operable fa§ade

CIB2007-250

Operable façade: an Open Building Approach for User Responsive

Architecture

Dr. JIA Beisi

ABSTRACT External façades are among the most expensive components in building construction. It provides social identities and environmental comfort for accommodation. It is an intermediate location where collective and individual needs meet. Technological trends and the demands of increasingly efficient building maintenance have made the external façade lighter, more transparent, and more flexible.

This paper firstly reviews the latest researches in theory and implementation of the façade designed for user participation and change. It concurs with previous findings that that single layered façade may encounter constrains, the technical difficulties and building regulations, for the user to exercise their influence. After a review the new development in double glazed façade in office buildings, it points out there is a technical solution not only for the energy saving and environmental comforts, but also for redefined territory boundaries between user inside, and the public outside. It suggests a double façade as a hypothetical solution to reach a social agreement. To exam the feasibility, the paper introduce a few low cost housing projects designed by Baumschlager & Eberle, an Austrian-based design firm famed for their sustainable building design over the last decade. The paper argues that the double façade should be operable—or, the façade easily controlled by the user — is an approach to maximize both environmental and social performance at the same time. Keywords: Double Façade, Operable Façade, Control, Environmental Performance

1652 CIB World Building Congress 2007

1. INTRODUCTION Building façade is one of the most complicated issues in building construction and management. Traditionally architectural design treated as an outlook, which may reflect the design styles of the time and interests of the clients or designers, beyond the basic functional needs, such as natural lighting and ventilation. Because of the recent development of technology, especially those related the glass and curtain wall construction, and the sustainable issues which requirements energy saving, more researches efforts are emerged.

It has realized that the built environment is a major consumer of energy across the domestic, industrial and service sectors. The construction and operation of buildings are responsible for about one-third of the energy use and one-half of the electricity use in lost industrialized countries. A large share of the energy use is associated with protection from the external climate and operation of systems necessary to give the occupants a comfortable indoor environment. These studies, however, were more technical and isolated with people and even internal spaces. Because natural light is seen as a key driver to people’s well-being both in the workplace and at home, a maximum glazing naturally became the solution. (Y. Kaluarachchi 2005, 89-95)

Researches on the interrelationship between façade and indoor space, except the physical quality, are still very limited. Karni (2001 p.113) did a hypothetical study on the inter-relation between openings in facades and possible locations of adjacent partitions. A research conducted by the author for the particular public housing in Hong Kong in 1999, also intended to find the optimal size and location openings on the façade which may allow more variability in location of the partition. (Jia 2003) In the revised Harmony schemes, the most widely constructed housing prototype in Hong Kong, window facades of living room and bedroom are lined up by repositioning the bathroom inwards (Figure 1). This change creates more possibilities for the user; the non-load bearing wall between the living room and the bedroom can be relocated or even removed. Users therefore have more choices to layout their space according to their needs.

(a) (b)

Figure 1 Typical unit plans of Harmony block with (a) existing, and (b) proposal for line-up façade to provide more possible location of the partition

CIB World Building Congress 2007 1653

There have been comprehensive studies in the history of Open Building movement, ranging from addressing basic relationship between the people and built form including façade, and the industrial technology. The following paper first introduce the concepts of Open Building with brief review of a few implementation of demountable façade. It highlighted the façade as a territory of interactions various of “powers” worked on different space levels, as the major contributions of the Open Building theory. It will also discuss a few problems experienced with these projects, revealed by some studies. It address that there are still gaps between the theory and actual behaviors with the technology. Then the paper will give introduction to the latest research and development in double façade concepts and implementation. The newest technology regarding climatic control is effective while the potential of users participation provided by the technology is not fully understood. The final part of the paper will review a few design works conducted Baumschlager & Eberle, which indicate a tendency of integration of potential of user participation and energy saving within the double façade as a multiple instrument facilities by new, but modest technology. Finally, giving the context of Hong Kong, the paper introduce a conceptual solution to the dilemma of private and public interests with double facades: • An outer façade clearly making the public domain and reflecting a

collective public interests, while with elements operable from private interests; and

• An internal façade responding the private interests; and • The two also function as adjustable buffer zone for environmental

control also for saving energy. 2. FAÇADE AS MARGIN OF TERRITORY POWERS As early as in 1960s, N.J Habraken considered along two lines of development for mass housing. On the one hand, the occupant had to be re-introduced as an actor in the building process in order to restore the natural relation between the user and the dwelling. (Jia 2001) “Dwelling is after all doing something; it is the sum of human actions within a certain framework, within the protective environment created by man…”(Habraken, 1972: P18 a) As he continued in the book “Supports: An Alternative to Mass Housing”, dwelling is indissolubly connected with building; building and dwelling together comprise the notion man housing himself. “Dwelling is building.” (Habraken, 1972: P18 b) On the other hand, in the contemporary world, technical solutions had to evolve to give households opportunity for full control of his/her environment. A building production process, both rational and industrially based, should develop in such a way that the occupant can chose and can directly show interests to the producers.

In this new industry, a building should be treated as industry products working on separated systems. There are several subsystems, including


the facade, working independently from the structural system. These subsystems are consists of product completely subject to the choice of the

individual consumer. They are made oriented on the great variety of wishes of the individual occupant and can be used in new construction as well as in renovation. (Van Randen, 1992: P. 82) To make the building production as efficient as any other buildings, these products should be standardized and systematic. “Within each group (of infill elements) an infinite variety of combinations is possible.” (Habraken, 1985: P63) (Figure 2-3)

Figure 2 Façade and its demountable components in a situation of row houses in Holland

(Resource: Iformatiseren van de Bouwknoop. 1995 February.)

Figure 3 Façade of a unit in NEXT21, Osaka, composed by standardized and sophisticated components was changed effectively after user occupation with coordination of a modular

system. (resource: catalog �� NEXT21. Pg. 15)

For Habraken and Open Building the issues related to façade is not only technical, but also social. It is a location which should be understood as margins of two territories controlled by different powers. A territory means a space, or an arrangement of spaces that is under control of one power (Habraken, 1983: P29). And by using “power”, Habraken give the significance of people in any built environment, or any person or group of persons with the ability to change the physical reality of the territory (Habraken, 1983: P15)

Façade as margins is a timeless and universal phenomenon found everywhere. However a detailed illustration from Kobets-Singh (2001 p.135) on the cases in a settlement of Nepal make give a better picture of how it


actually work. “Specific qualities of the façade that can allow “growth” as any form of transformation, including addition, reduction or simply relocation of the elements, and there fore can make facades into living configurations.” Walls here function a specific part of a territory, located adjacent to the boundary, which displays characteristics of both neighboring territories.

Territories function in a hierarchical structure, marked and divided by the facade. Façade identifies the transition from one territory to another. One of them is on a higher level in hierarchy, which is more public in general understanding, and the other on a lower level of the hierarchy, which is more private. Firstly, walls are examples of boundaries, with fascinating richness of meaning attached to this simple word. They separate and protect, while representing the character and values of the power controlling the wall. In the cases investigated by Kobets-Singh Relations between territorial boundaries and the margins can be narrowed down to three basic ways. • A Margin located within territory T2, but regulated by T1 territory; • A Margin located in territory T1, but controlled by T2; • A Margin straddling territorial boundary. (p.141)

Territory powers exercise their influence to the territory by changing the elements. Façade as a marginal spaces also consisted of elements in two groups: elements of the façade and elements identifying boundaries. Usually building regulations established by “higher” powers are the way of influencing distribution of these elements. (p.139)

Although he pointed out that the problems identified as preventive for the development of living facades are commonly not “technical”, he believes that better design with better understanding to the territory power in relations to the façade elements can achieve a “living facade”.

However another case with designed “living façade” seems suggest a dead end, as reviewed by Peng Liu (2001 p.174). The Student Dormitory of Medical Faculty, designed by Lusien Kroll in Belgium (1968-1972) is featured by the façade, built with standard industrial products designed to be changeable. Based on the SAR Tartan grid, façade elements with limited standard sizes are arranged in an apparently random way. (Kroll, The connections among façade elements and those between them and the main structure are clearly separable, enabling them to be independently changed. However, more than 20 years after this project was build, there is almost no change accomplished on the façade of this building. The author seems accuse the students who live temporarily reduce their interest in any change. And she insisted that changing façade elements, no matter how technically easy, is a large scale technical action. And she also accuse the building regulation. “Of the two territories along the two sides of a façade, on is on higher hierarchical level. The rules of higher-level powers influence changing the façade.” However if we look at the original intention, the consequence is not a surprise: “First, he wanted to reject the monolithic and bureaucratic uniformity of typical university architecture.” Still there is a


need from the designer to demonstrate an outlook of the building through designed façade to the public.

In a later renovation project designed by the same architect, the interior function and appearance seems the major concern of a random façade, rather than demountability. “The intention of the architect in regard to the façade is not to make it changeable but to make it complex and fit for individual needs…”

In conclusion, similar as Kobets-Singh, the author fails in giving a solution to the conflicts between the users interests and public interests, presented by building regulation. “Regulation is an often-accepted “invasion” of territory by another power.” However, “Conventions are informal regulations. Regulations and conventions are influenced by local cultures”. “Changing facades is forbidden in some areas because the quality of the modified facades is low and the low quality not only destroys the appearance of the building but also results safety problems such as leaking water and falling parts.”

However she give the direction of living façade: moving the façade towards interior. “If change of façade will result in a change of territory, it will be very difficult to be realized in the real world, especially when there are strict rules defining territories and boundaries or interfaces. It is much easier to alter a façade when it is inside a territory.” 3. DOUBLE FAÇADE BEYOND THE NEEDS OF ENERGY SAVING According to the theory of N.J Habraken and Open Building, there are at least two territories and two territorial powers in hierarchy on two sides of façade. It naturally leads to a thinking of double façade as a strategic solution to the problem of “invasions” from either side: an outer façade representing the interests of the power in higher territory power, and an inner façade for the exercise of lower territory power(s). The simple fact that most Open Building implementation did not involve much about double façade, may justify more effort need to put in the experiments in the area. More encouraging finds actually are available form building engineering, with of course strong interests to the climatic control effect of the double glazing façade in office buildings.

Single-glazed windows result in high winter-month heat loads, whereas modern double- or triple-glazed units could result in summer overheating without additional solar protection or ventilation. (Kaluarachchi 2005, 89-95) Persons working in buildings considered the possibility to control the conditions of their own post (lighting, temperature and air conditioning) to be of very high importance. The owners of the buildings preferred objectives like long service life, technical and functional advantages and additional value of good and developing place to work keeping in mind environmental conditions. “The owners thought the investments to double façade were worthwhile and considered it as the only solution for glass buildings in northern circumstances.” (O. Tenhunen 2001, 141-148) It is


already possible to classify five types of double glazing façade according the major function: • “The rain coat” gives a long service life and clear benefits in service

costs. The inner façade may be made of any material. The inner façade may be made of any material.

• “The northern light” makes it possible to reflect day light and control circumstances individually.

• “Environmental consciousness” produces electricity for local use and sells the rest to the common network.

• “Cool buffer” zone protects against weather and works as a room for pause and temporary stay-active forum in institutes.

• “Green circle” creates its own specific micro climate. It changes carbon dioxide into oxygen by assimilation. It creates a new kind of city park.

The first type is directly related to our question about territories. The rest

are more about environment and energy resolution. This is because much of the energy exchange with the environment takes place at the building envelope interface, primarily façade and roof. For example, heat losses owing to the glazing of domestic buildings are thought to account for as much as 6% of the UK’s energy consumption. Electrical lighting accounts for approximately 5% of overall UK energy consumption, but in many commercial buildings this can be as high as 60%. In addition, air-conditioning systems, which are used on many buildings, are often oversized and it is believed that plant capacity in UK buildings exceeds peak loads by approximately 30%. (Y. Kaluarachchi 2005, 89-95) And even a new low U-value façade is not a simple solution, because with a high degree of air tightness could result in reduced air exchange leading to overheating, stale air and poor comfort.

The development of the double façade solutions that can respond to the needs of the occupants of both new and refurbished buildings is, therefore, key area for the development. The façade of a building can account for between 15 and 40% of the total building budget. And it has been shown that, when designed carefully, innovative systems do not represent additional initial building costs, running cost are lower and energy costs can be reduced by approximately 30% compared with conventional solutions. (Y. Kaluarachchi 2005, 89-95) Figure 3 showing the new office building stands in center of Berlin, which primarily an advanced solution for energy saving and environmental comforts. But apparently the outlook provides a landmark identity for the place. And one of the interesting strategies to bring out such effect was from the users, who frequently open or close the orange solar protective devise between the double façade.


(a)

(b)

Figure 4 GWS Office Block in Berlin (2000) designed by Sauerbruch Hutton Architects (a) Constantly changing of façade (b) environmental concept with ventilation by double façade

(Picture resource: http://www.hku.hk/mech/sbe/case_study/case/ger/GSW_Berlin/GSW-Index.htm)

4. DOUBLE FAÇADE FOR HOUSING: A LESSON BEYOND TECHNICAL SOLUTION Double glazing façade normally found in office building maybe too costly for residential buildings. The limited control of users also found almost unacceptable. Double façade for housing needs a different approach, in which the basic climatic control principles are also different.

Baumschlager & Eberle based in Vorarlberg, Austria, started by designing small, reasonably-priced, detached houses, and slowly developed a typology for mass housing developments with compact, flat–roofed buildings, with which they distinguished themselves in. Today, they are involved in the construction of many, large, multi-storied buildings, including, hospitals, office blocks and industrial buildings, schools, community centers, and shopping centres, in European but also in China. Their architectural characteristics can be summarized as having a “strict economy with respect to material and artistic/architectonic means and a keen of cultural and social responsibility…. Their tectonic achievement deserves the highest recognition on a world-wide scale.” (Frampton, P. 19)

Firmly rooted in practice, Baumschlager & Eberle have demonstrated a particular skill in which flexibility, sustainable building, a high level of craftsmanship, and the beauty of the architecture are expertly integrated together in a reasonably-priced, simple compact building. (Jia 2005) A compact form uses less material, less energy and costs effective. Basically there are two very simple built structures in the plan of a typical housing


http://www.hku.hk/mech/sbe/case_study/case/ger/GSW_Berlin/GSW-Index.htm


they designed. In the middle of building there is a stairwell surrounded by closets and ancillary rooms. On the outer fringe there is a surrounding wall, which serves as structural as well as an enclosure. There are no divisions of rooms between these two structures. To omit or to add a room, all one has to do is to remove or insert a partition wall. (Figure 6)

These architects see the façade of a building as being of particular importance, since it is the structure, which provides the key to saving energy, the complicated inter-relationship between the exterior and the interior, the private and the public, as well as being responsible for creating the crucial syntactical enrichment of the public outdoor space. It is expensive to build, with high embodied energy, technically complicated and difficult to maintain. Therefore, it is treated as part of the support, which according to Habraken, is designed by the architects according to the collective decision made by community. It is not an area where individual or private needs dominate. However, they also see that it is important and crucial for the users to be able to operate and be in control of part of the façade, i.e. to adjust the lighting, ventilation, shading, and views. Consequentially the outlook of the building changes according to the actions and the wishes of the buildings’ occupants. In this sense the façade accommodates the most flexible elements in the building and changes constantly. (Figure 5, 6) A variety of technologies and materials have been applied, which have resulted in intensifying this flexibility. “A housing problem is about establishing the border between individuals and community. It is about establishing the levels of community in spatial terms.” (Dietmar Eberle: Lecture at HKU on the 24th October, 2003)

Figure 5 Sebastianstrasse Residential Project featured by a set of white and sliding glass panels as the outer façade.

Figure 5 featured a white, glass building configuration that presents a

different façade according to the weather conditions, the hour of the day and the day of the week. It is often closed, although it is also opened from time to time, according to the user’s mood in each individual apartment. In front lies a mass-produced sliding mechanism. Glass panels that feature silk screens create the following effect: A person outside cannot look inside,


but a person on the inside can see the goings on outside. This leads to a second effect: it is possible to adjust what can be seen from the outside; layering the panels over one another results in a visually almost impenetrable glass wall. The theme was: individual living, and that includes allowing everyone to choose how many windows they want to have, where they want them to be and how much distance they require from their environment. And the geometry of the outer façade is an exciting addition to the surroundings. (Modified from project introduction by Lisbeth Waechter-Böhm)

Figure 6 Housing “Living in Lohbach”, Hötting-West, Austria, 1998

Figure 6 illustrates the plan, a changing outlook of the building and the technical section of the double façade. All openings in the internal facade are French windows from floor to ceiling providing access to the very narrow terraces/balconies that run around the buildings. As a result, each apartment disposes of generous out door marginal spaces, which are accessible from every living space and room. Private activities and belongs are displayed, however, partially covered by the outer façade. On the outer façade, shutters made of copper and parapets of glass, both mounted in front of the terraces/balconies, serve as a protection from sun and weather and provide different and changeable privacy.

Baumschlager and Eberle double façade shows following differences with the double glazing façade in office buildings: • The Users has wider range of control the operation of the façade, from

complete open to entirely close. Sometimes this operation may affect the effectiveness of energy performance of the building.

• Space between the two façade becomes the margin where the residents can use more intensively.

• Outer façade function more for privacy protection, lighting, shadow and vista adjustment, than single environmental protection.

• The outer façade are constructed with solid or translucent materials. It is understandable, because they are effective in protect the building over heat than any kinds of glass.

Their projects show clear difference with user participatory design. They

basically not allow any construction by the users. They provided maximum


possibility for the user to operate the façade, including the changing the position of window anytime. While at the same time, the façade maintain its high quality in architectural, construction and environmental quality. High cost of construction, and sophistications in technology associated with the façade maybe the additional arguments to put façade under the architects control. And it is certainly easy to cope with general building regulation. However, they believe this facade is also derived from the division of roles among territory powers. For them both the outer façade and internal façade representing the physical quality of buildings stands for the collective identity of the all the residents, and their relationship to the larger community through outdoor space made by the facade. There is no need for the individuals to invade into the collective territory. “These issues related to the facade can be discussed publicly. But it can not be decided on individual level.” (Eberle interviewed by the author in October 2003) 5. CONCLUSION: OPERABLE AND DOUBLE FAÇADE AS AN INSTRUMENT TO BALANCE OF PUBLIC AND PRIVATE INTERESTS Building façade is very complicated issue. It is related to the internal layout of the floor plan, the environmental performance of the building, the cost and technology provided, and the relationship between the territories between inside and outside, and through which, the relation between private and public. And finally, it is still the major component of the building form which imposes a large impact to the larger environment if not limited in visual.

However there is already a matured theory dealing the built environment through understanding of territory hierarchy and territory powers. Façade is a location of two territory in different levels. It is preferred to be a marginal space where the element of boundary and elements for the performance of territory powers are clarified. However, performance of the lower powers, even provided with demountable but standardized façade elements for the users to chose, may still conflict with power from upper level presented by building regulations, quality control, and demand of collective identity. This thinking leads to double façade hypotheses: the outer façade representing upper territory power and inner façade representing the lower. A review to the latest development of double glazed façade in office buildings and double façade in residential buildings does not give a clear cut answer, although their technology experience show much more potential. The most interesting example are found in the projects designed by Baumschlager & Eberle, which provides a maximum control for the residents, even in the changing the location of openings on the wall with instant effect. There is a marginal space between the outer façade and internal façade, where the user can use as extension of private domain. However, it dose not involve any construction activity from the users, and therefore easy going with the building regulation. Each building provides a strong architectural identity to the place, and a high tectonic quality by itself, appreciated by the collective users. There is still a lack of


systematic post occupancy evaluation on these buildings. Experience on increased influence and even constructions on the internal façade from the users, and technical possibility to support such influence are still pending on future study. (Acknowledgement: This study presents some of the findings of the research project “Recycling Infill Components: its implication and development potentials in Hong Kong”, funded by the Direct Allocation of Research Grant Committee (RGC) of Hong Kong. Dr. Sam Hui of Engineering Faculty at the University provided reference material used for the construction of the paper section “3. Double façade beyond the needs of energy saving”. The author would like to thank RGC and Dr. Hui for the aid to this paper.) 6. REFERENCES Das Dusseldorfer Stadttor, Dusseldorfer,

http://www.hku.hk/mech/sbe/case_study/case/ger/Dusseldorfer_Stadttor/Das-Index.htm

GSW office block, Berlin, http://www.hku.hk/mech/sbe/case_study/case/ger/GSW_Berlin/GSW-Index.htm

Jia Beisi, 2001, “Infill Components in High Density Housing: The Past, Present and Future of Hong Kong Housing Sustainable Development”, Open House International, Vol.28 no.3 2001,UK.(ISSN 0168-2601) 9-18. Jia Beisi, 2003, “Three Attempts to Mobilize High Rise Housing Interiors” (co-authored with Ada, Y.W. Ho) Proceedings of Dense Living Urban Structures: International Conference on Open Building (ed. by JIA Beisi), The University of Hong Kong, Hong Kong, October 23-26, 2003 (ISBN9627757055), 243-249 Jia Beisi, 2005 “A theory of Architectural Practice: Open Building Interpreted by Baumschlager & Eberle”. SB05 Tokyo Proceedings (CDRom), Action for Sustainability: The 2005 World Sustainable Building Conference in Tokyo, September 27-29, 2005. Published by SB05 Tokyo National Conference Board. N.J. Habraken, 1983, Transformation of the site. Cambridge, Massachusetts: Awater Press. Peng Liu, 2001, “Living Facades”, Agile Architecture Proceedings – Conference of CIB W104: Open Building Implementation, edited by Ype Cuperus, Delft University of Technology, The Netherlands, 171-182 J.H.M. Kapteij & J.W.Bleeker A v W, 1995, Iformatiseren van de Bouwknoop. Open Bouwen Ontwikkelings Model, 1995 February. O. Tenhunen, K. Lintula, T. Lehtinen, J. Lehtovaara, M. Viljanen, J. Kesti, P. Mäkeläinen, 2001, “Double Skin Facades – Structures and Building Physics”, 9th Nordic Steel Construction Conference, Helsinki, Finland. Proceedings book: NSCC 2001 Proceedings, edited by Mäkeläinen, P., Kesti, J., Jutila, A., Kaitila, O., 141-148, 2001.http://www.tkk.fi/Yksikot/Rakennus/Teras/9NSCC.PDF Y. Kaluarachchi, K. Jones, P. James, M. Jentsch, A. S. Bahaj, D.






http://www.tkk.fi/Yksikot/Rakennus/Teras/9NSCC.PDF

Clements-Croome, D. Gann 2005 “Building facades: sustainability, maintenance and refurbishment”, Proceedings of the institution of Civil Engineers: Engineering Sustainability 158, June 2005 Issue ES2, 89-95 ��: ��NEXT21�catalog in Japanese�


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