
air filter
product
input
air flow
air flow
input
light materials
heavy mateials
Reverse Air Flow Sorting Technique
Zig-Zag Air Flow Sorting Exhaust of Foreign Matter
Cross Air Flow Sorting Technique
Figure 3.16 Main principles of flow based separating techniques [2], [12]
3.6.3.2 Pollutant Sources in Buildings In order to enhance materials recyclability, recycled construction materials from deconstructed buildings should be available in such quality, that they meet the required profile for natural construction materials. It should also be observed that both plain and mixed grades of building waste could contain pollutants which could damage the environment during storage or re-use. These pollutants are contained in construction materials due to their natural material composition, or were artificially added during manufacture, for example in the form of additives. Nevertheless, very few materials in demolition waste are invariably hazardous (as defined in the European Council Directive 91/689/EEC). The major pollutant sources in buildings were identified mainly through studies in building examination laboratories and are presented in Table 3 [37,28]. A great share of pollutants is caused by surface area treatment such as paint. They are added partly for improvement and partly to protect the construction materials.
97
Table 3.11 Potential Pollutant Sources in Buildings
Origin Relevant Pollutants Natural stone Heavy metals Gypsum Sulphate, heavy metals Asbestos Asbestos Treated wood Heavy metals, lime, phenol, PCP Plastics Phenol, CHx, organic components Sealant PCB Roofing felt CHx, PAH, phenol Tech. installation PCB, Hg, Cd Soot Heavy metals, PAH Dust Heavy metals Fire PAH, PCDD/PCDF Accidents (use) Includes oil, alkalis, acid
In order to classify pollutants according to their damaging properties, a modelling approach has been developed (cf. [38]). This methodology helps to set up a detailed deconstruction planning with the aim of minimal pollutant remaining in materials arising after deconstruction (cf. below).
3.6.3.3 Recovery and Reuse of Construction Materials In Germany, about 1600 landfills for construction and demolition waste exist. In general, however, according to the requirements set up in the TA Siedlungsabfall (see above), mineral and unsorted construction and demolition waste may not be disposed to landfill. Disposal of other construction and demolition waste is strongly affected by the Recycling and Waste Management Act and by the corresponding ordinances (see above). Additionally, there is a considerable capacity for the treatment of demolition waste. There are about 650 companies operating around 1000 crushers (mobile, semi-mobile and stationary/fixed facilities). Nevertheless, the availability of processing facilities highly depends on the regions. As an example Figure 4 demonstrates the location of recycling facilities for demolition waste in the region of the upper Rhine Valley, covering an area of 16450 km² (Baden (D), Regierungsbezirk Freiburg/Karlsruhe and Alsace (F), Département Du Bas-Rhin/Haut-Rhin) [50,42].
98
N
Département Du Haut-Rhin
RegierungsbezirkKarlsruhe
RegierungsbezirkFreiburg
Département Du Bas-Rhin
Extraction of raw materials Gravel and sand Natural stoneRecycling (mineral building materials) Recycling installation for demolition waste Recycling installation for roofing tiles
Collection and recycling of other building materials Plate glass Metals Used wood and wood waste Plastics Cable, electronic waste
Figure 3.17 Extraction of raw materials and recycling in the Upper Rhine Valley [42] Recovery and direct re-use can be supported by waste exchanges that have been established both, on national and regional levels. Furthermore, specialised operators dealing with used construction materials have established several outlets.
3.6.3.4 Deconstruction as a Method for Increasing Materials Recyclability Although sophisticated recycling facilities for demolition waste are already available in several Europen countries, recycling becomes problematic when mixed materials or materials containing pollutants are introduced in recycling facilities. In order to examine the influence of the processing techniques on the environmental compatibility of the components of recycling material, unsorted material from the demolition of
99
similar buildings was processed and characterised (for details see [37,28,49,21]). This was carried out in two recycling plants of different configuration, one mobile and one stationary facility. Mobile facilities are set-up on larger demolition sites, so that the demolition waste can be processed on site. The advantage of processing building waste in a stationary facility is that this process type, due to its' complex configuration, makes it possible to produce high quality recycling material. Pollutant balances show that the coarse fraction have a low pollutant content (see Figure 3.18). Most of the pollutants were to be found in the finer fractions, so that through the removal of these fractions the total pollutant content can be significantly reduced (e. g. up to 51% of polycyclic aromatic hydrocarbons (PAH) and 79% of the lead content.
Lead
79 %0 - 8 mm
21 %8 - 100 mm
M. F. S. F.
19 %0 - 4 mm
31 %4 - 25 mm
23 %0 - 45 mm
27 %45 - x mm
Hydrocarbons
43 %0 - 8 mm
57 %8 - 100 mm
27 %0 - 4 mm
40 %4 - 25 mm
27 %0 - 45 mm
6 %45 - x mm
M. F. S. F.
Zinc
21 %0 - 4 mm
29 %4 - 25 mm
37 %0 - 45 mm
13 %45 - x mm
74 %0 - 8 mm
26 %8 - 100 mm
M. F. S. F.
PAH
51 %0 - 4 mm
27 %4 - 25 mm
22 %0 - 45 mm1 %
45 - x mm
S. F.
43 %0 - 8 mm
57 %8 - 100 mm
M. F.
M.F. = Mobile Facility S.F. = Stationary Facility Figure 3.18 Distribution of Pollutants in Processing Facilities The examinations demonstrated in the previous show the borders of the pollutant removal through the existing process technical operations. Therefore, the aim of this section is to show the influences of the composition of the demolition waste on the quality of recycled components, with regard to environmental compatibility. Different compositions can be achieved through the division of the material before processing, for instance through a pre-sorting in a sorter facility, or even through the separation of the demolition waste by application of adequate deconstruction methods on-site. By the use of appropriate deconstruction techniques construction elements containing pollutants can be dismantled and the quality of the remaining materials can be improved. Figure 6 illustrates the influence of the deconstruction, respectively the demolition method on the environmental compatibility of processed recycling materials.
100
electrical conductivity
0
500
1000
1500
2000
Demolition Dismantling
µS/cm
DOC
012345
Demolition Dismantling
mg/l
Chloride
0 2 4 6 8
10 12
Demolition Dismantling
mg/l
Sulphate
0200400600800
1000
Demolition Dismantling
mg/l
Figure 3.19 Eluate analysis of demolition waste (Fraction 0 - 8 mm) resulting from demolition and dismantling
It could be shown for instance that only by the separation of chimneys, or more specifically their inner walls from the rest of the demolition waste, the pollutant content could be significantly reduced. Dismantling or separation techniques for the removal of chimneys must be found so that the occurring masses of the deposited chimneys are not excessive. Options here include the use of a milling cutter or sandblaster to wash the chimney or the surface construction of the inner walls of the chimney.
3.6.4. Economics of Deconstruction and Marketing of used Building Materials
3.6.4.1 Deconstruction Assessment Tools The aim of efficient deconstruction is to reduce the whole duration for dismantling on the site to lower the costs, to improve the working conditions, and to assure the required quality of the materials. In order to optimise deconstruction, a methodology for the deconstruction and recycling management for buildings has been developed, which is explained in the following. To facilitate the task described, a sophisticated computer aided dismantling and recycling planning system is used [40,41,42]. The methodology for optimisation is based on resource-constrained project scheduling, described in detail in [42,43,44]. The structure of this system is illustrated in Figure 7.
101
results
Material Flow Management
optimisation-
algorithm
constraints
objective function
Scheduling and Optimisation
dismantling-
planning
recycling-
planning
results
dismantling order
resource requirements
recycling options
data-bases
...
...
bill of materialscomposition ofconstruction materialsquantity of harmfulmaterials
...
recycling techniquesquality of recyclingproducts
ressources > human resources > machinery > space on construction site ...durationcostsrecycling paths...
...
capacity of ressources
project makespan
audit of
buildings
costs for dismantling and recycling
resource profiles
start and finish times for dismantlingactivitiesdismantling techniques
durations
material flows
generation of different
scenarios/modes
data and information flow sys_CIB_uk.ds4
environmentalassessment
recycling quotasresource allocation
Figure 3.20 Structure of the deconstruction planning system Audit of Buildings An essential step both for deconstruction planning and for the quality assurance of materials that are encountered as a result of demolition is a proper pre-deconstruction survey, also called building audit [45]. Although it is not absolutely certain what will be found when structures are broken open during dismantling of demolition, carrying out such a building audit can reduce much uncertainty. The building audit mainly consists of making a detailed description of the building and identifying materials. Based on the documents of the building (construction plans, descriptions, history) detailed data on the composition of the building has to be collected and analysed. Due to the fact that deconstruction normally affects older buildings, reliable information documenting the current state is rarely available. During this audit indications of substances contained in the building which may influence the quality of the materials needs to be collected and analysed. The audit also provides precise information for further investigation on possible pollutant sources and contamination of the building. The planning system outlined supports the audit by the preparation of bills of materials, which contain details of the materials and the locations of building elements and pollutant sources (cf. Table 4). The content of pollutants can be addressed by a methodology using so-called pollutant vectors for materials and surfaces [38].
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Table 3.12 Bill of materials for a residential building (excerpt) Item no. construction room connected length width area height volume volume quantity no. building density portion coating
element no. room material [m] [m] [m²] [m] [m³] [kg] [kg/m³] [%]
33120 masonry 01010 01001 4.67 2.95 10.6 0.5 5.29 12375 1 1140 sandstone 2500 80 (exterior) 2110 lime mortar 1700 20 33410 door 00070 00001 0.85 2.10 1.79 0.03 0.04 36 1 5100 cast iron 7800 8 (exterior) 6300 spruce 600 92 paint 33411 door-frame 00070 00001 6.00 0.35 2.1 0.02 0.04 20 1 5100 cast iron 7800 2 6300 spruce 600 98 paint 33430 window 01090 01002 0.60 1.22 0.73 0.05 0.04 83 2 4100 sheet glas 2500 80 5100 cast iron 7800 2 6300 spruce 600 18 paint 33440 window-ledge 01080 01002 2.20 0.20 0.44 0.15 0.07 165 1 1140 sandstone 2500 100 33450 window-frame 01090 01002 3.60 0.20 0.72 0.2 0.14 360 1 1140 sandstone 2500 100 paint 33510 plaster (exterior) 02080 02002 2.89 3.20 5.45 0.02 0.11 185 1 2110 lime mortar 1700 100 paint 34120 masonry 02020 02090 4.90 3.20 15.7 0.08 1.18 1682 0.5 3300 solid brick 1400 90 (interior) 2110 lime mortar 1700 10 02090 02020 4.90 3.20 15.7 0.08 1.18 1682 0.5 3300 solid brick 1400 90 2110 lime mortar 1700 10 total: 0.15 2.36 3364 1 34410 door 00140 00150 0.86 1.98 1.70 0.01 0.017 16 0.5 5100 cast iron 7800 5 (interior) 6300 spruce 600 95 paint 00150 00140 0.86 1.98 1.70 0.01 0.017 16 0.5 5100 cast iron 7800 5 6300 spruce 600 95 paint total: 0.02 0.034 33 1 34510 plaster (interior) 01010 01020 3.60 2.65 7.86 0.02 0.16 189 1 2210 gypsum mortar 1200 100 adhesive35110 ceiling 00010 11.14 2.86 31.9 0.15 4.78 6834 1 2110 lime mortar 1700 10 3300 solid brick 1400 90 35112 ceiling filling 02050 4.97 3.71 18.4 0.22 4.06 1988 1 1530 expanded clay 600 35 material 1610 slag 700 30 paint 6830 thatch 200 35 35210 floor covering 03100 3.60 1.20 4.32 0 0.02 26 1 7100 plastic 1500 100 adhesive36300 roof covering 03010 0.40 0.25 0.1 0.02 0.002 3 280 3600 roofing tile 1700 100 36370 downspout 9.00 0.20 1.8 0.01 0.01 15 2 5600 zinc 7200 100 41242 W.C. 01060 21 1 3900 porcelain 1100 100
Dismantling Planning With the available information about the composition of the building combined with the information about the regional framework for waste management, the planning of the dismantling work can be carried out. On the basis of the bill of materials, appropriate dismantling techniques are selected and aggregated to dismantling activities. Information about dismantling techniques and corresponding costs can be found in [42,9]. The configuration of the dismantling activities comprises the determination of the corresponding construction elements (found in the bill of materials) and the selection of the resources necessary. Since the aim of the dismantling planning can be dismantling with minimal costs, dismantling with the aim of preserving building elements intact for later re-use, or dismantling due to technical restrictions etc., the determination of dismantling activities may vary considerably. The computer-supported configuration of a dismantling activity is illustrated in Figure 8 [36]. For the temporal planning of the dismantling work reference numbers, stored in a database, can be chosen for each construction element depending on the dismantling techniques available (cf. Figure 3.?).
103
eng-dgko ds4 / Ver1 0e Figure 3.21 Configuration of dismantling activities [42]
Figure 3.22 Computer aided dismantling planning [42] The dismantling order respecting technological relations as well as security aspects and environmental requirements (like the decontamination of buildings) can be illustrated in so called dismantling networks. Figure 10 gives an example of a dismantling network for a residential building [38].
104
exterior equipment2 2 h
plumbing work 3 4 h
project start
0 0 h
reusable components1 14 h
doors, windows,shutters4 15 h
electricalinstallations7 46 h
sanitaryinstallations8 17 h
joinery
9 77 h
roof covering
5 14 h
roof frame
10 43 h
covering of the ceilings11 89 h
floor covering(mineral)13 25 h
floor covering(plastic)14 26 h
chimneys
15 14 h
walls
18 445 h
stairs
16 104 h
heatinginstallations6 8 h floor covering
(wood)12 36 h
ceilings 17 116 h
project end
19 0 h
Figure 3.23 Dismantling-network for a residential building After determining the dismantling activities and precedence relations the target of dismantling planning is to find feasible or “optimal“ working schedules. If resources (machines, workers, space on the construction site, budget) are limited this problem becomes extremely complex. Recycling and Reuse Planning The objective of recycling planning is the design of optimal recycling techniques for processing dismantled materials and building components into reusable materials. Depending on the stage of dismantling, the feed can be either a single material or a mix of all building materials. For certain individual materials such as metals, glass, and minerals or plastics, recycling techniques already exist. In this case, recycling planning is a simple co-ordination. Recycling is difficult, when materials are mixed, when composite materials occur or when pollutants like hydrocarbons or asbestos are present. In order to obtain materials in an optimal composition for recycling facilities, the available recycling techniques as well as the location of processing facilities (see above) have to be considered during dismantling planning. Case studies have shown that direct re-use of elements can be a promising alternative if dismantling is planned well (cf. [39,30,20,18]).
3.6.4.2 Optimization of Deconstruction Works The projects carried out in practice and analysed so far have shown a potential for further improvements concerning cost reduction as well as environmental benefits. Based on these results, a computer simulation helps to reveal improvement potentials for deconstruction. In order to show some possible improvements, various simulations and optimisations using the planning tool described above were carried out. Due to this high complexity of the dismantling and recycling planning a sophisticated mathematical optimisation model is used as decision support. The model takes into account the interrelations between material flow management (concerning dismantling and recycling) and project management. The consideration of both, material as well as monetary flows during the various planning stages, enables the elaboration of time and cost efficient as well as environmental friendly deconstruction strategies. In order to evaluate optimal schedules for dismantling different scenarios might be applied, for instance: - Dismantling of buildings using the possibilities of parallel work as much as possible, - dismantling using mainly manual techniques,
105
- dismantling using partly automated devices, and a - dismantling strategy strictly focused on “optimal” recycling possibilities according to the
material flow analysis. Computational results for different deconstruction strategies for a building show considerable economic improvement compared with a deconstruction project in practice. As illustrated in Figure 3.? construction site management can be drastically improved. Optimised dismantling schedules, based on the same framework as in practice, show cost savings up to 50 %. In some cases the dismantling time can be reduced by a factor 2 applying partly automated devices. Furthermore, a recycling rate of more than 97 % can be realised [38,42].
218221
Scenario 1
408
165 185
0
10000
20000
30000
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50000
600001400
1200
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800
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]
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Recycling/disposal
Duration [Man hours]
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22252
22125
11593
23296 18151 20100
6814
54259841
16913
16910 6734
Figure 3.24 Cost and duration of different dismantling strategies for a residential building Based on selected deconstruction strategies the detailed planning and optimisation of deconstruction work can be done. Figure 3.? shows the results of minimising the duration of deconstruction. The complete schedules for two different dismantling scenarios (partly automated and material oriented) and the corresponding project costs show that an environmental oriented dismantling strategy imposes a higher effort to the dismantling work. That is, more jobs have to be carried out in order to avoid a mix of hazardous and non-hazardous materials. Nevertheless, environmental oriented dismantling strategies will not necessarily be disadvantageous from an economic point of view if disposal fees are graded according to the degree of mixed materials.
106
18
11
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010 20 30 40 50 60 70 80 90
18
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sche
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d ex
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stra
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costs
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and
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)
cost
s of d
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and
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l flo
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(s
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g re
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costs
, cum
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cost
s of d
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and
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l flo
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stra
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(cum
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Dismantling activities Cost for dismantling and recycling (cumulated) [DM *10³]
2
56
34
16
8
26
3
34
11
6
19
6
20
6
18
6
14
21
26
3
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9
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11
exte
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quip
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t
elec
trica
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latio
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nd d
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es
sani
tary
insta
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nd d
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fillin
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nd w
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plum
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roof
cove
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(pla
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)
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)
floor
cov
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wal
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stai
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plas
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chim
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dura
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[h]
abla
u_uk
.ds4
wal
ls 1
st fl
(cl: cellar; gf: ground floor; fl: floor)
Figure 3.25 Schedule and project costs for the dismantling of a domestic building
3.6.5. End-of-Life Management: case studies
In recent years, several case studies about deconstruction and End-of-Life Management have been carried out. Reports of case studies in Germany and France can be found in
107
[39,30,20,18,29,31,24,25,26,27,28,24,6,19,3,1,13,9,17,35,34]. Nevertheless, only few studies are well documented. An overview about different deconstruction studies can be found in [42,32]. A comparison between these studies is impeded not only because of the heterogeneity of the documentation, but also because of the scope of the projects and the different conditions. In fact, the same aspects in the studies are not addressed in the same way (e.g. costs, recycling rates etc.). As a consequence, results have to be compared with great care. Bearing in mind these obstacles Table 3.13 shows a coarse comparison between some of the case studies indicated above. Table 3.13 Comparison between different case studies [42]
Rec
yclin
g ra
te
94 %
> 96
%
94 %
74 %
> 90
%
n.a.
95 %
98.5
%
n.a.
97 -
98 %
98 %
98 %
Cos
ts
11.8
EU
R /
m3
n.a.
13.5
EU
R /
m3
27.1
EU
R /
m3
n.a.
n.a.
13.3
EU
R /
m3
9.7
EU
R /
m3
n.a.
n.a.
1.5
EUR
/ m
³
15.1
EU
R /
m³
Dis
man
tling
Ti
me,
Pro
ject
du
ratio
n [w
eeks
]
n.a.
n.a. 6 11 n.a. 13 11 6 n.a. 22 4 18
Volu
me
2630
00 m
3
2100
00 m
3
4950
m3
5800
0 m
3
684
m3
1831
00 m
3
4200
m3
2208
6 m
3
1100
0 m
3
n.a.
1325
0 m
3
5000
0 m
³
Con
stru
ctio
n
Mas
onry
Con
cret
e an
d M
ason
ry
Tim
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ram
e
Con
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e
Con
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e
Mas
onry
Mas
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Mas
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, St
eelfr
ame
Mas
onry
Mas
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Mas
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Mas
onry
Type
of b
uild
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Foun
dry
Brew
ery
Res
iden
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Indu
stria
l
Res
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Indu
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l Bui
ldin
g
Res
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Indu
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l Bui
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Indu
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l Bui
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l Bui
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Ye
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D, 1
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ect
1 2 3 4 5 6 7 8 9 10 11 12
D: G
erm
any;
F: F
ranc
e
Case studies using the same approach concerning cost allocation, recycling rates etc. could be compared quite well. For the evaluation of different dismantling techniques and the determination of the resulting dismantling times and costs, the French-German Institute for Environmental Research launched several projects in Germany and France. During the first project in Germany that was well documented [29,31], a timber framed building located in the black forest was completely dismantled and more than 94 % of all the materials could be recycled (cf. Figure 13).
108
Figure 3.26 Dismantling of the Hotel Post in Dobel [29] In order to compare deconstruction with demolition, the deconstruction carried out in practice has been analysed and compared with the alternative of demolition. While in this project demolition was calculated using simulation with the computer tool described above, another project was especially focused on the comparison between deconstruction and dismantling in reality [30,24,33]. The buildings located in Mulhouse (F) were divided into two parts, of which one part was demolished (using a backhoe) and the other one was dismantled (cf. Figure 3.27). The location of the building near to the Swiss and German border also allowed the analysis of the possibilities of recycling of materials on an international level.
conventional demolitionselective dismantling
allev-uk.ds4 Figure 3.27 Dismantled and demolished buildings in Mulhouse
During these projects detailed data on the composition of the dismantled buildings, the duration of the dismantling, and demolition activities, the associated dismantling costs, and on the recycling options were collected and analysed. Results show that dismantling can already be an economical solution, depending on the type of the building, the recycling options available, and the prices charged for mixed and sorted demolition materials. As Figure 15 shows, the costs for deconstruction were in some cases lower than those of demolition (data based on [42,24,26,27]). Due to different types of buildings, different disposal fees, and different transportation distances, costs for dismantling and recycling show tremendous variations.
109
Figure 3.28 Comparison of selective dismantling and demolition
REFERENCES
1 Andrä, H. P.; Schneider, P. Recycling am Bau. In Deutsche Bauzeitung, (11), 1994, pp. 144-151. 2 Bilitewski, B. ; Gewiese, A. ; Härdtle, G.; Marek, K.: Vermeidung und Verwertung von Reststoffen in der Bauwirtschaft. 3. Auflage Berlin : Erich Schmidt Verlag,. In Beiheft zu Müll und Abfall, Berlin, 1995. 3 Bilitewski, B.; Wagner, S.; Klupak, M.; Ibold, H.; van der Meer, S. Kontrollierter Teilrückbau eines Industriekomplexes in Dresden-Klotzsche. Final Report to the Sächsische Staatsministerium für Umwelt und Landesentwicklung, 1994. 4 Buntenbach, S. ; Petit, E.: Nassmechanische Aufbereitung von Bauschutt. In Aufbereitungs-Technik (38) 1997 Nr. 3, pp. 130/138. 5 Buttenwieser, I.: Les déchets de démolition et de construction. Cahier du CSTB, Confort - santé – environnement, livraison 352, September 1994. 6 Construction and Demolition Waste Management Practices and their Economic Impact. Report of the Project Group to the European Commission, DGXI, Symonds, ARGUS, COWI and PRC Bouwcentrum, February 1999. 7 Construction and Demolition Waste Project in the framework of the Priority Waste Streams Programme of the European Commission. Report of the Project Group to the European Commission, Part 1 – Information Document, Symonds Travers Morgan, ARGUS, August 1995. 8 Deutscher Ausschuss für Stahlbeton. Heft 462, Umweltgerechter Rückbau und Wiederverwertung mineralischer Baustoffe, Beuth Verlag, Berlin, 1996.
Location use of building type of building
-5
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40
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50
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ts [E
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³]
recycling / disposal / transport dismantling or demolition
selective dismantling
selectivedismantling
conventional demolition
Dobel (D) hotel
timber framed building Mulhouse (F)
dwelling -housemasonry building
selectivedismantling
conventionaldemolition
Strasbourg (F)industrial buildingmasonry building
selective dismantling
conventionaldemolition
Rottweil (D)school building
masonry building
vgl-dbmhstrw
13.5 16.7
13.3
7.9
1.5
3.5
15.1
44.4
conventionaldemolition
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9 Eldracher, A. Gebäuderückbau, Diploma Thesis, Karlsruhe, 1995. 10 Gallenkämper, B. Verstärkte Erschliessung des Verwertungspotentials von Baustellenabfällen durch organisatorische und technische Massnahmen. Report to the Federal Environmental Agency (Umweltbundesamt), 1997. 11 Hanisch, J. Aktueller Stand der Bauabfallsortierung, in: Aufbereitungs-Technik (39) 1998 Nr. 10, pp. 485/492. 12 Kaiser, F. Der Zickzack-Sichter – ein Windsichter nach neuem Prinzip. In Chemie-Ing.-Technik (35) 1993 Nr. 4, pp. 273/282. 13 Klose, B. Selektiver Rückbau. In Baustoff-Recycling und Deponietechnik, (2) 1996, pp. 12-15. 14 Kolb, W.; Rohou, P. Selektiver Rückbau von Industriebrachen am Beispiel der ehemaligen Halberger Hütte in Ludwigshafen. Abfallwirtschaftsjournal, (6) 1994, pp. 215-219. 15 Kühn, J. Gesetzliche Rahmenbedingungen für die Verwertung von Baureststoffen, Vortrag im Rahmen der Fachtagung „Entwicklungspotentiale bei der Verwertung von Baureststoffen“, Informationsbüro Kreislaufwirtschaft, Oberhausen, 22.01.1997. 16 Länderarbeitsgemeinschaft Abfall (LAGA): Zuordnung LAGA-Abfallschlüssel zum Europäischen Abfallartenkatalog und zu den OECD-Codes, Berlin, 1996. 17 Marek, K. A.; Baron, M. Kostenfalle - Rückbau, Teilentkernung oder Abbruch (Teil 1). Baustoff-Recycling und Deponietechnik, (10), 1997, pp. 10-14. 18 Mettke, A. Bausubstanzerhaltung durch Rückbau und Recycling. Ratgeber Abbruch und Recycling, Stein Verlag, Baden-Baden, 1999. 19 Palapys, M. Systematischer Rückbau von Industrie- und Produktionsanlagen. Proceedings 9. Symposiums Recyclingbaustoffe, 1993. 20 Pitzini-Duée, B.; Schultmann, F.; Zundel, T.; Rentz, O. Audit et déconstruction sélective d’un bâtiment: une opération rentable. Annales du Bâtiment et des Travaux Publics (2), avril, 1999, pp. 31-40. 21 Pitzini-Duée, B.; Schultmann, F.; Seemann, A.; Rentz, O. Qualitätssicherung von mineralischen Bauabfällen aus dem Hochbau. In Rasemann, W. (Ed.): Qualitätssicherung von Stoffsystemen im Abfall- und Umweltbereich – Probennahme und Datenanalyse, Trans Tech Publications, Clausthal Zellerfeld, 1999, pp. 177 – 183. 22 RAL Deutsches Institut für Gütesicherung und Kennzeichnung e.V.: Recycling-Baustoffe für den Straßenbau - Gütesicherung RAL-RG 501/1, Sankt Augustin 1999 23 Rentz, O.; Pitzini-Duée, B.; Schultmann, F., Zundel, T. Déconstruction sélective du lycée de Nantua – Audit du bâtiment – Planification du chantier et de la gestion des déchets, Report to the Agence de l’Environnement et de la Maîtrise de l’Energie (ADEME) and the Région Rhône-Alpes, French-German Institute for Environmental Research, Karlsruhe, 1998. 24 Rentz, O.; Ruch, M.; Schultmann, F.; Sindt, V.; Zundel, T.; Charlot-Valdieu, C.; Vimond, E. Déconstruction sélective – Etude scientifique de la déconstruction sélective d’un immeuble à Mulhouse, Societé Alpine de Publications, Grenoble, 1998.
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25 Rentz; O.; Pitzini, B.; Schultmann, F. Audit avant démolition du bâtiment n° 3, Internal Report to Steelcase Strafor (Strasbourg), French-German Institute for Environmental Research, Karlsruhe, 1997 (unpublished). 26 Rentz, O.; Pitzini-Duée, B.; Schultmann, F. Audit et déconstruction sélective d’un bâtiment à ossature métallique, Internal Report, French-German Institute for Environmental Research, Karlsruhe, 1997 (unpublished). 27 Rentz, O.; Schultmann, F.; Seemann, A. Rückbau des staatlichen Aufbaugymnasiums Rottweil - Gebäudeauditierung, Rückbau- und Verwertungsplanung, Internal Report to the State of Baden-Württemberg/Staatliches Vermögens- und Bauamt Rottweil, French-German Institute for Environmental Research, Karlsruhe, 1998 (unpublished). 28 Rentz, O.; Schultmann, F.; Ruch, M.; Sindt, V. Demontage und Recycling von Gebäuden – Entwicklung von Demontage- und Verwertungskonzepten unter besonderer Berücksichtigung der Umweltverträglichkeit, Ecomed Verlag, Landsberg, 1997. 29 Rentz, O.; Ruch, M.; Nicolai, M.; Spengler, Th.; Schultmann, F. Selektiver Rückbau und Recycling von Gebäuden dargestellt am Beispiel des Hotel Post in Dobel, Ecomed Verlag, Landsberg, 1994. 30 Rentz, O.; Ruch, M.; Schultmann, F.; Sindt, V.; Zundel, T.; Charlot-Valdieu, C.; Vimond, E. Selektiver Gebäuderückbau und konventioneller Abbruch - Technisch-wirtschaftliche Analyse eines Pilotprojektes, Ecomed Verlag, Landsberg, 1998. 31 Ruch, M; Schultmann, F.; Rentz, O. A case study of integrated dismantling and recycling planning for residential buildings. Proceedings of the First International Conference on Buildings and the Environment, Watford, UK, 16-20 May 1994, paper 10, pp. 1-8. 32 Ruch, M.; Schultmann, F.; Sindt, V.; Rentz, O. Selective Dismantling of Buildings: State of the Art and New Developments in Europe. Proceedings of the Second International Conference on Buildings and the Environment, Paris, France, 9-12 June 1997, Vol. 1, pp. 433 – 440. 33 Ruch, M.; Schultmann, F.; Sindt, V.; Rentz, O. Integrated Approach for the Reduction of the Environmental Impact of Demolition and Recycling of Buildings. Proceedings of the R’97 International Congress Recovery, Recycling, Re-integration, Geneva, Switzerland, 4-7 February 1997, Vol. 2, pp. 193-198. 34 Roos, H.-J.; Walker, I. Aufkommen, Zusammensetzung und Stand der Entsorgung von Bauabfällen in der Bundesrepublik Deutschland. Bauabfallentsorgung, von der Deponierung zur Verwertung und Vermarktung, Tagungsband des 8. Aachener Kolloquiums Abfallwirtschaft, RWTH Aachen, 1995. 35 Schrader, M. (Ed.) Bergung historischer Baumaterialien zur Wiederverwendung - Das Tabaklager Herbolzheim, Selektiver Rückbau an Stelle von konventionellem Abriß, Suderburg, 1996. 36 Schultmann, F.; Ruch, M.; Sindt, V.; Rentz, O. Computer aided dismantling and recycling planning of buildings using project scheduling models. Proceedings of the 1996 WOBO Fourth World Congress Built Environment at the Crossroads - Towards a Sustainable Future, Hong Kong, 2-8 November 1996, 10 p. 37 Schultmann, F.; Sindt, V.; Ruch, M.; Rentz, O. Strategies for the Quality Improvement of Recycling Materials., Proceedings of the Second International Conference on Buildings and the Environment, Paris, France, 9-12 June 1997, Vol. 1, pp. 611–618.
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38 Schultmann, F.; Rentz, O. Material flow based deconstruction and recycling management for buildings. Proceedings of the R’99 International Congress Recovery, Recycling, Re-integration, Geneva, Switzerland, 2-5 February 1999, Vol. 1, pp. 253-258. 39 Schultmann, F.; Ruch, M.; Spengler, T.; Rentz, O. Recycling and Reuse of Demolition Waste - A Case Study of an Integrated Assessment for Residential Buildings. Proceedings of the R’95 International Congress Recovery, Recycling, Re-integration, Geneva, Switzerland, 1.-3 February 1995, Vol. 1, pp. 358-363. 40 Schultmann, F.; Rentz, O. Development of a Software Tool for the Optimal Dismantling and Recycling of Buildings. Proceedings of the Symposium Computers in the Practice of Building and Civil Engineering, Lahti, Finland, 3-5 September 1997, pp. 64-68. 41 Schultmann, F.; Pitzini-Duée, B.; Zundel, T.; Rentz, O. Développement d’un logiciel d’audit de bâtiment avant démolition. Annales du Bâtiment et des Travaux Publics (2), avril, 1998, pp. 41-50. 42 Schultmann, F. Kreislaufführung von Baustoffen – Stoffflußbasiertes Projektmanagement für die operative Demontage- und Recyclingplanung von Gebäuden, Erich Schmidt Verlag, Berlin, 1998. 43 Schultmann, F.; Rentz, O. Scheduling of deconstruction projects under resource constraints. In Construction Management and Economics 20 (2002) 5, pp. 391-401. 44 Schultmann, F.; Rentz, O. Environment-oriented project scheduling for the dismantling of buildings. In OR Spektrum 23 (2001) 1, pp. 51-78. 45 Schultmann, F.; Rentz, O. Stoffstrommanagement für Baureststoffe aus dem Hochbau - Methodische Planung der Auditierung des selektiven Rückbaus und des Recyclings von Gebäuden. In Müll und Abfall 31 (1999) 4, pp. 206-217. 46 Schultmann, F.; Seemann, A.; Garbe, E.; Rentz, O. Methodologies and Guidelines for Deconstruction in Germany and France. In: Chini, A. R. (Ed.): Deconstruction and Materials Reuse: Technology, Economic and Policy, CIB Report, Publication 266, Rotterdam, 2001, pp. 27-41. 47 Seemann, A.; Schultmann, F.; Rentz, O.: Cost-effective deconstruction by a combination of dismantling, sorting and recycling processes. In: Chini, A. R.; Schultmann, F. (Eds.): Design for Deconstruction and Material Reuse, CIB Report, Publication 272, Rotterdam, 2002, 12 p. 48 Silbe, K.; Schubert, E. Wirtschaftlichkeit kontrollierter Rückbauarbeiten. Ratgeber Abbruch und Recycling, Stein Verlag, Baden-Baden, 1999, pp. 64-68. 49 Sindt, V.; Ruch, M.; Schultmann, F.; Rentz, O. Gestion de la qualité des déchets de démolition. In Cases, J. M.; Thomas, F. (Eds.) Proceedings of the International Congress on Waste Solidifiaction-Stabilisation Processes, Nancy, France, 28 November – 1 December 1995, pp. 407–411. 50 Spengler, T.; Ruch, M.; Schultmann, F.; Rentz, O. Stand und Perspektiven des Bauschuttrecyclings im Oberrheingraben (Baden-Elsaß), Konzeption integrierter Demontage- und Recyclingstrategien für Wohngebäude. In Müll und Abfall, (2), 1995, pp. 97–109. 51 Tomas, J. Aufschließen und Abtrennen von Wertstoffen aus Bauschutt, Teil 2: Sortierung aufgeschlossener und teilgeschlossener Bruchstücke. In Entsorgungs-Praxis 12/99, pp. 16-20. 52 Verordnung zur Einführung des Europäischen Abfallartenkataloges (EAK-Verordnung - EAKV), vom 13. September 1996, Bundesgestzblatt. I S. 1428-1446.
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53 Walker, I.; Roos, H. J. Im Aufbruch - Bei der Bauabfallverwertung und der Vermarktung besteht Handlungsbedarf. In Müllmagazin, (3) 1996, pp 40-45.
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4. Development of building concepts
4.1 Some principles for increasing the productivity and life cycle quality
4.1.1 Systematisation In order to accelerate development of international industrialised building technology, the research should be directed into further systematisation of performance concepts and of the modularised system rules in product systems, organisation system and information system. The systematics shall be presented as model designs, alternative organisational models and applied product data models. The productivity factors are important to be identified and analysed. The results can then be used in development of methods for improving productivity. 4.1.2 Simplicity In product development of buildings we have to focus on the most expensive parts: Surfaces and building service systems. But we have to keep in mind, that drastical changes in surface technology and building service systems can be done only changing also structural system. The product changes are serving also premise for productinal development. Leading principle in the product development of a building must be simplicity: for example building service systems can be drastically simplified in low energy buildings, combining ventilating and heat distribution systems. 4.1.3 Openness Today the industrialization of building means the application of modern systematized methods of design, production planning and control as well as mechanized and automated manufacturing processes (Sarja, 1987). The required openness refers to the capability to assemble products from alternative suppliers into the building and to exchange information between partners of the building process and inside the consortia and business networks. The application and exchange of products, services and information nationally and internationally and the adaptation of the products and services into varying local needs and cultures is essential. For this purpose an effective international cooperation is needed in order to develop proposals for definitions, rules and models for this kind of regional and local open building, utilising global technologies and methods into local applications. The overall system is aimed at forming an entire building from interacting items. The system thus can be defined as an organised whole consisting of its parts, in which the relations between the parts are defined by rules. The system can be a product system, an organisational system or an information system. In the open industrialised building product system, organisational system and information system are bound together. The central scope of open industrialisation includes the following areas:
- Demand -Side, dealing with user requirements and with the introduction of the requirements into designs.
- Supply- Side, dealing with the production requirements and and with the linking of demand and supply.
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- Building process organisation and communication in building projects Open system building is a global framework for the building industry, including modular systematics of products, organisation and information, dimensional co-ordination, tolerance system, performance based product specifications, product data models etc., so that the suppliers serve products and service modules that will fit together. Openness is a concept with many aspects, like:
- OPEN for competition between suppliers - OPEN for alternative assemblies - OPEN for future changes - OPEN for information exchange - OPEN for integration of modules and subsystems.
In advanced building systems we can apply so called modular systematics of open building. Modulation involves division of the whole into sub-entities, which to a significant extent are compatible and independent. The compatibility makes it possible to use interchangeable products and designs that can be joined together according to connection rules to form a functional whole of the building. Typical modules are: Bearing frame, facades, roofing system, partition walls and building service systems. The industrialised building technology is developing globally and internationally, but applications into building concepts and designs will be made very locally in order to fulfil the local cultural, environmental, operational and economical requirements. Individual buildings have to be adapted into the needs of their owners and users. The industrial production can be either prefabrication in factories or mechanised and automated site production, or a combination of them both. General industrial principles and methods can be applied in building. The open industrialisation can be developed as global technology, which then can be applied regionally and locally on different ways using locally and regionally produced products and materials. The general rules and models can be concretised into building concepts for defined consortia or networks of contractors and suppliers. During this and future decades the information technology will continue to revolutionize the working in building projects. It is important to recognize the potential benefits of computers in all phases of the service life of buildings as well as the barriers in the practical use of computers. In addition, large changes must be considered even to organizations and processes 4.2 Basic principle for achieving competitiveness in life cycle quality
Referring to the discussion above, the following can be claimed:
- Increased competitiveness in building can be achieved with radical reduction of construction costs, and thus gaining margin for investing in sustainability, ecology and total life cycle quality.
It is well known from other branches of production, that effective industrialised production is a key for drastical decrease of production costs together with satisfactory level of quality. The following common indicators of leading to serious past and current difficulties can be found:
1. Closed and non-flexible building systems can be applied only in large building projects, where the high investments can be amortised in one single project. The reason
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is, that the same building concept and design is not able to be applied into different build environments and into different requirements of use. This problem has been reported both from USA and from South Asian countries. In fact this factor was one of the main reasons into the draw-back of industrialised building in European countries at the mass production time period [1].
2. Aesthetically, functionally and technically improper design and manufacture of buildings and products.
3. An improper utilisation of the benefits of industrial production regarding to production costs, speed and quality.
In some industrialised countries the difficulties described above, have been mainly overcome. The factors leading to this kind of success can be identified as follows:
1. Application of open, flexible systematics 2. Effective application of mechanisation and automation in prefabrication 3. Post-industrialised information society Application of different materials and composite
structures, which are concurring with each others. 4. Skilled architects and structural designers, who understand the specialities of
prefabrication and industrialisation. 5. Advanced education of workers. 6. Liberal standardisation, which allows new, non-traditional products. 7. Generally high level of industrialisation and computer application in design,
manufacture and communication in the society. 8. Tradition of networking between companies and organisations. 9. Interest in international export of building products, engineering know-how and
building projects. 10.Mass production due to high need of building.
Future perspectives of the open industrialisation in building are promising, because there exist several driving forces in general development of societies, which are pulling the development into the industrial way. Such kinds of driving forces are e. g. the following:
1. There exist a global need for an increase of productivity in the building sector in order to reduce the production costs in developed countries and in order to increase the production capacity in developing and newly industrialised countries. The statistics show in factories of building products a drastically higher growth of productivity than in site works.
2. The increasing demand of guaranteed quality can be better fulfilled in industrial and automated production both in developed and in developing countries.
3. The increasing goal towards sustainable development in building can in industrialised countries better be solved with industrial production, where energy and materials can be saved and wastes can be recycled better than in manual production on site. However, in least industrialised countries an alternative solution can be a very local production in manual methods using local natural materials.
4. In industrialised countries the skillness in manual works has generally disappeared and this development still continues. Without modern methods and industrial ways of production it will be impossible to get skilled workers in building sector.
5. In industrialised countries the workers are not eager to work on often strong and unsafe site conditions. This is already now leading into lack of workers at the same time when high rate of unemployment exists.
There exist a global need for an increase of productivity in the building sector in order to reduce the production costs. Several existing experiences show, that a rapid increase in productivity can be reached through industrialisation of the building process through increased prefabrication.. As an example, in the
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last 20 years, the productivity, including the labour and capital productivity, in Finland has grown by 40 % in building products industry and only 10 % in the site works (Figs. 4.? and 4.?). Labour productivity has doubled in the products industry, while also improving by a third on site. The productivity of capital has thus somewhat decreased especially on sites, because of the recession in building production.
Electrical products
Printing andpublishing
Manufacturingindustry
Buildingconstruction
Buildingmaterials
and products
1975 1980 1985 199040
80100120
160
200
240 Index 1975=100
Source: Statistics Finland 1997
40
80100120
160
200
240
Figure 4.1 Productivity increase in some industrial branches in Finland during 20 years /6/. The development of the productivity reflects the increase of industrialisation in building, which has caused an increase in the share of prefabrication and decreased the share of site works (Fig. 4.2). Through the industrialisation, the quite good development of productivity in building products industry has been utilised for benefit of total productivity.
1960 1970 1980 1990 2000
20
40
60
80
100%
SITE
M ATERIALS
SERVICES
Prefabricated com ponentsM ateria lEquipm ent
1997 Figure 4.2 Distribution of building costs in Finland /6/. The increased productivity has reflected mainly into costs of the structures, which are owing a rapidly decreasing share of total costs of buildings (Fig. 4.3). The costs of building services and finishing are increasing especially in office and commercial buildings due to the increasing number of equipment and quality of products. However, in 1990`s, during 1990-1996, the building costs have increased totally
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only five percent, which is clearly less than the inflation and less than the increase in living costs. In housing the share of building services is less, about 20 %, and the share of structures still is dominating in costs.
1997
1960 1980 20000
100
50
%
0
100
50
%
Service systems
Structures
Surfaces%
Figure 4.3 Distribution of building costs in Finland between different parts of the building /6/. 4.3 Tools for productivity development
4.3.1 Integrated information
The modern information system is based on the rapid communication network between the partners of the building projects. All communication is increasingly integrated into the computers thus integrating the design and production planning and control into the communication between partners and general databases (Fig. 4.4). This helps to avoid the difficulty caused by long distances. Internet is helping in international communication thus increasing the efficiency of application of internationally most advanced technology and knowledge. Corporate and project information systems may provide a more integrated and immediate view of all aspects of a project all partners of construction project. Computer aided communication will have a significant impact upon building processes in the future. New technologies in telepresence and virtual reality can lead to new working methods.
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Figure 4.4 A scheme of computer integrated construction. On the way towards real computer-integrated construction (CIC), we have to solve several problems which are typical of building production. These problems arise from the complex organisational structure of the building design and construction with its very many partners and external connections with the market and society. In order to guarantee a fluent information flow between the partners of the building process, open systematisation of the data structure and data transfer is needed. In computer-integrated construction (CIC), the whole information process controlling the material process is produced and exchanged between partners and stored in digital form with the aid of computers. The design database is built by designers during the design process. The database is based on an object-oriented product data model of the building. In the final stage it includes all the information needed to construct and maintain the building. The system defines the hierarchical classification of the object, as well as their attributes and mutual relationships. The partners in the building process, namely the owner, the design partners, the controllers and the manufacturers, can get their basic information from the design database. Utilising their own computer-aided information-processing systems, all partners modify and add information, thus producing final information for the execution and control of the building process as well as for the operation and maintenance of the building. The designers employed by the manufacturer work in very close co-operation with the manufacturer, which is either a factory or a contractor. The product planning in the production unit makes possible the effective production of the building components. Through the open system, interactive data transfer between designers and manufacturers is possible. In the advanced building technology of the future, the design data will even be transferred directly in digital form into numerically controlled automated machines and robots. In the manufacture of some components like windows, doors and some structural elements, automated numerically controlled machines are already in use. 4.3.2 Site automation
Beside the industrialisation through increased prefabrication, there exists also another possibility, which has been developed especially in Japan /10/. That is the high mechanisation and automation of the site processes. The goal is to create a “field factory”. This concept can be either a combination of prefabrication with automated assembly on site, or an automated site manufacturing process, or a combination of both of them. As an existing model for this concept are the shipbuilding yards. There exist some prototype sites already in Japan. In a smaller scale, there are site robots for spraying of
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paintings and for block assembly on sites under development in the prototyping phase also in Israel /11/. It is probable, that the site automation will be increasingly applied, first on large building sites and later even on smaller sites. The applications will first be prototypes, but a wider application can be estimated in a time period of 10 to 15 years. Most common development of site automation will be continued in small steps through increasing automation and computer control of site machinery and equipment. Examples of such developments already exist e. g. in cranes, in shotcreting machines, in drilling machines, components assembly manipulators e. t. c.. 4.3.3 Networking
The networking is a central principle in the modern production infrastructure, where a network of contractor and specialised suppliers can be effectively utilised. The network typically includes continuous development of the products, manufacturing, production and design as co-operational projects between the partners. The increase in the use of specialised suppliers in building will increase the role of suppliers at the development and at the execution of building projects. In the network different issues and phases of the design and manufacture can be integrated into general technical development and evolution of the building production applying best local resources combined with international knowledge and technology. The computer aided design, manufacture, project management and communication is supporting the networking. Internet is helping in international communication thus increasing the efficiency of application of internationally most advanced technology and knowledge. The suppliers are increasingly combining services, like design and assembly works, into their deliveries. Some suppliers are specialising in technology and know how deliveries.
Subproductof thebuilding
Parallel production
a) b) c)
a) Productionplanning
b) Production
c) Assembly andfinishing
1
2
3..
n
Time t
Productionphase
Sequential production
1
2
3..
n
Time t Figure 4.5 Rapid parallel construction through networking between the contractor and suppliers. The roles of partners in the networking is developed towards a specialisation and increased skills. The contractors are increasingly focusing the skills and the development into management of building projects while the suppliers are focusing into their special technologies, products and services. This kind of transition in the infrastructure of companies is identified in last years. It has been recognised, that even during recession time period in construction, the number of small specialised supplier enterprises is rapidly increasing /6, 12/. 4.3.4 Advanced materials and structural engineering
It is important to recognise, that the managerial, organisational and design development alone can not lead the building technology to fulfil the multiple requirements without a strong support of the core techniques: materials and structural engineering. The development of materials and structures shall be done in close interaction with the managerial, organisational and design development. It means, that the materials and structures must be suited for mechanised and automated manufacture and taylored for different requirements. This interaction between different techniques and skills is described in Fig. 4.6.
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The development of materials and structural techniques will happen mainly by specialised suppliers in interaction with the development of the manufacturing technique and applying integrated life cycle design for fulfilment of the multiple requirements of each system. Module or component. The contractors are concentrating into the link between client, building as a final product and project planning and management applying the multiple requirement analysis, optimisation and decision making.
Material technology Structural engineering
1. Planning and control systemof the building project
2. Building system3. Design system4. Production planning and
control system
Machine, equipment andautomation technology
Information technology
Figure 4.6 Basic technologies and their interaction in building. Regarding materials and structures we have to develop new basic knowledge especially on hygrothermal behaviour, durability and service life of materials and structures under varying environments. That knowledge has to be put into practice through standards and practical guides. The creation of new types of materials and structures, in which the properties can be taylored separately for each specific need is of vital importance. Both strong and soft solutions are needed, depending on the specific life cycle requirements in each application. Another challenge for materials engineering is the effective recycling of building and demolition wastes. The construction area is producing about 10% of all wastes in the society. There are already good examples, how these wastes can be reused in construction. As a major consumer of materials, construction can apply many byproducts and recycling materials from industry and general consumption, but new creative innovations and applications are still needed for meeting those targets. 4.4 Building concept development
Building concept development is an effectice way for concretising high life cycle quality in a production of a contracting company, or for the production of an owner. The building concept is aiming to respond to the following basic and generic needs and requirements:
- The new and stronger requirements: lifetime economy, functionality in use and in changes of use, technical lifetime performance, energy efficiency, healthy, safety, ecology and local culture, are serving a challenge for the building technology.
- The pressure towards decreasing the construction costs with the increase of productivity of the work and capital is increased.
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The development process starts with creating alternative building concepts, which allow production of individually designed buildings. These alternatives are then trieted with methodology and methods to optimise the building concepts and individual buildings in relation to the lifetime quality. Building concept is a repeatable and documented way of design and construction, which can result in individual buildings with an optimised and high lifetime quality. Lifetime quality is the capability of a building to fulfil the requirements of the users, owners and society during entire design period of the building. The building concept is usually focused on a number of specific dictating components of classified and optimised lifetime quality (incl. the viewpoints of lifetime functionality, performance, economy, ecology and culture).
The realisation of advanced production (incl. new models of building design and construction, simplification of building systems and products, decrease of the number of parts of buildings, improvement of finishing of the prefabricated components and modules, and improving the interaction and compatibility of structures and building service systems). As a result are presented:
- systematised and classified definitions of performance properties of buildings
- corresponding specifications of building systems, modules and components
- design principles, process descriptions
- examples (incl. routings of technical building services, specification and classification of the health and comfort properties of indoor air, calculations of lifetime economy and ecology, and methodology and methods of lifetime optimisation and decision-making)
As a case is presented a design, economic and ecological optimisation and multiple attribute decision-making of an experimental building.
As examples can be mentioned the Finnish development of the INDUCON- concept [Asko Sarja, Juhani Laine, Sakari Pulakka, Mikko Saari , 2003] and Finnhouse-concept [Asko Sarja, Pekka Leppänen, Juhani Laine, Markku Kiviniemi, Sakari Pulakka, 1994]. One of the selected dictating components of lifetime quality of the INDUCON Concept was the energy efficiency. The four alternative concepts were then ranked in relation to lifetime monetary economy and ecology. The nominal rate of interest was 4 %, the real interest rate being 2 %. The ranking of the concept alternatives both in relation to lifetime economy and in relation to the lifetime ecology, starting from the best one was the following:
1. Minimum energy house ( annual consumption of space heating energy = 25 kWh/living area m2) 2. Low energy house ( annual consumption of space heating energy = 75 kWh/living area m2) 3. Standard house, Finnish energy standard 2003 ( annual consumption of space heating energy = 100
kWh/living area m2)
4. Standard house, Finnish energy standard 1985-2002 ( annual consumption of space heating energy = 150 kWh/living area m2)
The result was this mentioned above, if the design life period was between 15 and 50 years. This result shows, that it is economic, from the viewpoint of lifetime economy in the design period 15 to 50 years to build buildings with much higher energy efficiency than the current standard level. The sensitivity analysis showed that this result is valid until the real interest rate of 4 %. If the real interest is more, the low energy house will be ranked to the first place. 4.5 References to Chapter 4
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1. Sarja, Asko (Editor), Open and industrialised building. Manuscript, accepted for printing by Chapman&Hall, SPON Co, June 1998.150 p.
2. Sarja, Asko, Towards life cycle oriented structural engineering. 3. Sarja, Asko, Environmental Design Methods in Materials and Structural Engineering 4. Sarja, Asko, Principles and solutions of the new system building technology (TAT).Technical
Research Centre of Finland, Reserach Reports 662. Espoo, Finland, 1989. 61 p. 5. Sarja, A. & Hannus, M. Modular systematics for the industrialized building. VTT publications 238. Technical research centre of Finland, Espoo 1995. 216 p. 6. Sarja, Asko, Integrated life cycle design of materials and structures. CIB World Congress, Gävle,
Sweden, June 8. - 13., 1998. 7. Sarja, A., Prefabrication in relation to sustainable building. Symposium Report: Prefabrication
Facing the New Century. Concrete Association of Finland, Helsinki, October 1997., pp. 143 - 146. 8. Well-being through construction in Finland 1997. Technical Research Centre of Finland (VTT),
Building Technology. Vammalan kirjapaino Oy, Vammala, 1997.32 p. 9. Sarja, A., Framework and methods of life cycle designs of buildings. Int. Congress “Recovery,
Recycling, Re-integration”, R`97, Geneva, Switzerland, 4-7- February, 1997, Vol. VI, pp. 100-104. 10. Sarja, A. Guide for integrated life cycle design. Manuscript for the report of RILEM TC EDM / CIB
TG 22, May 1999. p. 11. Study on innovative and intelligent field factory. International Robotics and Factory Automation
Center. IMS Promotion Center, Tokyo, March 1997. 33 p. 12.Warzawski, A. Industrialization and Robotics in Building. A Managerial Approach. National Building Research Institute Technion-Israel Institute of Technology. 1990 New York. 466 p. 13. Asko Sarja, Juhani Laine, Sakari Pulakka, Mikko Saari, INDUCON Building Concept (In Finnish with English summary). Research notes 2206, 66 pp. + 4 Appendices. Espoo Asko Sarja, Juhani Laine, Sakari Pulakka, Mikko Saar. ISBN 951–38– (URL: http://www.inf.vtt.fi/pdf/) ISSN 1455–0865 (URL: http://www.inf.vtt.fi/pdf/). VTT Building and Transport, Technical Research Centre of Finland, Vuorimiehentie 5, P.O.Box 2000, FIN–02044 VTT, Finland, phone internat. + 358 20 7221, fax + 358 20 722 4374 14. Asko Sarja, Pekka Leppänen, Juhani Laine, Markku Kiviniemi, Sakari Pulakka, Finnhouse- economic building concepts (in Finnsih with English Summary).. Technical Research Centre of Finland, >Research Notes 1604.. 31 pp. + Appendix 39 pp. Espoo 1994
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5. Central methods of lifetime engineering Central methods of lifetime engineering are the following:
1. Methods for Life cycle costing (working life costs) 2. Risk and reliability principles, analysis and control 3. Service life planning 4. Modelling of performance and service life 5. Service life design 6. Ecological analysis and calculations 7. Cultural acceptance criteria 8. Multiple Criteria Decision making 9. MR&R (Maintenace, Repair and Rehabilitation) planning
5.1 Life cycle costing
Definition Life Cycle Costing is a technique for economic evaluation which accounts for all relevant costs during the investor`s time horizon and adjusting for the time value of money. Procedure of LCC General procedure of LCC as a part of Lifetime design or MR&R (Maintenance, Repair and Rehabilitation) planning of a building or building system are as follows:
1. Identify objectives, planning or design alternatives, and constraints 2. Establish basic assumptions for the analysis 3. Compile cost data 4. Compute the LCC for each alternative 5. Compare LCCs of each alternative to determine the minimum LCC 6. Make the ranking of the alternatives in relation to LCC results, as well as funding
constraints 7. Make sensitivity analysis, including consideration of risk and uncertainty 8. Make final ranking in relation to LCC, including the risks and uncertainty 9. Move this result into Multi Attribute Optimisation and Decision Making procedure as a
component
1. Objectives, alternatives and constraints Specify the objective of a plan, design, system, module or component, that is to be accomplished, identify alternative plans, designs or products that accomplish that objective, and identify the available options to be considered. 2. Objectives, alternatives and constraints An example is the optimal energy economy level of a building, including the following energy consumption levels:
1. Minimum energy house ( annual consumption of space heating energy = 25 kWh/living area m2)
2. Low energy house ( annual consumption of space heating energy = 75 kWh/living area m2)
3. Standard house, ( annual consumption of space heating energy = 100 kWh/living area m2)
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3. Basic assumptions Basic assumptions include:
- Calculation method: present-value or annual-value method - The base time and calculative time period (design life) - The nominal discount rate - The inflation rate - The marginal income tax rate (if relevant) - The comprehensiveness of the analysis - The operational profile of the building or product to be evaluated
The LCCs of the alternatives must be calculated uniformly in present-value or annual-value terms. In the former all costs are discounted to the base time; in the latter, all costs are converted to a uniform annual amount equivalent to the present value when discounted to the base time. Calculative time period is usually the same as the design life of the building, but can also differ from it. The same calculative time period must be used for all alternatives. The calculative time period can be selected with following guidelines:
- In general calculations the calculative time period is the same as the design life of the building (usually 50 years).
- When analysing a project from an individual investor`s standpoint, the calculative time period should reflect the investor`s time horizon.
- For a homeowner, the study period for a house-related investment might be based on the length of the owner´s lone duration, or on the length of time the homeowner expects to reside in the house.
- For a commercial property owner, the calculative time period might be based on the anticipated holding period of the building.
- For an owner/occupant of a commercial building, the calculative time period might correspond to the design life of the building or the part of the building (product) to be evaluated.
- For a speculative investor, the calculative time period might be based on a relatively short holding period.
- For investments by government agencies and large institutions, specific internal policies often direct the choice of calculative time period, but is often quite long: the same as the design life.
When the calculative time period is selected to be significantly shorter than the design life of the building, it is important that a realistivc assessment of the residual resale value at the end of the calculative time period will be included in the LCC analysis. General price inflation (or the building cost increase) is the annual reduction of the currency in purchasing power of the currency (e. g. Euro). LCC analysis should be preferably calculated in constant-currency (Euro etc.) value: net of general inflation, or in current currency (Euro etc.) terms: including inflation. If the latter is nused, a consistent projection of general price inflation must be used throughout the LCC analysis, including adjustment of the discount rate to incorporate the general inflation rate. It is usually easier to express all costs in constant currency (e. g. Euros, net of inflation), when income tax effects are not included, as in the case of government-owned or non-profit buildings and owner-occupied houses. Price changes for individual cost categories that are higher or lower than the rate of general inflation can be included by using differential rates of price change for those categories. Price
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changes for individual cost inflation can be included by using differential rates of price change for those categories. When income tax effects are included in the LCC analysis, it is usually easier to express all costs in current currency (e. g. Euro, including inflation), because income taxes are tied to current currency cash flows. The discount rate should reflect the investor`s time value of money. The discount brate is used to convert costs occurring at different times to equivalent costs at a base time. Selection of the discount rate should be guided by the rate of return on the best available use of funds. Where the discount rate is legislated or mandated for a given institution, that rate should take precedence. A discount rate may include general price inflation over the calculative time period, referred to as the “nominal discount rate”. The discount rate may also be expressed in terms net of general general price inflation, referred to as the “real discount rate”. The real discount can be calculated with equation:
r = 1+i _ 1 or I = (1+r)(1+I) -1
(1) 1+I
111
−++
=Iir or ( )( ) 111 −++= IrI (1)
where I = the rate of general price inflation A real discount rate should be used if estimates of future costs are expressed in constant currency, that is, if they do not include general inflation. A nominal discount rate should be used if estimates of future costs are expressed in current dollars, that is they include general inflation. The comprehensiveness – different levels of effort can be applied in undertaking an LCC analysis. The appropriate level of comprehensiveness depends upon
- the degree of complexity of the problem - the intended purpose of the evaluation - the level of monetary and non-monetary impacts contingent upon the investment
decision, the cost of the different levels of comprehensiveness, and the resources available to the investor or decision maker.
For building investments that are subject to income tax, adjustments of capital costs, expenses, and resale value to reflect income tax effects may have an important effect on the results of the LCC analysis and therefore should be included in the analysis. Compile the cost data required to estimate the LCC of each alternative design or product. This includes the timing of each cost as it is expected to occur during the study period. The measurement of the LCC may require data on:
- initial investment costs of planning, design, engineering, site acquisition and preparation, construction, purchase, and installation
- financing costs (if specific to the investment decision) - annually and non-annually recurring operating and maintenance costs, including
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scheduled and non-scheduled maintenance, repairs, rehabilitation, energy, water, wastewater, property taxes, and insurance
- capital replacement costs costs - resale value, or - end-of life costs and possible incomes: selective dismantling-recovery,-reuse-
recycling-disposal costs Data will be required also for functional use costs, if these are significantly affected by the design or product alternatives. The shorter the calculative time period of the LCC analysis relative to the design life, the more important the assessment of resale value becomes, even if the building or product will not be sold at the end of the calculative time period. Costs that are not significantly affected by the design decision or product selection, can be omitted from an LCC calculation. Often some key-costs and key-components of the lifetime quality can be used for selection between design alternatives or products. When there are performance advantages that favour differences between the alternatives, an adjustment of to incorporate such differences into the LCC measure should be made. Adjustments may be needed to reflect higher rental income, higher sales, improved comfort, improved employee productivity for one alternative to the other. These differences will be included in the Multi Attribute Optimisation and Decision Making calculations. In addition to compiling all relevant costs, the timing of each cash flow must be determined. The time of occurrence is needed so that costs incurred at different points in time can be discounted to their time-equivalent values before summation. Cash flows may be single events, such as a one-time replacement cost or a resale value. They may be recurring and relatively constant in nature, such as routine maintenance costs, or they may occur at regular intervals but change over time at some projected rate of increase or decrease, such as energy costs. Cash flows may occur in lump sum amounts, concentrated at a certain time of the year, such as an annual insurance premium. athey may be spread out evenly over the year, such as salaries, or they may occur irrecularly during the byear. Rather than accounting for the specific pattern of each cash flow, a simplifying model of cash flow is usually adopted for an LCC analysis. In the simplified cash flow model, all cash flows in a given year are assumed to occur at the same point in time within a year, usually at the end of the year. Current dollar analysis When cash flows over caoculation time period are to be denominated in current currency (e. g. Euro), that is: inflation is included in projecting all future costs, the following guidelines:
- Future cash flows that are fixed in amount (such as loan payments) should be used without adjustments.
- Future cash flows that are expected to change at rates significantly different from general rate of price increase (for example energy costs) should be estimated on the basis of the specific rate of price change expected, be it faster or slower than the general rate of price inflation.
- All other future cash flows should be estimated to reflect the rate of general price inflation
Constant currency (e. g. Euro) analysis When all cash flows over the study period are to be denominated in constant currency (the inflation is excluded in projecting future costs), the following guidelines apply:
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- Cash flows expected to increase at the same rate as general price inflation require no adjustment. Their values should be stated in base-year currency (e. g. Euro).
- Future costs expected to change faster or slower than the rate of general price inflation, I, can be estimated in base-year constant currency by multiplying the base-time value of such costs by the differential rate of price change, as follows:
( )t
t eCC += 10 , (2) where: e = the differential price calculation rate C t = the constant currency (e. g. Euro) value of a cost in year t, and C0 = the cost at the base time (the beginning of the calculation time period) The constant differential rate of price change, e, and the actual rate of price change, E, are related as follows:
IEe
++
=11 or ( )( ) 111 −++= IeE
e = 1+E or E = (1+e)(1+I) -1
(3)
1+I where I = the rate of general price inflation If e and I are not constant in each time period i , then:
( )( ) ( )it eeeCC +++= = 1...11 21 , Ct = C0 (1+e1) (1+e2)… (1+ei) where: ei = 1+Ei – 1 or Ei + (1+ ei)(1+Ii) -1
1+Ii Compute LCC To compute the LCC of a building or part of building, all relevant cash flows in periods t=0 through t=N are ddiscounted to a common point in time and summed. Conceptually, the computation of an LCC in present-value terms (PVLCC) can be presented as:
∑= +
=N
tt
t
iC
PVLCC0 )1(
(4)
where: Ct = the sum of all relevant costs occurring in year t N = length of the calculation period, years, and I = the discount rate
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Typical meanings of Ci are:
- When t=0, C0 is the initial investment cost - in each subsequent year (t=0 to N) Ct is typically equal to the sum of operating,
maintenance repair, and rehabilitation (MR&R) costs in that year - at the end of the calculation time period (t=N), Ct also includes a credit for resale value
(residual value) of the building.
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Computing method Using the discount formulas of Table 5.1 the Present Value (PV) of each cost category can simply be summed, as follows: PVLCC = IC+PVM+PVR+PVE-PVS where: PVLCC = present value of the life cycle costs IC = initial cost at the base time (usually at the delivery of the ready building) PVM = Present value of MR&R (MNaintewnance, Repair, Rehabilitation) costs PVR = Present value of Replacement costs PVE = Present value of Energy costs PVS = Present value of Resale value Each of the following patterns of cash flows has a specific type of discounting procedure that can be used to expedit the calculation of the present value for each cost category:
- Amounts expected to occur at a single point in time can be discounted to present value by multiplying that amount by single present value value factor. These factors for different discount rates and calculation time periods can be found in manuals.
- Amounts expected to occur in approximately the same amount from year to year (for example operating and basic maintenance costs when expressed in constant currency) can be discounted to present value by multiplying the annual cost by the uniform present value factor for the specified calculation time period and discount rate.
- Amounts changing over time at some projected rate (for example energy costs) can be discounted to present value by multiplying the annual cost, as of the base time, by the modified uniform present value factor for the specified study calculation time period and discount rate.
Different possibilities for presenting LCC are presented in Table 5.1.
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Table 5.1 Discount formulas
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Income Tax adjustments For investor-owned building facilities, income tax adjustments may be a significant factor, and should therefore be included in the LCC analysis. One method is to adjust all costs that are tax deductible to their after-tax equivalents before discounting, deduct any tax credits from investment costs, establish a depreciation schedule for capital components and compute the corresponding tax savings in each year, and adjust the resale value (if any) for additional tax liabilities or savings related to capital gains, capital losses, and depreciation recapture, as appropriate. Calculate the present value of each cash flow category and the depreciation tax savings and sum these present values to find the after-tax PVLCC. The present value of the depreciation tax savings is treated as a negative cost and therefore has a negative sign in the PVLCC equation. An alternative method is to establish a separate category for all income tax adjustments in each year, calculate these annual amounts and discount them to present value, sum them, and adjust the PVLCC accordingly.
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CompareLCCs and make final ranking After computing LCC measures for each alternative design or product, compare them to determine the economic ranking. Move the results into Multi Attribute Optimisation and Decision Making procedure for final selecting between the alternatives. Risk and Uncertainty Sensitivity analysis is is a testest of the outcome of an analysis to alternative values of one or more parameters about which there is uncertainty. It shows decision makers how the economic viability of a building changes as, for example, energy price escalation, discount rates, calculation time periods, and other critical factors vary. An example of sensitivity analysis is presented in Fig. 5.? Funding constraints When insufficient funding is available to finance the project alternative with the lowest LCC, the economic solution may be constrained to an alternative with a lower initial cost but higher future costs. The constraint of the initial cost is then included in the Multiple Attribute Decision Making procedure.
Figure 5.1 Sensitivity of present value energy savings to study periods, discount rates and energy escalation rates
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Report A report of LCC analysis should state:
- the objective - the constraints - the alternatives considered - the key-assumptions - the present-value or the annual-value, or both of each alternative:
of each category total value
- assumptions or costs that have a high degree of uncertainty and have significant impact on the results should be specified and
- a sensitivity analysis carried out and described Limitations LCC can not usually be used alone in decision making, but also other relevant categories of lifetime quality have to be taken into account through Multi Attribute Optimising and Decision Making procedure. Literature
ASTM E 917-94. Standard Practice for Measuring Life-Cycle Costs of Buildings and Building Systems. ASTM E06.81 Building Economics.
Life Cycle Costing, ‘LCC’, is used to identify and quantify consequences regarding costs related to a product during its entire life cycle. The term LCC was defined by Kirk and Dell’Isola (1995) as; an
economic assessment of investment alternatives that considers all significant costs of ownership discounted over the lifetime of a product.
In literature many different LCC methods are mentioned /3/, but the basic idea is always the same, "to reduce the total cost of a product or a system or an asset or human factors such as labour". The many equations for calculation of different LCC analysis cases or the extensive economic terminology of general LCC are not repeated here, but the reader is referred to references /1/, /4/ and /Error! Reference source not found./. The basics will be briefly presented also in this text.
As defined earlier, life cycle cost is the total discounted monetary cost of owning, operating, maintaining, and disposing of a building, building system, infrastructure facility over a period of time. Keeping this definition in mind, one can breakdown the LCC equation into the following three variables: the pertinent costs of ownership, the period of time over which these costs are incurred, and the discount rate that is applied to future costs to equate them with present day costs.
The first component of the LCC equation is time. Study period is the period of time over which ownership and operations expenses are to be evaluated. The study period varies, depending on owner's preferences, as mentioned in the Lifecon Generic Handbook, /Error! Reference source not found./. For governmental organisations the study period can mean the whole lifetime of the facility while for a speculative investor 10 years is a long time. In Lifecon context, the study period is normally replaced with term "design life".
´Costs` embrace all costs incurred during the study period, before and after the occupation of the facility. In Lifecon costs include for example inspections, condition surveys, yearly maintenance works, monitoring, cleaning, repairs etc. In case of new build, the initial investment would also be taken into account.
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The third component is the discount rate, which can be defined as "the rate of interest reflecting the investor's time value of money" /5/. Basically, it is the interest rate that would make an investor indifferent as to whether he received a payment now or a greater payment at some time in the future.
The advantage of LCC is best reached when a selection of alternatives can be compared. The different MR&R methods need interventions at different intervals, so the costs are also dated at different times. To be able to compare the costs (occurring somewhere in the future), a term called present value must be introduced. The present value can be defined as "the time-equivalent value of past, present or future cash flows as of the beginning of the base year" /5/.
After defining the three components, the basic LCC equation can be expressed as follows:
∑∑= = +
=t
ii
n
jijPV r
CCi
0 1; )1(
1 (1)
where
Cj;i is costs of the jth maintenance action in year i
ni number of maintenance actions in year i
t number of years in the treated time frame (in the study period)
CPV sum of discounted (present value) costs from the study period
r discount rate.
Discounted present value (PV) costs refer to maintenance costs discounted to the present day by the discount factor. As the discount factor diminishes with time, the PV costs of actions scheduled in a late time (from the beginning of the study period) are smaller than the PV costs of the same actions scheduled near to the start of the time frame /Error! Reference source not found./. The residual value or the disposal costs of the structure should be included when comparing different alternatives.
For further interest in LCC analyses in general, a standard practice procedure and a good example of LCC calculations are presented in /1/.
In many applications, the profit is also taken into account (Dale, 1993). In practice, it is difficult to
exclude revenues, as there are normally such consequences related to any decision, from the owner’s perspective. The initial and operating costs are seen in the same context as rent and the residual value and, therefore, an expression such as life cycle economy would be more appropriate. The term Whole Life Costing, abbreviated ‘WLC’, has been introduced in later years as an alternative expression with
equivalent meaning. An international standard for Whole Life Costing is being developed by ISO. Rutter and Wyatt (2000) argue that LCC is seen only as a tool for first decisions regarding design options and that it should be given a firmer link between the initial intentions and the subsequent implementation. To
indicate this, the term LCC should be exchanged for ‘Whole Life Costing’. Tupamäki (2003) however states that this discussion on wording only contributes to confusion as the term LCC has been
understood and used in practise for a long time. LCC is used in this study.
Stone at the Building Research Establishment introduced LCC in the British building industry during the 1950s, with the term ‘cost-in-use’ (Ashworth, 1993). Stone used present values and annual costs to
assess the cash flows throughout the lifetime of a building. In the UK, LCC replaced the term cost-in-use
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through the work of Flanagan and Norman (1983), who together with Meadows and Robinson also published the handbook Life Cycle Costing: Theory and Practice.
The British Standards Institution presented a standard, BS 3811, in 1974 describing the life-cycle
phases from design to replacement, which fits well with the organisation of LCC (and LCA cf. Section 2.5). The method was further developed in the UK during the 1980s, promoted by The Royal Institution of Chartered Surveyors (RICS, 1980, 1986). There is also a Norwegian Standard, NS 3454, Life cycle
costs for building and civil engineering work – Principles and classification. In Figure 2.10 the cost categories from the Norwegian standard is displayed to indicate the relevant cost items for LCC on
buildings.
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Occurrence Year
Real cost at time of occurrence
Initial cost 2005 500Annual operating cost
2006-8 100
Residual cost 2009 300
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Figure 5.2 Cost categories for LCC of buildings according to Norwegian standard NS 3454, ‘Life cycle costs for building and civil engineering work – Principles and classification’
.
5.1.1 The discount rate The discount rate is of significant importance for any LCC-calculation with a time horizon longer than 3-5 years, irrespective of which of the methods described below is used. A low discount rate emphasizes the value of a future event. With the discount factor 0 time becomes irrelevant, cf. Section 2.3. In principle the discount rate should be equal to the alternative cost of capital. Therefore it is different for different entities and varies over time. The state may for instance use the interest on state bonds. This can be regarded as the lowest possible discount rate. A company may set the discount rate to the:
• Cost to use saved capital, which may be equal to the interest rate for long-term loans on the
capital market (lowest discount rate). • Yield of other company investments (highest discount rate).
Companies often determine the discount rate on the basis of the mean cost of capital and the risk of the particular investment. The capital in the company normally is a combination of own and foreign capital. The mean cost of capital is the weighted average of the expected profit from two categories. The discount rate should thus match the expected yield of the company to ensure its long-term survival. A high-risk venture, furthermore, motivates a higher discount rate than a secure investment.
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The discount rate can be determined using assumptions of the real interest rate and the change of the price of the particular item in relation to the consumer price index, ‘CPI’. The real interest rate is defined as the nominal interest rate minus inflation according to the CPI. Compare Section 5.1.1.
5.1.2 Present Value The idea of the method is to calculate the total capital value, or ‘net present value’, of an investment, at a specified point in time, after satisfying a selected discount rate (SK, 1996). The investment is profitable if the net present value is positive. When comparing alternative investments the highest net present value is advantageous. If there is no profit involved the least negative present value is preferred. Alternatives with different working life are normalised by attaching residual values and the end of calculation period. The method is usually applied for large and long lasting one-time investments with several future consequences that need to be aggregated and assessed. It is easy to interpret and well suited for permanent buildings and infrastructures. The only weakness of the method is that if the amount of capital for the investment is restricted and the alternatives have significantly different investment cost and net present values, the alternative with higher investment costs may be unduly preferred in comparison with an alternative with smaller investment. In such a case the profitability index is a better indicator.
5.1.3 Profitability index Using the profitability index the net present value is divided by the initial investment. The quote indicates which alternative that yields the highest profit in relation to the invested capital (SK, 1996).
5.1.4 The annuity method. ‘Annual cost’ The annuity method is used to sum up all costs and distribute them evenly to an equal annual mean cost over a specified time period (SK, 1996). Comparing alternatives the annuity method will give the same result as the present value. The method provides information on the average annual cost or profit and can be utilised for instance to establish the rent for a building or flat. The method is also practical to use when comparing investment alternatives with different lifespan, as it is not necessary to use the same calculation horizon.
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Example of present value and annual cost calculation:
Occurrence Year
Real cost at time of occurrence
Initial cost 2005 500Annual operating cost
2006-8 100
Residual cost 2009 300
Discount factor 8%
Figure 5.3 Example of LCC calculation. Present value and annual cost.
5.1.5 Internal rate of return With this method the internal rate of return defined as the discount rate that gives the present value = 0 is calculated (SK, 1996). The investment is deemed to be profitable if the internal rate of return is higher than the discount rate of the investors. This method is not suitable for comparisons between alternatives as the internal rate of interest, which is used to move costs and revenues in time, may differ from the discount rate that is used by the investor.
5.1.6 Simple payback The payback or payoff method is used in particular by the manufacturing industry to guide short-term investments and is the simplest way to establish profitability (SK, 1996). The shorter time to balance the investment the more profitable the investment is. The basic form, simple payback, does not take interest rate into account. The method is mostly used as a rough estimate to distinguish if an investment is profitable or not, which is the case if the service life of the investment is larger than the payback time. The method is short-termed excluding inflation, interest and cash flow and favours investments with large early positive yields.
5.1.7 Value or cost of a building at the end of the life cycle In a full LCC a value or cost is attached to the product at the end of the life cycle. That is referred to as ‘residual costs’. For a dwelling building this could be the sales value of the house or the cost to demolish and handle the final disposal of materials and components. The second hand value of a multi-dwelling building is governed by technical as well as external factors. It is thus difficult to make relevant predictions concerning differences in theoretical value or sales price many years ahead, for alternative designs. The general quality level of all attributes plays an important role. Aspects such as flexibility and robustness are normally particularly interesting. Because of the long life span of dwelling buildings the economical consequence of what is happening at the end of life 100 years ahead seldom is significant when comparing alternatives, by calculation of present value at the design phase. With a long calculation horizon the differences in cost of demolition and final disposal as well as second hand value becomes so small that they often can be neglected in a comparison between alternatives.
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5.1.8 LCC calculation procedure
ASTM E 917 presents a simple and logical procedure for calculating the LCC of building or building system. The same principles can be easily applied also in civil infrastructure sector. The ASTM procedure /1/, which is also the recommended Lifecon's LCC of MR&R procedure, consists of five steps:
1. Identifying objectives, alternatives, and constraints
The system objective must be specified, and clear boundaries set. Within those boundaries, alternatives that accomplish the objective must be defined. To get advantage from LCC calculations, at least three different alternatives should be defined. It is very important to remember that each alternative should be capable of satisfying the requirements and if the decision is made on LCC basis only, then the alternative with lowest LCC is the preferred choice. Boundary or constraint can mean for example, that only MR&R actions that can be executed without foreign contractor's and their expertise, are to be considered.
2. Establishing basic assumptions for the analysis
This includes choosing of the calculation method (consistently either present-value or annual-value calculation method), base time, study period (reflects investor's time horizon, in Lifecon normally the design life), general inflation rate, discount rate and comprehensiveness of the LCC analysis.
3. Compiling cost data
Simplifying, this means timing of each cost as it is expected to occur during the study period. However, this phase needs a lot of expertise and knowledge and is the most crucial phase in making LCC analysis. Costs that do not have significant difference between alternatives can be omitted from the analysis where the purpose of the analysis is solely comparative. It should be remembered that the primary object of LCC analysis is to rank alternatives on LCC basis, and the secondary object is to get exact numbers!
4. Computing the LCC for each alternative
When the cost compilation for each alternative is ready, the LCCs of the alternatives can be made comparable by using the equation (1) and its derivatives.
5. Comparing LCCs of each alternative to determine the one with the minimum LCC
If the decision is made on LCC basis only, then the alternative with the lowest LCC is the preferred choice on economic grounds.
If the decisions (about MR&R strategy) were based only on costs, the described five steps would be enough, but in Lifecon LMS final decisions are made after taking into consideration also the human, cultural and ecological effects and factors. They can change the ranking order of the alternatives, depending on the importance and weighting of those viewpoints. LCC calculations of MR&R give, however, great impact to the final decision making.
5.1.9 References to Chapter 5.1
[1] ASTM E 917-94 (Standard Practice for Measuring Life-Cycle Costs of Buildings and Building Systems)
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[2] Elinjaksokustannus (LCC)- ja -tuotto (LCP) laskenta - Laskentamallin kehittäminen, VTT Automaatio, Tampere 1999 (in Finnish)
[3] Durairaj, S.K., et al., Evaluation of Life Cycle Cost Analysis Methodologies., Corporate Environmental Strategy, Vol. 9, No. 1 (2002)
[4] ISO 15686 - Buildings and Constructed Assets - Service Life Planning - Part 5: Whole Life Costing (draft 2002-09-11)
[5] State of Alaska - Department of Education & Early Development, Life Cycle Cost Analysis Handbook 1999
[6] Barringer H. Paul, Life Cycle Cost and Good Practices, NPRA Maintenance Conference May 19-22, 1998, San Antonio Convention Center, San Antonio, Texas
[7] Australian National Audit Office, Life-Cycle Costing, Better Practice Guide, December 2001
[8] Probabilistic Approach for Predicting Life Cycle Costs and Performance of Buildings and Civil Infrastructure, Lifetime Cluster - EuroLifeForm Report, October 2002
[9] Wiley, John & Sons Ltd, Sensitivity Analysis, Chichester, England, 2000.
[10] Öberg, Mats, Integrated life cycle design applied to Swedish concrete multi-dwelling buildings. Lund University, Division of Building Materials: Manuscript, December 2004. 253 p.
[11] Dr. Stephen J. Kirk, AIA, CVS, Alphonse J. Dell Isola, PE, CVS, Life Cycle Costing for
[12] Life cycle costing for Design Professionals, Second Edition. Mc Graw-Hill Inc, 1995. pp.
262. ISBN 0-07- 034804-9.
[13] Sarja, Asko, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002.
ISBN 0-415-25235-0.
[14] Life Cycle Management of Concrete Infrastructures for improved sustainability LIFECON.
Co-ordinator: Professor Asko Sarja, Technical Research Centre of Finland (VTT).
http://www.vtt.fi/rte/strat/projects/lifecon/
[15] Kelly, John and Male, Steven, Value Management in Design and Construction - the
economic management of projects.E&FN SPON, London, 1996. 181 p. ISBN 0 419 15120 6
5.2 Risk and reliability principles, analysis and control
5.2.1 Aim and role of risk assessment and control in LMS
The aim of this deliverable is to cope with lifetime risks of concrete facility management keeping in mind the four principal viewpoints of LMS, i.e human conditions, culture, economy and ecology. The main objectives of risk assessment and control are:
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− to make facility owner aware of the risks in relation to the Generic Requirements − to form a solid framework and base for risk-based decision making − to give guidelines how to use the risk approach in decision-making process Risk is a subject that has normally been interlinked with highly complex and complicated systems, like operation of power plants, processing industry, pipelines, oil rigs, space industry and so on. Risk analysis techniques have also for long been a part of project management when economical issues have been treated. In construction industry risks have traditionally been treated just in structural safety context. Of course that is the main concern and target of the designer: how to design and maintain a structure in such a way that it satisfies the structural safety limits set by the authorities but at the same time would not be too conservatively designed and maintained? Differing from processing industry, in construction sector the facilities can be in quite poor condition and still "satisfy" the basic need. In processing industry for example cracks in the pipelines can not be accepted, because they would be fatal for the system. In concrete facilities cracks are unwanted but unfortunately rather common phenomena, but unlike in processing industry, the cracks do not cause immediate fatal threat to the safety of the system. Fortunately, the present societal trends in construction industry promote sustainable development and customer orientation and satisfaction, which all work in favour of better-maintained concrete facilities. Little by little limit states are becoming more and stricter. With increasing national and global wealth more emphasis is placed also on environmental, human and cultural issues and not just on minimising construction and maintenance costs. At the same time with the development of the computational potency of modern computers, better and more accurate decision making and risk analysis methods have been and are being developed. This fact is known also by authorities, stakeholders and funding partners, and consequently the decisions as well as the explanations for allocation of expenses must be better optimised and argued. As an answer to these new challenges, risk analysis techniques have been proposed. They are flexible and can be applied to help in decision making in very wide range. However, the construction industry in general is very traditional discipline with old role models, and implementing new ideas and methods take time, but sooner or later risk analysis methods will be routine also in construction sector. Dealing with risks should not be a separate item to be introduced just in case of emergency. Instead, it should be a part of the management like any management: cost management, time management, etc. and it should have a logical structure. A possible structure for risk management is shown in figure 5.20.
Monitoring
Riskcontrol
Decision-making
Riskassessment
Riskevaluation
Riskanalysis
Hazardidentification
Riskestimation
Riskacceptance
Optionanalysis
RISKMANAGEMENT
Figure 5.20 Structure of risk management [1]. As can be seen in Figure 5.20, risk analysis is an essential part of the risk management, but on the other hand, just doing a risk analysis is not enough, it must not be excluded from the bigger context.
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Traditionally 'risks' have been treated in two different ways. The other is diagnostic risk analysis and the other risk-based decision making. The former is basics, concentrating on identification of the main contributors of risks, while the latter goes much further, trying to use the information of diagnostic risk analysis and then quantify the risks. Theories and methods for quantification exist, but the implementation into practise is still low in construction sector.
5.2.2 Quantitative approach
Qualitative approach in risk analysis is quite simple. More than anything it is logical thinking, structuring down the problem into smaller pieces, which can then be dealt with, one by one. An experienced engineer can produce rough estimations for failure frequencies and consequences, and a brainstorm session of many experts can make the estimations even better. If relative measures are used the quality of results normally maintains a good level. But if exact numbers are wanted, the situation is not the same. In some discussions it has been estimated, that even the best risk calculations should be regarded as accurate to only within 1 or 2 orders of magnitude, when it comes to small probabilities [2]. In structural safety matters some limits are gaining consensus, namely 10-3 for the service limit state and 10-6 for the ultimate limit state, when new structures are concerned. However, the situation is different when old structures are concerned, and the consensus about the probabilities of failure is no more complete. Numbers between 10-2 and 6*10-4 have been suggested but even then the discussion has been considering only the ultimate limit state [3]. In Lifecon context this structural safety issue is only one part of the human viewpoint, and there are three more whole viewpoints (i.e. economical, ecological and cultural) without any established number-based limits. Of course there are some legislation about these issues also, but the regulations and restrictions are of qualitative form. With fatal accidents a principle of ALARP (As Low As Reasonably Practicable) is gaining popularity. The idea of ALARP is that if the probability of death is low enough (the frequency of death for an individual is for example 10-6/year), the situation is acceptable. But if the frequency is greater than say 10-3/year, the situation is unacceptable and improvements for the safety must be made immediately. In between these two limits the ALARP principle is applied: the probability of death is reduced to As Low As Reasonably Practicable, meaning that if the costs of reducing the probability of death exceed the benefits or improvements gained, then the original risk is accepted. The question is once again of qualitative form, "reasonably practicable". And what are the ALARP-limits for cultural, ecological and economical risks? One problem in quantification is the use of deterministic values instead of statistical distributions. It is true that stakeholders (practical engineers, decision-makers, facility owners etc.) are more familiar with exact numbers than distributions, but if a numerical estimation for risk is required, then using distributions in calculations gives better results. By using a characteristic value and a safety factor it is possible to check if some condition for the risk is fulfilled, but the actual value of risk is not obtained. The variation and uncertainty of variables are best described with either standard mathematical or experimental distributions. The simulation methods will eliminate the problem of the difficult analytical integration. Most commercial QRA (Quantified Risk Analysis) softwares use simulation techniques. By using distributions in calculations the results of analyses will also be distributions which tell a lot more than a single value. Unfortunately, to find out the source distributions for different variables is not an easy task. In processing industry (where the risk analysis methods were developed) the situation is easier. Although the whole process may seem highly complex, it can be split into discrete phases, where the successful operation of that phase is a function of just few variables. The high degree of automation has reduced the possibility of a human error, the operation conditions are always the same, access to the area is restricted etc. All this has enabled consistent gathering of relevant information from the functioning of the process. With concrete civil infrastructures the situation is different. The facilities stand in various open environments, access is quite easy for everybody, construction and maintenance require a lot of manpower, etc. The multi-dependent nature of construction or maintenance project is not easy to handle or model. A characteristic feature in construction industry compared to processing industry is the lack of consistent source data and information, which causes problems in quantification the uncertainty and risks. One more problem in quantitative analysis is caused by the mathematical definition of risk. Risk, being a product of two uncertain factors (i.e. probability of occurrence of a scenario and consequences of that scenario) can mislead the decision-maker, if it is introduced as one number only. This is illustrated in the figure 5.21. The two cases have the same yearly risk (the numbers are more or less arbitrarily chosen for
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illustration purpose only), but for the facility owner the second case is disastrous, while the first one can be handled. The case number two is not as probable as the first one, but the consequences are huge and will bankrupt the owner if the scenario comes true. But still the risk is the same in both cases, namely 150 €/year.
Case (= adverse scenario) Probability ofoccurrence Consequences Risk
Power failure silences theskyscraper for two hours 0,0001/year 1 500 000 € 150 €/year
Aeroplane crashes theskyscraper 0,00000001/year 15 000 000 000 € 150 €/year
Figure 5.21 Illustration of the shortcoming of defining risk with only one number. The example in Figure 5.21 is quite macabre, but it clarifies the problem when using only one number for risk. On the other hand, this very example highlights one more unsolved problem of risk analysis, namely "the low probability - high consequences" -problem. These scenarios can not be included in normal risk analysis models, but somehow they should be taken into account in decision making. 5.2.3 Risk analysis methods
The risk analysis methods were developed within the processing industry, where the systems and procedures are quite automatic and the role of human activity is not decisive. However, the principles of the methods are quite applicable also in other sectors of industry. For example, many routines in concrete facility management can be thought as discrete processes with logical structure, so in evaluating uncertainties the general risk analysis methods can be applied. The risk analysis methods as such are simple logical chains of thinking, there is no higher mathematics included in the principle. As mentioned before, the methods were first used in processing industry, and because that sector had the early head start there exist many detailed and case-tailored risk analysis methods in processing industry, while in construction sector more general methods are used. But the three basic questions to be answered remain the same, regardless of the method:
− What can go wrong? − How likely is it? − What are the consequences? The choice of analysis method depends on many variables like source data, resources, expertise, risk category, phase of the project, and especially the nature of the problem. In every method the basic structure of "dealing with risks and uncertainty" is a logical, phased process that is roughly divided in five steps. These steps are: 1. Identification of the possible adverse incidents (hazards, mishaps, accidents) 2. Identification of the causes and consequences of the adverse incidents, and building of structured
causal relationships between them 3. Estimation of the likelihood of causes and consequences, as well as the severity of the consequences 4. Evaluation and quantification of the risks 5. Decisions and actions to deal with the risks The first two steps are an essential part of any risk analysis (being a part of qualitative diagnostic risk analysis), while the next two are necessary only if some quantitative values are needed. The last step is again an obviousness. Apart from the logic of risk analysis procedure, another fact binds the different risk analysis methods: strong expertise is needed and the results depend highly on how rigorously the analyses are performed. No shortcuts should be taken if real benefits are wanted. It should be remembered that a huge part of the accidents, failures and unintended events happen due to negligence, not ignorance. All risk analysis
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methods (when pertinently carried out) include brainstorming and prioritisation processes performed by a multi-discipline team consisting of members from different stakeholder groups. These people who give "raw material" (data, opinions, estimations etc.) for risk analyses, must be experts with solid experience in their business. These are for example maintenance engineers, facility owners, statisticians, inspectors, material suppliers, etc. The person who conducts a risk analysis, on the other hand, does not have to be an expert in facility management, repair methods or materials etc. Instead, he must have other skills, for example such as:
− experience in the risk management process − routine and experience with risk management tools − neutrality in the project (e.g. no partnership with contractors) − analytical way of thinking − superior facilitation skills − excellent communication skills The most utilised risk analysis methods are briefly presented in the following chapters, with some guidelines about their normal use and applications, and notes about their benefits and shortcomings. 5.2.4 Fault tree analysis (FTA)
Fault tree analysis is one of the best and most used risk analysis methods. It is a deductive method, trying to answer to the question: "What causes...?" The idea of FTA is to go backwards from the failure or accident (so called top event) and trace all the possible events that can cause that top event, and then go on to the lower levels until the final level is reached and the basic causes are found. Like any other risk analysis method, FTA starts with the description of the system (or project, process, etc.), where the fault tree is going to be applied. The bounds of the system and the level of complexity must be clearly defined. The fault tree is constructed by using standard logical symbols. The most used symbols and their meanings are presented in figures 5.22 and 5.23. Although many more symbols exist, most fault tree analyses can be carried out using just four symbols (rectangle, circle, and-gate and or-gate).
Rectangle: Resulting event (final or intermediate eventresulting from a logical gate)
House: Basic event (an event which occurs under normaloperational conditions)
Circle: Basic failure (a basic failure - event which does notneed to be developed further)
Diamond: Assumed basic failure (a failure - event which willnot be developed further because of lack of interestor information, thus being assumed to be basic)
Conditional event (as part of logical gates)Ellipse:
Figure 5.22 The basic symbols for events in fault tree analysis.
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AND
S
E1 E3
AND:
The outputevent S appearsif all inputevents E1, E2,E3, ... occur.
Conditional AND:
The output event S appears if all input events E1, E2,E3, ... occur and, at the same time, the condition x issatisfied (for example, E1 occurs before E2 does).
AND
S
E1 E2 E3
Cond.x
OR
S
E1 E2 E3
OR:The output event S appears ifat least one of the input eventsE1, E2, E3, ... occurs.
Conditional OR:
The output event S appears if at least oneof the input events E1, E2, E3, ... occursand, at the same time, the condition x issatisfied (for example, no simultaneousoccurrence of the events E1, E2, E3, ...).
Cond.x
OR
S
E1 E2 E3
E2
Figure 5.23 The basic symbols for logical gates in fault tree analysis. The identification of the top event starts the construction of the fault tree. The top event is normally some undesired event, for example fire in a tunnel, falling of a worker from scaffolding, exposure to asbestos, cracking of an abutment etc. There are basically no strict rules for the definition of the top event, but the identification of the top event sets the framework for the elaborateness of the analysis. The process of constructing a fault tree is explained in Fig. 5.24.
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OR
AND
1. Identify adverseincident = TOP event
3. Link first-level contributorsto TOP event by logic gates
2. Identify first-levelcontributors
4. Identify second-levelcontributors
5. Link second-levelcontributors to first-levelcontributors by logic gates
6. Continue the process "identify andlink contributors" until thefundamental level is reached
Fundamental level: basic or assumed basic events (or failures) only
Figure 5.24 "Step by step" -construction of the fault tree. Note the order (numbers) of the steps. FTA is very useful because it can take into account not just internal causes of the system, but also external factors like human carelessness, natural disasters and so on. FTA can be used qualitatively or quantitatively. For most cases the qualitative part of the FTA is enough, because the construction of the fault tree forces "the risk team" to improve their understanding of the system characteristics, and most of the errors and hazards can be removed or reduced to acceptable level already in that phase. In quantitative phase of FTA the target is to find the probability for the occurrence of the top event. The probabilities for the other events of the fault tree are evaluated, and using the minimal cut sets (the smallest combination of basic events which, if they all occur, will cause the top event to occur) the probability for the top event can be calculated very easily. The OR-gate represents union and the AND-gate represents intersection, and the probabilities are obtained by summing and multiplying, respectively. The mathematical expression of union and intersection is explained in Fig. 5.25.
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Propagation through AND-gate
P1
Propagation through OR-gate
PT = 1 - [(1-P1) (1-P2) (1-P3) ... (1-Pn)]
= 1 - [(1-P1) (1-P2) (1-P3)]
PT = P1 + P2 + P3 - P1P2 - P1P3 - P2P3 + P1P2P3
PT = P1P2P3...Pn
P3P2
PT
Pn
PT = P1P2P3
P3P2P1
PT
P1
P1P2P3
P2P1
P2
P3
P1
PT = P1P2
P2P1
PT
P1
P1P2
P2 P1
P1P2P3
P2P3
PnP3
PT
P1P3
P3P2
PT
P2P1
P1P2
P3
P2
PT = P1 + P2 - P1P2
P1P2
PT P1P2
Figure 5.25 Mathematical expression of intersection (AND-gate) and union (OR-gate) in FTA. As an illustration of the procedure from fundamental level to top event, a fictitious fault tree is constructed in Fig 5.26, with fictitious probabilities of the basic (or assumed basic) events. The probability of the top event of this fictitious fault tree is calculated in Fig. 5.27.
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AND
OR
OR
OR
AND
E8P(E8)
E1P(E1)
E12P(E12)
E4P(E4)
E3P(E3)
E11P(E11)
E10P(E10)
E2P(E2)
E7P(E7)
E6P(E6)
E9P(E9)
E5P(E5)
EP(E)
Probabilities ofthe basic events:
P(E1) = 0.001P(E2) = 0.3P(E3) = 0.2P(E4) = 0.4P(E5) = 0.07P(E6) = 0.25P(E7) = 0.1P(E8) = 0.15
Probabilities to becalculated:
P(E9)...P(E12)and the probabilityP(E) of the TOPevent E
Figure 5.26 Illustrative example of a fault tree, with fictitious events (Ei) and the probabilities of their occurrence (P(Ei)).
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AND
OR
OR
OR
AND
E80.15
E10.001
E12P(E12)
E40.4
E30.2
E11P(E11)
E10P(E10)
E20.3
E70.1
E60.25
E9P(E9)
E50.07
EP(E)
P(E9) = P(E7) + P(E8) - P(E7)P(E8)= 0.1 + 0.15 - 0.1 * 0.15= 0.235
P(E11) = P(E9) + P(E6) - P(E9)P(E6)= 0.235 + 0.25 - 0.235 * 0.25= 0.42625
P(E10) = P(E3)P(E4)P(E5)= 0.2 * 0.4 * 0.07= 0.0056
P(E12) = P(E2)P(E10)P(E11)= 0.3 * 0.0056 * 0.42625= 0.0007161 ≈ 0.00072
P(E) = P(E12) + P(E1) - P(E12)P(E1)= 0.00072 + 0.001 - 0.00072 * 0.001= 0.00172
Figure 5.27 Calculation of the probability of occurrence of the top event (it is assumed, that the events (Ei) are independent from one another) of the fault tree of figure 5.26
FTA can be used for almost every type of risk assessment application, but it is used most effectively to find out the fundamental causes of specific accidents, where complex combination of events are present. FTA has (like any other risk analysis method) some limitations. It examines only one specific accident at a time, and to analyse the next one, another fault tree must be created. This is expensive and time consuming. FTA is also very dependent of the analyst and his experience. Two analysts with the same technical experience will probably get different fault trees. Third drawback is the same as with all the other risk analysis methods, namely the quantification problem. It needs a lot of expertise, knowledge, effort, data, patience, etc. However, carried out properly, FTA is extremely "readable" and it makes the causes and interrelationship
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very visible. As a consequence, the actions and corrections are easily channelled to where they are most needed. 5.2.5 Risk assessment and control procedure
5.2.5.1 The steps of the procedure In short the Lifecon risk assessment and control procedure can be described with the following four steps, which are then explained in the sub-chapters. 1. Identification of adverse incidents 2. Analysis of the identified adverse incidents
− deductively (downwards), in order to find causes − inductively (upwards), in order to find consequences
3. Quantitative risk analysis 4. Risk-based decision making (and continuous updating of risk database) The steps 1, 2 and 4 are always performed if risk analysis is used, forming qualitative risk analysis. The step 3 is only performed if qualitative risk analysis is not enough for decision making and if quantification is possible. A very important feature in the procedure is the continuance. Management of concrete infrastructures is a continuous process and new experience gained every day. The same applies to risk management. The steps described above form Lifecon risk management loop that is continuously maintained and updated, with strict documentation.
5.2.5.2 Identification of adverse incidents The risk analysis starts with identification and listing of adverse incidents (threats, fears, unwanted happenings, mishaps), with regard to the whole lifetime of a facility or stock of facilities. Adverse incident means the same as top event in fault tree analysis, or initiating event in event tree analysis. For easy follow-up and updating, the identified adverse incidents should be logically labelled and stored into the database. "The whole lifetime of a facility" is too big a category, so smaller categories must be created. The lifetime of a facility is built up of a few functionally different, but chronologically overlapping or coinciding phases. While identifying adverse incidents, also the phase - i.e. the moment when the adverse incident can happen - is automatically identified. A logical categorisation of adverse incidents follows those functional phases, which are normally - every day use - inspection and condition assessment - MR&R actions - extremities (high floods, exceptional snow loads, collisions, high overloads etc.) Of course facility owner can categorise the identified adverse incidents differently, according to his/her own preferences. In theory there is no limit for the number of categories, but easily the database becomes cumbersome, if the number of categories increases too much. It is not only facility owner's task to identify adverse incidents. Incidents are best identified by those who deal with them in their every day work, i.e. contractor can help in identifying adverse incidents connected with MR&R actions, inspectors are suitable persons to identify the mishaps at inspection work, and so on. In addition to instinct and experience, information about possible adverse incidents are gathered from statistics, research, expert opinions, statistics, accident reports, failure logs, MR&R data, monitoring data, material tests, material producers, future studies, etc. The importance of rationality in identification of adverse incidents cannot be overemphasised. The idea is not to create horror scenarios, but to answer reasonably to the first question of risk analysis: "What can go wrong". In Lifecon this means "What can go wrong in the management of a concrete facility, during its whole lifetime". Possible adverse incidents to be identified in this first step could be for example (functional phase in brackets):
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- inspector hit by a car (inspection and condition assessment) - falling from road bridge in every day use (every day use) - exceeding of limit state in spite of LMS system (every day use) - exceeding of MR&R budget (MR&R actions).
5.2.5.3 Analysis of the identified adverse incidents After the adverse incidents are identified, they are analysed further. The goal of this second step of Lifecon risk control procedure is twofold: firstly to find the underlying causes of the adverse incidents, and secondly to find the consequences of the adverse incidents. The result - unbroken nexus of events from causes to consequences - forms a structured skeleton that helps decision-maker to perceive causalities and logic of the risk problem at hand. This step is the most important in the whole risk analysis process and that is why it should be made very carefully. The sources of information for construction of the skeleton are the same as in step one. It must be noted that risk analysis is not "one man's show", but requires multi-discipline expertise. The downward analysis - to find causes for the identified adverse incidents - is made using fault tree analysis (FTA). As explained above, the primary factors that lead up to top event (i.e. adverse incident) are looked for. The intermediate events are linked with corresponding logic gates, until the desired fundamental level is reached. The desired fundamental level depends on the end user. For example, for one end user it can be enough to know that there happens approximately one severe car accident on a certain bridge every year, while another one wants to go further and find out why the accident frequency is so high. The structure of a fault tree is illustrated in Figure 5.28. The top event refers to the adverse incident example from step one, namely the "falling from road bridge". The fault tree of Figure 5.28 is presented only for illustrative purpose. The idea is to show what a fault tree looks like and how it can be utilised. The depth of the analysis is stopped to a level that satisfies the fictitious decision-maker. At first glance the leftmost branch in figure may seem strange. Why should facility owner worry about intentional falling? The answer is that if the number of falling accidents is relatively high, the authorities may require some explanations. Consequently, if it is revealed that the bridge for some reason tempts people to climb on the railings, the authorities may demand immediate actions to impede climbing. For example, in high rise buildings, lighthouses etc. the access to the top is normally controlled, whereas with bridges the access is (logically) free. In Figure 5.28 the two branches on the right are not developed further, because the fictitious decision-maker is not interested in traffic accident induced fallings or fallings during MR&R works, but wants to focus only on fallings under normal circumstances, in every day use.
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Person falls, but railing remains unbroken.
Bolts and nuts missing, loosened,
broken.
Falling under normal circumstances.
Railing lattice too sparse.
Railing too low.
Person(climbing on bridge
railing) falls.
Railing has "functional" defect(s).
People leaning against railing.
Suicidejump.
Intentional falling, or "self-made" accident.
Railing post totally corroded
at joint.
Edge beam concrete broken
at joint.
Railing bars broken or totally
corroded.
People leaning against railing.
Railing does not bear lateral thrust.
Railing gives way and person falls.
Fallingdue to traffic
accident.
Person(s) falling off from a road bridge (bridge with concrete deck, steel railing).
Fallingduring MR&R
works.
Figure 5.28 Illustration of a fault tree. The upward analysis - to find consequences for the identified adverse incidents - is made using event tree analysis (ETA). The goal of event tree analysis is to find consequences and final outcomes for initiating event (i.e. adverse incident). In Lifecon the consequences are divided in four main categories of the generic requirements, which are - human conditions - culture - economy - ecology. The four main categories are further divided into sub-categories. In the risk control procedure all these categories are examined (one by one) when finding out consequences for the identified adverse incidents. Once again it is up to the facility owner to decide, how strictly the general Lifecon categorisation is complied with, when looking for consequences. For example, one facility owner may be interested only in direct economic consequences, whereas a more conscious facility owner takes into account also the consequences for culture. Of course all adverse incidents do not necessarily have consequences in all Lifecon categories. The event tree analysis is not as exhaustive as fault tree analysis described above. Normally after one or two nodes the final consequences can be reached. Sometimes the identified adverse incidents are incidents that must not happen (collapse of main girder, pollution of ground water, fire in tunnel, etc.). In such cases the fault tree analysis is enough, revealing causes of the incident, and if the top event probability is too high, decision must be made to lower the probability. An illustration of a possible event tree is presented in Figure 5.29. The consequences of falling result mainly from safety category because the repair costs of a railing are almost nil compared to possible compensations in case of death or permanent injury. Falling from bridge can induce consequences also in culture category, if for example the 100-year-old decorated railing is found to be the cause of the falling and consequently authorities demand that the old railing must be replaced by a modern standard
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railing.
Consequences
Compensations, investigations, fines etc.
Investigations, fines, warnings etc.
Heavy compensations, possibly law cases, police investigations, use restrictions etc.
Heavy compensations, possibly law cases, police investigations, use restrictions etc.
Person badly injured
due to falling.
Person falls of
from the bridge.
No harm or only
slight scratches.
Person survives
the falling.
Person badly injured
but recovers.
Person dies due
to falling.
Person permanently
disabled.
Subsequent eventsInitiating event
Figure 5.29 Illustration of an event tree. The first two steps described above, i.e. the "identification of adverse incidents" and the "analysis of the identified adverse incidents", are enough if risks are treated qualitatively only. With the aid of a visual, logical causes-consequences structure a facility owner can in most cases estimate the risk and make a consistent decision, even if no numbers are presented in the analysis.
5.2.5.4 Quantitative risk analysis If the qualitative risk analysis - described in steps one and two above - is not enough, a quantitative risk analysis must be performed. The quantitative risk analysis utilises the same fault and event tree skeletons that were created in step two above. In this quantitative phase, estimations about probabilities of basic events (or assumed basic events or failures are added to the fault tree part of the analysis. Likewise, in the event tree part of the analysis, estimations about the probabilities of the subsequent events are added to the event tree skeleton. The initiating event probability of ETA is the same numerical value that is obtained as a result from the fault tree analysis, i.e. top event probability of FTA. Because risk is defined as the product of probability and consequence, mere estimation and calculation of probabilities is not enough in calculating risk. Also the consequences must be evaluated numerically. The consequences of very different categories of the generic requirements are taken into account, so there is no commensurate unit for all these different consequences. However, in practice the very final consequences are always calculated using some monetary unit. That is also the Lifecon approach: in this quantitative phase of risk analysis, all the ETA consequences generated in the qualitative phase are estimated in euros. In estimation of probabilities and consequences, the same sources of information are of help as in qualitative analysis, i.e. statistical data, experience and subjective opinions of experts. It must be noted that if quantification is not possible, quantitative risk analysis should not be requested at all. In literature the quantification is usually presented using deterministic values for probabilities. However, in reality it is impossible to give exact numerical values for uncertain probabilities and consequences. For that reason the use of distributions and simulation is preferred in this quantitative part of Lifecon risk procedure. When giving estimates for probabilities and consequences, it is much easier to find a range of possible values instead of one consensual value. In FTA part the basic probabilities are expressed with appropriate distributions and after that the top event can be calculated using simulation. Likewise, in ETA part the numeric values for subsequent events and consequences are expressed with
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distributions. Then, using top event probability of FTA as the initiating event probability of ETA, the risk can be calculated with the aid of simulation. The result is of course a distribution, as all the input parameters are distributions.
5.2.5.5 Risk-based decision making When the identified adverse incidents have been analysed and risks estimated (qualitatively or quantitatively, according to need), risk evaluation can be performed. In this phase judgements are made about the significance and acceptability of the risks, and finally, decisions are made on how to deal with the risks. In this phase all the adverse incidents should be already analysed and stored into the risk database with documentation. If the analyses described above are performed in Lifecon extent, there should be risks in all four main categories and their sub-categories. If quantitative analyses have been performed for the adverse incidents the risks can be summed category-wise. If only qualitative risk analysis has been performed, still the number of adverse incidents that have impact on a certain Lifecon consequence category is easily obtained. With normal database commands the primary factors of these risks in certain category can be easily listed, and consequently they can be dealt with. If the risk is acceptable, it is enough that the decision-maker is aware of the risk attendant upon the decision, but the evaluated risk does not have to be reduced. The decision is then made according to Lifecon decision making procedure. Whether the risk is in that case one of the factors having impact on the decision, is up to the end user. If the risk is estimated and evaluated quantitatively, it can be easily included to the decision tree or MADA as a criterion. In decision tree the limit for risk criterion is decided by the end user and in MADA the impact of risk is taken into account by giving appropriate weight to the risk criterion. If the risk is not acceptable, further considerations must be made. Basically, there are four options to choose from: - lowering the probability of the adverse incident - reducing the consequences of the adverse incident - rejecting the risk - transferring the risk The best option is to lower the probability of the adverse incident. With visual causes-consequences structure it is easy to see, which factors affect the top event, and consequently effort can be effectively directed to the problematic factors. If quantitative risk analysis has been performed, the allocating of efforts is even easier, because sensitivity analysis reveals automatically the biggest contributors to the top event. Another way of reducing risk is to reduce the consequences of the adverse incident. Sometimes it can be easier to accept relatively high probability of adverse incident and create safeguards against severe consequences than to overspend resources in trying to reduce the probability. For example, input errors - when inserting information manually into any system - are unavoidable, but the system can be created so that one input error does not affect the system. Floods cannot be easily prevented, but an old stone bridge in weak condition can be closed for the flood peaks to avoid casualties, etc. Rejecting risk in this context means rejecting an option in which unacceptable risk is involved. In Lifecon decisions are normally made between different alternatives, so rejecting one alternative because of too high risk can be very usable means in Lifecon decision making process. Risk transfer is used a lot but it cannot be recommended, if sustainable development is to be emphasised. If this means is chosen, the risk itself does not diminish at all, only the responsibility is transferred to another party. In practise risk transfer means taking out insurance against the risk. Whatever the risk-based decision is, it must be well documented (who made the decision, what were the circumstances, etc.). By this means the quality of the decision can be followed up and improvements and updatings made to the fault tree and event tree analyses for future needs.
5.2.5.6 Qualitative or quantitative risk analysis In many cases of management troubles the qualitative evaluation of risks is enough for decision making.
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The qualitative evaluation shows the weakest links and areas to the facility owner, and counsels him to put more effort into solving problems on those areas. The routines (modelling, inspections, MR&R actions, etc.) are basically well established, and if some deviations from the plans occur, they are most probable due to human activity (negligence, carelessness, etc.). Unfortunately, in the management (and especially with MR&R actions) of concrete facilities human labour is needed in all phases, and unlike with machines and processes, the human behaviour in different situations is very difficult to predict. If there is no real need or possibility to get exact numbers for risks, then the heavy-scale quantitative risk analysis should not be carried out. Qualitative analysis and comparative estimations are more reliable and readable than absolute values, especially when single numbers are used instead of distributions in quantification. It should always be remembered that running a rigorous quantified risk analysis is extremely expensive at present (mostly due to lack of consistent source data) and in normal cases out of question in maintenance policies. So far there have not been demands for the quantitative risk analyses from the authorities in maintenance sector, but the trend is in favour of more accurately calculated and explained decisions and in the future quantitative risk analyses can be some kind of routine. For example, in off shore oil industry there are already regulations about quantitative risk analysis. However, the quantified analyses in oil industry are not applied as extensively as is the goal of Lifecon (economical, ecological, human and cultural aspects), but have concentrated more on the human safety and environmental issues. Applying qualitative risk analyses in the maintenance policy will be an improvement to the present day practise. The risk procedure proposed above does not require any miracles or higher wisdom from facility owners, when used in a qualitative way. In addition, by applying FTA- and ETA-based qualitative risk analysis to the management policy already now the facility owner can prepare for the future, because this qualitative phase always precedes the quantitative analysis. Of course decisions are easier to explain and justify if they are based on numeric facts. Unfortunately in construction sector these numeric facts have not been easy to find. Methodologies exist but without appropriate numeric input they do not give consistent numeric results. On the other hand, the qualitative versions of risk methods can be applied already with good results, but they do not help decision-makers who are playing only with numeric values. References to Chapter 5.2
[1] Thoft-Christensen P., Faber M.H., Darbre G. and Høj N.P., Risk and Reliability in Civil Engineering - Short Course, Lecture Notes. Zürich 2001.
[2] James M. (Ed.), Risk management in civil, mechanical and structural engineering, Conference Proceedings, Thomas Telford, London 1996.
[3] Rissanen T., Probabilistic Traffic Load Model Applied Especially to Composite Girder Bridges, Master's Thesis, Espoo, 2001. (in Finnish)
[4] Modarres M., What Every Engineer Should Know About Reliability and Risk Analysis, Marcel Dekker, Inc., New York, 1993.
[5] Goldberg B.E., Everhart K., Stevens R., Babbitt III N., Clemens P. and Stout L., System Engineering "Toolbox" for Design-Oriented Engineers, NASA Reference Publication 1358, 1994.
[6] Vose D., Quantitative Risk Analysis: A Guide to Monte Carlo Simulation Modelling, John Wiley & Sons, Chichester, 1996, 328 pp.
[7] Wang J.X. and Roush M.L., What Every Engineer Should Know About Risk Engineering and Management, Marcel Dekker, Inc., New York, 2000.
[8] Faber M.H., Risk and Safety in Civil Engineering, Lecture Notes, Swiss Federal Institute of Technology, 2001.
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[9] Risk Assessment and Risk Communication in Civil Engineering, CIB report, Publication 259, March 2001.
[10] Safety, Risk and Reliability - Trends in Engineering, Conference Report, Malta, March 2001.
[11] Sarja A., Integrated Life Cycle Design of Structures, Spon Press, London, 2002, 142 pp.
[12] Söderqvist M.-K. and Vesikari E., Generic Technical Handbook for a Predictive Life Cycle Management System of Concrete Structures (LMS), Lifecon Deliverable, draft, 2003.
[13] Lair J. and Sarja A., Multi-Attribute Decision Aid Methodologies, Lifecon Deliverable, draft, 2003. 5.3 Service life planning and obsolescence
5.3.1 Service life planning The objective of service life planning is to ensure, that the service life of a facility, its modules and components are functionally, technically and economically optimised over the design life. A fact is that service life of different parts (modules or components) of a building are different. Also the decisive factor which is dictating service life varies, it might be either defective performance, or functional, technical or economic obsolescence. From experiences we know that roughly fifty percent of the demolition of buildings are done due to defective performance and the same fifty percent is demolished or retrofitted due to obsolescence. For each part of the building and for each alternative of design and of product the dictating factor has to be identified separately at life cycle planning process. After identification the optimisation of the system through sequential comparisons between alternatives will take place. Because of multiple categories of requirements some feed back during the planning process is needed, why the process is partly iterative. Service life of buildings and their subsystems, modules and components is classified e. g. using the classification presented in chapter 2. Another classification is presented in draft Standard ISO/DIS15686-1. The rough classification serves a framework for service life planning and optimisation at briefing, conceptual and initial design phases, but more exact service life estimation is carried out at detailed design phase during selection between different products. A model of modulated service life planning scheme is presented in table 5.3.?. As it can be seen, the target service life of some key modules like foundations and bearing frame can be defined to be longer than the calculation life cycle of the building. This means, that those modules own a certain residual value after the calculation life time, which can be taken into account in economic life cycle calculations both in monetary economy and in economy of nature (ecology).
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Table 5.3.?. A model of modulated service life planning scheme of a building which has design life of 50 years.
Ordinary Target / Design Life due to Functional module
Functional obsolescence y
Technical obsolescence y
Economic obsolescence y
Defective performance y
Target service life CSL y 1
1.Foundations
>100 >100 >100 50 - >100 >=50
1. Bearing frame
>100 FL 2)
>100
>100
50->100
>=50
2. Envelop/ Walls
>50
>50
50
30-200
30 - >50
3. Envelop/ Roof
50
50
50
15->100
20- >50
4. Envelop/ Ground Floor
>50
>50
>50
30->100
>=50
5. Envelop/ Windows
30-50
25-50
20-50
20-50
> = 30 R3)
6. Envelop/ Doors
>=20
20-30
> 50
30- >100
20->50 R3)
7. Partition Floors3)
1 - 50
20 - 50
>100
> 100
>=50 C5)
8. Partition walls (incl. doors) 3)
9.
5 - 50
>50
>50
40 - >100
5 - 50 R3) C4)
Bathroom and kitchen3)
20 - 30
15 - 30
25 - 40
20 - >50
20- 50 C5) R2)
10. Building service systems
2 - 40
3 - 50
3 - 50
5 - 40
5-40 C5) R3)
1) Target or design life will be defined inside the defined range through multiple requirements optimisation process
2) Flexibility for changes of internal spaces is needed in periods of changes of other modules
3) Recycleability of components is important
4) Modules include compatibility between structures and installations
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5) Changeability of parts of module is highly needed
Following the scheduled target service life, a multiple requirements life cycle optimisation can be done for each building separately. The optimisation is carried out in order to determine optimal target service life values above the calculation service life of building, and optimal target service life inside the specified range of possible suited values as presented in table before. Roughly in 50 % of demolition and retrofitting of old buildings is done due to defective performance of key structures while in same amount of 50 % the reason is obsolescence. 5.3.2 Service life dictated by defective performance Defective performance is controlled in design with properly service life planning which results in realistic target service life for key modules of the building, and in detailed durability service life design which results in key structures which are owing an adequate performance over design service life. 5.3.3 Service life dictated by obsolescence Obsolescence means inability to satisfy changing functional, technical or economic requirements. Obsolescence can be regarding to entire building or some of its modules or components. The objective of service life planning is to ensure, that the service life of the facility is functionally, technically and economically optimised over the design life. The decisive factor that dictates service life varies. It might be either defective performance, or functional, technical or economic obsolescence. Because of different optimal lengths of service life of different parts of a facility, a modular planning principle can be used. Obsolescence means the inability to satisfy changing functional, technical or economic requirements. Obsolescence can be with regard to an entire traffic system or its structures. Functional obsolescence is connected to changes in the functions of a building, traffic system or other built facility, when the facility partly or even totally looses their function. Functional obsolescence is often strongly tied to the planning of the infrastructural system. Technological obsolescence is mostly connected to changes in technical requirements. Typical changing requirements are those of increasing traffic loads. Often this is connected to changes in the entire society, region, technology or technical system. Technological obsolescence can sometimes be avoided or diminished with an estimation of the future technical development in the design. Economic obsolescence means unacceptably high operation and maintenance costs in comparison to new systems and facilities. This can partly be avoided in design by carefully minimising the operation and maintenance costs through the selection of such materials and structures that need the minimum amount of work and materials in their maintenance and operation. Often this means simple and safely working structures that are not sensitive to defects and their influences. 5.3.4 Elements of obsolescence analysis
The obsolescence analysis can be divided into three elements:
1. Meaning of obsolescence 2. Factors and causes of obsolescence 3. Strategies and decisions on actions against obsolescence
Meaning of obsolescence
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In this part of the analysis - when kept on general level - the owner should ask him/herself, what does the obsolescence really mean with the type of facility in question (bridge, tunnel, wharf, lighthouse, cooling tower, etc.). Before the obsolescence can be made a subject of a deeper study, it must be clearly defined. The task can be facilitated with appropriate questions like: • How do the different types of obsolescence (functional, technical, social...) show? What are the
problems caused by obsolescence? Who suffers (and how) because of obsolescence? (users, owner, environment..?)
• Are there commonly accepted limit states for these different types of obsolescence? If not, how is obsolescence defined? Is the definition a result of a cost-benefit study? Or is the pressure from the public or authorities pushing hard and setting limits, etc? What should the obsolescence limit states be for the facility type in question, and what other viewpoints than just the economic ones should be taken into consideration when defining obsolescence limit states? Who defines the obsolescence limit states? What are the obsolescence indicators?
• Is there data from the past available? What kind of data banks, sources of information or resources are there available for a deeper analysis? Does the decision-maker (facility manager, management team, etc.) have a comprehensive picture (including also societal approach, not just technical) of the obsolescence problem?
• Etc. Of course this part of the analysis is a lot easier if the owner has documented examples of obsolescence cases in his/her facility stock. In any case, the previous task and its results should be duly documented. Factors and causes of obsolescence In this part of the obsolescence analysis the possible causes for the different obsolescence types are sought after. This part follows straightforwardly the risk analysis procedure presented in deliverable D2.3, where the causes of adverse incidents - i.e. so called top events - are revealed using fault tree analysis. In the obsolescence analysis these top events mean the obsolescence indicators of different obsolescence types. The reader is referred to the deliverable D2.3 for detailed description of the procedure. The factors and causes of obsolescence can be physical needs, e.g. increased traffic on the route where the bridge is located, new type of ships that cannot dock to the existing wharf, etc. Many times the obsolescence causes can be traced to promulgation of new standards (that require for example stricter sound insulation in floors, etc. Although normally the existing facilities are exempted of these requirements, there will be pressure to follow the new standards). The factors can be fashion-originated: the existing façade of a building looks grim, the building is not located in "the right part of the city", etc. Although it is obvious that the top-level cause of obsolescence is the general development of society (technological, cultural etc.), it must in this part of the analysis be studied in deeper level. In ideal case the facility owner would become aware of the reasons behind trends, new norms and standards, migration, employment policy and all possible societal causes that have effect on the use of the facilities. After having these factors on hand it is much easier for facility owner to estimate the direction of the general development and plan the future actions for the facility. But as mentioned earlier, this requires quite comprehensive touch to the whole process of facility management, and the resources may be scarce in many organisations. Strategies and decisions on actions against obsolescence When the obsolescence indicators of possible obsolescence types and their causes for the facilities are identified, the owner should try to find actions to avoid or defer obsolescence. These actions generally have the purpose of minimising the impacts of obsolescence by anticipating change, or accommodating changes that cause obsolescence before the costs of obsolescence become substantial.
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Although obsolescence is best fought before entering the operations and maintenance phase in the life cycle of a facility, something can be done to minimise obsolescence costs also when dealing with existing structures. Good maintenance practices have the same effect in maintenance phase as quality assurance in construction phase, enhancing the likelihood that performance will indeed conform to design intent. Training of maintenance staff, preparation and updating of maintenance manuals and use of appropriate materials in maintenance activities contribute to avoiding the costs of obsolescence. Existing and new computer-assisted facility management systems that support condition monitoring, document management and maintenance scheduling, should be able to provide useful information that can help the facility manager to detect problems that could presage obsolescence. An idea of multidimensional "obsolescence index" has been presented as target for research, but so far this issue has been staying on theoretical level. The obsolescence studies and discussions have concentrated on buildings and on the business inside the building, like schools, hospitals, office or industrial buildings. In these cases the location, inner spaces etc. have great impact on the possible obsolescence, as the use of building can change radically when the tenant or owner changes. The possible strategies include post occupancy evaluation and report cards to achieve performance approaching the optimum of the facility, adaptive reuse, shorter terms for leasing and cost recovery calculations, etc. Often the strategy with obsolescence is "making-do", which means finding low-cost ways to supplement performance that is no longer adequate. Normally making-do is a short-term strategy with high user costs, leading eventually (after high complaint levels, loss revenue, loss of tenants, etc.) to refurbishment of the facility [12]. However, with infrastructure facilities - on which Lifecon is focusing, like bridges, tunnels, wharves, lighthouses, etc. - the situation is not the same, as these facilities normally are already located in the most optimal place to serve that one certain business they were built for. Normally this business (for example port activities, passing traffic through or over obstacles etc.) cannot be totally halted, so the demolishing of obsolete but otherwise sound facility and construction of a new one is not common nor wise solution. One traditional solution (especially with bridges) has been to build a new facility near the old one and keep the old one for lesser service.
5.3.5 Limit states
In order to make possible the analysis of obsolescence, the obsolescence itself must be defined. For that definition limit states are needed. While in stability and durability analyses of structures there appear clear signs in the facility when limit states are reached (ruptures, cracks, spalling, corrosion, deflections, vibration, etc.), with obsolescence the case is not that simple. The signs about obsolescence are normally found outside of the facility (loss of revenue, complaints from users, traffic jams, increased maintenance costs etc.). The decision when those obsolescence indicators have increased excessively, meaning that the limit states have been reached, is difficult and in most cases organisation-specific. However, some qualitative limit states of obsolescence can be defined on generic level. These are presented in table 14.
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Table 14. Functional level usability limit states of obsolescence of structures.
Reason of limit state Serviceability limit state Ultimate limit state
1. Human requirements Functional usability Weakened functional usability Total loss of functional
usability Convenience of use Weakened convenience Healthiness of use Minor health problems in use Severe health problems in
use Safety of operation Weakened safety of operation Severe problems in safety of
operation 2. Economic requirements Economy of operation Weakened economy in
operation Total loss of economy in operation
Economy of MR&R Weakened economy in MR&R Total loss of economy in MR&R
3. Cultural requirements Cultural requirements of the society
Minor problems in meeting cultural requirements
Severe problems in meeting defined cultural requirements
4. Ecological requirements Requirements on the economy of nature: - Consumption of raw
materials, energy and water
- Pollution of air, waters and soil
- Waste production - Loss of biodiversity
- Minor problems in meeting requirements of owners, users and society
- Minor environmental problems
- Total loss of meeting the most severe requirements of society
- Severe environmental problems
As can be seen in table 14, the difference between service limit state and ultimate limit state in obsolescence analysis is a question of interpretation. For example, there exists no standardised definition for "minor problems" or "severe problems", but they are organisation-specific matters. The obsolescence indicators are the same for service and ultimate limit states, but in ultimate limit state they are just stronger than in service limit state. Using analogy with the traditional static and dynamic limit states definitions, one can come to conclusion that the ultimate limit state in obsolescence means that there is no recovery from that state without heavy measures while in service limit state minor actions can return the situation to the pre-obsolete state. In the traditional static and dynamic analysis reaching the ultimate limit state means permanent deformations in the structure, while in the service limit state the deformations are not permanent. To proceed in the obsolescence analysis, the generic level limit states of table 14 must be converted into more specific and tangible descriptions. In this conversion the facility type has a decisive role, because the specific obsolescence indicators and their reasons vary a lot depending on the facility type (for example, traffic jam is obviously a bridge-related obsolescence indicator, but cannot be used for lighthouses). In table 15 some obsolescence indicators for two different facility types are listed, categorising also the obsolescence type.
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Table 15. Obsolescence indicators for different obsolescence types.
Functional and human Economic Ecological Cultural
Bridge
- service capability of the bridge or network of bridges in the actual global, regional or local logistic system not adequate
- weak capability to transmit the current traffic
- weak bearing capacity for present traffic loads
- low height for under-going road or water-borne traffic
- heavy noise from traffic on bridge
- heavy degradations cause uneasiness for users
- high costs for users because of traffic jams
- high operation costs (e.g. bascule bridge)
- high MR&R (Repair, Rehabilitation and Maintenance) costs
- high production of environmental burdens because of traffic jams
- high production of environmental burdens because of need for the use of by-pass roads
- high production of environmental burdens because of highly increasing MR&R works
- robust intermediate piers and long approach embankments impede free flow of water
- the imago of the bridge does not meet the local imago goals
- the bridge is preserved as a cultural monument without adequate possibilities for changes
- heavy abutments and intermediate piers block the free view of the under-going roadway users
Building
- the changeability of spaces not enough for the actual or future needs
- the accessibility not adequate
- not adaptable for modern installations
- the quality of internal air does not meet actual health requirements
- the emissions from materials cause danger for health
- lighting does not meet the requirements of living or working
- the living or working comfort does not meet present day requirements
- too high energy costs
- too high operation costs
- potential residual service life too short in comparison to required repair or rehabilitation cost
- the energy efficiency does not meet the current requirements of owners, users or society
- high production of environmental burdens because of highly increasing MR&R works
- the spaces are not adaptable for the current ways of living or working
- the architectural quality does not meet the local actual requirements
- building does not reflect the imago that user wants to give
5.3.6 Methods for obsolescence analysis and decision making
Although obsolescence is increasing in importance, no standards addressing obsolescence of civil infrastructure or building facilities have been enacted so far. Principled strategies and guidelines for dealing with obsolescence have been presented [5, 12] but the real analysis methods have not been applied. As obsolescence progress of a facility depends on the development of local conditions, as well
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as on the general development of society during the service life (or residual service life) of a facility, there is lot of uncertainty involved in obsolescence analyses. Like in any uncertainty-filled problem, also in obsolescence situation the case must be structured down to smaller parts, which can be consistently handled. It must be noted that he obsolescence avoidance thought should be present in all life cycles of the facility: planning and programming; design; construction; operations, maintenance and renewal; retrofitting and reuse. The obsolescence analysis should be performed before the onset of obsolescence, as a part of the facility owning and management strategy. The following methods can be applied in obsolescence analysis:
- Quality Function Deployment method (QFD) [Lifecon Deliverables D2.3 and D5.1] - Life Cycle Costing method (LCC) [Lifecon Deliverable D5.3] - Multiple Attribute Decision Aid (MADA) [Lifecon Deliverable D2.3] - Risk Analysis (RA) [Lifecon Deliverable D2.3]
5.3.5 QFD in obsolescence analysis and decision making
Quality Function Deployment method QFD can be used for interpreting any "Requirements" into "Specifications", which can be either "Performance Properties" or "Technical Specifications" [Lifecon Deliverable D2.3]. Thus QFD can serve as an optimising or selective linking tool between:
- changing "Requirements" - actual and predicted future "Performance Properties" and - actual and predicted future "Technical Specifications"
of facilities.
In the obsolescence issues QFD can be used for optimising the "Technical Specifications" and/or "Performance Properties" in comparison to changing "Requirements" and their changing ranking and weights. These results can be used for selection between different design, operation and MR&R alternatives for avoiding the obsolescence. Simply the QFD method means building of a matrix between requirements (=Whats) and Performance Properties or Technical Specifications (=Hows). Usually the Performance Properties are serving only as a link between Requirements and Technical Specifications, why the Performance Properties often are not treated with QFD method additionally weighting factors of Requirements and Technical Specifications as well as correlations between Requirements and Technical Specifications are identified and determined numerically. In practical planning and design the application shall be limited into few key Requirements and key Specifications in order to maintain good control of variables and in order not to spend too many efforts for secondary factors. The following procedure can be applied in LIFECON LMS when using QFD for analysis of functional requirements against owner's and user's needs, technical specifications against functional requirements, and design alternatives or products against technical specifications:
1. Identify and list factors for “What” and “How” 2. Aggregate the factors into Primary Requirements 3. Evaluate and list priorities or weighting factors of “What`s” 4. Evaluate correlation between “What`s” and “Hows” 5. Calculate the factor: correlation times weight for each “How” 6. Normalise the factor “correlation times weight” of each “How” for use as a priority factor or
weighting factor of each “How” at the next steps
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The obsolescence analysis and decision making procedure includes two steps:
1. Define the individual "Requirements" corresponding to alternative obsolescence assumptions 2. Aggregate the individual "Requirements" into "Primary Requirements" 3. Define the priorities of "Primary Requirements" of the Object for alternative obsolescence
assumptions 4. Define the ranking of alternative solutions for avoiding the obsolescence. One of these solutions
is the demolition 5. Select between these alternatives using the priorities from step 1 6. Decide between the alternative solutions for avoiding the obsolescence, or demolishing the
facility.
The QFD method is described in more details in Lifecon Deliverable D2.3, and applied into MR&R planning in Lifecon Deliverable D5.1.
5.3.7 LCC in obsolescence analysis and decision making
Life cycle costing LCC can be effectively used in obsolescence analysis and decision-making between alternative obsolescence avoidance strategies and actions. It can be either alone, focusing on economic obsolescence options, or one part of the multiple analysis and decision-making, connected to other methods: QFD, MADA or FTA. The methodology of LCC in this connection is the same as presented for general MR&R planning and decision making in Lifecon Deliverable D5.3. In obsolescence issues the alternatives are different obsolescence options, and alternative strategies and actions for avoiding the economic obsolescence. Because economic obsolescence usually is only one of several categories of obsolescence, beside LCC also other methods: QFD, MADA or FTA is applied as mentioned above.
5.3.8 MADA in obsolescence analysis and decision making
Multiple Attribute Decision Aid MADA method is described in detail in Lifecon Deliverable D2.3. In order to “measure” the influence of obsolescence factors and options into the ranking and choice between alternative strategies and actions for avoiding obsolescence, the method of sensitivity analysis of MADA can be applied. Sensitivity analysis with Monte-Carlo simulation consists then in four steps (Fig 9.): 1. Random assessment of the weights or alternatives assessments simulating small variations (e.g. ±5%,
±10% ...) 2. Application of the Multi-Attribute Decision Aid methodology 3. Ranking of alternatives 4. Statistical analysis of the various rankings.
1 - Randomassessment ofweights/criteria
2 - Muti-AttributeDecision Aid
3 - Ranking ofalternatives
4 - Statisticalanalysis
n times
Fig 9: Monte-Carlo simulation in sensitivity analysis of MADA [Lifecon Deliverable D2.3].
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A simulated weight/alternative assessment is obtained by multiplying the initial weight/alternative assessment (given by the user) by a multiplicative factor (variation) modelling small variations. For instance, an initial weight W=30, subjected to small variations [-10%, +10%], will vary in the range [30 × 0, 9; 30 × 1, 1], i.e. [27, 33]. These small variations can be calculated by means of a bounded Gaussian distribution defined with:
⎪⎩
⎪⎨⎧
=σ
=µ
3iationvar:deviationdardtanS
1:Mean
It is then bounded in lower values and upper values respectively by (1–variation) and (1+variation). The bounds and standard deviation are chosen that way to include 99, 7% of the values (99, 7% of a Gaussian distribution is included between (µ–3σ) and (µ+3σ)).
0
0.005
0.01
0.015
0.02
0.025
0.03
0.0350.
8
0.85 0.9
0.95 1
1.05 1.1
1.15 1.2
Multiplicative factor
-3σ
µ
+3σ
Fig 10. Example of multiplicative factor (Variation 20%) [Lifecon Deliverable D2.3]. After n simulations, the various ranking of alternatives of strategies and actions, and analyse the variations will be carried out.
5.3.9 FTA in obsolescence analysis and decision making
The use of Fault Tree Analysis (FTA) is explained with some examples of different cases. Case 1: Bridge In this illustrative example the top event is the first obsolescence indicator in table 15, namely "service capability of the bridge or network of bridges in the actual global, regional or local logistic system is not adequate": Top event clarification: Primary function of a bridge is to transmit traffic over an obstacle (another route, railway, ravine, etc.) and at the same time to make possible the transit under the bridge. So the service capacity refers both to over-going and under-passing traffic. Primary parameters of traffic are volume and weight, the corresponding counterparts of the bridge being free space (horizontal and vertical) and load bearing capacity, respectively. This leads to the conclusion: The top event happens when the dimensions or the load bearing capacity of the bridge do not meet the demands anymore. Two cases must be identified, i.e. traffic over the bridge and traffic under the bridge. For the under-passing traffic (vessels, trains, vehicles) the only important parameter of the bridge is free space as the traffic does not have contact with the bridge. For the over-passing traffic also the load bearing capacity of the bridge is very important. Note: Of course there are also other requirements that the bridge has to fulfil, like aesthetics, MR&R economy, ecological demands etc. and consequently the bridge can be obsolete regarding those issues. However, in this example only the service capacity was of concern.
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After this short reasoning, at the latest, the scope of the analysis should be defined: is the analysis going to be carried out for the whole stock of bridges, for the bridges on some certain area or route, or for just one certain bridge. Logically, the more general the scope, the more branches the fault tree will have. In this illustrative example the obsolescence problem will be studied on the "whole stock of bridges" (i.e. network) level. The fault tree for an individual bridge would of course be much smaller, because useless branches can be cut off immediately from the tree. The resulting fault tree is shown in the figure 11 below. First the whole tree is displayed to illustrate the possible extent of the analysis, and then it is shown in more detailed pieces to make the texts readable.
UC5
UT10UT9
UW5
UT2
UT5 UT6 UT7UT4 UT8
UW10
UT3
UT1 T=Trains
UW6UW4
UW11
UW7
UW2 UW3
UC4UW8 UW9
UC9 UC10
UC2
UW1
U=UnderU
W=Water
AL9 AL10
AL4
AL1
AD11UC14
UC8UC6
UC12UC11
UC7
UC13
UC3
AD4
AD10
UC1 C=Cars
Top(service capability not adequate)Top = Top event
AD14
AD6AD5
AD12
AD7
AD13
AD2 AD3
AD8 AD9
AD15
AL3
AD1 D=Dimensions
A=AboveA
AL5
AL7AL6 AL8
AL2
L=Load
UT1 UW1
U=UnderU
Top = Top event(service capability not adequate)
UC1
Top
AD1
A
AL1
A=Above
T=Trains W=Water C=Cars D=Dimensions L=Load
Abbr. Explication of the event U Service capability not adequate for the traffic Under the bridge A Service capability not adequate for the traffic Above the bridge UT1 Service capability not adequate Under the bridge for railway traffic (Trains) UW1 Service capability not adequate Under the bridge for Water-borne traffic UC1 Service capability not adequate Under the bridge for road traffic (Cars) AD1 Service capability not adequate Above the bridge due Dimension-related causes AL1 Service capability not adequate Above the bridge due Load-related causes
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UT10UT9
UT7UT5UT4 UT6
UT1
UT2
UT8
UT3
Abbr. Explication of the event UT1 Service capability not adequate Under the bridge for railway traffic (Trains) UT2 Vertical clearance for railway traffic limited UT3 Horizontal clearance for railway traffic limited UT4 Special cargo track (e.g. harbour activities) needs higher clearance UT5 Electrification problem: no room for installations (wires etc.) under the bridge UT6 Railway norms concerning vertical clearance are to be changed UT7 More tracks wanted but horizontal clearance does not allow that UT8 Wider clearance needed for special cargo tracks (e.g. harbour activities) UT9 Railway norms to be changed on international level UT10 Railway norms to be changed on national level
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UW9
UW11UW10
UW5UW4
UW2
UW7UW6 UW8
UW1
UW3
Abbr. Explication of the event UW1 Service capability not adequate Under the bridge for Water-borne traffic UW2 Vertical clearance for water-borne traffic limited UW3 Horizontal clearance for water-borne traffic limited UW4 New water-level regulation policy keeps the water level very high UW5 Commercial water traffic needs higher clearance than what is the current situation UW6 Recreational yachting increases, with higher motor and sailing boats UW7 New route for seagoing ships requires wider navigation channel UW8 Intermediate piers badly situated in the middle of the watercourse UW9 Narrow navigation channels between abutments and piers cause difficult currents
(e.g. for slow towboats, log floating, etc.) UW10 Deep-water channel to be opened, higher ships to be expected on watercourse UW11 Log floating to be commenced, towboats need higher clearance
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UC10UC9 UC11 UC13UC12 UC14
UC6
UC2
UC4 UC5
UC1
UC3
UC7 UC8
Abbr. Explication of the event UC1 Service capability not adequate Under the bridge for road traffic (Cars) UC2 Vertical clearance for under-passing road traffic limited UC3 Horizontal clearance for under-passing road traffic limited UC4 Road traffic norms concerning vertical clearance on normal roads are to be changed UC5 Special loads route (e.g. minimum height 7.2 m) network to be extended, including
the under-passing road in question, need for higher clearance UC6 Stricter safety standards call for wider clearance between columns and abutments UC7 Change of the existing under-passing road into a "wide lane road", but the clearance
between columns is too narrow for that UC8 Change of the existing two-lane under-passing road into multilane road UC9 Road traffic norms to be changed on international level UC10 Road traffic norms to be changed on national level UC11 Standard to be changed on international level UC12 Standard to be changed on national level UC13 Too much traffic for two-lane road, more lanes needed UC14 Change from normal road to motorway
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AD10 AD11 AD13AD12 AD15AD14
AD9
AD2
AD5AD4
AD3
AD7AD6 AD8
AD1
Abbr. Explication of the event AD1 Service capability not adequate Above the bridge due Dimension-related causes AD2 Vertical clearance on bridge limited AD3 Horizontal clearance on bridge limited AD4 Road traffic norms concerning vertical clearance on normal roads are to be changed AD5 Special loads route (e.g. height 7.2 m) network to be extended, need for higher
clearance on the (truss) bridge in question AD6 New standard call for wider lanes AD7 Change of the existing road into a "wide lane road", but the horizontal clearance
between railings is too narrow for that AD8 Change of the existing two-lane road into multilane road AD9 Pedestrians need a lane of their own, separated (e.g. elevated) from traffic lanes AD10 Road traffic norms to be changed on international level AD11 Road traffic norms to be changed on national level AD12 Standard to be changed on international level AD13 Standard to be changed on national level AD14 Too much traffic for two-lane road, more lanes needed AD15 Change of the road from normal road to motorway
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AL7 AL8AL6
AL10AL9
AL5AL4
AL3AL2
AL1
Abbr. Explication of the event AL1 Service capability not adequate Above the bridge due Load-related causes AL2 Loads increased AL3 Load bearing capacity decreased AL4 Overloads increased AL5 Legal loads increased AL6 Road class change from lower to higher AL7 Change of standards for normal road traffic loads AL8 Special loads (harbour, mine, foundry, factory) AL9 Standard to be changed on international level AL10 Standard to be changed on national level
Fig 11. Fault tree in obsolescence analysis. After finding out the primary reasons of obsolescence (circles in figure 11), decisions can be made about countermeasures. There exist no thumb rules "do this, avoid that", but the decisions are case- and organisation-specific. The general Lifecon recommendation is that demolition of obsolete but otherwise sound facilities should be avoided as far as possible. Case 2: Building Another short obsolescence analysis example relates to the last obsolescence indicator of table 15, which are related to buildings: "Building does not reflect the imago that user wants to give". This example "Building does not reflect the imago that user wants to give" is more difficult to analyse, but eventually can be handled with the same procedure as the bridge example above. The idea is again to split the problem into "smaller pieces" (or parameters) in a structured way, and to find out the possible causes why the value of those parameters and their sub-parameters do not fit into user's imago.
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The splitting of the top event into smaller pieces could follow the following reasoning: The parameters of the building that have effect on the imago of the user are mainly
• location • outlook • internal spaces, surfaces, decorations, hallways etc • Comfort feeling generally: inside and outside the building.
Each of those three main contributors can be further divided, for example the outlook of the building can be further split to the following five sub-contributors:
• Style of the building (castle, storehouse, box...) • Colour of the building (colourful, trendy, old-fashioned, grim...) • Dimensions of the building (overall size of the building, doors/windows, height, width...) • Materials of the building (stone, brick, concrete, steel...) • Condition of the building (brand new, worn, near to collapse...)
This way the analysis goes on until the fundamental level is reached. After finishing the fault tree it can be seen which basic factors contribute to the contradiction between the present building and the imago promotion of the user. Depending on the source data the relative importance of the basic factors can be estimated and consequently countermeasures launched. All the time those factors must be studied with imago-orientated approach, i.e. throughout the analysis it must be studied how the identified parameters affect the imago of the user. Parameters that have no effect on the imago will be excluded from this imago-related obsolescence analysis, although these excluded parameters might have considerable effect on the overall business of the user. These contradictions must be taken into account in other analyses (e.g. in multi-attribute decision analyses) on corporate strategy level. An example of this kind of contradiction might be following: The company wants to give imago that they are open and very accessible to customers, and consequently have decided to have very large windows in the facade and open-plan office. However, the workers feel uncomfortable working close to windows, where all the passers-by can see them through the window, there is nasty draft especially during cold days near the windows and the open-plan office cause a lot of interruptions in work. If the company has not deemed workers' satisfaction as an imago factor, it will be excluded from the imago analysis, although it surely has effect on the business of the company. References to Chapter 5.3
1. Asko Sarja, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002. ISBN 0-415-25235-0. 2. Aikivuori, Anne 1994, Classsification of demand for refurbishment projects. Acta Universitatis
Ouluensis, Series C, Technica 77.University of Oulu, Department of Civil Engineering. ISBN 951-42-3737-4.71 pp.+7 Appendices.
3. Iizuka, Hiroshi 1988, A statistical study of life time of bridges. Structural Eng./Earthquake Eng. Vol. 5 No1, pp. 51-60, April 1988. Japan Society of Civil Engineers.
4. Lifecon Deliverable D2.3. http://www.vtt.fi/rte/strat/projects/lifecon/
5.4 Modelling of performance and service life
5.5 Service life design
Durability design, also titled service life design, means the designing and detailing of structures for a specified design service life. The design service life specifications are produced during the service life planning as a result of life cycle optimisation. Structural service life design can also be called durability design.
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Durability design methods can be classified starting with the most traditional and ending with the most advanced methods as follows:
1. Design based on structural detailing 2. The reference factor method 3. Statistically calculated lifetime safety factor method 4. Statistical durability design
Structural detailing for durability is a dominant practical method applied to all types of materials and structures. The principle is to specify structural design and details as well as materials specifications in such a way, that either deteriorating impacts on structures or the effects of environmental impacts on structures can be eliminated or diminished. The first principle is typically dominating in the design of structures that are sensitive to environmental effects, like wooden structures. The second principle is suited to structures that can be designed to resist even strong environmental impacts, like concrete structures and coated steel or wooden structures. The methods for durability detailing are presented in current the norms and standards. The factor method is aimed at estimating the service life of a particular component or assembly under specific conditions. It is based on a reference service life- in essence the expected service life under the conditions that generally apply to that type of component or assembly - and a series of modifying factors that relate to the specific conditions of the case. The method uses modifying factors for each of the following:
A. component quality B. design level C. work execution level D. indoor environment E. outdoor environment F. in-use conditions G. maintenance level
Estimated service life of the component (ESLC) = RSLC x A x B x C x D x E x F x G Where RSLC is the Reference Service Life of the component. For more detail refer to ISO/CD 15686-1, where the method is described. The lifetime safety factor design procedure is somehow different for structures consisting of different materials, although the basic design procedure is the same for all kinds of materials and structures. The design service life is determined by formula [4]:
gtd tt ⋅= γ , (4)
where td is the design service life, γt the lifetime safety factor, and tg the target service life.
The lifetime safety factor can be calculated with equation [5]
( ) nDt
11+⋅= νβγ (5)
where
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β is the safety index corresponding to the statistical reliability level
νD the coefficient of variation of degradation
n the exponent of the degradation function .
The lifetime factor design procedure is as follows:
1. Specification of target service life and design service life 2. Analysis of environmental effects 3. Identification of durability factors and degradation mechanisms 4. Selection of a durability calculation model for each degradation mechanism 5. Calculation of durability parameters using available calculation models 6. Possible updating of calculations of the ordinary mechanical design (e.g. own weight of
structures) 7. Transfer of durability parameters into final design
The simplest mathematical model for describing the event "failure" comprises a load variable S and a response variable R [5]. In principle the variables S and R can be any quantities and expressed in any units. The only requirement is that they are commensurable. Thus, for example, S can be a weathering effect and can be the capability of the surface to resist the weathering effect without unacceptably large visual damage or loss of the reinforcement concrete cover.
If R and S are independent of time, the event "failure" can be expressed as follows [5]: {failure} = {R < S} (6) (4) The failure probability Pf is now defined as the probability of that "failure": Pf = P{R<S} (7) (5) Either the resistance R or the load S or both can be time dependent quantities. Thus the failure
probability is also a time dependent quantity. Considering R(�) and S(�) are instantaneous physical values of the resistance and the load at the moment � the failure probability in a lifetime t could be defined as:
Pf(t) = P{R(τ)<S(τ)} for all τ < t (8) (6a)
The determination of the function Pf(t) according to the formula 6a is mathematically difficult. That
is why R and S are considered to be stochastic quantities with time dependent or constant density distributions. By this means the failure probability can usually be defined as:
Pf(t) = P{R(t)<S(t)} (9) (6b) Considering continuous distributions, the failure probability Pf at a certain moment of time can be determined using the convolution integral:
( ) ( )P F s f s dsf R S=
−∞∞∫
(10)
where FR(s) is the distribution function of R, fS(s) the probability density function of S, and s the common quantity or measure of R and S.
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The integral (10) can be solved by approximative numerical methods. The statistical method can in principle be used for individual special cases even in praxis, but this will not find any common use. The main use of statistical theory is in the development of deterministic methods. Such a method is the lifetime safety factor method presented above. References to Chapter 5.5
1. Sarja, Asko & Vesikari, Erkki (Editors). Durability design of concrete structures. RILEM Report of TC 130-CSL. RILEM Report Series 14. E&FN Spon, Chapman & Hall, 1996. 165 pp.
2. Sarja, Asko, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002. ISBN 0-415-25235-0.
3. Sarja, Asko 2004, Generalised lifetime limit state design of structures. Proceedings of the 2 nd International Conference, Lifetime-Oriented Design Concepts, ICDLOC, pp. 51-60. Ruhr-Universität Bochum, Germany, 2004. ISBN 3-00-013257-0
4. Sarja, Asko, Generic limit state design of structures. Proceedings of the 10DBMC International Conférence On Durability of Building Materials and Components, LYON [France] 17-20 April 2005. 8 pp.
5. Sarja, Asko et al, Predictive and optimising management of buildings and civil infrastructures. Manuscript, 569 p., To be published in 2005, SPON Press
5.6 Ecological analysis and calculations (economy of the nature)
The generic life cycle ecology (LCE) includes the following components [Lifecon D2.1]. • raw materials economy • energy economy • environmental burdens economy • waste economy • biodiversity
These components are weighted differently in different areas and places of the world, because the critical components are varying. Therefore we have to treat LCE on different levels:
• global level (e. g. the green house gas production and energy consumption) • regional level (e. g. water consumption and biodiversity) • local level (e. g. wastes, biodiversity, raw materials)
LCE should ideally include assessment of environmental impacts caused by all human activities throughout the whole life cycle of a structure. This is, however, a very difficult process since the relationship between the external environment and the category endpoint can be very complex. Normally, the Life Cycle Ecology (LCE), will stop at the step before category endpoint, showing only the impact categories, which is fairly easy to do, and then interpret the results from the various category indicators. The methodological framework for the assessment of environmental impacts from rehabilitation and maintenance of concrete structures is based on the ISO-standards 14040 - 14043. From the condition survey of a concrete structure, the method of maintenance and type of maintenance are first selected. The selections depend on type and extent of damage and type of external environmental conditions as well as type of equipment and materials to be used for the repair. The next step in the process is to determine the functional unit. The functional unit is the reference unit used in a life cycle study. All emission, energy and flow of materials occurring during the repair process are related to this unit. The functional unit shall be measurable and will depend on the goal and scope of the analysis. The goal of the Life Cycle Ecology (LCE) shall unambiguously state the intended application and indicate to whom the results will be communicated. Thus, the functional unit for a paint system may be defined as the unit surface (m²) protected for a specified time period. The maintenance/life cycle inventory (LCI) phase will consist of:
4. Quantifying the amount of all raw materials, chemicals and equipment, which are necessary to fulfil the maintenance function. This quantification gives the reference flow, for which all inputs and outputs are referred to and are closely connected to the functional unit.
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5. Providing environmental data of consumed raw materials, chemicals and equipment from the suppliers (specific data) or from databases (generic data) or from a life cycle inventory (LCI) carried out at supplier level. All materials used are recommended to have an environmental declaration with scope “Cradle to port”. The environmental declaration shall include use of resources such as energy (renewable, non renewable), materials (renewable, non renewable), water and waste as well as emissions to air and water.
6. Quantifying and classifying the waste from the process as recycling, disposal or hazardous waste. In order to demonstrate how the methodological framework for the assessment of environmental impacts can be applied to various types of repair and maintenance systems for concrete structures, two examples of commonly used systems have been selected for analysis. The one system is a patch repair with shotcreting, where the damage has been caused by a chlorideinduced corrosion of embedded steel. The other system is a preventive measure based on a hydrophobic surface treatment, which is commonly used as a general protection of the concrete surface both against moisture and chloride penetration. References to Chapter 5.6
[1] Lifecon Deliverable D 5.3: Methodology and data for calculation of LCE (Life Cycle Ecology) in repair planning. Authors: Vemund Årskog, Sverre Fossdal , Odd E. Gjørv. http://www.vtt.fi/rte/strat/projects/lifecon/. [2] Asko Sarja, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002. ISBN 0-415-25235-0. [3] Asko Sarja et al, Predictive and Optimising Life Cycle Management of Buildings and Infrastructures. Manuscript 2005. 631 pp. To be published in 2005 by Taylor&Francise, SPON PRESS.
5.7 Cultural acceptance criteria and analysis
Buildings and civil infrastructures are a very essential factor of our current quality and of the cultural heritage of our societies. The cultural criteria are quite local or regional, and they thus must be taken into consideration quite individually. In the ongoing globalisation process also these criteria are getting more and more unified, but in order to save local identity it is needed to keep some criteria local or regional alos in the future. The cultural criteria are coming from the following factors: - Building traditions - Life style - Business culture - Aesthetics - Architectural styles and trends - Image The analysis and planning and design methodologies are belonging to the expertise of architects, and they do not belong in details into technics. However it is important alos for engineers to learn to understand these requirements and criteria, and to treat them in co-operation with architects, owners and users in the multi-disciplinary design teams.
5.8 Multiple Criteria Optimisation and Decision making (MADA, QFD)
5.8.1 Analytical Hierarchy Process (AHP) as a set of Multi-Attribute Decision Analysis (MADA)
ASTM Standard E 1765-98: Analytical Hierarchy Process deals with “Standard Practice for Applying Analytical Hierarchy Process (AHP) to Multiattribute Decision Analysis of Investments Related to Buildings and Building Systems”.
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The Analytical Hierarchy Process (AHP) is one of a set of multi-attribute decision analysis (MADA) methods that considers non-monetary attributes (qualitative and quantitative) in addition to common economic evaluation measures (such as life-cycle costing or net benefits) when evaluating project alternatives. Because the method is presented in details in the ASTM standard E 1765-98, only a short general presentation of the method is described in this report. Each user can directly apply the standard in all calculations using the generic classification of attributes and criteria, as to be presented in this report in The procedure of the AHP method is as follows:
1. Identify the elements of your problem to confirm that a MADA analysis is appropriate. Three elements are common to MADA problems:
- MADA problems involve analysis of a finite and generally small set of discrete and predetermined options or alternatives.
- In MADA problems no single alternative is dominant, that is, no alternative exhibits the most preferred value or performance in all attributes.
- The attributes in a MADA problem are not all measurable in the same unit. 2. Identify the goal of the analysis, the attributes to be considered, and the alternatives to evaluate.
Display the goal and attributes in a hierarchy. - A set of attributes refers to a complete group of attributes in the hierarchy which is
located under another attribute or under the problem goal. - A leaf attribute is an attribute which has no attribute below in the hierarchy.
3. Construct a decision matrix with data on the performance of each alternative with respect to each leaf attribute.
4. Compare in pairwise fashion each alternative against every other alternative as to how much better one is than the other with respect to each leaf attribute. Repeat this process for each leaf attribute in the hierarchy.
5. Make pairwise comparison of the relative importance of each attribute in a given set; starting with sets at the bottom of the hierarchy, with respect to the attribute or goal immediately above that set.
6. Compute the final, overall desirability score for each alternative (this mathematical procedure is presented in details in the ASTM Standard: E 1765-98)
The ASTM Standard: E 1765-98 includes also examples which help in understanding and applying the method for different types of buildings. This standard refers also to several other ASTM standards which support the applications on different fields, e.g. the following:
- E 1670 Classification of the Serviceability of an office facility for management of operations and maintenance
- E 1701 Classification of serviceability of an office facility for manageability - E 917 Practice for measuring life-cycle costs of buildings and building systems - E 1480 Terminology of facility management (building related) - ASTM Adjunct: Computer program and user´s guide to building maintenance, repair
and replacement database for life cycle cost analysis, Adjunct to practices E917, E964, E1057, E1074 and E1121
- ASTM Software Product: AHP/Expert Choice for ASTM building evaluation, Software to support practice E 1765.
5.8.2 Principles of Quality Function Deployment Method (QFD)
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Quality Function Deployment (QFD) method is related to methods of linear programming which have been developed in 1950's and were widely used in 1960`s in product development of industry. In current formulation QFD was developed in Japan and it was first used in 1972 by Kobe Shipyard of Mitsubishi heavy industries in 1972 [Zairi, QRM, vol.12, 1995 p 9-23]. In different fields of application appeared a need to modify the basic linear programming methodology for specific needs of each application field. Results of these applications are all the methods mentioned above: QFD, MADA and RAMS. QFD has been increasingly used in Japan and since 1980's also in USA and Europe and world wide. Mainly the use until now has been in mechanical and electronics industry, but applications exist also in construction sector. In industrial engineering, manufacturing companies have successfully applied Concurrent Engineering tools, e.g. Quality Function Deployment (Akao, 1990) to determine customers' needs for the features of the product into design at its early stages of development, to integrate concurrent design of products and their related processes, and to consider all elements of the product life cycle. Customer-oriented “champion products” may also be priced higher than their competitors, and still become as market leaders. In spite of its “success stories” in other industries during the past decade, QFD has been little applied in construction. Examples from Japan, United States, Finland, Sweden and Chile show, however, its potential also in building design. (Nieminen&Huovila 1997 [47]) Simply the QFD method means building of a matrix between Requirements and Performance Properties or Technical Specifications. The QFD matrix (House of Quality) is presented in Figure 5.11. This matrix will be filled with Requirements and their Weighting Factors in the rows along the left hand side, and Performance Properties of the actual alternative in the columns along the top portion. The centre describes the matrix-relationship of requirements and corresponding solutions. The importance measures (weight factors) are at the bottom, and the right hand side of the box shows the evaluation of competing alternatives. The correlations and weights can not usually be estimated with exact calculations, but they must be estimated with expertise knowledge, client questionnaires, long term experiences and expectations on the future trends. The weights can be expressed in different scales, for example on the range of 0 (no importance) to 10 (extremely important). As final results of the matrix calculations the weight factors of Requirements and Properties are normalised, as shown in following case examples and in Lifecon Deliverbale [D5.1]. Usually the Performance Properties are serving only as a link between Requirements and Technical Specifications, why the Performance Properties sometimes are not treated with QFD method. Additionally weighting factors of Requirements and Technical Specifications as well as correlations between Requirements and Technical Specifications are identified and determined numerically. As a computer tool is Excel program very suited for this calculation, as it has been used in examples [D5.1]. QFD procedure usually has three main phases, as presented in the application examples in attached Appendix and in Deliverable D5.1:
1. Selection of the Primary Requirements and their weight factors from a set of numerous detailed Requirements with the aid of QFD matrix
2. Moving the Primary Requirements and weight factors into second QFD matrix for selection between the alternatives of plans, designs, methods or products
3. Sensitivity analysis with simulation of variances of Primary Requirements and Properties [D5.1].
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Properties of the alternative plan/design/ method / product
Correlation coefficients between each Requirement and each Property
weight factors of Requirements
Requirements of user/owner/society
weight factors of Properties
Figure 5.11 House of Quality [47 ].
5.8.3 General Use of QFD Method Fundamental objectives of QFD are:
- Identification of customers demands - Interpreting customers demands first into functional and then into technical
specifications of the building - Optimising the technical solutions in comparison to requirements - Selection between different design alternatives
Quality Function Deployment is a tool for optimisation and decision making, which has a strong numerical character thus serving especially following functions:
- analysis and weighting of the requirements - optimisation of solutions with a choice between different modifications of the solution - choice between alternatives of plans, designs, methods or products.
QFD can be used for interpreting any requirements into specifications which can be either functional or technical specifications. Thus QFD can serve as an optimising or selective linking tool between requirements and specifications. It can be used at product development, at design of individual civil infrastructures or buildings, and at maintenance and repair planning QFD can be applied both on strategic level and on operational level of construction and asset management organisations. The strategic development of the owner, user, construction or management organisation may have following focuses:
- strategic planning of the organisation - product development (product can be an entity: house, office, road, bridge, tunnel etc.),
or a more detailed product (module, component or material) In practical planning and design the application shall be limited into few key Requirements and key Specifications in order to maintain good control of variables and in order not to spend too much effort for secondary factors.
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At product development some more detailed application can be used. The principle of the key attributes and parameters can be applied in each type of design cases differently in order to get an optimal use of QFD method. In practical construction or repair process QFD has to be applied in four stages:
1. Analysis of the Requirements of the client, and their weights of importance. As results of the first stage are the weights of Requirements.
2. Choice of the Properties of the Product (e. g. a house, office, bridge, railway, tunnel etc.) basing on the Requirements and their weights, which have been resulted from stage 1. Result of the second stage is a list of the Properties of the Product, and the weights of these Properties.
3. Analysis of the Requirements of the Product for the Production Process. Third stage results in a list of Requirements of the product and their weights for a fluent production process. This stage consists of analysis of correlations between focused phases of the production process and the properties that the product requires from these phases.
4. Analysis of the Requirements of the Production Process for the Product. Fourth stage includes analysis on, what the production process and its phases require from the product. This leads into an iterative optimisation between the properties of the product and the properties of the production process. The Requirements from the first stage serve as constraints in this optimisation but they may have to be slightly modified, if the iteration does not converge otherwise.
This means, that interactions between all phases of the planning, design and production are analysed and optimised with the QFD method. An example of this procedure is presented in the repair planning examples of Lifecon deliverable D5.1, where QFD is used in combination with RAMS (reliability, availability, maintainability, safety) methodology. The words in the title: RAMS include the requirements of the properties of the product and manufacting process for the alternative repair technologies or materials. This in fact is a mix of points 3 and 4 above [D5.1]. The following phases of a construction process are identified potential for QFD implementation in construction:
1. PROGRAMMING: Customers’ requirements for the building and design objectives 2. DESIGN: Design objectives and construction drawings 3. PRODUCTION: Construction drawings and production plans 4. CONSTRUCTION: Production plans and construction phases.
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Correlation between Design Specifications Primary functional attributes: 1. 2. 3. 4. 5.
Primary Demands
Correlation between Design Specifications and Requirements, c
Priorities of
Demands, p
1.Monetary Economy
1 0,5 0,2 0,5 0,3 9
2.Functionality 0 1 0 0,1 0 10 3.Natural Economy
0 0 1 0 0 8
4.Health 0 0,1 0 1 0,2 10 5.Aesthetics 0 0 0 0,2 1 8 Σ( c x p) 9 15,6 9,6 15,7 12,7 Σ = 62,6 Priorities of functional attributes = c x p/Σ( c x p) 0,14 0,25 0,15 0,25 0,20
Figure 5.12 Demands and their priorities. Primary functional attributes: 1. Life cycle monetary costs 2. Life cycle functionality 3. Life cycle maintenance 4. Life cycle environmental costs 5. Healthy, aesthetics and comfort
Primary technical specifications 1. Product structuring for changes and
reuse 2. Service life specifications 3. Static and dynamic specifications 4. Energy specifications 5. Environmental specifications 6. Hygro-thermal specifications 7. Acoustic specifications 8. Fire safety specifications 9. Health specifications 10. Maintainability and repairability
Schedule for analysis between primary functional attributes and technical specifications can be presented as follows:
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Correlation between Design Specifications Primary technical specifications: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Primary
functional attributes
Correlation between Design Specifications and requirements, c
Priorities of functional
attributes, p 1. 0,3 0,2 0,2 0,2 0,0 0,2 0,0 0,0 0,0 0,3 9 2. 0,5 0,3 0,3 0,3 0,0 0,3 0,2 0,1 0,3 0,3 10 3. 0,5 0,5 0,4 0,1 0,0 0,4 0,1 0,1 0,2 0,8 9 4. 0,2 0,1 0,1 0,8 1 0,2 0,0 0,0 0,1 0,3 8 5. 0,0 0,0 0,0 0,4 0,2 0,8 0,3 0,1 1 0,5 10
Σ( c x p) 13,8 10,1 9,2 16,1 10 18 5,9 2,9 15,6 20,3 Σ = 121,9
Priorities of technical
specifications = c x p/Σ( c x p) 0,11 0,08 0,08 0,13 0,08 0,15 0,05 0,02 0,13 0,17
Figure 5.13 Functional attributes and their priorities. Priorities of technical specifications can again be used as weighting factors for comparisons between different design alternatives and products regarding to owner`s and user`s demands and requirements. Similar scheme with earlier schemes have been applied in the following case studies [47]. CASE 1: VILLA 2000
The design of Villa 2000 was teamwork, where each designer had a possibility to influence decision-making within other design fields outside his own design responsibilities. A design briefing process was organised to capture the owner’s requirements for the building. QFD method was experimented to set design guidelines for Villa 2000. The IEA task 23 criteria were expressed in a form of performance requirements and they are given weights (scale 1 to 5) depending their importance. The potential design solutions are then created in a from of properties and their correlation with the requirement is given (scale 0, 1, 3 or 9). The QFD spreadsheet tool summarizes numeric values of the properties in the bottom of matrix by multiplying the correlation with their weights so that high values indicate high priorities. The user may then select the most important properties as a basis for next phase of development. The exercise was conducted together with ten experts of different backgrounds. The following objectives were set for the working session:
- to share common understanding of the performance-based objectives of the end product (a building to be designed and constructed)
- to prioritize the project objectives - to strive for innovative design solutions that meet these objectives.
The first matrix (figure 6) shows the selected main objectives of a housing project (adaptability, indoor conditions, economy, environment friendliness, constructability and architecture) taken as a basis for building design. The second matrix (figure 4) shows the structured approach in the design process based on the selection made in phase 1. The importance of the whole design and construction process was
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recognised as the key to fulfil the requirements, and the functionality and adaptability of the house as the key to future housing.
PHASE 1
Requirements ada
ptab
ility
res
ale
valu
e
ind
oor
cond
ition
s
attr
activ
enes
s
eco
nom
y
aut
onom
y
fri
endl
ines
s to
the
envi
ronm
ent
fut
urity
hab
itabi
lity
res
pond
to th
e en
viro
nmen
t
goo
d in
door
clim
ate
con
stru
ctab
ility
ide
ntity
tot
al e
colo
gy
arc
hite
ctur
e
sim
ple
user
inte
rfac
es
rec
ycla
ble
fair
hous
e
tra
nsfe
rabi
lity
dis
mou
ntab
ility
Im
port
ance
fact
or
functionality Utilisability 9 9 9 9 3 9 3 0 9 0 9 0 1 1 0 9 3 1 0 5 Adaptability 9 3 0 9 3 1 9 3 9 0 0 1 1 9 0 1 9 9 9 2 Maintainability 3 3 3 3 9 9 9 0 9 0 3 0 0 9 1 3 1 1 1 2
environmental Operation 9 3 9 3 9 9 9 1 1 9 9 0 0 9 0 0 0 0 0 4loading Construction 0 0 0 3 3 0 9 0 0 0 0 9 1 9 1 0 9 9 9 2
resource Energy 9 3 9 3 9 9 9 9 0 9 9 0 3 9 0 0 1 1 1 5use Water 9 1 0 1 3 9 9 3 1 0 0 0 0 3 0 1 0 0 0 1
Materials 3 9 9 3 9 1 9 9 9 0 9 9 9 9 3 0 9 9 9 1life Investment cost 9 9 3 3 9 3 0 0 0 3 3 9 1 0 0 1 3 3 3 3
cycle Operating cost 9 9 1 3 9 9 9 3 0 3 1 0 3 3 9 9 3 3 3 4cost Maintenance cost 9 9 3 9 9 9 9 9 0 9 3 0 3 3 9 3 3 3 3 2
indoor Acoustic comfort 9 9 9 9 0 0 0 9 9 0 0 3 3 0 9 0 0 0 0 2quality Thermal comfort 9 9 9 9 0 0 3 9 9 9 9 3 3 0 9 3 0 0 0 3
Lighting 9 9 9 9 3 9 3 9 9 9 0 3 9 1 9 1 0 0 0 4 Indoor climate 3 9 9 9 0 0 3 9 9 9 9 9 9 1 0 0 0 0 0 5
architecture Architecture 9 9 9 9 9 3 0 9 9 3 0 9 9 0 9 1 3 3 3 3Weight factor 393 355 322 307 285 273 258 250 248 246 241 182 180 179 169 118 112 102 97 0 4317Weight factor % 9 % 8 % 7 % 7 % 7 % 6 % 6 % 6 % 6 % 6 % 6 % 4 % 4 % 4 % 4 % 3 % 3 % 2 % 2 % 0 % 100 %Votes 4 1 3 2 1 3 1 2 4 4 1 1
Selected x x x x x x
Properties
Figure 5.14 Design objectives for a housing project, phase 1 (Nieminen & Huovila 2000). PHASE 2
Requirements
SPACE
PROCESS
STRUCTURES
MATERIALS
ENERGY
EQUIPMENT
Importancefactor(P1)
adaptability, simple interfaces, re-usable fair house 9 9 9 3 3 1 3indoor conditions, responds to the environment 9 9 9 9 9 9 4economy, resale value 9 9 9 9 9 9 1environmental,autonomy, total ecology 9 3 9 9 9 9 5constructability 1 9 3 1 1 1 3architecture 9 9 3 9 1 0 2Weight factor (P1) 138 134 133 120 104 95 724Weight factor % 19 % 19 % 18 % 17 % 14 % 13 % 100 %
Properties
Figure 5.15 Design objectives for a housing project, phase 2.
CASE 2: NURSERY SCHOOL The second QFD example was to set the project objectives with a view to the building user’s needs and requirements and, to show how the chosen criteria and the view, the user’s view affect the results. QFD matrix was used to capture, record and verify the client’s requirements and, to test the dependency between the requirements and the properties of the introduced building concept. The project used in the test is a nursery school for about 100 children to be built in the year 2000. The design process of the building is to be finished towards the end of 1999, based on an architectural
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competition. The nursery school Merituuli will be built in a new suburban housing area, a former industrial area, where the basic infrastructure has already been developed (streets, access to main roads, district heating net, etc.). The location of the area is very close to the city of Helsinki with a good public access to the city, a fact that has made the area very popular especially among young families. This has also grown to be a design feature for the nursery school building and it’s connection to the surrounding housing area. The building will serve as nursery school daytime, and in the evening as a meeting point for local inhabitant activities. The total building area is 1260 m2 one story. The owner of the building is the City of Helsinki, and the Construction Management Division (HKR) of the City of Helsinki constructs the building. In a number development sessions, arranged both between the client and VTT in the beginning of the project and, later on between the designers, project management and VTT, the project goals and limits were discussed and the requirements were set. The decision making in the project was tested against the main criteria adopted from the IEA Task 23 framework. The results of the design briefing sessions were used as building owner defined sub-requirements in compiling the QFD matrix (figure 7). According to the QFD results, the main properties of the nursery school building corresponding to the given requirements are district heat, bicycle access to the site, cleanable ventilation ductwork, multi-use playrooms for children and low-energy building envelope. Environmental goals of the project prioritized as the most important properties. Even though the builder has an environmental program to support sustainable construction, it is not surprising, that the requirements dealing with functionality or air quality in a nursery school are dominating the pre-design process. MCDM-23 tool was used to evaluate the introduced technical design solution and to compare the design with typical existing nursery schools. Also a low-energy concept for the nursery school was developed and analyzed accordingly. The proposed solution (basic design, figure 8) brings along improvements compared to typical nursery school. By improving the energy efficiency of the building, both user friendliness (functionality, indoor climate) and environmental properties and life cycle costs are improved.
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PHASE 1
Requirements dis
tric
t hea
t
bic
ycle
acc
ess
to s
ite
cle
anab
le d
ucts
mul
ti-us
e pl
ayro
oms
low
ene
rgy
enve
lope
mec
hani
cal v
entil
atio
n +
HR
cha
ngea
ble
duct
com
pone
nts
sep
arat
ed s
ervi
ce s
pace
sup
er w
indo
ws
floo
r hea
ting
sol
ar c
ontr
ol
yar
d fa
cing
Sou
th
stim
ulat
ing
spac
es, c
hild
sca
l
L-fo
rm
sep
aret
ed p
ublic
eve
ning
use
ord
inar
y w
indo
ws
trad
ition
al e
nvel
ope
radi
ator
s
Impo
rtanc
e/W
eigh
t fac
tor (
P1)
low investment cost 9 1 0 9 0 0 0 0 0 0 0 0 0 3 0 1 3 0 5LCC low service cost 9 1 9 3 9 0 0 3 9 3 3 0 0 3 0 0 0 0 4
low maintenance cost 9 1 9 3 0 0 9 9 0 1 0 0 0 1 0 0 0 3 1low electricity consumption 9 0 3 3 1 0 0 0 0 0 3 9 0 0 0 1 0 0 4
resource use low water consumption 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4long service life 0 0 3 0 0 0 9 3 0 0 3 0 0 0 0 0 0 1 3low CO2, NOx, SO2 emissions 9 0 0 0 9 9 0 0 9 0 9 0 0 0 0 0 0 0 5
environmental particles 0 0 9 0 3 9 9 0 0 0 0 0 0 0 0 0 0 0 5loading existing infrastructure 9 3 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 1
home-like 0 9 0 9 0 0 0 1 0 3 0 3 3 1 0 0 0 1 3archit. quality attractive to children 0 3 0 9 0 0 0 0 0 9 0 3 9 1 0 0 0 0 4
public service building 3 9 3 0 1 3 3 1 1 0 0 0 0 1 9 0 0 0 1air purity + emissions 0 9 9 0 0 3 3 0 0 0 0 0 0 0 0 0 0 0 5high thermal quality 0 0 0 0 9 9 0 0 9 9 9 0 0 0 0 0 0 1 3
indoor quality illumination 0 0 0 0 0 0 0 0 0 0 0 3 0 3 0 3 0 0 5echoing 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1low HVAC noise 0 0 1 0 3 0 0 9 0 1 0 0 0 0 0 0 0 0 2user access to site 0 9 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 4service access 0 0 0 0 0 0 0 9 0 0 0 0 0 3 0 0 0 0 3
functionality safety in use 3 3 0 0 0 0 3 9 0 3 0 3 9 3 0 0 0 0 5evening use 0 9 0 0 0 0 0 0 0 0 0 3 0 0 9 0 0 0 1high adaptability 0 0 1 9 1 0 9 3 1 3 1 0 0 1 9 0 0 0 2
Weight factor (P1) 207 169 163 153 136 135 132 130 111 108 107 90 90 89 42 24 15 12 0 0 1913Weight factor % 11 % 9 % 9 % 8 % 7 % 7 % 7 % 7 % 6 % 6 % 6 % 5 % 5 % 5 % 2 % 1 % 1 % 1 % 0 % 0 % 100 %g ( )gSelected X X X X X X X X
Propert ies
Figure 5.16 Design priorities for a nursery school (Nieminen & Huovila 2000).
Figure 5.17 Analysis of two design solution and comparison to properties of a typical nursery school building. 5.8.4 Alternative applications of QFD in Life Cycle Management System (LMS)
QFD method basically means only handling the Requirements and Properties, analysing their interrelations and correlations as well as their weights and finally optimising the LCQ (Life Cycle Quality) Properties and selecting between alternative solutions of asset management strategies or MR&R plans, designs, methods and products. This is why QFD can be applied in many variables, depending on the characteristic aims and contents of each application. In Lifecon LMS QFD can be used for following purposes:
- Identifying functional Requirements of owner, user and society
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- Interpreting and aggregating functional Requirements into primary Performance Properties
- Interprating the Performance Properties into Technical Specifications of the actual object
- Optimising the Performance Properties and Technical Specifications in comparison to Requirements
- Selection between different design and repair alternatives and - Selection between different products
The following detailed procedure can be applied in LIFECON LMS when using QFD for analysis of functional requirements against owner's and user's needs, technical specifications against functional requirements, and design alternatives or products against technical specifications:
1. Identify and list factors for “Requirements” and “Properties” 2. Aggregate and select the Requirements into Primary Requirements 3. Evaluate and list priorities or weighting factors of “Primary Requirements” 4. Evaluate correlation between “Requirements” and “Properties” 5. Calculate the factor: correlation times weight for each “Property” 6. Normalise the factor “correlation times weight” of each “Property” for use as a priority
factor or weighting factor of each “Property” at the next steps QFD can be used on all levels of LMS system:
- Network level: prioritising the requirements of users, owners and society, strategic optimisation and decision making between alternative MR&R strategies
- Object level: ranking of priorities between objects, optimising and decision between MR&R alternatives, technologies, methods and products
- Module, Component and Detail/Materials levels: refined optimising and decision between MR&R alternatives, technologies, methods and products
5.9 MR&R (Maintenance, Repair and Rehabilitation) Planning
Author: John B. Miller, Managing Director of Millab Consult a.s., Oslo, Norway.
5.9.1 Concepts
Maintenance, repair and rehabilitation are related activities that merge and overlap without there being clearly defined boundaries between them. Maintenance is usually perceived as being upkeep characterised by operations such as cleaning, touching-up, minor repairing, replacing worn materials and the like, which are expected during a structure's lifetime, and are regarded as being reasonable and inevitable. Maintenance becomes repair when the extent and type of work required tends to fall outside of that of the routinely and reasonably expected. The necessity for repair arises when deterioration cannot, or can no longer, be prevented by routine maintenance. Examples of deterioration which lead to the necessity for repairs are those caused by agencies such as carbonation, chloride contamination, frost, moisture ingress, chemical attack, thermal movement and the like. When deterioration has advanced to a stage where repair work becomes global to the structure, or major parts of it, the concept of rehabilitation arises.
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Maintenance, repair and rehabilitation are also relative concepts. The maintenance in one type of structure which may reasonably be expected during its lifetime may be viewed as catastrophic failure in others. For example, one would not be surprised by the damage caused to industrial floors subject to thermal shock in, for example, foundries, and the routine maintenance scheme would be expected to deal with it. Damage of similar severity in a parking facility, from whatever cause, would not be expected and could not be handled by normal routine maintenance. Likewise, in the agricultural facilities of some countries, rehabilitation is often not considered until the structure is near collapse. For civil and domes-tic structures, rehabilitation is normally required long before damage has advanced to such a degree. When planning maintenance and repair of a structure, its maintainability and reparability have to be considered. Rehabilitation has no such corresponding concept. In rehabilitation, the aim is to bring the structure's condition back to near its original condition, often with some improvement, and one is not to the same degree bound by the constraints of working with existing configurations or even with the same materials. Nevertheless, maintainability and reparability are concepts that have to be considered in rehabilitation work also, since nothing is everlasting and maintenance and repair will be required at some point in time after rehabilitation. In passing, it is mentioned that the term 'restoration' is reserved by the author to apply to the specialist works required for the preservation and repair of listed, protected and historic structures that have little to do with the upkeep of ordinary commercial, civil and domestic structures. Sometimes also, the term 'remediation' is used in connection with repair and maintenance work. This term is unfortunate since it applies rather to the removal of destructive influences than to the repair or maintenance work made necessary by these influences. Another much bandied word is 'refurbishment'. This word properly refers to what may be regarded as 'brightening up' or 'redecoration' rather than to the relatively intensive intrusions required in the repair and rehabilitation of concrete structures. The terms repair and rehabilitation have dictionary definitions which are close to the concepts understood and applied by contractors, End Users, authorities and consultants to concrete structures. However, the concept of maintenance has a wider compass and includes contingent actions which are not connoted by dictionary definitions. Thus, in the Lifecon project (1), maintenance is defined to be the 'combination of all technical and associated administrative actions during the service life (required) to retain a repair and/or upgrade in a state in which it can perform its required functions'. 5.9.2 Necessary planning elements
There are many possible ways to make MR&R plans, but there are five overriding, basic elements which should to be incorporated into any proper plan. These elements are: - Survey and condition assessment - RAMS characterisation (Reliability, Availability, Maintainability and Safety) of materials,
techniques and personnel - LCC (Life cycle cost) - LCE (Life cycle ecology) - Combined quantification of results In the first place, and necessary to get anywhere at all, is a proper survey which allows an accurate condition assessment and which is sufficiently predictive to allow sensible plans for future MR&R to be made. In the second place, the types of damage and deterioration suffered by a structure should be classified according to their RAMS characteristics, as should the RAMS characteristics of the possible repair materials and techniques which may be used to rectify that damage and deterioration. In the third place, the life cycle cost of the MR&R actions necessary to keep a structure serviceable for its projected lifetime needs to be estimated. In the fourth place, the LCE of the MR&R actions throughout the lifetime of the structure need to be estimated. Finally, a tool is needed for the combined quantification
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of all aspects of MR&R planning, including the more diffuse aspects such as, for example, health and happiness, culture, tradition, etc., in order that totalities may be compared. To make MR&R plans encompassing these five elements is a complex task, and is practically insurmountable without effective tools. The purpose of the following is to attempt to show how these tools can be constructed and how they can be used.
5.9.3 Survey and condition assessment
In order to manage a structure properly, it is necessary to collect and systematise as much information as possible about its history, design, construction, and present and probable future condition. Thus, the management of structures involves the registration, systematising and treatment of large amounts of data in the form of drawings, notes, building descriptions, diaries, photographs, weather conditions, loads, environmental factors, concrete mix designs, anomalaties, survey results etc.. MR&R planning therefore involves the administration of documents of all kinds, and includes the registration of field and laboratory survey data, the mathematical treatment of the latter, and, finally, the generation of reports. To do this efficiently requires the use of a sutiable IT tool, such as that used by the author (2) which consists of the four basic modules shown in Figure 1 and described below. The tool is in the form of a computer programme which can be installed on an ordinary PC.
5.9.3.1 Module 1 - Archiving module
End Users and their caretakers have a need to register, store and maintain much information pertaining to the properties and structures for which they are responsible. Very often, much of this information is lost due to lack of proper systemisation and safe deposition in a easily overviewed and easily accessible archiving system. The core of Module 1 is therefore be a relatively simple programme for
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Figure 5.18 Model for the construction of a tool for MR&R information collection and administration
the administration of documents. Data is entered principally by scanning paper documents (to the extent that digital material is not available) with a facility for the conversion of varying formats to common formats. Digital enhancement and clean-up features for photos, faded texts, and soiled and creased drawings would be useful, though they are not as yet integrated in the author's programme because such features are available in third party programmes.
The module makes it possible to keep all documentation safe, in multiple copies, and in easily accessible form, for example by storage on CD or DVD ROM discs, or on any other suitable medium.
5.9.4 RAMS (Reliability, Availability, Maintainability, and Safety).
When planning repair or maintenance, the four characterising aspects of Reliability, Availability, Maintainability, and Safety have to be considered. In the Lifecon project (1), these terms have been defined as follows:
Reliability: The ability to reduce maintenance to a minimum during service life. Availability: The ease of supply of methods, systems, materials or qualified personnel.
Maintainability: The ease with which the combination of all technical and associated administrative
actions during the service life can retain a repair and/or upgrade in a state in which it can perform its required functions.
1. Archiving module for:
Drawings Protocols Maintenance works Paper document of all kinds, etc
2. Registration module for:
Co-ordinate system Carbonation depths Chloride data from analyses Cover thickness measurements Humidity measurements ECP measurements
4. Report module
Damage development prognosis Control intervals and extent Calcultion of quantities Repair strategy
3. Number crunching
Calculation of carbonation constants Calculation of critical chloride
content Calculation of chloride penetration
rate Reduction of ECP easurements
Statistical analyses
Surveys Alterations Photos
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Safety: The health and accident risks that can be directly connected to methods, systems, products and their end results.
Each of these characteristics is important in its own right, but their relative importance to a structure is varies and has to be thoroughly understood before relevant planning of maintenance, repair and rehabilitation can sensibly be undertaken. Thus these four concepts will be discussed somewhat before proceeding to the task of quantifying their qualitative aspects. Reliability If, in an ideal case, a structure is easily accessible with high maintainability, and the required materials are cheap, plentiful and easily applied by non-skilled personnel with near zero health or accident risks, then the reliability of the materials or methods used does not have to be very high. It can, in fact, be rather low. An example of such a case could be the painting of an outside wall at ground level with a simple latex paint because the old paint was worn or unsightly.. If, on the other, paint for protection against corrosion has to be renewed on aerial masts on top of a communications tower, the reliability of the paint and its method of application has to be very high because the maintainability is low, while the risk of health injuries, perhaps due to chemical substances in the paint, or to accident, could be relatively high. In this case, also, the availability of the material would be of importance, but not necessarily primely so.
Availability. The ease with which materials, trained personnel, methods and/or systems can be had is measured by the time necessary to have them available for use on site. This time has a direct bearing on reliability and can also have a bearing on maintainability. Obviously, for example, if a particular product is difficult to obtain with a long lead time, then the reliability should be high compared to that of more easily acquired products. In cases where particular materials, methods, systems or trained personnel no longer exist or can be obtained, a structure requiring thier use becomes difficult to maintain and its maintainability would therefore be low. This can happen when products or equipment go out of production for one reason or another, or when necessary licences are denied, unattainable, or undesirable, or when skills have been lost. Availability of materials, methods, systems and qualified personnel have a decided impact on maintenance and repair planning. Apart from numerous instances of materials which have fallen out of production, or materials the use of which has became restricted for health and/or environmental reasons, restrictions or difficulties imposed by patents or licences have to be considered, as do difficulties in obtaining planning permission. On occasion, materials and qualified personnel can be difficult to find and lead times can be long. Sometimes personnel capable of applying older materials or techniques, or the materials themselves, simply cannot be had. In addition, the future of the supply of maintenance and repair materials has to be considered before proper planning can proceed.
Maintainability Circumstances causing structures to have low maintainability, besides the obvious and common one of difficult access, could be the availability issues discussed above, such as difficulties in obtaining permission to carry out the maintenance, or the materials used in the structure being inherently dif-ficult,.or perhaps even impossible to repair. Maintainability can also be low because of onerous but necessary health and environmental precautions, such as those required when radiation or toxic substances are present. Work in confined spaces, in high or very low temperatures, in foul atmospheres, in high winds, on unstable footing, in poor visibility, or in heavy seas can all lead to low maintainability.
The question of access is often of overriding importance in maintenance planning. If access to concrete structures entails the building of disproportionately extensive scaffolding systems, or the closure of im-portant traffic facilities, or the removal of extensive installations, then these would be examples of structures of low maintainability. Imagine, for example, a service tunnel to a subway station where the station also serves as an atomic shelter. Such a tunnel could be literally crammed with technical equipment such as warning, signalling,
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measuring and communication equipment, control panels and associated electronic and electrical equipment, air filters, decontaminators, pipes and cables, emergency generators with necessary fuel and exhaust systems, transformers and converters, battery banks, medical supplies and equipment, emergency rations, kitchen equipment, etc., To repair the surface of such a tunnel, say to stop water leaks, could entail the entire removal of all the technical installations with the consequent closure of the station and perhaps even of some subway routes for a lengthy period of time. In such a case, maintainability would be near zero, and the demand for reliability would be extremely high whilst availability would tend to become a secondary aspect providing that whatever was required was actually obtainable. This is a far cry from our ground level paint job where the janitor can buy a can of paint at the nearest store and slap it on with a brush in fair weather troubling no-one.
Safety Safety in maintenance, repair and rehabilitation planning has to do with the risks to which the workforce, the general public, and the environment are exposed during the performance of the relevant works. Safety is a function of the structure under consideration. Safety aspects are very different in the cases of our ground level paint job and the painting of the aerial masts atop the communications tower. It is thus obvious that the type of structure, its use, its location, its exposure, its artistry, and the installations which it contains or supports, all have an influence on its maintainability, reparability or ease of rehabilitation, and consequently on the planning of its maintenance, repair or rehabilitation. In addition to these four characterising aspects, there are others at least as important, but more difficult to quantify, which have to be considered. Chief amongst these are environmental impingements and effects on human well-being, health and social functioning. Finally, no MR&R plan would be truly complete unless some consideration is given to the ultimate demise of the structure in question. At the end of a structure's serviceable life, it does not simply disappear. We have all seen unsightly derelict buildings which have stood neglected and vandalised, often literally for decades, before a decision is made to remove them or convert them into useable structures. Letting structures slowly decay and contaminate the environment and human well-being is becoming less and less of an option, and the necessity to plan for the old age of structures is coming more and more to the fore. Though this aspect properly falls outside of the realms of maintenance, repair, and perhaps even of rehabilitation, it should be borne in mind that the removal of structures has a cost, both financially and environmentally. For some types of structures the cost can be very high. Cases in point here are the removal of the large North Sea concrete gravity platforms and atomic reactors.
5.9.4.1 Re-iterative decision making Existing standards and norms relating to MR&R planning describe condition assessment works, rehabilitation methods, and suitable repair materials, but they do not offer a complete decision making tool, nor do they include the environmental and human aspects found in today’s legislation. At present, MR&R strategies are developed by the End Users using some form of in-house decision making technique, often using poor quality information from inadequate or inaccurate surveys. A decision making tool, which integrates lifetime considerations, environmental aspects, total costs, and accurate and adequate surveys, all balanced against the actual available resources, is clearly needed. This need can be met by a decision making process which can be tailored to meet the End User’s needs, such as that illustrated by the flow diagram shown in Figure 2 and described below. The flow diagram shows the re-iterative process of finding the best MR&R strategy within the budgeted resources. Note that the diagram includes Life Cycle Ecology (LCE) and Life Cycle Cost (LCC) considerations. Note too that the concept of 'Total Cost' is introduced and encompasses the monetary value placed on health and environmental factors. At present, these last two factors are not always taken into account by the End User, and are unlikely to be unless governing legislation is in place. The former can nevertheless be estimated, and for the latter, models for calculating environmental consequences in a quantitative fashion exist [4,5].
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In Figure 5.19, Box no. 1 contains the End User, normally the End User of the structure in question. An End User can be an individual, a company, an authority, a co-operative, a municipality, the military, or even a government. For our purposes, the End User is whoever, or whatever, is footing the bill. It may be objected that the proper End Users are those who actually use the structure, for example motorists in the case of roads, passengers in the case of public transport, and the like. However, such a view is untenable in that these people are not normally in a position to make the necessary strategy decisions, and they have therefore somehow delegated their End-Usership to representatives whose job it is to take care of their interests. How well the representation does is another matter.
Figure 5.19 The re-iterative decision making process As a starting point in the planning of MR&R of a structure, the End User would normally commission a survey to be performed in order to gain sufficient information on its condition as indicated in Box no. 2. Obviously, such a plan is only as good as the information upon which it is based, and it is thus of paramount importance that the survey provides sufficient, relevant, good quality data, which unfortunately is not always the case. The intention contained in Box no. 6 is that data must provide information on the degradation mechanisms which are at work, and on the extent to which they have wreaked their damage, and, not least, on the rate of deterioration. In addition, the survey must take cognition of the destructive effect of singularities which may have arisen at some time in the structure's
Re-iterations (Repair strategy development)
END USER
Familiarity with the structure
Lifetime considerations
BudgetingGoverning
factor
Knowledge of degradation mechanisms and extent
Best use of money and resources
Applicable products and methods
What can be done?
Where can products and technology be had?
Who can do it?
What is the total** cost?
Possible outcomes:
-viable not achievable
Condition assessment
De
1
2
3 4 5 6
7
8
9 10 11 12
13
14
15
** Total cost means all incurred costs, environmental and health costs included.
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past, whether from constructional errors or from singular agencies such as fire, explosion, collision, earthquake, flooding or the like. Another ingredient in the making of plans is the End User's familiarity with the structure indicated in Box 3; its history, how it has been used, its environment, its operation, and its value. The End User will also have decisive views on the desired lifetime of the structure with respect to its usefulness as represented in Box 4. Much has been written on the various aspects of the lifetime of structures, but it is nevertheless the End User who has the dominant view of a structure's lifetime in terms of its cost effectiveness. And this brings us to the final, and overriding ingredient in the making of plans, and that is money. It is important to realise that there is always only a certain amount of money available for the upkeep and repair of structures as emphasised by the shading of Box no. 5. There is always a limit which cannot be surpassed. Even, some would perhaps say especially, governments have budgetary limits, and it is folly to try and exceed them no matter how good the argumentation may be. When there is no more money, there is no more money. Financing is thus the absolute limiting factor on the extent and type of MR&R which may be undertaken. In this connection, it should be borne in mind that intrusions which require closures or limitations in the use of the structure often have a decided effect on the overall financial situation. Loss of income incurred during MR&R can be onerous to the extent that the project may not be viable. Having collected the information represented in Boxes 3, 4, 5, and 6, it is now possible for the End User to study the best use of the available money and resources, Box 7, with respect to the maximum return for the investment . For this, the prognostic results of the survey work of Box 6 are crucial to the evaluation of future damage development and residual lifetime. Surveys should thus be done in such a way that it is possible to evaluate the probability of the damage development to expect at various times. Having decided on the best scenario, it is now time to examine the means by which the MR&R may be implemented. At this stage, possible methods, systems and materials, Box 7, should be identified to single out those which are most suitable to the structure in hand and the ambition to be achieved. This exercise can be sub-divided into four more or less distinct aspects represented by Boxes 8, 9 , 10 and 11. The question of 'What can be done' posed in Box 8 has to be answered. In each case, there will be only a limited number of possible actions which can be undertaken from a technical point of view. These have to be identified before the next questions in Boxes 9 and 10 of 'Where and when can products and technology be had?' and 'Who can do it?' can be answered These questions have to do with the Avail-ability characteristic of RAMS and are important ones. Here it should be borne in mind that it is not usually sufficient to consider present day availability, but also to evaluate similar future needs. Care must also be taken, as far as possible, to avoid one way of repairing from excluding or exacerbating alternative methods or products which may be needed in the future. To cite examples, the use of coatings could easily preclude corrosion monitoring, or render more it difficult; the use of hydrophobing agents could make future electrochemical realkalisation or chloride extraction much more difficult to perform than it otherwise would have been; and the use of waterglass based sealers could impair the adhesion of coatings. Last, but not least, the question in Box 11 concerning the total cost should be answered as far as possible. At present, an End User will have a tendency to relate to the actual, financial cost of MR&R. However, there is now a trend towards the realisation that such factors as environmental impact and influences on health and human well-being are extremely important, and that indeed the financial costs of taking due care of these factors are part and parcel of the MR&R bill. This tendency is being driven by public opinion, by new legislation, and by simple recognition by End Users of the importance of these issues. All the foregoing considerations culminate in the 3 possible outcomes in Box no.12. Either one or more viable solutions will have been found, or the solutions thus far evaluated have been found not to be achievable, or to be too costly. In the two latter cases, the entire evaluation process represented by Boxes 3 to 12 inclusive will have to be gone through again as indicated in Box 13 until a viable solution or solutions have been found and it becomes possible to reach the decision of Box 15. This may require
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the re-examination of available resources, methods, materials and personnel, supplementary survey work, or a reduction in the End User's ambition. The final outcome of the decision making process will be the MR&R strategy adopted by the End User. This strategy could be any one of a number, ranging from doing nothing at all for financial or operational reasons and simply taking out the remaining lifetime as is, to complete rehabilitation, or perhaps even to closure or demolition of the entire structure. The strategy adopted will be dictated by cost effectiveness within the confines of the total available financing.
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6. Future trends and research, development and education needs 6.1 Knowledge development
The lifetime based engineering principles will change even the paradigm of building and civil engineering. If the new principles will be only inserted into the traditional processes and organisations, the result will not be optimal. Several parts of the practice can be simplified and made much more efeective and reliable, which will increase the productivity of activities and the lifetime quality of buildings and civil infrastructures. Conretising this change effectively rise needs for basic research and modelling of this new technology. In this work can be widely utilised basic and applied sciences, like:
• Theories of Natural Sciences in research, education and training o Mathematics o Physics o Chemistry o Biology
• Theories of Technical Sciences in research, education and training o traditional:
structural mechanics materials technology building physics building economics information and communication technology
o new: systems engineering information and communication technologies: ICT
• expert systems • virtual reality • fuzzy systems • neural networks • sensor technology • remote monitoring • mobile communication and data transfer
environmental engineering nanotechnology building biology
As a result of this research and development and thus applying modern technology and knowledge the Building and civil Engineering will be developed onto a new level of knowledge. This means that this technology area will be developed into a knowledge intensive technology. Change of the current fragmented and sequential building and management process into an integrated lifetime oriented design-construct-asset management process in added value networks of firms and other stakeholders, combined with new goals and requirements. A special challenge for investors and owners is the management of the life cycle of a facility, in order to guarantee the future value of facilities under continuous changing environment of use. This means several re-development phases during the survival life of a facility
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6.2 Development of processes and organisations
The optimisation procedure can be adopted into current management process as effective computer programs, beside the existing design programs of the stakeholders (figure 6.1). IT-programs content the optimising methods of multi-attribute analysis and decision making as different versions for different life cycle phases and management levels. Organisationally this means especially in first phases on the concept, spaces and system levels a high need of multi-disciplinary planning team, including investor, owner (if different from investor), user (if possible), architect, technical experts of design, operation and MR&R (Maintenance, Repair and Rehabilitation).
Figure 6.1 Interaction between databases, optimising and decision making programs, and general managerial, planning and design programs (Sarja, 2005[15]). 6.3 Development of building technology
The development of the productivity in building sector is a key factor for the development of economic building concepts, which can serve margin for investing in the lifetime quality (Sarja, 1998 [12]. The “hard” factor for the development of productivity is the industrialisation. In order to accelerate development of international industrialised building technology, the research and development will be directed into further systematisation of performance concepts and of the modularised system rules in product systems, organisation system and information system. The systematics shall be presented as model designs, alternative organisational models and applied product data models. In product
General databases Databases of stakeholders
Value management level 5: Investment planning
Value and cost management programs
General databases Databases of stakeholders
Value management level 4: Spaces
Architectural design programs Product data modelling
General databases Databases of stakeholders
Value management level 3: Technical Systems
Architectural and technical design programs Product data modelling
Architectural and technical design programs Product data modelling
General databases Databases of stakeholders
Value management level 1: Components
Architectural and technical design programs Product data modelling
General databases Databases of stakeholders
Value management level 2: Modules
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development of buildings we have to focus on the most expensive parts: Surfaces and building service systems. But we have to keep in mind, that drastical changes in surface technology and building service systems can be done only changing also structural system. The product changes are serving also premise for productinal development. Leading principle in the product development of a building muast be simplicity: for example building service systems can be drastically simplified in low energy buildings, combining ventilating and heat distribution systems. The central scope of open industrialisation includes the following areas:
- Demand -Side, dealing with user requirements and with the introduction of the requirements into designs.
- Supply- Side, dealing with the production requirements and and with the linking of demand and supply.
- Building process organisation and communication in building projects Open system building is a global framework for the building industry, including modular systematics of products, organisation and information, dimensional co-ordination, tolerance system, performance based product specifications, product data models etc., so that the suppliers serve products and service modules that will fit together. Openness is a concept with many aspects, like: * OPEN for competition between suppliers * OPEN for alternative assemblies * OPEN for future changes * OPEN for information exchange * OPEN for integration of modules and subsystems. General industrial principles and methods can be applied in building. The open industrialisation can be developed as global technology, which then can be applied regionally and locally on different ways using locally and regionally produced products and materials. The general rules and models can be concretised into building concepts for defined consortia or networks of contractors and suppliers. During this and future decades the information technology will continue to revolutionize the working in building projects. It is important to recognize the potential benefits of computers in all phases of the service life of buildings as well as the barriers in the practical use of computers. In addition, large changes must be considered even to organizations and processes.
References to Chapter 6
[1] Life Cycle Management of Concrete Infrastructures for improved sustainability LIFECON. Co- ordinator: Professor Asko Sarja, Technical Research Centre of Finland (VTT). http://www.vtt.fi/rte/strat/projects/lifecon/. [2] Probabilistic approach for prodicting life cycle costs and performancer of buildings and civil infrastructure (EUROLIFEFORM). C co-ordinated by Taylor Woodrow Construction Ltdoordinator: Prof. Phil Bamforth, Taylor Woodrow Construction Ltd [3] Decision-making tool for long-term efficient investment strategies in housing maintenance and refurbishment ( INVESTIMMO). Co-ordinator: Dr. Dominique Caccavelli, Centre Scientifique et Technique du Bâtiment (CSTB) , France. [4] Life cycle assessment of mining projects for waste minimisation and long term control of rehabilitated sites (LICYMIN). Co-ordinator: Professor Sevket Durucan, Imperial College of Science, Technology and Medicine, UK. [5] Life-time prediction of high performance concrete with respect to durability (CONLIFE). Project Co-ordinator: Prof. Dr. Max J. Setzer/ Ms. Susanne Palecki - Universität Essen (DE) [6] Lifetime Engineering of Buildings and Civil Infrastructures (LIFETIME). Co-ordinator:
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Professor Asko Sarja, Technical Research Centre of Finland (VTT). [7] Sarja, Asko, Bamforth, Phil, Caccavelli, Dominique, Durucan, Sevket. Cluster "Lifetime" Description. 2001-01-05. Unpublished. [8] Sarja, Asko, Principles and solutions of the new system building technology (TAT).Technical Research Centre of Finland, Reserach Reports 662. Espoo, Finland, 1989. 61 p [9] Sarja, A. & Hannus, M. Modular systematics for the industrialized building. VTT publications 238. Technical research centre of Finland, Espoo 1995. 216 p. [10] Sarja, Asko (Co-ordinator), Lifetime Engineering of Buildings and Civil Infrastructures. Work Description. Technical Research Centre of Finland. Espoo 10. 12. 2001. [11] Sarja, Asko, Integrated Life Cycle Design of Structures. 142 pp. Spon Press, London 2002. ISBN 0-415-25235-0. [12] Sarja, Asko (Editor), Open and industrialised building. E&FN SPON, London and New York, 1998. 228 p. [13] Sarja, A. Towards the advanced industrialized construction technique of the future. Betonwerk + Fertigteil-Technik 4/1987 pp. 236-239. [14] The Sixth Framework Programme. Work Programme. EU Commission XII, 2002. [15] Asko Sarja et al, Predictive and Optimising Life Cycle Management of Buildings and Infrastructures. Manuscript 2005. 631 pp. To be published in 2005 by Taylor&Francise, SPON PRESS.
7. Conclusions
Application of life cycle principles is widening the scope of building and civil engineers to the extent that the entire working processes must be re-engineered. As a challenge for education and life long learning, new capabilities for applying the multiple calculation methods are needed. Concerning materials and structures, new basic knowledge will be needed especially regarding environmental impacts, hygrothermal behaviour, durability and service life of materials and structures in varying environments. Structural design methods that are capable of life cycle design, multiple analysis decision-making and optimisation will have to be further developed. Recycling design and technology demand further research in design systematics, recycling materials and structural engineering. The knowledge obtained will have to be put into practice through standards and practical guides. Currently the generic requirements of sustainability and performance are defined both in research results and also in international and European standards (basic requirements of Euronorms, ISO standards etc.). Also several organisations and firms of stakeholders (owners, designers, contractors, manufacturers) have defined specific requirements of their products. There is however a gap in introducing these basic, generic and specific requirements into all optimisation and decision making procedures of the lifetime process on different levels of planning and design. For this are needed simple but effective IT tools, including both procedure models and tools for optimisation methods in each phase and on each level of hierarchy. Relevant databases of data which are needed for these calculations will support the use of this optimising lifetime engineering software.
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APPENDIX 1. Terms and Definitions of Lifetime Engineering
A draft Glossary of the Lifetime Engineering (Based on the Glossary of Lifecon LMS). 10. 05. 2004
TERM DEFINITION Life cycle and life time
Life cycle The consecutive and inter-linked stages of a facility or structure, from the extraction or exploitation of natural resources to the final disposal of all materials as irretrievable wastes or dissipaced energy.
Life time - design
period - procure-
ment period
The time period from start of the use of a facility or structure until a defined point in time A specified period of the life time, which is used in calculations as a specific time period. The period of responsibility of the contractor on the maintenance and possible operation of the asset
Serviceability and service life Serviceability Capacity of a structure to perform the service functions for which it is designed and
used.
Service life - target life - characte-
ristic life - design life - reference
service life
Period of time after installation during which a facility or its parts meet or exceed the performance requirements. Required service life imposed by general rules, the client or the owner of the structure or its parts. A time period, which the service life exceeds with a specified probability, usually with 95 % probability. Service life used in the design to provide a required probabilistic safety against falling below the target service life. Design life is calculated dividing the characteristic life with lifetime safety factor. Design service life has to exceed the target service life. Service life forecast for a structure under strictly specified environmental loads and conditions for use as a basis for estimating service life.
Residual service life
Time between moment of consideration and the forecast end of service life.
Service life planning
Preparation of the brief for the structure and its parts to achieve to control the usability of structures and to facilitate maintenance and refurbishment on an optimised way
Service life design
Preparation of design of the structure and its parts to achieve the desired design life on the defined reliability level.
Reliability and performance Performance
Measure to which the structure responses to a certain function
Performance
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requirement or performance criterion
Qualitative and quantitative levels of performance required for a critical property of structure.
Life time quality
The capability of the facility to fulfil all requirements of the owner, user and society over the specific life time period.
Failure - Durability
failure
Loss of the ability of a structure or its parts to perform a specified function. Exceeding the maximum degradation or falling below the minimum performance parameter.
Failure probability
The statistical probability of failure occurring.
Risk Multiplication of the probability of an event; e. g. failure or damage.
Obsolescence Loss of ability of an item to perform satisfactorily due to changes in economic, performance, human (safety, health, convenience) or ecological requirements.
Limit state
-Serviceability limit state -Ultimate limit state
A specified measure or performance parameter exceeding or falling below a defined value. State which corresponds to conditions beyond specified service requirement(s) for a structure are no longer met. State associated with collapse, or other similar forms of failure.
Lifetime safety factor
Coefficient by which the characteristic life is divided to obtain the design life.
Factor method Modification of reference service life by factors to take account of the specific environmental loads and in use conditions.
Attribute - Multiple attributes
A property of an object or its part, which will be used in optimisation and selective decision making between alternatives. A set of attributes, which will be used in optimisation and selective decision making between alternatives.
Durability Durability The capability of a structure to maintain minimum performance under the influence
of actual environmental degrading loads.
Durability limit state
Minimum acceptable state of performance or maximum acceptable state of degradation.
Durability model
Mathematical model for calculating degradation, performance or service life of a structure.
Performance model
Mathematical model for showing performance with time.
Condition
Level of critical properties of structure or its parts, determining its ability to perform.
Condition model
Mathematical model for placing an object, module, component or sub-component on a specific condition class
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Deterioration
The process of becoming impaired in quality or value.
Degradation Gradual decrease in performance of a material or structure.
Environmental load
Impact of environment onto structure, including weathering (temperature, temperature changes, moisture, moisture changes, solar effects etc.), chemical and biological factors.
Degradation load
Any of the groups of environmental loads, and mechanical loads.
Degradation mechanism
The sequence chemical, physical or mechanical changes that lead to detrimental changes in one or more properties of building materials or structures when exposed to degradation loads.
Degradation model
Mathematical model showing degradation with time.
Procurement and Construction Lifetime period procurement and construction
Management and maintenance Maintenance Combination of all technical and associated administrative actions during the service
life to retain a structure in a state in which it can perform its required functions
Repair Return of a structure to an acceptable condition by the renewal, replacement or mending of worn, damaged or degraded parts.
Restoration
Actions to bring a structure to its original appearance or state.
Refurbish-ment or Rehabilitation
Modification and improvements to an existing structure to bring it up to an acceptable condition.
Renewal Demolition and rebuilding of an existing object M&R Maintenance, plus repair, restoration, refurbishment and renewal, or some of them Project Planning and execution of repair, refurbishment. Restoration or dismantling of a
facility or some parts of it.
Life cycle cost Total cost of a structure throughout its life, including the costs of planning, design, acquisition, operations, maintenance and disposal, less any residual value.
Environmental Burden
Any change to the environment which. permanently or temporarily, results in loss of natural resources or deterioration in the air, water or soil, or loss of biodiversity.
Environmental Impact
The consequences for human health. for the well-being of flora and fauna or for the future availability of natural resources. attributable to the input and output streams of a system.
Integrated lifetime design of materials and structures
Producing descriptions for structures and their materials, fulfilling the specified requirements of monetary economy, human requirements (safety, health, convenience), ecology (economy of the nature), culture and social needs, all over the life cycle of the structures. Integrated structural design is the synthesis of mechanical
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design, durability design, physical design and environmental design.
Environmental structural design
The part of the integrated structural design that considers environmental aspects during the design process
Integrated lifetime management
Planning and control procedures in order to optimise the economic, human, ecological, cultural and social conditions over the life cycle of a facility.
Hierarchical system System An integrated entity which functions in a defined way and whose components have
defined relationships and rules between them.
Hierarchical system
A system consisting of some value scale, value system or hierarchy.
Modulated system
A system whose parts (modules) are autonomous in terms of performance and internal structure.
Structural system
A system of structural components which fulfil a specified function.
Network Stock of of objects (facilities), (e. g. bridges, tunnels, power plants, power plants, buildings) under management and maintenance of an owner.
Object A basic unit of the Network serving a specific function.
Module or assembly
A part of an object, or a set of components which is designed and manufactured to serve a specific function or functions as apart of the system, and whose functional and performance and geometric relations to the structural system are specified.
Structural component
A basic unit of the structural system, which is designed and manufactured to serve a specific function or functions a s part of a module, and whose functional and performance and geometric relations to the structural system are specified.
Sub-component
Manufactured product forming a part of a component.
Material Substance that can be used form products. Stakeholders
Stakeholders Owners, users, designers, contractors, industry sectors. public interest organisations, regional interests. and/or government agencies connected to the structure during the life cycle.
Owner Person or organisation for which structure is constructed and/or the person or organisation that has the responsibility for maintenance and upkeep of structural, mechanical and electrical systems of the building.
Designer Person or organisation that prepares a design or arranges for any person under his control to prepare the design.
Contractor Person or organisation that undertakes to, or does, carry out or manage construction work. The contractor bids a contract for a new building with information from manufacturers/suppliers. The contractor’s representative on the building site is the site supervisor.
Manager At take over the building is administrated by a property manager who engages maintainers to be responsible for proper maintenance inspections or to carry out the necessary maintenance.
Supplier Person or organisation that supplies structures, parts of structures or services for construction or maintenance of structures.
User Person, organisation or animal which occupies a facility. Dismantler any person who carries out dismantling work
Methods
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Allocation The division of specified re sources (financial and physical) into objects, projects and other actions on the Network level.
Briefing Statement of the requirements of a facility Service life planning
Preparation of the brief and design for a facility and its parts in order to optimise the required properties of the facility for owner and facilitate maintenance and refurbishment.
Condition assessment
Methodology and methods for quantitative measurements and visual inspection of the properties of an object and its parts, and conclusions drawn from the results regarding to the condition of the object.
Optimisation -Short term optimisation -Long term optimisation
Selection between alternative properties of an object or its parts, or of an action in order to reach best solution or result Optimisation in a short time period (usually one or couple of years) Optimisation in a long term period (usually several years or even tens of years)
Decision making
Methodology for rational choices between alternatives, basing on defined requirements and criteria.
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APPENDIX 2. EU Directives relating to Lifetime Engineering
• Construction Products Directive • Energy Performance of Buildings Directive • Framework Directive in the field of water policy • Framework Directive on waste disposal • Integrated pollution prevention and control:
o IPPC Directive, o Public works contracts, o public supply contracts and public service contracts, o Public procurement in the water, energy, transport and postal services sectors
Construction Products Directive 1) OBJECTIVE To ensure free movement of construction products within the EU by harmonising national laws with respect to the essential requirements applicable to the products in terms of health, safety and stability. 2) ACT Council Directive 89/106/EEC of 21 December 1988 on the approximation of the laws, regulations and administrative provisions of the Member States relating to construction products [Official Journal L 40 of 11 February 1989]. Amended by Council Directive 93/68/EEC of 22 July 1993 [Official Journal L 220 of 30 August 1993].
Act Date of entry into force
Final date for implementation in the Member States
Directive 89/106/EEC 27.12.1998 27.06.1991 Directive 93/68/EEC 02.08.1993 02.08.1993
3) SUMMARY Scope: the Directive applies to construction products, i.e. any products produced with a view to their incorporation in a permanent manner in construction works. Compliance with the essential requirements: construction products may only be placed on the market if they are fit for their intended use. In this regard, they must be such that works in which they are incorporated satisfy, for an economically reasonable working life, the essential requirements with regard to mechanical strength and stability, safety in the event of fire, hygiene, health and the environment, safety in use, protection against noise and energy economy and heat retention, as set out in Annex 1 to the Directive. The essential requirements are defined in the first instance in interpretative documents drawn up by technical committees and are then elaborated further in the form of technical specifications. The latter may consist of: harmonised European standards adopted by the European standardisation bodies (CEN and/or CENELEC) acting on a mandate from the Commission and following consultations with the Standing Committee on Construction; a system of European technical approvals to assess the suitability of a product for its intended use in cases where there is no harmonised standard, no recognised national standard and no mandate for a European standard and where the Commission feels, after consulting the Member States within the Standing Committee on Construction, that a standard cannot or cannot yet be prepared.
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In order to facilitate this task, the European Organisation of Technical Approvals (EOTA), which groups together the national approvals bodies, would be in a position to draw up technical approvals guidelines in respect of a construction product or family of construction products, acting on a mandate from the Commission and after consulting the Standing Committee on Construction. Where neither a European standard nor guidelines for European technical approval exist yet, construction products may continue to be assessed and marketed in accordance with existing national provisions conforming to the essential requirements. Energy Performance of Buildings Directive 1) OBJECTIVE To create a common framework to promote the improvement of the energy performance of buildings. 2) ACT Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002 on the energy performance of buildings [Official Journal L 001 of 04.01.2003]. 3) SUMMARY Context The Directive forms part of the framework of Community initiatives on climate change (commitments under the Kyoto Protocol) and security of supply (the Green Paper on security of supply). Firstly, the Community is increasingly dependent on external energy sources and, secondly, greenhouse gas emissions are on the increase. The Community can have little influence on the energy supply but can influence energy demand. One possible solution to both the above problems is to reduce energy consumption by improving energy efficiency. Energy consumption for buildings-related services accounts for approximately one third of total EU energy consumption. The Commission considers that, with initiatives in this area, significant energy savings can be achieved, thus helping to attain objectives on climate change and security of supply. Community-level measures must be framed in order to deal with such Community-level challenges. This Directive is a follow-up to the measures on boilers (92/42/EEC), construction products (89/106/EEC) and SAVE programme provisions on buildings. Though there is already a directive on the energy certification of buildings (Directive 93/76/EEC), it was adopted in a different political context. Having been adopted before the Kyoto agreement and before the uncertainties recently raised in connection with the security of energy supply in the Union, it does not have the same objectives as this Directive. The latest is an additional instrument, putting the subject into the context of new challenges and proposing more concrete action to fill any gaps. Scope The Directive concerns the residential sector and the tertiary sector (offices, public buildings, etc.). The scope of the provisions on certification does not, however, include some buildings, such as historic buildings, industrial sites, etc. It covers all aspects of energy efficiency in buildings in an attempt to establish a truly integrated approach. The Directive does not lay down measures on equipment such as household appliances. Measures on labelling and mandatory minimum efficiency requirements have already been implemented or are envisaged in the Action Plan for Energy Efficiency. Main aspects of the general framework The four main aspects of the proposed general framework are as follows:
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a common methodology for calculating the integrated energy performance of buildings; minimum standards on the energy performance of new buildings and existing buildings that are subject to major renovation; systems for the energy certification of new and existing buildings and, for public buildings, prominent display of this certification and other relevant information. Certificates must be less than five years old; regular inspection of boilers and central air-conditioning systems in buildings and in addition an assessment of heating installations in which the boilers are more than 15 years old. The common calculation methodology should include all the aspects which determine energy efficiency and not just the quality of the building's insulation. This integrated approach should take account of aspects such as heating and cooling installations, lighting installations, the position and orientation of the building, heat recovery, etc. The minimum standards for buildings are calculated on the basis of the above methodology. The Member States are responsible for setting the minimum standards. Energy performance certificates should be made available when buildings are constructed, sold or rented out. The proposal specifically mentions rented buildings with the aim of ensuring that the owner, who does not normally pay the charges for energy expenditure, should take the necessary action. Furthermore, the Directive states that occupants of buildings should be enabled to regulate their own consumption of heat and hot water, in so far as such measures are cost effective.
Act Date of entry into force
Final date for implementation in the Member States
Directive 2002/91/EC 04.01.2003 04.01.2006
Implementation The Member States are responsible for drawing up the minimum standards. They will also ensure that the certification and inspection of buildings are carried out by qualified and independent personnel. The Commission, with the assistance of a committee, is responsible for adapting the Annex to technical progress. The annex contains the framework for the calculation of energy performances of buildings and the requirements for the inspection of boilers and of central air conditioning systems. Framework Directive in the field of water policy 1) OBJECTIVE To establish a Community framework for the protection of inland surface waters, transitional waters, coastal waters and groundwater, in order to prevent and reduce pollution, promote sustainable water use, protect the aquatic environment, improve the status of aquatic ecosystems and mitigate the effects of floods and droughts. 2) ACT Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000, establishing a framework for Community action in the field of water policy [Official Journal L 327, 22.12.2001], as amended by Decision No 2455/2001/EC of the European Parliament and the Council, of 20 November 2001 [Official Journal L 331, 15.12.2001]. 3) SUMMARY
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Under this Directive, Member States have to identify all the river basins lying within their national territory and assign them to individual river basin districts. River basins covering the territory of more than one Member State will be assigned to an international river basin district. By 22 December 2003 at the latest, a competent authority will be designated for each of the river basin districts. At the latest, four years after the date of entry into force of this directive, Member States must complete an analysis of the characteristics of each river basin district, a review of the impact of human activitiy on the water, an economic analysis of water use and a register of areas requiring special protection. All bodies of water used for the abstraction of water intended for human consumption providing more than 10 m³ a day as an average or serving more than 50 persons must be identified. Nine years after the date of entry into force of the Directive, a management plan and programme of measures must be produced for each river basin district, taking account of the results of the analyses and studies provided for in point 2. The measures provided for in the river basin management plan seek to: prevent deterioration, enhance and restore bodies of surface water, achieve good chemical and ecological status of such water and reduce pollution from discharges and emissions of hazardous substances; protect, enhance and restore all bodies of groundwater, prevent the pollution and deterioration of groundwater, and ensure a balance between astraction and recharge of groundwater; preserve protected areas. The abovementioned objectives have to be achieved at the latest fifteen years after the date of entry into force of the Directive, but this deadline may be extended or relaxed, albeit under the conditions laid down by the Directive. The Member States will encourage the active involvement of all interested parties in the implementation of this Directive, in particular as regards the river basin management plans. Temporary deterioration of bodies of water is not in breach of the requirements of this Directive if it is the result of circumstances which are exceptional or could not reasonably have been foreseen and which are due to an accident, natural cause or force majeure. By 2010, Member States must ensure that water pricing policies provide adequate incentives for users to use water resources efficiently and that the various economic sectors contribute to the recovery of the costs of water services including those relating to the environment and resources. The Commission submitted a list of priority substances selected amongst those which present a significant risk to or via the aquatic environment. Measures to control such substances, as well as quality standards applicable to concentrations thereof, will also be proposed. The aim of such measures is to reduce, stop or eliminate discharges, emissions and losses of priority substances. This list forms Annex X to the present Directive. Two years after the entry into force of this Directive, the Commission will publish a proposal with specific measures to prevent and control the pollution of groundwater. At the latest twelve years after the date of entry into force of this Directive and every six years thereafter, the Commission will publish a report on the implementation of the Directive. The Commission will convene when appropriate a conference of interested parties on Community water policy which will involve Member States, representatives from the competent authorities, the European Parliament, NGOs, the social and economic partners, consumer bodies, academics and other experts. The Directive lays down that Member States will determine penalties applicable to breaches of the provisions adopted which are effective, proportionate and dissuasive. Seven years after the entry into force of the Directive, the following legislation will be repealed:
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Directive 75/440/EEC; Decision 77/795/EEC; Directive 79/869/EEC. Thirteen years after the entry into force of the Directive, the following legislation will be repealed: Directive 78/659/EEC; Directive 79/923/EEC; Directive 80/68/EEC; Directive 76/464/EEC, with the exception of Article 6, repealed on the date of entry into force of this Directive.
Act Date of entry into force Final date for implementation in the Member States
Directive 2000/60/EC 22.12.2000 22.12.2003 Decision No 2455/2001/EC 16.12.2001 -
Framework Directive on waste disposal 1) OBJECTIVE To set up a system for the coordinated management of waste within the Community in order to limit waste production. 2) COMMUNITY MEASURES Council Directive 75/442/EEC of 15 July 1975 on waste, as amended by Council Directive 91/156/EEC of 18 March 1991; Council Directive 91/692/EEC of 23 December 1991; Commission Decision 96/350/EC of 24 May 1996; Council Directive 96/59/EC of 16 September 1996. 3) CONTENTS These measures apply to all substances or objects which the holder disposes of or is obliged to dispose of in pursuance of the national provisions in force in the Member States. They do not apply to radioactive waste, mineral waste, annual carcasses and agricultural waste, waste water, gaseous effluents and wastes that are subject to specific Community Regulations. Member States must prohibit the uncontrolled discarding, discharge and disposal of waste. They shall promote the prevention, recycling and conversion of wastes with a view to their reuse. They shall inform the Commission of any draft Regulations which may involve the use of products which can give rise to technical difficulties and excessive disposal costs and which may encourage decreasing as regards the quantities of certain wastes, the treatment of waste for the purpose of their recycling or their reuse, the use of energy deriving from certain wastes or the use of natural resources which may be replaced by reclamation materials. The measures provide for cooperation between the Member States with a view to setting up an integrated, adequate network of disposal installations (taking account of the best technologies available) which would enable the Community itself to dispose of its wastes and the Member States individually to work towards that aim. That network would have to enable waste to be disposed of in one of the closest installations that guaranteed a high level of environmental protection. Member States shall ensure that all holders of wastes shall hand them over to a private or public collection agency or to a disposal company, or else shall themselves conduct the disposal in compliance with the requirements of the current measures.
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Companies or establishments treating, storing or dumping waste for another party must obtain an authorization from the competent authority which concerns, in particular, the types and quantities of waste to be treated, the general technical requirements and the precautions to be taken. The competent authorities may routinely check compliance with those authorization conditions. The same monitoring by the competent authority is reserved for transport, collection, storage, dumping or treatment companies working on their own account or for third parties. Upgrading centres and companies disposing of their own wastes have to get an authorization. The cost of disposal of waste must be borne by its holder, who will hand over his waste to a collector or company and/or else by earlier holders or by the producer who has generated the waste in accordance with the "polluter pays" principle. The competent authorities appointed by the Member States in order to implement the current measures shall draw up at least one management plan governing, in particular, the types, quantities and origins of the wastes to be upgraded or disposed of, the general technical requirements, all of the special arrangements concerning specific wastes, and the appropriate locations and installations for the disposal. 4) DEADLINE FOR IMPLEMENTATION OF THE LEGISLATION IN THE MEMBER STATES Directive 75/442/EEC: 18.07.1977 Directive 91/156/EEC: 01.04.1993 Directive 91/692/EEC: 01.01.1995 Directive 96/59/EC: 16.03.1998 5) DATE OF ENTRY INTO FORCE (if different from the above) Decision 96/350/EC: 28.05.1996 Directive 96/59/EC: 16.09.1996 Integrated pollution prevention and control: IPPC Directive 1) OBJECTIVE To prevent or minimise emissions to air, water and soil, as well as waste, from industrial and agricultural installations in the Community, with a view to achieving a high level of environmental protection. 2) ACT Council Directive 96/61/EC of 24 September 1996 concerning integrated pollution prevention and control [Official Journal L 257 of 10.10.1996]. 3) SUMMARY Integrated pollution prevention and control concerns highly polluting industrial and agricultural activities, as defined in Annex I (energy industries, production and processing of metals, mineral industry, chemical industry, waste management, livestock farming, etc.). The Directive defines the basic obligations to be met by all the industrial installations concerned, whether new or existing. These basic obligations cover a list of measures for tackling discharges into water, air and soil and for tackling waste, wastage of water and energy, and environmental accidents. They serve as the basis for drawing up operating licences or permits for the installations concerned.
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Accordingly, the Directive: lays down a procedure for applying for, issuing and updating operating permits; lays down minimum requirements to be included in any such permit (compliance with the basic obligations, emission limit values for pollutants, monitoring of discharges, minimisation of long-distance or transboundary pollution). A transitional period (30 October 1999 - 30 October 2007) is laid down during which existing installations can be brought into conformity with the requirements of the Directive. The Member States are responsible for inspecting industrial installations and ensuring they comply with the Directive. An exchange of information on best available techniques (serving as a basis for emission limit values) is organised between the Commission, the Member States and the industries concerned. Reports on the implementation of the Directive are drawn up every three years.
Act Date of entry into force Final date for implementation in the Member States
Directive 96/61/EC 30.10.1996 30.10.1999 The material contained in Appendix A is an edited version of the material published on the official EU website, www.europa.eu.int and is reproduced here for ease of reference. Public works contracts, public supply contracts and public service contracts The European Union is updating the rules concerning procurement procedures for public works contracts, public supply contracts and public service contracts. This revision is based on the fundamental principles of the internal market and basically strives for simplification, harmonisation and modernisation. It introduces a new procedure - the competitive dialogue - and promotes the development of electronic procedures. Recourse to social and environmental criteria is authorised for the selection of economic operators and is based on Court of Justice case-law.
ACT Directive 2004/18/EC of the European Parliament and of the Council of 31 March 2004 on the coordination of procedures for the award of public works contracts, public supply contracts and public service contracts. SUMMARY The European Union is updating and simplifying the legislation on public procurement procedures * . Applicable in a Union of 25 Member States, this revision merges the four existing European directives into two legal instruments: The so-called "traditional" Directive 2004/18/EC for public works contracts, public supply contracts and public service contracts; Directive 2004/17/EC on the "special sectors" of water, energy, transport and postal services. SCOPE Revised thresholds The "traditional" directive applies to public works contracts, public supply contracts and public service contracts which have a value excluding VAT estimated to be no less than the following thresholds: EUR 154 000 for public supply and service contracts awarded by central government authorities (ministries, national public establishments);
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EUR 236 000 for public supply and service contracts: awarded by contracting authorities * which are not central government authorities; covering certain products in the field of defence awarded by the central government authorities; concerning certain services in the fields of research and development (RTD), telecommunications, hotels and catering, transport by rail and waterway, provision of personnel, vocational training, investigation and security, certain legal, social and sanitary, recreational, cultural and sporting services; EUR 5 923 000 in the case of works contracts. The Commission verifies the thresholds every two years. The calculation of their value is based on the average daily value of the euro, expressed in special drawing rights (SDR), over the 24 months ending on 31 August for the revision with effect from 1 January. For those Member States which have not adopted the single currency, the European Commission publishes the values in national currencies of the applicable thresholds in the Official Journal. In principle, these values are revised every two years from 1 January 2004. Certain contracts are excluded or reserved The following public contracts are excluded from the scope of the directive: contracts covered by the "special sectors" directive and contracts awarded with the purpose of providing or exploiting public telecommunications networks; contracts which are declared to be secret or affect the essential interests of a Member State; contracts concluded pursuant to international agreements; contracts concerning the following services: the acquisition or rental of existing buildings; the acquisition, development, (co)production of broadcasting programmes; arbitration and conciliation services; the purchase, sale or transfer of financial instruments, in particular loans; central bank services; employment contracts; RTD services which do not belong exclusively to the contracting authority or which are not wholly financed by it; service contracts awarded on the basis of an exclusive right; service concessions * . Member States may reserve certain public contracts to sheltered workshops or provide for such contracts to be performed in the context of sheltered employment programmes where most of the employees concerned are handicapped persons. Public procurement in the water, energy, transport and postal services sectors The European Union is updating the rules concerning procurement procedures in the water, energy, transport and postal services sectors. This revision is based on the fundamental principles of the internal market and basically strives for simplification, harmonisation and modernisation. It promotes the development of electronic procedures. Recourse to social and environmental criteria is authorised for the selection of economic operators * and is based on Court of Justice case law.
ACT Directive 2004/17/EC of the European Parliament and of the Council of 31 March 2004 coordinating the procurement procedures of entities operating in the water, energy, transport and postal services sectors. SUMMARY The European Union is updating and simplifying the legislation on public procurement procedures * . Applicable in a Union of 25 Member States, this revision merges the four existing European directives into two legal instruments: The so-called "traditional" Directive 2004/18/EC for public works contracts, public supply contracts and public service contracts;
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Directive 2004/17/EC on the "special sectors" of water, energy, transport and postal services. SCOPE Contracting entities The "special sectors" directive applies to: all contracting authorities * or public undertakings * which pursue activities in one of the following fields: gas, electricity, water, transport services, postal services * , the extraction of fuels, or the provision of ports or airports; all contracting entities which, when they are neither contracting authorities nor public undertakings, pursue one (or more) of the above activities and enjoy special or exclusive rights * granted by a competent authority of a Member State. Non-exhaustive lists of contracting entities are given in the Annexes. Member States must notify the Commission of any changes. Activities concerned The directive applies to the following activities: the provision or operation of fixed networks intended to provide a service to the public in connection with the production, transport or distribution of gas, heat or electricity, or the supply of gas, heat or electricity to such networks; the provision or operation of fixed networks intended to provide a service to the public in connection with the production, transport or distribution of water, or the supply of water to such networks; where the contracting entity is active in the drinking water sector, contracts or design contests connected with irrigation, land drainage or hydraulic engineering projects, or contracts connected with the disposal or treatment of sewage; the provision or operation of networks providing a service to the public in the field of transport by railway, automated systems, tramway, trolley bus, bus or cable. Bus transport services are excluded from the scope of the directive where other entities are free to provide those services, either in general or in a particular geographical area, under the same condition as the contracting entities; the provision of postal services. * These services cover: postal services which are reserved under the terms of Directive 97/67/EC, as well as those which may not be reserved under Directive 97/67/EC; all of the following services are also covered, on condition that such services are provided by an entity which also provides postal services and that the market is not yet open to competition: mail management services (e.g. mailroom management services), added-value services linked to and provided entirely by electronic means (e.g. the secure transmission of coded documents, address management services), direct mail bearing no address, financial services (e.g. postal money orders and postal giro transfers), philatelic services and logistics services; the exploitation of a geographical area for the purpose of 1) exploring for or extracting oil, gas, coal or other solid fuels, or 2) the provision of airports and maritime or inland ports or other terminal facilities to carriers by air, sea or inland waterway. Contracts awarded in the sectors in question are no longer subject to the Directive if effective competition exists. Since 30 April 2004, Member States have had the possibility of asking the Commission to adopt a decision testifying to the existence of effective competition in a Member State for a given sector in accordance with a specific procedure. This procedure is based on the characteristics of the goods and services under consideration, the existence of alternatives, prices and the presence of several competitors. On its own initiative or at the request of the national contracting entities, when the national transposition of the directive allows them to do so, the Commission may adopt a decision testifying to the existence of effective competition in a Member State and for a given sector. If no decision is made within the deadline set, the exclusion becomes applicable. Revised thresholds The directive applies to contracts that have a value excluding VAT estimated to be no less than the following thresholds: EUR 473 000 in the case of supply and service contracts; EUR 5 923 000 in the case of works contracts.
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The Commission verifies the thresholds every two years. The calculation of their value is based on the average daily value of the euro, expressed in special drawing rights (SDR), over the 24 months ending on 31 August for the revision with effect from 1 January. For those Member States that have not adopted the single currency, the European Commission publishes the values in national currencies of the applicable thresholds in the Official Journal. In principle, these values are revised every two years from 1 January 2004. Certain contracts are excluded or reserved The scope of the directive excludes: works and service concessions in the sectors of activity concerned; contracts awarded for purposes of resale, lease to third parties, for purposes other than the pursuit of an activity in the sectors concerned or for the pursuit of such an activity in a third country. The Commission may publish in the Official Journal the list of the categories of products and activities excluded; contracts which are secret and require special security measures or are awarded pursuant to international rules; certain contracts awarded by a contracting entity to an affiliated undertaking or awarded by a joint venture formed exclusively by a number of contracting entities for the purpose of carrying out the activities concerned. By definition, an affiliated undertaking has annual accounts which are consolidated with those of the contracting entity or is subject to a dominant influence by virtue of ownership, financial participation, or the rules which govern it. Contracting entities must notify the Commission of the names of the undertakings or (joint) ventures concerned and the nature and volume of the contracts involved; service contracts awarded on the basis of an exclusive right; service contracts for the acquisition or rental of land, existing buildings or other immovable property or concerning rights thereon (excluding financial service contracts concluded at the same time as, before or after the contract of acquisition or rental); arbitration and conciliation services; financial services in connection with the issue, sale, purchase or transfer of financial instruments (such as transactions to raise money or capital); employment contracts; and research and development (RTD) services wholly remunerated by the contracting entity; contracts awarded by certain contracting entities for the purchase of water and for the supply of energy or of fuels for the production of energy; certain contracts subject to special arrangements in Germany, Austria, the Netherlands and the United Kingdom and in the field of the exploration or extraction of oil, gas, coal and other solid fuels. Member States may reserve certain public contracts to sheltered workshops or provide for such contracts to be performed in the context of sheltered employment programmes where most of the employees concerned are handicapped persons.
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APPENDIX 3. State of the Art Summary of International laws, norms, regulations, guides and rules
5 INTERNATIONAL AND EUROPEAN STANDARDS ON LIFE CYCLE COST, ENVIRONMENTAL PERFORMANCE, AND SERVICE LIFE PLANNING 5.1 ISO/TC207 “ENVIRONMENTAL MANAGEMENT” Standards written by ISO/TC207 “Environmental management” are the basis for assessment of environmental performance of buildings. The basic tool for assessing environmental performance is the Life Cycle Assessment (LCA). The Environmental Product Declaration (EPD) is the basic tool for communicating environmental information. ISO/TC207 standards are generic in nature because they can be applied to all materials, products and services. Relevant standards
• ISO/CD14025 Environmental labels and declarations – Type III environmental declarations – Principles and Procedures (ISO TC207/SC3) • BS EN ISO 14040:1997 Environmental management. Life cycle assessment. Principles and framework (ISO TC207/SC5)
• BS EN ISO 14041:1998 Environmental management. Life cycle assessment. Goal and scope definition and inventory analysis (ISO TC207/SC5) • BS EN ISO 14042:2000 Environmental management. Life cycle management. Life cycle impact (ISO TC207/SC5) • BS EN ISO 14043:2000 Environmental management. Life cycle assessment. Life Cycle Interpretation (ISO TC207/SC5) • PD ISO/TR 14047:2003 Environmental management. Life cycle impact assessment. Examples of application of ISO 14042 • DD ISO/TS 14048:2002 Environmental management. Life cycle assessment. Data documentation format • PD ISO/TR 14049:2000 Environmental management. Life cycle assessment. Examples of application of ISO 14041 to goal and scope definition and inventory analysis
5.2 ISO/TC59 “BUILDINGS” ISO/TC59 is developing standards to assess sustainability in the building sector and for service life planning of buildings. The draft ISO technical specification for the assessment of environmental performance of buildings forms a good framework for a European horizontal standard for the assessment of environmental performance of buildings. The basic tool for assessment of economic performance in terms of sustainability is Life Cycle Costing, and this is the subject of a Draft ISO. Relevant standards
• ISO 15686-1 Buildings and constructed assets – Service life planning – General principles (ISO/TC59/SC15) • ISO 15686-2 Buildings and constructed assets – Service life planning – Service life prediction procedures (ISO/TC59/SC15) • ISO/DIS 15686-5 Buildings and constructed assets – Service life planning – Whole life costing (ISO/TC59/SC15) • ISO 15686-6 Buildings and constructed assets – Service life planning – Guidelines for considering environmental impacts (ISO/TC59/SC15) • ISO/DIS 15686-8 Buildings and constructed assets – Service life planning – Reference service life and service life estimation (ISO/TC59/SC15) • ISO/AWI 15686-9 Buildings and constructed assets – Service life planning – Service life declarations (ISO/TC59/SC15)
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• ISO/DIS 21930 Building construction - Sustainability in building construction – Environmental declaration of building products (ISO/TC59/SC17) • ISO/TR 21932 Building construction - Sustainability in building construction – Terminology (ISO/TC59/SC17) • ISO/TS 21931 Building construction - Sustainability in building construction – Framework for environmental performance of buildings (ISO/TC59/SC17) • ISO/WD 15392 Building Construction – Sustainability in building construction – General Principles (ISO/TC59/SC17) • ISO 6707-1 Building and civil engineering – Vocabulary – General terms (ISO/TC59/SC2) (a further 9 parts are currently out for ballot as ISO DIS.)
5.3 INTERNATIONAL AND EUROPEAN STANDARDS IN RESPONSE TO ENERGY PERFORMANCE OF BUILDINGS AND DIRECTIVE 2002/91/EC AND HEALTH & COMFORT PERFORMANCE The future standards for the framework for assessment of integrated building performance and environmental performance of buildings, health & comfort performance of buildings and life cycle cost performance of buildings should apply the standards under development for assessment of energy performance of buildings. According to the EC standardisation mandate M/330 EN based on the Directive 2002/91/EC on the energy performance of buildings, CEN is developing an integrated and interacting methodology for the calculation of the energy uses and losses for heating and cooling, ventilation, domestic hot water, lighting, natural lighting, passive solar systems, passive cooling, position and orientation, automation and controls of buildings, and auxiliary installations necessary for maintaining a comfortable indoor environment of buildings. The standards under the mandate M/330 shall be prepared by the CEN/TC89 “Thermal performance of buildings and building components”, CEN/TC156 “Ventilation for buildings”, CEN/TC169 “Light and lighting”, CEN/TC228 “Heating systems for buildings” and CEN/TC 247 “Building automation and building management”. Relevant standards by CEN/TC89:
• EN ISO 13790 Thermal performance of buildings – Calculation of energy use for space heating • EN ISO 13791 Thermal performance of buildings - Calculation of internal temperatures of a room in summer without mechanical cooling - General criteria and validation • EN ISO 13792 Thermal performance of buildings - Calculation of internal temperatures of a room in summer without mechanical cooling - Simplified methods • EN 13829 Thermal performance of buildings - Determination of air permeability of buildings - Fan pressurization method • Energy performance of buildings – Methods of assessment to be used for the energy certification of buildings • Energy performance of buildings – Overall energy use, primary energy and CO2 emissions • Energy performance of buildings – Ways of expressing energy performance of buildings • Energy performance of buildings – Application of calculation of energy use to existing buildings • Energy performance of buildings – Additional applications of calculations for the inclusion of the positive influences of daylighting, solar shading, passive cooling, position and orientation, renewables, quality district heating and cooling, quality CHP (including on-site) and for modular inclusion of future technologies • Thermal performance of buildings – Calculation of energy use for space heating and cooling – Simplified method with extension of scope of EN ISO 13790
Relevant standards by CEN/TC156:
• CR 1752 Ventilation for buildings - Design criteria for the indoor environment • Criteria for the Indoor Environment including thermal, indoor air quality (ventilation), light and noise • Ventilation for buildings - Terminals - Comfort criteria
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• EN 13465 Ventilation for buildings - Calculation methods for the determination of air flow rates in dwellings • Ventilation for buildings – Calculation methods for the determination of air flow rates in buildings • Ventilation for buildings – Calculation methods for energy requirements due to ventilation and infiltration in buildings • EN 13779 Ventilation for non residential buildings - Performance requirements for ventilation and room conditioning systems
Relevant standards by CEN/TC169:
• Energy performance of buildings – Energy requirements for lighting (including daylighting) • EN 12665 Light and lighting - Basic terms and criteria for specifying lighting requirements
Relevant standards by CEN/TC247:
• Building Management Services • Building Management Services - Part 1: General Terms and Definitions
ISO/TC 205 “Building environment design” is developing standards for design of new buildings and retrofit of existing buildings for acceptable indoor environment and practicable energy conservation and efficiency. In the scope of ISO/TC205 the indoor environment includes air quality, and thermal, acoustic, and visual factors. Relevant standards by ISO/TC205:
• ISO/CD 16813 Building environment design - Indoor environment - General principles • ISO/CD 16814 Building environment design - Indoor environment - Methods of expressing the quality of indoor air for human occupancy
5.4 INTERNATIONAL AND EUROPEAN STANDARDS ON TEST METHODS FOR INDOOR AIR POLLUTANTS AND HEALTH & COMFORT PERFORMANCE OF BUILDINGS AND EC MANDATE M/XXX (DANGEROUS SUBSTANCES) According to the EC standardisation mandate M/XXX EN based on the Construction Product Directive 89/106/EEC, CEN will develop horizontal test standards dedicated to the emission of specified regulated dangerous substances from construction products into indoor air. ISO/TC146/SC6 “Air quality – Indoor air” and CEN/TC264 “Air quality” are developing emission test methods for indoor air pollutants. The future standards relating to the assessment of health & comfort performance of buildings and EPD of building products should refer to the relevant existing and draft standards for emission test methods for indoor air pollutants from building products. Relevant standards by ISO/TC146/SC6 and CEN/TC264:
• ISO 16000-3 Indoor air -- Part 3: Determination of formaldehyde and other carbonyl compounds -- Active sampling method • ISO 16000-4 Indoor air -- Part 4: Determination of formaldehyde -- Diffusive sampling method • ISO 16000-6 Indoor air -- Part 6: Determination of volatile organic compounds in indoor and test chamber air by active sampling on Tenax TA sorbent, thermal desorption and gas chromatography using MS/FID • EN ISO 16000-9 Indoor air -- Part 9: Determination of the emission of volatile organic compounds -- Emission test chamber method • EN ISO 16000-10 Indoor air -- Part 10: Determination of the emission of volatile organic compounds -- Emission test cell method Circulated for Information - B/500/-/2.0080/04Page 8 • EN ISO 16000-11 Indoor air -- Part 11: Determination of the emission of volatile organic compounds -- Procedure for sampling, storage of samples and preparation of test specimens
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• ISO 16000-13 Indoor air -- Part 13: Measurement of polychlorinated dioxins/furans and polychlorinated biphenyls (PCBs) • ISO 16000-15 Indoor air -- Part 15: Measurement of nitrogen dioxide (NO2) • ISO 16000-17 Indoor air -- Part 17: Measurement of the concentration of airborne mould spores -- Sampling with gelatine/polycarbonate filters followed by a culture-based