comparsion of risk analysis and preparing template

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COMPARISON OF RISK ANALYSISMETHODS AND DEVELOPMENT OF A

TEMPLATE FOR RISK CHARACTERISATION

J.M. Ham, M. Struckl, A.-M. Heikkil, E. Krausmann,C. Di Mauro, M. Christou, J.-P. Nordvik

Institute for the Protection and Security of the Citizen

2006

EUR 22247 EN


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European Commission

Directorate-General Joint Research CentreInstitute for the Protection and Security of the Citizen

Contact informationEuropean Commission DG Joint Research Centre, Institute for the Protection and Security of

The Citizen, Traceability and Vulnerability UnitTP 361, Via Fermi 1

21020 Ispra(VA), ITALY

E-mail: [email protected].: +39 0332 78 5021Fax: +39 0332 78 5145

http://www.jrc.cec.eu.int

Legal NoticeNeither the European Commission nor any person acting on behalf of the Commission is

responsible for the use which might be made of this publication.

EUR 22247 ENLuxembourg: Office for Official Publications of the European Communities

European Communities, 2006

Reproduction is authorised provided the source is acknowledged

Printed in Italy


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3PREFACEManaging risk associated with technological systems has always been a demanding task. Today thistask is becoming even more challenging for politicians and risk-decision makers. Different factorscontribute to this situation such as an always increasing complexity of technological systems, theincreased expectations of the European citizen for a knowledge-based society and transparent decision-making processes, and the emergence of new threats like sabotage and terrorism. In fact, when man-made and environmental risk-related issues are concerned, it appears that a lack of balance existsbetween citizen's expectations and decision-maker's behaviour. This discrepancy can be traced back tothe variety and complexity of the risk assessment pproaches n use today as well as to the uncertaintiesthat affect the results of these studies.Decision makers are confronted with a large variety of approaches o assessand manage a specific risk;a fact that makes the comparison of risk studies performed by different analysts or for differ j nt end-users a difficult task and, consequently, has significantly hampered the widespread use of risk

Iassessment or certain decision-making purposes. ,Currently, the existing risk assessment approaches differ in their terminology, their underlyingassumptions, the way they are applied in practice, and the [mal format of their results. In 1999, the JRClaunched a number of activities to better understand the structural characteristics of the results of suchstudies -the so-called risk figures -and to investigate how the quality of these risk figures I can beevaluated. iThese activities resulted in the following two events: (a) a JRC International Workshop on Promotion ofTechnical Harmonization on Risk-based Decision Making, held at Stresa & Ispra, Italy, 22-25 May2000 and (b) a meeting in July 2001 with other Directorates-General of the European Commiss~onandrepresentatives from standardization organizations. IAs a follow-up of these events, an Institutional Activity called COMPASS (Risk Comparability andIntegrated Risk Assessment) was started in 2003 under the 6th Research Framework Program of theEuropean Commission. During the period 2003-2004, a main study of the COMPASS Activity wasthe development of a common format, also called template, to characterize a risk figure as wen as theoverall process that lead to this risk figure. The template was intended to comprise the presentation ofthe results and of the structure of a specific risk-analysis process, therefore facilitating the verificationof the completeness and adequacy of the process. It should be noted that the development of a generictechnical standard on how to perform a risk assessmentwas no objective of the project. Thi! reportpresents the final results of that study.Although the template is intended to cover as many risk-related activities as possible, the current studyfocuses only on the comparison of risk assessment n chemical industrial facilities and transportation ofdangerous goods. This way, it benefited from the experience with risk assessment in Sevesoinstallations and the work that is being carried out in the JRC, and it received significant input fromother Seveso-related activities, such as the European Working Group on Land-use Plannin~ in theContext of Article 12 of Directive 96/82/EC (Seveso II Directive). IThe study was funded entirely by JRC and was carried out by TNO Environment, Energy and ProcessInnovation (TNO-MEP)a under Service Contract No. 21503-1003-12, and JRC staff from theCOMPASS team and from the Major Accident Hazards Bureau (MAHB).

r ~

I.-P. NordvikIOMPASS ction Leader, RCRPSC

/~) /J. /l.t.~:fL~~i~:~~~~M. Christou

MAHB NEDIES Action Leader, JRC/IPSC

aSince 1 stJanuary 2005 known as: TNO Built Environment and Geosciences,Team Industrial and External Safety.1


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CONTRIBUTORS

J.M. Ham,

TNO Built Environment and Geosciences, Team Industrial and External Safety

M. Struckl,MAHB, JRC-IPSC

A.-M. Heikkil,

COMPASS, JRC-IPSC

E. Krausmann

MAHB, JRC-IPSC

C. Di Mauro

COMPASS, JRC-IPSC

M. Christou

MAHB, JRC-IPSC

J.-P. Nordvik

COMPASS, JRC-IPSC


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SUMMARY

In the context of the Institutional Activity COMPASS Risk Comparability and Integrated Risk Assessment

of the Joint Research Centre of the European Commission, a specific study entitled: Comparison of Risk

Analysis Methods and Development of a Template for Risk Characterisation was conducted.

The objective of this study was twofold:

1. to carry out a comparative analysis of existing risk analysis approaches, for estimating thetechnological accidental risks related with the process industry and the transportation of dangerous

goods by road, rail and pipelines, over member States (MS), Candidate Countries (CC) and other

relevant countries; and

2. to develop a template for the characterisation of the outcome of risk analysis and of the risk analysisprocess itself.

Objective 1: Comparison of risk analysis practices

The first objective was realised by collection of risk analysis requirements and practices in twelve

countries, mainly in the EC. The formal requirements of risk analysis mainly refer to the regulatory

obligations following from the (implementation of) the Seveso-II Directive.

National requirements in the various EC Member States show considerable differences in the way risk

analysis is implemented, both in formal regulations and in risk acceptance criteria as well as in the

standardisation of practices and availability of tools and guidance for the subject.

The most prominent difference is a deterministic approach versus a probabilistic approach in risk

analysis and risk evaluation. The choice of either of the two approaches whether determined by

technological, or by political and historical reasons appears to be not only a strict country preferred

issue. The objective of conducting a risk analysis in a specific situation and the purpose of application

of the results, are criteria to give preference to one approach rather than the other. The required nature

of a risk analysis depends on the field of decision making for which the results of such an analysis are

needed. In this study, at least four objective areas have been distinguished:

Application of environmental permit and licence to operate (LIC)

Demonstrating the technological safety (state-of-the-art) of an installation and its operation, anddefining measures for risk reduction (RRM)

Land-use planning (LUP)

Preparation for Emergency response (ERP)

In Safety Reports, mandatory as per Seveso-II, all these four issues have to be addressed. Differences,

however, exist between countries of the role and priority of risk analysis therein. The conclusions of the

actual comparisons are given in this report and in an extensive appendix with the results of data

collection through questionnaires. As an additional result, a spreadsheet table has been developed for

item-wise comparison of the different risk analysis practices.

Objective 2: Development of template(s) for risk characterisation

A set of pilot templates has been developed that decision makers can apply to verify the completeness

and the quality of a given risk analysis. A set of four different templates is proposed based on the

mentioned differences in approach in risk analysis studies, in the area of application of their results and

in the interest of the different decision makers. The templates are presented for the purpose of:

LIC & RRM, with a deterministic approach;

LIC & RRM, with a probabilistic approach;

LUP & ERP, with a deterministic approach;

LUP & ERP, with a probabilistic approach.


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Each template comprises a comparison table with:

The five elements of the risk analysis process, chosen for these templates: (i) hazardidentification, (ii) frequency assessment, (iii) consequence assessment, (iv) risk figure

determination, and (v) decision making.

For each element: (i) the method(s) applied; (ii) the tool(s) and model(s) available or used; and(iii) the result obtained in the respective phase.

The templates can be used as a tick-table and may be completed with specific data drawn from the risk

analysis report.

Recommendations for introduction of the templates

The templates were developed in a desk exercise. The objectives and the envisaged end-users

(stakeholders) were determined in communication with the JRC.

It is advised to test and validate these templates on practical use among (categories of) stakeholders, by

e.g. translating past risk-analysis studies into the format of the templates. This test and validation should

reveal:

Whether the format of the template is workable;

Whether its contents are complete, in phases and items;

Whether it provides the information the decision maker needs;

Whether a system of scoring of the quality of a risk analysis shall/can be developed, andwhich weighting factors shall then be applied;

Whether written guidance and instruction in the application would be sufficient, or practicaltraining will be required;

How the template(s) can be made to living documents, to satisfy the application on the longerterm in the dynamic discipline of risk analysis.


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CONTENTS

1 Introduction................................................................................................................................................ 7

2 Issues of the study ...................................................................................................................................... 7

2.1 Background to this study..................................................................................................................... 72.2 Objectives of risk analysis .................................................................................................................. 8

2.3 Different appreciations of risk analysis............................................................................................... 8

3 General procedure for risk analysis............................................................................................................ 9

3.1 Main phases ........................................................................................................................................ 9

3.2 Steps of the risk analysis procedure.................................................................................................... 9

3.3 Example: Risk analysis for land-use planning.................................................................................. 10

3.3.1 The consequence-based Methods........................................................................................... 10

3.3.2 The risk-based Methods ......................................................................................................... 103.3.3 Hybrid Methods......................................................................................................................... 10

3.3.4 State-of-the-Art Approach................................................................................................... 11

3.4 Other objectives of risk analysis and their approaches..................................................................... 11

4 Inventory of data from various countries: methods and results ............................................................... 12

4.1 Inventory sources and methods......................................................................................................... 12

4.1.1 Questionnaire............................................................................................................................. 12

4.1.2 Selection of countries ................................................................................................................ 12

4.2 Inventory results................................................................................................................................ 134.2.1 The Netherlands......................................................................................................................... 13

4.2.2 Belgium / Flanders..................................................................................................................... 13

4.2.3 Germany .................................................................................................................................... 13

4.2.4 France ........................................................................................................................................ 14

4.2.5 United Kingdom ........................................................................................................................ 14

4.2.6 Spain .......................................................................................................................................... 15

4.2.7 Finland ....................................................................................................................................... 15

4.2.8 Switzerland ................................................................................................................................ 154.2.9 Greece ........................................................................................................................................ 16

4.2.10 Sweden....................................................................................................................................... 17

4.2.11 United States of America........................................................................................................... 17

4.2.12 Israel .......................................................................................................................................... 17

4.3 Observations and conclusions from comparison over seven countries............................................. 17

4.3.1 General observations ................................................................................................................. 17

4.3.2 Conclusions on comparability ................................................................................................... 18

5 Risk analysis practices for transport of dangerous materials ................................................................... 215.1 General.............................................................................................................................................. 21

5.2 Pipelines transport............................................................................................................................. 21


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5.3 Road and rail transport...................................................................................................................... 22

5.4 Acceptance criteria............................................................................................................................ 23

5.5 Developments and current studies .................................................................................................... 23

6 Template Development: Risk analysis Comparison scheme.................................................................... 24

6.1 Objectives of the template................................................................................................................. 24

6.2 Considerations on structure and contents of the template................................................................. 24

6.3 Templates instruction for use........................................................................................................... 26

6.4 The templates .................................................................................................................................... 26

6.5 Recommendations for introduction of the templates ........................................................................ 37

7 References ................................................................................................................................................ 37

Appendices

Annex 1 Risk Analysis Comparison Scheme: Fixed installations

Annex 2 Results of Comparison, Item-Wise

Annex 3 Explanation of Terminology

Annex 4 Detailed description of risk analysis process in seven EU countries

Annex 5 Risk analysis methods and practices in seven EU countries, spreadsheet for comparison


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1 Introduction

Under the 6th

Framework Program of the European Commission (EC), DG Joint Research Centre is

carrying out an Institutional Activity called COMPASS Risk Comparability and Integrated Risk

Assessment. In this context, DG JRC conducted, in close cooperation with TNO Environment, Energy

and Process Innovation (TNO-MEP)b

, The Netherlands, a study entitled Comparison of Risk Analysis

Methods and Development of a Template for Risk Characterisation.

The objectives of this study were:

(i) To carry out a comparative analysis of existing risk analysis approaches, for estimating thetechnological accidental risks related with the process industry and the transportation of

dangerous goods by road, rail and pipelines, over member States (MS), Candidate Countries

(CC) and other relevant counties; and

(ii) To develop a template for the characterisation of the outcome of risk analysis and of the riskanalysis process itself.

The results of the study are presented in this report.

2 Issues of the study

2.1 Background to this study

In all decision making processes where risks to the public, to employees, to the environment or to

property are involved, some kind of risk analysis is required.

This particularly holds for the so called higher tier Seveso-II enterprises, where the operator has to

demonstrate that he has identified the risks of the hazardous installation(s) and that these risks are

controlled, managed and prepared for. But also for lower tier companies and for transport of

dangerous goods, the potential risks to the surrounding areas are often considered for decision making

on the prime objectives: environmental permits, land-use planning or emergency response planning.

Technological risks are dealt with differently in different applications (industries) and in differentcircumstances (regulatory regimes)

2,3,4,5,6. Decision-makers are therefore confronted with a variety of

approaches, methodologies and forms to evaluate and present a specific risk, a fact that makes the

comparison of risk studies performed by different analysts or for different end-users a difficult task.

Non-uniformity in methods, data and applications has significantly hampered the widespread use of risk

assessment for decision-making purposes.

In the EU Member States, considerably big differences exist in both the extent of prescribed procedures

for, and the type of result of risk analysis, as well as in the use of (quantified) risk criteria for decision-

making in the various purposes listed in section 2.2. These differences in approaches and results may

pose a problem to decision makers in interpretation of results of different risk studies. Another

complicating consequence arises for (management of) multi-national companies, who are confronted

with differing requirements between the different EU Countries even if production process & control aswell as the safety management systems are similar for the entire company, regardless in which country

a particular process unit is located.

This study distinguished the following issues of risk analysis approaches and practices in Europe:

Various objectives of risk analysis: why is it done, what are the results used for and what kindof decisions are based on it?

Various countries: what is the risk analysis approach, how is the RA-process carried out andwhat is the nature of results? Which steps in the process can be distinguished? Which input is

used and what are the uncertainties in this process?

Various approaches and risk results, and the strictness of regulations and directives in this

b Since 1st January 2005 known as: TNO Built Environment and Geosciences, Team Industrial and External Safety.


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field (or the freedom of application of preferred methods and models).

2.2 Objectives of risk analysis

Risk analysis for technological hazards can have different objectives, either in isolation or in

combination. The most important stakeholders and their objectives are:

Competent authorities, for the purpose of environmental permission;

Competent authorities, for the purpose of fulfilling safety report obligations, e.g. as perSEVESO-2 requirements;

Emergency Response organisations, for the purpose of response preparation;

Regional planning authorities, for the purpose of decision making on land-use planning in anarea with major hazard industries or dangerous goods transport;

Installation owners, for the purpose of identifying priorities in risk reduction or for costbenefitanalysis of different risk reduction options.

The objectives (or purposes) of a risk analysis may thus cover the following:

Licence application (LIC) Determination and evaluation of risk reducing measures (RRM)

Land-use planning (LUP)

Emergency response preparation (ERP),

or combinations of two or more of these. The various objectives logically lead to differences in the

nature and the extent of risk studies.

2.3 Different appreciations of risk analysis

As described in the IEC/ISO Guide 737

on risk management, it is fundamental to distinguish the risk

assessment and the decision-making steps. The guide explains that risk assessment is a part of the riskmanagement process, ended up with the decision. Risk assessment is a tool used to estimate the risk,

characterised by the likelihood and severity of specific events. A risk based decision-making process is

naturally based on risk assessment criteria, but must also integrate other criteria that can be economical,

cultural, ethical, etcetera.

It is obvious that the different stakeholders and the differing objectives will lead to a variety of

definitions and appreciations of risk. Though there is a common opinion about the definition of risk:

Risk = the Probability of an Undesired Outcome,

As the definitions of a deterministic and probabilistic approach in risk analysis are often disputed,

the key characteristics with respect to this document are the following: the traditional deterministic risk

assessment approach is based on conservatively defined values for design or structural reliability in

conjunction with a safety factor based on judgment, evidence of satisfactory performance or calibration

exercise; in simple words, safety is expressed with 0 (= insufficient safety) or 1 (=sufficient

safety).Deterministic quantities can be interpreted as random variables with deviations tending to

zero. The probabilistic assessment may be seen as an extension of the deterministic approach, taking

into account the variety of physical behaviour, poor information or human error, thus aiming at a more

realistic modelling of a structural behaviour.

This quantification or even the necessity to quantify- of risk is an issue of a long lasting debate. As far

as the risks of hazardous substances are concerned, this debate has as yet not resulted in uniformity in

definitions of neither the probability, nor the nature or extent of the outcome. Consequently, thedimension of the risk figure differs in the various applications, and so does the presentation of this

figure.


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In this report, the Outcome is mostly expressed in the consequences for humans of exposure to (the

effects of) a release of hazardous material. These consequences may vary from experience of nuisance

to serious injures or even death. Alternatively, and depending on the surroundings potentially to be

affected or on the objectives of the stakeholder, the outcome may also be damage to the environment,

e.g. area of polluted soil, number of killed sea species, etc.

The differences in the risk figures applied in various countries are partly due to historical or cultural

background. In some cases, a quantified risk value as a basis for decision making is explicitly excluded.This then results in a fully deterministic approach with qualitative outcomes and decision making, like

in Germany. In other countries, like UK and The Netherlands, a risk based approach has been adopted.

3 General procedure for risk analysis

3.1 Main phases

In general, the process of the risk analysis methodology comprises the following phases:

Hazard identification: to find the parts of the installation, which are of importance withrespect to safety including mapping of the origin and causes of possible accidents and the

quantities and properties of chemicals used. The HAZID phase may result either in direct

measures to reduce the risks (fully deterministic) or in (a list of) scenarios that are to be

considered quantitatively in consequences and/or frequencies.

Analysis of accident scenarios: to describe the possible modes how an accident can develop,e.g.: a malfunction in a valve triggers other failure modes and gives a release of a dangerous

compound to the environment threatening humans.

Analysis of frequencies and consequences: the accident scenarios are analysed morethoroughly. The frequency of a scenario occurring and the consequences resulting from the

scenario are assessed. The consequences are often measured as the impact on human health or

even as mortality. Also, the environmental impacts might be used as a measure.

Evaluation of the total risk: the final evaluation of the risk includes a ranking of the scenariosfound and might be expressed as a sum of the risk of all the scenarios. The probabilistic

approach will define the risk as the product of the frequencies and the consequences. Thequantified deterministic approach is based on the possible consequences.

3.2 Steps of the risk analysis procedure

A stepwise procedure of a risk analysis could be listed out as followse.g.8

:

Gathering of all relevant information regarding the hazardous activity (e.g. chemical plant) to beanalysed and its environment (plant documentation).

Listing of the plant sections containing special hazardous substances and having special safetysystems (hazard-preventing and consequence-limiting technical and organisational systems).

Analysis (e.g. by HAZOP, FMEA, etc.) of the plants danger potential with consideration of theeffectiveness of existing safety systems.

Evaluation of the results of the hazard analysis as to completeness and accuracy of triggering eventsand possible hazard/incident scenarios.

Definition of the hazard/incident scenarios to be investigated resulting in event sequences;quantitative statement of the frequency of occurrence of triggering events; definition and analysis of

triggering events in the same manner.

Determination of the effects of individual hazard/incident scenarios (e.g. spread of toxic substances,pressure shock waves, thermal radiation). The calculated effects of the different hazard/incident

scenarios are evaluated on the basis of evaluation criteria (e.g. IDLH values or Probit functions for

substances that are toxic when inhaled, or limit values for pressure shock wave strength and thermalradiation intensity).

Combination of the quantitatively determined and evaluated effects and the determined/calculated


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frequencies of occurrence of individual hazard/incident scenarios for the purpose of risk estimation.

Summation of all individual scenarios resulting in the chemical plants total risk; evaluation of thetotal risk.

Most of the steps are common for both qualitative and quantitative risk analysis. Particularly the first

four steps are fully applicable to both the probabilistic as well as the deterministic studies. Differences

exist in the extent of quantification in steps 5 and 6. Especially the frequency statement (step 5) in the

deterministic approach will be qualitative in nature, and be expressed in terms of quite likely or thishas never happened in a similar process. Evidence is given through casuistry of accidents in the past

(databases) or through engineering judgements. The consequence assessment however is usually

quantified, even in the deterministic approach, especially for scenarios with the potential of affecting

people or the environment offsite.

In all cases, the eventual conclusions are derived by combination of the two steps 5 and 6. This

combination results in an expression of risk (qualitative or semi-quantitative or fully quantitative). This

risk figure forms the basis for decision making about acceptability of the level of risk, necessity of

risk reduction, required accident preparedness, etc.

In the following sections 3.3 and 3.4, the different approaches of risk analysis used for the purpose of

land-use planning are described. The purpose of these sections is mainly illustrative.

3.3 Example: Risk analysis for land-use planning

Currently the following methods in use for risk assessment in Land Use Planning may be

distinguished9.

3.3.1 The consequence-based Methods

The consequence based approach follows the assessment of consequences of pre-selected credible (or

conceivable) accidents, without quantifying the likelihood of these accidents.

The pre-selected reference scenarios can be chosen in various ways, either by a numerical or non-

numerical consideration of the likelihood of occurrence or by simple expert judgement. The

consequences of the accidents mostly are taken into consideration by calculating the distance in which

the physical and/or human health - relevant magnitude describing the effects (e.g. toxic concentration)

reaches, for a given exposure period, a threshold value corresponding to the beginning of the undesired

effect (e.g. irreversible health effect/harm or fatality).

3.3.2 The risk-based Methods

The risk-based approach presents the risk usually in the form of a numerical value for the likelihood

of a certain undesired effect. The related methods have an underlying calculation of the consequences

stemming from selected accidents. The consequence calculation may be identical like the one carried

out in the consequence-based methods; also the scenario selection may be the same. The main

difference lies in the additional use of the numerical value of the occurrence likelihood of the scenario

which finally defines the likelihood of the calculated undesired effect (with supplementary factors, e.g.

the likelihood of weather conditions).

3.3.3 Hybrid Methods

Semi-Quantitative Methods:

The semi-quantitative methods are a specific subcategory of the risk-based methods. Here explicitly

a quantitative element (e.g. likelihood analysis) is accompanied by a qualitative one (e.g. the

consequence assessment).

Tables of fixed distances:

Tables of fixed distances may be considered as a simplified form of the consequence-based method,most common as a rough consequence estimate based on selected scenarios, or in their most simple

form they may have been derived from expert judgment, including consideration of historical data

or the experience from operating similar plants and are developed on a rather conservative basis


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Tables of appropriate distances are often used because of the limited relevance of the case. The

distance extent depends mainly on the type of industrial activity or on the quantity and type of the

hazardous substances present; design characteristics, safety measures and particular features of the

establishment under question are not explicitly taken into account.

3.3.4 State-of-the-Art Approach

The State-of-the-Art Approach is not a RA method for LUP in the strict sense. The underlyingphilosophy is based on the idea that if measures exist sufficient to protect the population from an

accident considered to be the worst conceivable, sufficient protection will also be available for any

less serious incident. It is assumed that the consideration of the consequences of the worst conceivable

accident (including a precautionary element) has been carried out during the identification of a

specific State-of-the-Art. As the deterministic foundations of the underlying assumptions are mostly not

retraceable it is necessary to have an add-on consequence-based method.

As a synthesis of the summary above, the following most important common best practice elements of

risk assessment in LUP may be listed:

Scenarios: they are used either directly in different numbers, pre-selected (reference) or implicitlye.g. for generic distance tables scenario selection

Event Frequencies: the event frequency is either a factor directly necessary for the assessmentmethod or it appears implicitly in other form, e.g. as limiting condition for the scenario definition

determination models & frequency data.

Endpoint Values: they are applied either for individual consequence calculations or are consideredimplicitly in a generic form underlying basics for risk/consequence evaluation.

Technical Measures: they influence the event frequency consideration (the acknowledged level ofconfidence may vary) or are proposed as additional measures to reduce the likelihood of an

undesired event or limit the consequences (with different ways to impose them) feasibility of

technical measures vs. incompatibility of situations.

3.4 Other objectives of risk analysis and their approaches

The example in section 3.3 was worked out for various options of risk analysis for land-use planning. It

is obvious that this application requires some kind of measuring, either of risk (probabilistic) or of

consequences (deterministic). Setting safety zones or defining exclusion zones requires to some extent

the use of modelling and computation.

Also for off-site emergency response planning (ERP) and the definition of resource requirements,

estimation of potential consequence areas and/or numbers of potential victims of a calamity requires an

approach that indicates clearly the zones of concern. Response organisations often define a few

reference incidents (scenarios) for training and preparedness. Risk analysis for licence application (LIC)

or for identification of risk reducing measures (RRM) is often qualitative or semi-quantitative in nature.

Structured techniques and lessons learned are applied to determine the required level of safety, judged

against qualitative principles like State-of-the-Art, As Low As Reasonable Achievable (ALARA), or

Practicable (ALARP), Best Available Technique (BAT), Best Practice, etc. At the other hand, in

some applications a fully quantified probabilistic approach is followed, for instance in power generation

and in nuclear reactors. A last possible objective of risk analysis mentioned here, is occupational safety:

the risk that workers are exposed to during their job. Both deterministic methodologies as well as

probabilistic quantification are applied. Moreover, human reliability assessment and ergonomics are

disciplines that are exploited in occupational risk analysis. Statistical evaluation of accident histories

forms an important element of focussing on particular risky jobs. The issue of internal risks is

excluded from the scope of this study.e.g. 10


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4 Inventory of data from various countries: methods and results

4.1 Inventory sources and methods

The comparison of risk analysis methods applied in various countries and by various organisations was

aimed at describing the actual situation: which are the current practices and what is the nature of

results? In principle, the inventory should focus on information available in open bibliography in

sources like periodicals, conference proceedings and the internet.

These open sources however appeared not sufficiently detailed or accessible for a full comparison of all

issues of relevance. Therefore a direct collection of data from a representative sample of countries was

considered necessary to provide the issues that are relevant for the comparison of risk analysis practices

and for the development of a comparison template.

4.1.1 Questionnaire

During the study, it appeared that a thorough inventory of practices and methodologies would not be

feasible without enquiries of persons and organisations directly involved in decision-making about risk

analysis or in doing such studies. A format of an elementary questionnaire was developed and sent out

to representatives in a limited number of countries. The questionnaire comprised the inventory of thefollowing main issues:

1) Definition of risk, or risk characterisation

2) Methodology of risk analysis

Overall structure and phasing

Methods of hazard identification

Frequency assessment

Consequence assessment

Risk calculation and presentation

3) Risk mapping and decision making

The questionnaire (Annex 1), called Comparison Scheme, together with a Clarification document

were filled in for the situation in The Netherlands, serving as a format to other countries to ensure

uniformity in the collection of data.

4.1.2 Selection of countries

It appeared that in many countries, especially in the newly accessed EU Member States, a clear policy

on implementation of Seveso-II was not yet in place. It was therefore decided that the detailed inventory

could best be carried out for a limited number of key countries, based on intensity of industrialisation

and on regions where the policy development and the time of learning experience would be more or

less in a stage of maturity.

The following regions and countries were selected:

Western Europe: The Netherlands (NL), Belgium (BE), United Kingdom (UK), Germany (DE);

Southern Europe & Mediterranean: France (FR), Spain (ES), Greece (GR);

Northern Europe / Scandinavia: Finland (FI).

The questionnaire was sent to one representative per a country. From countries that were approached

with the full questionnaire, information was received from FR, DE, ES and FI. For BE and UK, part of

the information was gathered from various internet sites and in the scope of the project SHAPE-RISK11

.

Additional information from other countries that was collected during literature searches and/or fromhands-on experience within TNO is also included in the inventory. Such information is reported here as

well, but in a less structured format than for the above named countries. This also includes a few

countries outside Europe: USA and Israel.


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The findings of the various countries / practices are summarised in section 4.2 and in Annex 2. Section

4.3 summarises the key findings of the comparison, similarities and differences.

4.2 Inventory results

In this section, the results of the inventories in various countries are given.

4.2.1 The Netherlands

In The Netherlands, a fully quantified probabilistic risk assessment (QRA) is required in the safety

report for each of the top tier Seveso-II sites. Moreover, competent authorities may require a QRA to be

carried out as part of a permit procedure for new installations or for urban developments, also for non-

Seveso installations. The scenarios for the QRA have been prefixed by the national Committee for the

Prevention of Disasters (CPR).

Acceptance criteria are in place both for location specific risk (individual risk) and for societal risk,

outside the plants boundaries. Additionally, for specific types of enterprises fixed safety zoning

distances between the installation and the populated surroundings are applied. These zoning distances

are also risk based; they reflect the (average) distance for location specific risk LR = 10-6

/year.

The so called national Committee for the Prevention of Disasters (CPR)

12

has issued several guidelineson modelling and quantifying the risks and the consequences of dealing with dangerous materials.

These coloured books form the standard for QRAs in the Netherlands and are increasingly used in

countries abroad as well.

The Purple Book (CPR-18E)12

gives the standardised procedures for a QRA in the Netherlands,

including reference scenarios for equipment on industrial sites and for transport of dangerous goods by

road and rail and over inland waterways, and their frequency of occurrence.

The Yellow Book (CPR-14E)12

presents recommended models for physical effect calculations for the

release, evaporation and dispersion of hazardous materials and for assessing thermal radiation due to

fire, overpressures due to explosion and exposure to toxic dose.

In the Green Book (CPR-16E)12

one finds models for assessing the potential damage due to exposure to

the mentioned effects.

In practice, over 90% of the QRAs follow the mentioned CPR guidelines. Substitution of the

recommended methods, models and figures by alternative solutions would only be accepted if the

alternatives are demonstrated to be more appropriate to the subject of study. This then requires the

consent of the competent authority.

4.2.2 Belgium / Flanders

Belgium is a federal state where regulations and their implementation are different for the two regions

Flanders and Walloon. The Flemish approach is strongly related to the Dutch one (probabilistic). The

Dutch CPR guidelines are also recommended as standard in Flanders. For probability and frequency

assessment, the Flemish authorities13

have developed their own set of figures.For the acceptance criteria for location specific risk three types of surroundings are distinguished: the

boundary of the establishment, the boundary of the industrial area and the location of vulnerable

objects. Moreover, distinction is made in the tolerance limits between existing situations and new ones.

4.2.3 Germany

The German approach14

is a fully deterministic one. This follows from a constitutional requirement that,

in principle, activities that can lead to accidents with life- or health threatening effects shall never be

tolerated. This principle was further acknowledged in procedures around the Kalkar debate in the late

1970s. Whatever measures can be taken to reduce the possibility of occurrence of such accidents shall

be applied. The risk analysis thus forms the basis for evaluating whether state-of-the-art technologies

are applied. Application of this is in principle a strict condition for LIC procedures. Basis is a hazardidentification process using structured techniques like HAZOP, FMEA and Checklists, as well as

accident history and expert opinions.


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14

Germany applies generic safety distances between potentially hazardous installations and vulnerable

(populated) areas. The values of the safety distances have mostly been derived through expert

judgement and based on historical data and experience with similar installations / situations. Eventually,

for the remaining hazards the possible consequence areas are assessed. The outcome of the consequence

assessment is a consequence distance for (a limited number of) foreseeable accident scenarios.

Quantification of damage areas is practically limited to the purpose of LUP.

Recently, a discussion has started to explore the possibilities of introducing the probabilistic riskapproach in Germany as well. The Strfall Kommission15,16

has issued a discussion document for

exploring the feasibility of implementing the risk approach in Germany. This is partly driven by

developments like the definition of the Eurocodesc

which are of semi-probabilistic nature, partly by

the multinational character of companies; nevertheless the future implication cannot be foreseen

currently.

4.2.4 France

Till recently, the French regulations followed the deterministic approach. The requirements comprised

the presentation of consequence distances for a number of scenarios that are to be determined by the

plant owner. Some guidelines on modelling were available, but no strict requirements were set.

This has changed after the Toulouse tragedy in 2001 where a series of explosions of ammonium nitratecaused about twenty fatalities, multiple number of injures and extensive property damage. Since then,

the French government has issued several new and stricter regulations, especially for land-use

planning17,18,19,20. Several guidelines are now available giving the types of loss of containment,

analytical equations for assessing consequence distances for typical events, and prescription of the

presentation of the results. End points of calculations are clearly set, e.g. levels of heat radiation or toxic

exposure. Also the procedures followed to select scenarios to be included in the safety report, have

recently been set more clear and uniform. This includes mandatory consultation of accident databases,

structured identification methods (e.g. HAZOP) and selection of relevant scenarios with the help of a

risk matrix. A quantified frequency assessment is (will be) required to give evidence that the likelihood

of certain scenarios is sufficiently low (e.g. < 10-6/year) in order to rule them out from the external

effects calculations. A (revised) set of requirements is expected to be issued in 2005.

The French government has assigned a limited number of independent experts (Tiers Experts) that

will assist in the evaluation of safety reports submitted by the plant owners. These experts regularly

meet to exchange views and experiences, which results in more uniformity and increasing

understanding about the issues of risk analysis. Their conclusions will probably be reflected in the

future guidelines. It appears obvious that the current practice in France is a very dynamic one, in which

the probabilistic phenomena will receive an increasing interest.21,22

4.2.5 United Kingdom

In the United Kingdom, the risk analysis approach is primarily a probabilistic one. In safety reports

according to Seveso-II (COMAH), a quantified risk assessment is required. The procedures for a QRA

are not very strictly prescribed, though the competent authority, the UK-HSE, has developed severalguidance documents23,24,25

for assisting the risk analysts.

The QRA procedure and phasing is one according to proportionality, which means that the extent of

detail of a QRA shall be proportional to the risk generated and/or to the complexity of the process or

installation in question. In practice, this means that for relatively simple situations a deterministic or

even qualitative approach is followed. If then no (external) hazard is expected, the procedure of risk

analysis is satisfied. However, in cases where off-site hazard may occur or high societal concerns exist,

a more in depth analysis of scenarios, their causes and mitigating measures is required. Quantified

probabilistic assessment of these issues is then required. In decision-making, ALARP26,27

motivation

plays a crucial role.

Acceptability criteria are set for both individual risk and societal risk. The HSE will provide

recommendations with regard to a planned (urban or industrial) development: advise against or dont

c Eurocode: Harmonized European set of structural design codes for building and civil engineering works


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15

advise against.

4.2.6 Spain

In Spain, the formal national requirements with regard to Seveso-II are described in the Directriz

Basica28

. The approach with regard to risk analysis is basically a deterministic one. For a number of

accident scenarios, the consequence areas (distances) have to be assessed and mapped for a set of

prescribed effect values like heat radiation and explosion overpressure29

. Not only areas for fatalities arerequired, but also areas with potential injures. The values are directly related to emergency response

levels. Except for Catalonia, policy for using risk analysis for LIC or LUP appears hardly to exist in

Spain.

Regional differences are observed in Spain. In the province Catalonia for instance, the regional

authorities often require a probabilistic assessment to be provided in addition to the national

requirements. Use of the Dutch tools and CPR-models is encouraged.

4.2.7 Finland

In Finland30

, the deterministic risk assessment approach is applied in the industry related to dangerous

chemicals. Finnish chemicals legislation doesn't specify the methods that should be used in identifying

hazards or evaluating risks. The competent authority (TUKES) requires a description and the control ofpossible hazards at the plant, as well as measures for protection and intervention in the limiting of the

consequences of accidents. At the higher tier plants the use of systematic methods is required by the

competent authority. Consequences of major accidents are usually evaluated by using the models of

accidental releases. The results of risk analysis can also be used for emergency response planning, by

the local rescue services.

Risks are often evaluated by using a semi quantitative assessment, e.g. a risk matrix, in which an

evaluation is based on simple numerical values. In this method evaluated consequences are multiplied

by an evaluated likelihood of an incidence. The result describes a severity of a risk. This type of

assessment is a prevailing practice in the higher tier plants, but not a mandatory one for submission in a

safety report.

For the revising and evaluation of the Safety Reports, TUKES uses a "workbook" in which the method

is based on the EFQM model, on quality management. The workbook contains information on required

criteria. The book is not available to industries and consultants.

4.2.8 Switzerland

Although Switzerland is not an EU Member State, the Swiss Agency for the Environment, Forest and

Landscape (SAEFL, BUWAL) has reflected the Seveso II Directive in most of the regulations with

regard to major hazard industries: the Ordinance on Protection against Major Accidents (OMA)31

. This

Ordinance reflects well-established procedures in risk control, in particular those used in The

Netherlands in the context of the environment control policy, e.g. the quantitative risk approach. At the

same time, the OMA requires implementation of the state-of-the-art technology in agreement with the

German practice.

The following definitions for hazard potential and risk are given in OMA:

Hazard potential means the sum of all the consequences which substances, products, specialwastes, micro-organisms or dangerous goods could have as a result of their quantity and properties.

Risk shall be determined by the extent of the possible damage to the population or theenvironment, caused by major accidents and by the probability of the latter occurring.

Assessment of hazard potential and risks is done in a two steps procedure: (1) submission of a Summary

Report by the facility owner, and (2) submission of a quantitative risk assessment (QRA), in case the

Summary Report shows that major accidents and serious damage must be expected. Fault/Event-tree

assessment is an essential element in QRAs in Switzerland. In addition to this top-down approach, also

a bottom-up approach of causes is encouraged, for instance through HAZOP, FMEA and similar. The

need for consistency in the application of the OMA and in the conduct of QRAs was recognised in an

early stage. Therefore, the SAEFL published a series of guidance documents for risk analysts and


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reviewers.

The objective of risk assessment is twofold: (i) to control the risk level of the major hazard facilities,

and (ii) to inform the public. Considerable effort has been put into making the hazard and risk

assessment simple and accessible to the facility owners. Still, it is expected that both risk analysts and

reviewers be knowledgeable in the principles of QRA. The consequence models are supported by LoC

events defined in the Manuals. Typically, in Switzerland the (presentation of) risk assessment covers

more than only danger to life among the public. Damage indicators (Disaster Values) have beendefined in the OMA, covering damage to man, natural resources, and property.

For each hazard recipient the Disaster Values are expressed on a uniform scale of three categories:

Accident, Major Accident and Catastrophe. In the societal risk curve, these Disaster Values are

presented against the expected frequency of occurrence. The acceptability matrix of the curve presents

four domains, namely:

No serious damage, i.e. no group risk: < 10 fatalities, or < 100 injures;

Acceptable: 10 fatalities at f < 10-7/year, with N2 rule for risk aversion;

Unacceptable: 10 fatalities at f > 10-5/year, with N2 rule for risk aversion;

Transition, the area between Acceptable and Unacceptable.

4.2.9 Greece

In Greece, the requirements for the safety report are limited to common interpretations of the Seveso II

text, and thus neither quantitative risk analysis nor environmental risk studies are required.

As far as safety report supporting instruments are concerned, Greek practice is poor in instruments and

guidance32

. The single exception is a zoning system with certain consequence criteria that have been

widely accepted since they have been proposed by the Ministry of Environment for the external

emergency plan of industrial areas. The zoning system comprises three levels of consequences that are

based on damage criteria such as TLVs for toxic substances and certain thermal doses and

overpressures. This system is widely accepted but not formally adopted. Safety reports have been

developed using these criteria to identify the extent of possible damage in the surroundings of theestablishments.

In Greece, formal risk criteria are neither used, nor have they been proposed by any of the cooperating

authorities. Some safety reports were developed with the support of certain risk criteria used in

industrial practices of other EU member states. The Greek authorities have planned a programme to

develop national guidance documents and to provide training to authority employees, in order to create

more uniformity and consensus in risk analysis practices.

From an investigation (questionnaire) taken from a few Seveso higher tier companies in the scope of

SHAPE-RISK, the following information on used methods was collected:

For hazard identification and/or LoC definition: International databases of failure records, Reports

from equipment reviews, Checklists, Literature and international guidelines, Reports on lessonslearnt and on near miss analysis, LNG Standards from NFPA and EN.

For identification of failure causes: HAZOP, Accident analysis, What-If, Fault-tree & Event-tree,International guidelines.

For consequence assessment: Gas/toxic cloud dispersion model in PHAST-Pro (refineries),Scenarios for release and ignition of LNG: dispersion with DEGADIS.

For QRA: QRA is not required

Although QRA is not required nor guidance on quantitative data is given, the following information and

data sources are mentioned for risk assessment:

Seveso I: individual risk and societal risk; Seveso-II: Dose zones

Dose zones defined by the Ministry of Environment

Meteorological data


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Substance characteristics

Quantification of external effects based on distances of toxicity and radiation levels.

4.2.10 Sweden

From Sweden, the information is based on documentation from the Rescue Service Agency33

. Decision

support is based on a risk matrix approach, in which semi-quantitative classification of consequence

severity and incident likelihood are presented. Consequences are expressed in human life, damage to

the environment and financial loss of property. The results are used to prioritise risks in municipalities,

to evaluate possibilities for accident prevention and to plan for emergencies.

4.2.11 United States of America

In the USA, the responsibility of risk assessment requirements lays with the US-EPA. They have

developed the policy of Risk Management Plan (RMP)34

which requires major hazard industries to

submit an RMP document. This document shall provide information primarily required for emergency

response planning. Basically, the approach is a deterministic one.

At least two scenarios have to be evaluated and to be quantified in terms of consequence distances for

each relevant installation: The first one is a major or catastrophic incident, usually defined as the loss of containment of an

installation within 10 minutes, at constant rate;

The second one is a scenario that is considered to be a more likely serious incident, to be definedby the operator.

For both, the consequences have to be assessed and mapped. The results are communicated to the local

authorities and the public, and form the basis for the civil protection agencies and public forums.

US-EPA provides guidance documents and consequence assessment software to support a consistent

and uniform application of the matter. No evidence has been found that risk analysis results are used for

environmental permit procedures. The results do play a role in land-use planning, though no formal risk

based acceptance criteria are used.

4.2.12 Israel

Although a full QRA is not yet mandatory in Israel, the national Ministry of Environment has adopted

the approach of the Dutch Purple Book (CPR-18)12

and requires evaluating LoC events as defined

therein. Scenarios that have the potential of life threatening exposure to the public shall be mitigated to

a likelihood of occurrence of less than 10-6

per year. The base frequency is taken from the Purple Book,

and the effects of mitigating measures must be demonstrated for reduction of the likelihood of exposure

to below the set limits.

In the Haifa Town area, generally the QRA approach is followed, identical to the Dutch approach.

Results are used for permit purposes and for land use decisions.

4.3 Observations and conclusions from comparison over seven countries

The investigation in this report covers the risk analysis approach and practices of twelve countries. For

seven of them, an extensive investigation has been carried out. The most obvious or remarkable

conclusions of this inventory are discussed in this chapter and are summarised in Table 4.1. An

extensive overview of practices is given in Annex 4.

4.3.1 General observations

The investigation revealed that different situations exist with regard to homogeneous application of risk

analysis methodologies:

i) situations where the practices of risk analysis are strictly prescribed by the government orcompetent authority (e.g. the CPR coloured books

12in The Netherlands);

ii) situations where a generally accepted practice is followed without being precisely prescribed; and


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iii) situations where the initiative to choose and apply the preferred methodologies is left to the

operator, for instance because these belong to a companys strategy.

For situations (ii) and (iii) the countrys approaches cannot be exactly defined. The approach in Finland

for instance appears to be category (iii), while in Germany both (ii) and (iii) seem to exist. The

distinction in the mentioned situations is the most obvious in the phase of hazard identification.

Another obvious difference in practices applied (or required), even within a specific country, originates

from the objective of a particular risk analysis. One may distinguish in the following areas ofapplication:

a) permit / license application (LIC);

b) evaluating need and means of risk reduction / demonstration of ALARA (RRM);

c) land-use planning (LUP);

d) emergency response planning (ERP);

e) occupational safety (OCS).

And finally there is a category of purely administrative reasons: to fulfil the Seveso requirements,

because the Directive requires us so!

The principle of evaluation whether a certain situation is ALARA (or ALARP: As Low As

Reasonably Practicable; or State-of-the-Art) is followed in several countries, but with differentbackground. This can be explained e.g. for the situations in Germany and in United Kingdom. The

fundamental difference can be understood as follows: In Germany risk reduction measures are

investigated as an integral part of the risk analysis, and are evaluated and considered till the level of

justifiable risk is achieved as defined by the State-of-the-Art. Consequence assessment is done in a

last stage, when all reasonable options of minimising the risks have been implemented, and only for

specific purposes as LUP zoning or emergency response. Contrary, in United Kingdom the evaluation

starts with the quantification of consequence and likelihood, and additional risk reduction is proposed if

certain acceptance criteria are exceeded.

4.3.2 Conclusions on comparability

From the summary in the previous section and Annex 2, it is concluded that there is a big variation inthe risk analysis practices in the investigated countries. Comparison of the end results of a risk analysis,

the so called risk figure, will therefore be difficult if not impossible for most of the decision makers

and stakeholders defined for this investigation.

The differences are not only caused by the adopted approach (deterministic versus probabilistic), but

also by a number of other factors like:

The procedures of selecting scenarios relevant for the risk analysis, and for discarding others. Somesituations allow discarding scenarios because of their limited consequences (e.g. no harm outside

the fence), while others allow neglecting the worst case scenarios which are considered too

incredible (very low frequency), or they are entirely used only for emergency response. In other

words: in one case the selection (and negation) of safety-relevant installations and scenarios is done

on the basis of consequence, while in other situations this is done on the basis of likelihood.

The purpose of the risk analysis is another cause of differences in the analysis results. For example,it is obvious that differences occur in the levels of calculated consequences that will be used for

emergency response planning and those used for land-use planning. These differences are reflected,

among others, in the values of the end-point of calculation. These appear to vary by a factor of 3 to

6 for thermal radiation and overpressure, and even more for toxic materials.

There appears to be a significant difference in the definition of e.g. individual risk between the twoprobabilistic approaches of United Kingdom and The Netherlands. The main difference lies in the

definition of the respective consequences:

- In the Dutch definition, the reference consequence is (the likelihood of) fatality. For instance: if

at a certain location an effect occurs that would lead to 50% fatality, according to a probitfunction, then the individual risk is 0.5 times the frequency that the effect occurs. Likewise the

effect resulting in 1% fatality leads to an individual risk equal to 0.01 times the frequency of the

effect.


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- In the English definition, the figure of individual risk is not corrected for this consequencefactor. The IR is expressed as the frequency that a person receives a harm (= exposure to an

effect) that would result in 50% or 1% fatality.

Eventually, the risk figures may differ by a factor of 100 in the area away from the scene of the

accident, only due to this difference in definitions.

Regarding tools and methods, the following is observed:

- In most of the countries, casuistry of past accident is used as one of the means of hazardidentification. Accident databases are used for that. It appears that the various countries use

only their own database, while sharing experience between data sources would probably

reveal additional relevant scenarios which are now easily overlooked. The following databases

have been mentioned in this study: FACTS (NL), MHIDAS (UK), ZEMA (DE), ARIA (FR),

VARO (FI) and MARS (EU).

- Harmonisation in consequence modelling would probably also limit the variation in results, likein the Netherlands.


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Country Approach Objectives Risk HAZID Frequency Consequences End-point Ris

Netherlands P-QRA LUP-LIC-RM-ER IR, SR(cumul)

GenericLoCs, CPR-18

CPR-18 CPR-14/16 1% fatality: heat radiation 9.8kW/m^2, overpressure 100 mbar,toxic 1% lethality according to probitfunction

AGW, VRW

IR: 10

-

SR

Belgium /Flanders

P-QRA LIC-LUP-ER IR, SR(cumul)

Generic LoCs Aminal CPR-14/16 1% fatality: heat radiation 9.8kW/m^2, overpressure 40 mbar,toxic 1% lethality according to probitfunction

AGW, VRW

IR: 10

-

SR

Germany D-QL LIC-RM-LUP-ER N.A. HAZOP +Experts

N.A. VDI +internationalmodels

Toxic: ERPG-2 and ERPG-3; Heatradiation 1.6 kW/m^2; explosion 0.1bar

N.A

France D-QL/QN LIC-RM-LUP-ER N.A. Casuistry +HAZOP +generic LoCs

N.A.

Risk matrixfor selectionof LoCs

Distances SEL& SEI

Thermal radiation: SEL = 5 kW/m2 ,SEI = 3 kW/m^2. Overpressure: SEL= 140 mbar, SEI = 50 mbar. Toxics:SEL (1% and 5%) and SEI; IDLH.

SE

UnitedKingdom

D-QLP-QRA

(proportionality)

LIC-RM-LUP IR, SR Generic LoCs Genericfigures andCPR-18

Companymodels; HSEguidance; CPR-14

Probit-based values for hypotheticalperson: 1%, 10% and 50% fatality.Thermal radiation 500(kW/m^2)^4/3,s; overpressure 70mbar

IR:

GRLoC

Spain D-QN ER N.A.,except forCatalonia

No fixedmethod

N.A., exceptfor Cataloniawith CPR-18

Effects not fixed.Damage criteriain DB.

Probit-based for thermal radiationand toxics. Thermal: ZI = 250 TDU,ZA = 115 TDU, ZD = 8 kW/m^2.Overpressure: ZI = 125 mbar, ZA =50 mbar, ZD = 160 mbar. Toxics ZI =

ERPG-2, ZA = ERPG-1.

N.ACa

Finland D-QL/QN LIC N.A. No fixedmethod

N.A. No fixed models Not specified. Safety / separationdistances are specified for avoidingdomino effects.

N.A


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5 Risk analysis practices for transport of dangerous materials

5.1 General

The main scope of this investigation is primarily focussed on installations falling under SEVESO-II

Directive. In practice, local decision makers also have to deal with the risks of transport of dangerousgoods. Massive amounts of chemicals like chlorine, ammonia, LPG and gasoline are transported

between industrial sites and harbour terminals, often crossing country boundaries. Transportation routes

(road, rail, pipeline and sometimes also water) often cross densely populated areas and cities for which

urban development and emergency preparedness are a matter of great concern to the public and to the

local authorities. Especially around railway stations, which are usually located in city centres, the

presence of many people is a common issue (train passengers, other public transport, offices and

houses) together with passing transports of dangerous chemicals. An accident may result in many

casualties. Another issue of concern are road- and rail tunnels where high capital loss and societal

disruption may occur in case of an accident with flammable materials transport.

Essentially, there are three different situations (objectives) for which a risk assessment for transport can

be made:

A. Risk inventory for environmental or land-use planning: e.g. risk maps, of transport routes andemergency planning.

B. Risk comparison of different transport options, such as planning of transport streams and transportroutes: e.g. evaluation of different options for transport modes and/or transport routes.

C. Risk assessment for a specific location: e.g. check on risk criteria and the effect of specificmeasures.

From a global inventory of practices and experiences of application of risk analysis in various countries

it can be concluded that several transport risk studies have been conducted in the past, but that

harmonisation of approaches and criteria still hardly exist.

An in-depth evaluation of practices across Europe appeared not feasible within the scope of this study.

Insufficient data has been collected to develop a specific template for the comparison of risk analysis

approaches and results between the various countries.

Therefore, this chapter gives a non-limitative overview of observations of experiences and

developments in this field.

5.2 Pipelines transport

The major application of pipeline transport in Europe is for distribution of natural gas. Millions of

kilometres of NG pipelines cross the states and the continent. Other applications of pipeline transport

comprise oil products (crude oil, gasoline, diesel oil, kerosene, LPG) and general purpose chemicals

like ammonia, ethylene, propylene, etc. Moreover, between industrial sites and (harbour) terminalsseveral chemicals are transferred by pipelines, including acrylonitril, benzene, LPG products, chlorine,

etc.

In most countries, there exists a policy of reducing risks around natural gas pipelines by application of

safety zones. Within such zones, several activities will not be allowed; e.g. no houses or other

vulnerable objects shall be built, no ground works or no vegetation shall be applied. Basically, there

exist two approaches or philosophies in setting the zoning requirements.

The first one aims at protecting the pipeline from being damaged by activities within its direct vicinity.

Such activities include construction of buildings, ground digging, excavation, etc., but also (interference

with) other infrastructural objects like crossing roads, electrical power cables, etc. Guidelines and codes

of practice are in force for the construction and operation of such pipelines and for the design of their

surroundings. This includes both safety distances and depth of burial, as well as extra mechanicalprotection of the pipes. Traditionally, most of these practices have been developed by the pipeline

operators who also assume the responsibility of the enforcement of the requirements.


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The second approach aims at protecting the surroundings from potential hazards caused by the pipeline

and its contents. The objective of this approach is to create sufficient distance between the pipeline and

vulnerable areas and the public, so as not to cause an unacceptable risk of exposure to the consequences

of a release from the pipeline. In countries where this philosophy is followed, mostly the society and the

government have initiated the regulations.

From risk analysis point of view the two approaches seem to differ fundamentally. The first one

primarily aims at avoiding loss of containment from a pipeline, while the second one intends to reducethe (risk of) consequences. In fact, the first approach can be classified as qualitative and deterministic,

while the second one is quantified and even probabilistic in some cases. In the Netherlands, for

instance, the zoning distances are derived from a QRA determining the 10-6

individual risk contour.

In most cases the required safety distances are a function of pipeline properties like internal pressure

and pipeline diameter. In a risk based approach, also other protective parameters are taken into account,

like: depth of burial, presence of physical protection, presence of isolation stations, leak detection,

periodical monitoring of the pipeline track, external interference prevention, public information centre,

etc.35

For pipelines other than those for transport of natural gas, specific risk analysis studies are sometimes

required within the scope of an Environmental Impact Assessment (EIA). The approaches often follow

the national policy on risk assessment and acceptance criteria as applicable for industrial installations. Itappears that the development of dedicated methodologies, modelling and failure data sets is still

continuing, mostly at national scale. The problem with existing pipelines often is that the exact routes

of a pipeline networks are not properly documented in authoritys archives.

5.3 Road and rail transport

The transport of hazardous goods across Europe by road and by rail involves a wide range of chemicals.

Harmonisation of regulations exists mainly on the technical and mechanical provisions on the transport

vehicles (truck or rail wagon) in RID- and ADR-rules. Most of these requirements are based on

qualitative and deterministic approaches, often initiated by lessons from past accidents. Despite these

international rules, differences still appear to exist in specific national requirements like safety

provisions on the vehicle and traffic rules. Particularly for road transport, the management of risks tothe public living or working close to transport routes often appears to be a decentralised concern: a

concern of local and regional authorities.

Potential high risk situations, where transport routes run close to (or even cross) populated areas, are

often solved by assigning dedicated routes for dangerous transport. There are restriction areas for such

transports. In most cases, the assignment of routes is done on qualitative sound arguments or because

accident statistics show that a certain route poses higher than average risks of traffic accidents. Also the

vulnerable surroundings of a certain road may play a role: e.g. avoid dangerous goods transport through

a city centre or passing by a school or hospital.

A structured and detailed risk analysis is performed only by exception. In practice, a quantitative risk

analysis for the purpose of land-use planning or identifying alternative means of transport is only done

for large scale transports, e.g. on highways.

The option of assigning alternative routes hardly or not exists for rail transport. Public concerns about

rail transport through, or marshalling yards located inside densely populated areas have, in some cases,

initiated national risk studies for the comparison of alternatives for the mode of transport. In these

cases, the preferred approach of risk analysis is mostly the quantitative probabilistic one.

In the Purple Book (CPR-18)12

, a full section is dedicated to quantitative risk assessment for (road and

rail) transport in The Netherlands. The guidelines rely on a limited number of reference scenarios, like

catastrophic failure of a tank truck or rail wagon (e.g. BLEVE) or a leak resulting in pool formation of

predefined surface area. Also, the relevant substances are categorised, like flammable liquids,

flammable gases, very toxic gases, etc. Often, standard consequence distances are applied. Accident

frequencies are usually expressed in [LoCs /km.year] or [LoCs / vehicle.km.year]. Increased frequency

figures may be assigned to joints, shunts, crosses-over, etc.

The quantitative approach is applied in only few countries; it is known for Switzerland36,37

, United

Kingdom40

and The Netherlands.


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5.4 Acceptance criteria

Quantitative risk acceptance criteria for transport risks have been introduced in the Netherlands. The

location specific risk criterion along transport routes is enforced in a way similar to that of stationary

sites: no vulnerable objects shall be allowed within the 10-6

contour. Societal risk is calculated for each

kilometre of route length; the indicative acceptance level is a factor of 10 higher than the one for

stationary installations: 10-4

/year for 10 fatalities.

5.5 Developments and current studies

Within the scope of implementation of Chapter 1.9 of RID/ADR, an RID experts working group on

Standardised Risk Analysis was formed by the Intergovernmental Organisation for International

Carriage by Rail (OTIF). The first meeting of this experts group was held in April 2004, with

participation of representatives from 13 European countries, the EC, chemical industry and 4 transport

unions.

From the exchange of practices in the various countries, it appears that still big differences exist in the

approach of risk analysis and even in recognising the RA-tool as feasible for this purpose. The follow-

up of the activities and developments from this working group is considered very relevant for the future

risk analysis policy in the EU and abroad. The reports and contributions of the group and its members

may be followed via the internet:

http://www.otif.org/html/e/rid_CExp_RID_gt_analyse_risque_doc_inf2004.php.

Other recent developments are on tunnel safety and risk39. During the past few years, the need for

harmonisation of road tunnel regulations was recognised. Several contact networking is currently taken

up and R&D activities for developing risk analysis methodologies for road and rail tunnels are carried

out. Risk assessment for tunnels often requires specific models on effects and consequences that free

field flat terrain models cannot cope with. Moreover, evacuation modelling gets much attention.

In The Netherlands, a study has been carried out on the external risks involved in the entire chain of

production, handling and transport of three basis chemicals: chlorine, ammonia and LPG40

. When

compared to the risk acceptance criteria in the country, most risk constraint were identified in the

transport activities of these substances. Quantitative risk analysis on a wider scale was applied toevaluate possible risk reducing measures and alternative means or routes for transport. This evaluation

included cost benefit analysis.

In Italy, the risks of hazardous materials transport by rail between industrial sites have been studied.41
http://www.otif.org/html/e/rid_CExp_RID_gt_analyse_risque_doc_inf2004.phphttp://www.otif.org/html/e/rid_CExp_RID_gt_analyse_risque_doc_inf2004.php


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6 Template Development: Risk analysis Comparison scheme

6.1 Objectives of the template

The scope of this study is the development of a template for the characterisation of the risk analysis

procedure: a tool that will aid the decision/policy maker in verifying the completeness and the quality

of a given risk analysis (process). The template should therefore list out the minimum required

information that is necessary to establish:

whether a risk analysis contains all necessary steps (completeness);

how these steps have been implemented; and

whether these steps have been implemented and documented properly so that the risk figure can beused with confidence.

The collection of information on policy and practices in a large number of countries, described in the

previous sections, provided the data that needs to be included in the template.

6.2 Considerations on structure and contents of the template

The inventory of practices in several EU Member States and other countries, together with intensivebrainstorming about the envisaged comparison tool, has made a number of things clear:

The process of a risk analysis, and hence the required outcome, differs to a large extent, dependingon the purpose for which it is carried out. The following objectives have been recognised:

- Demonstrating that a technological process can be operated at an acceptable level of safety, andthat state-of-the-art technology is applied. This is often required for the purpose of obtaining an

environmental permit or licence to operate (LIC), for insurance premiums (INS) or for setting

acceptance criteria for occupational safety (OCC).

- Evaluating priority areas and measures of risk reduction in a given process or its design (RRM).

- Prioritising hazards and risks for which emergency preparedness (on-site and/or off-site) isrequired, and determination of the required resources (ERP).

- Determination of required safety zones around hazardous activities and of land-use planning /development (LUP).

- Administrative reasons, for instance because the risk assessment is required according togoverning regulations like the Seveso-II Directive or Environmental Impact Assessment

(ADM).

The respective different objectives relate to as many different stakeholders and decision makers,like: environmental authorities; land-use planners and developers; emergency services; local,

regional, national and even supra-national authorities; industrial operators; workers unions; etc.

More explicitly, the following users can be considered:

- A competent authority that wants to evaluate a given R.A. and to base decisions of LIC, LUP orERP upon it.

- Authorities that want to review their risk policy and reflect their own policy to the one of othercountries or regions.

- Countries and authorities that still need to develop a risk policy, or to choose a particularapproach from those available; this may hold for the newly accessed Member States.

- The European Commission that wants to compare safety studies across countries.

- A multi-national company that receives and evaluates safety reports of separate plants indifferent EU countries.

Different philosophies and practices in the risk analysis processes have been developed in the past,and are applicable nowadays. The need for these different approaches is not only related to the

mentioned different objectives (LIC, RRM, ERP, LUP, etc.), but also to historical and cultural


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background of countries and the nature of industrial activities. The most pronounced difference is

the distinction between the probabilistic risk approach versus the deterministic approach. A further

distinction lays in the extent of quantitative measuring of the risks, varying from a purely

deterministic approach (demonstrating state-of-the-art, like applied in Germany), via semi-

quantitative likelihood estimation and quantification of potential consequences (preferred approach

in France), to a fully quantified probabilistic approach (as followed in The Netherlands).

Differences are also found in the definitions of the dimension of the risk figures as well as in theapplication of risk acceptance criteria and their regulatory status. A large number of methods,guidelines and tools have been developed, by (multi-national) industries, by research organisations

and by national governments. National approaches vary from presenting suggestions of

methodologies that may be applied, to prescriptive manuals of accident scenarios to be considered

and models and

comparsion of risk analysis and preparing template

Documents