CIB2007-260
Development of an adaptable integrated façade system for housing
in Taiwan
Wei, Hao-Yang Tu, Kung-Jen Lee, Wei-Wei
ABSTRACT
Residents in apartment buildings in Taiwan have often customized their facades and conducted refurbishment to meet their spatial and functional needs. This implies the design and construction conventions of apartment buildings have failed to meet residents’ needs in spatial flexibility, climatic control, security, and functionality. To resolve these problems, the Integrated Façade System (IFS) was developed as a domestic and integral solution, by applying the theories, concepts, and technologies of open building, systems integration, and double façade. Then an IFS prototype was developed and a mock-up built to test its applicability to typical apartment building design and construction. By integrating five subsystems: the open RC frame structure, the adjustable outer envelope, the insulating inner envelope, the relocatable interior partition, and the accessible piping distribution, the IFS is expected to deliver the benefits of spatial flexibility, sustainability, effective climatic control and security, uncluttered and diverse façade appearance, improved functionality and facilitated maintenance. Keywords: Open Building, Systems Integration, Double Façade
1. INTRODUCTION
1.1 Background
‘Apartment building’ has become the major type of habitat in major cities in Taiwan. In apartment buildings, it is prevalent that the residents, once they
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have moved into their apartment units, conduct various types of refurbishment and customizations to meet their own spatial and functional needs (Tu, 2002a): • They install window grilles, with overhangs and standing out over the original openings, to provide sun shading, to screen rainwater and lessen leakage, to provide additional safety and security protection, and to gain additional space for storing goods, planting, drying clothes, etc.; • They install air conditioning units (with racks and conduits) on the façade to provide conditioned air to the rooms in the units; • Tear down unfit brick walls (partitions) in the apartment units and reconfigure the layouts to meet their new spatial needs.
The customization phenomena imply that the design and construction conventions of apartment buildings have failed to meet residents’ needs in spatial flexibility, climatic control, security, and functionality. As a result of these façade customizations and disorderly installed elements, the façades of apartment buildings have become cluttered, and the refurbishment works have generated large amounts of construction waste (Figure 1.1).
Figure 1.1 Different types of refurbishment conducted by residents to meet their needs.
1.2 Research Objectives
Over the years, the authors of this paper have worked closely with the Architectural and Building Research Institute (ABRI), Ministry of Interior and have conducted numerous research studies to promote the concept and implementation of ‘open building’ in the construction industry in Taiwan (Wei and Tu, 2003; Tu, 2003; Tu, 2002b). To resolve the problems described, the authors have collaborated with the ABRI for the past two years to find better solutions. By employing the theories, concepts, technologies of open building (Habraken, 1976; Kendall and Teicher, 2000), systems integration (Ehrenkrantz, 1989; Rush, 1986), and double façade (Kähler, 2002; Blum, 2001; Oesterle, 1999), the Integrated Façade System (IFS) was developed as a potential solution
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(Wei and Tu, 2005). Besides, an IFS prototype has been further developed and a full-scale mock-up built to examine the applicability of the Integrated Façade System (Wei and Tu, 2006). This paper is intended to report the following three major results of this two-year research effort:\ • To present the design objectives, classification of façade customization constructions, and design concepts of the Integrated Façade System (IFS). • To illustrate the detail design and integration of the five subsystems with the IFS prototype design and mock-up construction. • To demonstrate the potential benefits of the IFS.
2 IFS: OBJECTIVES, ANALYSES, AND CONCEPTS
2.1 Design Objectives
An investigation on numerous apartment buildings in Taipei City was first conducted to identify the ways residents customized their facades, their reasons for doing so, and their specific needs. By analyzing residents’ façade functional needs, it was decided that the design objectives of the IFS should satisfy the following nine functional needs: spatial flexibility, structural integrity, effective climatic control, integrated design and materials, security and protection, adopting local construction conventions, planting, improved façade appearance, and multi-functionality.
2.2 Classification of Façade Customization Constructions
Analyses of residents’ customization constructions on their building façades were also performed. It was found that there are two kinds of opening (window and balcony) customized; two types of elements added to the openings (glazed sash, window frame or grille) in two possible forms and locations (flush with opening or standing out from opening). Nine types of façade customization construction methods were summarized. It was also found that the ‘functional structure’ of the construction interfaces among elements of the nine types of customizations could be categorized by their ‘opening types’. Three kinds of ‘functional structure’ were identified: window, balcony, and window-balcony combination (Table 1.1).
2.3 Concepts and Composition
It’s decided that a new double façade system consisting of elements with the ‘balcony type’ functional structure should be developed. With explicit considerations of reconfiguration needs, local climate features, domestic construction conventions and skill levels, the Integrated Façade System was developed as an integral solution for existing façade problems.
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The design concepts are to build an open ‘support’ structure with RC construction adaptable to ‘infill’ systems, to design double-layer envelope systems for better climatic control, security, and appearance; to utilize the buffer zone between envelopes for equipment allocation and other functional uses; to layout trenched floor for accessible piping distribution and flexible allocation of wet spaces; and to employ relocatable interior partition system for spatial flexibility and sustainability (Figure 1.2).
Table 1.1 Nine types of domestic façade customization and three types of façade functional structure: categorized by the type of opening, the elements added, and their forms.
Type Window opening Balcony I Balcony II
Form Flat Standing-out Flat Standing-
out Flat + Standing-out
1. 2. 5. 6. 9.
- ±¤ º¥ [µ
¥ ~¥ [¥ Yµ
¥ ~¥ [¥ Yµ ¡
- ±¤¥ [µ
Add glazed sash
3. 4. 7. 8.
- ±¤¥ [Å Kµ
- ±¤ º¥ [Å Kµ
Add w
indow fram
e or grille
Functional structure
FS1 Window type FS2 Balcony type FS3 Combo type
Structure
Equi.
Interior
Inner envelo pe
Outerenvelo pe
Exterior
Pipe Structure
Structure
Structure
Interior
Inner envelope
Outer envelo pe
Pipe
Outer envelope
Exterior
Equip.
Buffer
Structure
Structure
Interior
Inner envelope
Outer envelope
Exterior
Pipe
Equip.
Buffer
Out BalconIn In OutOut InOut Balcon In
Out
Out In Out In Out In Balcon BalconOut In
Balcon In
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Trenched floor cover
RC column
Wet space
RC slab
Vertical shaft
Figure 1.2 The IFS is employed at the perimeter of conventional RC structures to ensure spatial flexibility, sustainability, climatic control, security, appearance, and functionality.
3. THE IFS PROTOTYPE AND MOCK-UP
3.1 The IFS Prototype
An IFS prototype was developed and a full scale mock-up was built to test its applicability (constructability, reconfigurability, and sustainability) to the perimeter spaces of typical apartment building design and construction in Taiwan: eight-floor tall, six-meter spanned frame structural system, and RC construction. In addition, the IFS mock-up was built with the intention to be transportable as a container and exhibited at any desired locations. The IFS prototype, with an external dimension of 680cm long, 300cm wide, and 350cm high, contains a general living space, a wet space (bathroom), and a corridor (Figure 1.3). The IFS prototype and mock-up are intended to show the integration of the following five sub-systems: structure, outer envelope, inner envelope, interior partition, and piping distribution (Figure 1.4), and to accommodate further testing and experiments.
Figure 1.3 The floor plan and cross section of the IFS prototype.
Trenched floor Piping distribution
General living space
Wet space
Corridor
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5.Piping distribution
1.Structure
2.Outer envelope
Figure 1.4 The constructed IFS mock-up showing the five integrated subsystems.
3.2 Open RC Frame Structural System
The structural system of the IFS prototype, adopting domestic conventional RC frame structure, consists of two columns (70cm*70cm) six meters apart, an upper and a lower beams (40cm*60cm), two sets of flat slabs (15cm thick) and trenched floors, and two perpendicular walls (12cm thick). In front of each column, T-shape vertical RC elements (12cm thick) form two sets of vertical shaft spaces (Figure 1.5 and Figure 1.6). The structural system is designed to be an open ‘support’ structure that provides maximum capacity for accommodating ‘infill’ elements, as well as to distribute various types of piping elements (water supply, wastewater, air vent, and gas). The vertical shaft space distributes primary vertical pipes; and the trenched floor space distributes secondary horizontal pipes. Four holes are punched on the slab (180cm apart) to allow access of pipes distributed from the pre-wall installation in the wet space to the secondary horizontal pipes within the trenched floor.
3.Inner envelope
4.Interior partition
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Columns
Beams Vertical
shaft
Flat slab
Trenched floor
Figure 1.5 The open RC frame structure, the trenched floors, and the vertical shafts.
Figure 1.6 The construction of the structural elements of the IFS mock-up.
3.3 Adjustable Outer Envelope System
The outer envelope system is designed to be adjustable and modular to function as the first layer of visual and climatic control as well as protection. The outer envelope can be adjusted to redirect or shade natural lighting to acquire appropriate lighting at any time during the day, and to screen rain while allowing views to outside scenery. When it is closed, it serves as anti-theft, privacy, and security protection.
When the façade faces east or west, an outer envelope with vertical elements is devised. With the dimensions of 90cm wide, 210cm tall, a modular two-fold vertical unit is made of durable metal such as galvanized steel grilles or aluminum plates, whose pattern, style and design are customizable. These prefabricated vertical units are assembled and
Figure 1.7 The sectional detail of the vertical elements of the outer envelope. system.
Sliding rail
Steel grille
Hinge
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hung from the channel screwed under the RC structure. The vertical units can be fully extended, partially folded, and fully folded to allow different levels of view, climatic control and protection. When the façade faces south, an outer envelope with horizontal elements is devised (Figure 1.7, Figure 1.8, & Figure 1.9).
Figure 1.8 The vertical and horizontal designs of outer envelope system.
Figure 1.9 The installation of the vertical elements of the outer envelope system.
3.4 Insulating Inner Envelope System
The inner envelope system is designed to function as the ‘insulating separator’ between the interior and exterior, and to deliver sound building performance of ventilation, air tightness, thermal insulation, sound insulation, waterproofing, and fireproofing. The ‘opening’ component of the inner envelope system adopts existing horizontal sliding sash window products (aluminum frame) to ensure effective natural lighting and ventilation. The ‘wall’ component onsists of the following three elements (Figure 1.10 and Figure 1.11): c
• Modular sandwich wall panel (60cm wide): C-channel steel studs with 24K fibreglass for sound insulation and fireproofing, cement fiber boards on the outside, and calcium silicate boards on the inside. • Insulation: aluminium foil thermal insulation and PE waterproofing membrane are placed outside of installed modular sandwich wall panels.
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• Exterior finish: wood studs and modular cement fiber boards with open joints (60cm, 120cm) are place on the outside of waterproofing membrane. The elements of the inner envelope system can be easily removed, relocated, and reassembled to ensure optimal spatial flexibility and reusability. The interface between the inner envelope system and structural, interior partition, and electrical distribution systems are highly integrated.
Aluminum window Aluminum window
Modular sandwich wall panel
Exterior finish (cement fiber board)
Cover
Runner Wood stud
C-100*50*20*2.3mm 1cm Cement fiberboard
1cm Calcium silicate board
Waterproof membrane 24k fiberglass
Wood stud Plastic pad
C-channel steel stud
Figure 1.10 The sectional detail and decomposed elements of the inner envelope system.
Figure 1.11 The installation of the elements of the inner envelope system.
3.5 Relocatable Interior Partition System
The interior partition system is designed to be relocatable to achieve optimal spatial reconfigurability and flexibility. The major component of the interior partition system is the modular sandwich partition panel (multiples of 30cm wide), which consists of light gauge steel studs (C-channel), fibreglass for sound insulation and fireproofing, and calcium silicate boards on both sides (Figure 1.12). When the interior partition system is used to enclose a ‘wet space’ such as bathroom or kitchen, additional waterproofing work is required Figure 1.12, Figure 1.13): (
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• A sheet of PE membrane is set on the inside of the installed modular sandwich partition panels to provide the first layer of waterproofing; • Wood studs are placed on the membrane and partition, on top of which a layer of calcium silicate boards is affixed; • A thin layer of epoxy is plastered on the surface of the installed calcium silicate boards to provide an additional layer of waterproofing; Ceramic tiles or other finished materials are finally mounted. •
During remodeling, the elements of the interior partition system can be removed, relocated, and reassembled to form a new interior layout.
15cm RC floor
Cement fiber board
Figure 1.12 The decomposed elements of the interior partition system for wet spaces.
Figure 1.13 The installation of the interior partition system elements to enclose a wet space (bathroom).
3.6 Accessible Piping Distribution System
The distribution of various types of piping elements (water supply, wastewater, air vent, and gas) are designed to allow free allocation of wet space at any place along the perimeter of the building to achieve optimal spatial flexibility for interior layout configuration, and to allow easy access to pipeworks to facilitate inspection and maintenance process. Connected from the equipment in the wet space (bathroom or kitchen), the piping elements are first distributed horizontally within the pre-wall installation, then travel downwards through the punched holes on the
Ceramic tile
Wood studs
Insulation
C-channel steel stud
Air exhaust & return
Calcium silicate board
C-channel Flashing
PVC Film Silicate board Insulation
10*10 Tile3*4.5 Wood stud
9mm Calcium silicate board
3.6*3.6 Wood sill
Stainless steel basin
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slab, merge into the secondary horizontal pipes in the trenched floor, and finally join the primary vertical pipes in the vertical shaft (Figure 1.14 and Figure 1.15).
Pre-wall installation
Vertical shaft Primary vertical pipes
Trenched floor
Secondary horizontal pipes
Figure 1.14 The distribution of pipes from equipment in wet spaces to vertical shafts.
Figure 1.15 The piping elements in the trenched floor and vertical shaft, as well as the pre-
wall installation with connected bathroom equipment.
4. BENEFITS OF THE IFS
4.1 Spatial Flexibility and Sustainability
The IFS was employed to design a typical linear-shape apartment building to exemplify its benefit of spatial flexibility. After several trials, it was determined that the best structural spans are 6.0m and 8.4m. The linear-shape building has three major areas separated by two service cores (one,
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three, and two bays respectively). At the ‘floor’ level, these major areas can be flexibly divided to produce five different sizes of apartment units (30m2, 60m2, 90m2, 120m2, and 180m2). At the ‘apartment unit’ level, the trenched floor design with integrated piping distribution system allows wet spaces (bathroom or kitchen) to be located anywhere along the perimeter, and thus in turns provides maximum flexibility in configuring other types of spaces and rooms in the unit (Figure 1.16). From the ‘life cycle’ and ‘refurbishment’ perspectives, the use of modular and relocatable interior partition system and the 30cm modular reference grid system ensure that the original partitions within units be reconfigured flexibly into almost any new interior layouts desired. The demountable and reusable designs of the inner envelope and interior partition systems allow elements to be recycled during remodelling, reduce construction waste, and thus achieve a high degree of sustainability.
One bay Three bays Two bays
60m2 90m2 90m2 120m2
30m2 60m2
60m2
120m2
30m2 60m2
30m2
90m2
60m2 180m2
Figure 1.16 Various floor plans of a typical linear-shape apartment building showing great flexibility at the ‘floor’ level (producing five sizes units) and at the ‘apartment unit’ level
(allowing flexible configurations and diverse interior layouts).
4.2 Effective Climatic Control, Security, and Orderly Appearance
In the IFS, the outer envelope, the inner envelope, and the 60cm wide buffer zone (corridor) in between ensure effective climatic control as well as security and protection. When sun shines on the façade, heat will be
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accumulated and trapped in this buffer zone. With the ‘hollow’ elements of the outer envelope system, the heat in the buffer zone can be effectively ventilated and removed, thus reducing the heat gain conducted through the inner envelope system and into the interior. Besides, when it rains, most of the rain is kept out by the outer envelope system. With less rain fall on the inner envelope system, effective waterproofing can be easily achieved. By employing the adjustable outer envelope and hiding the equipment from behind, the appearance of the building façade will not only be uncluttered overall, but also diverse among apartment units (Figure 1.17).
Figure 1.17 The IFS results in uncluttered as well as diverse façade appearance.
4.3 Improved Functionality and Facilitated Maintenance
The buffer zone can also become a space for other functions such as planting and drying clothes. After watering the plants, the water is drained and discharged into the primary waste water pipe in the vertical shaft. The clothes-racks are hung by ropes from the bottom of the slab above and can be lifted and dropped easily. The outer envelope can be fully extended and closed to block the view of hung clothes from outside (Figure 1.18). The buffer zone can accommodate critical equipment such as air conditioners, water heaters, washing machines, and dryers. The ‘hollow’ design of outer envelope elements ensures that hot air exhausted from the equipment can be easily ventilated, and that building façade appearance is not cluttered by air conditioners. Besides, plumbing pipes (water supply and waste water) can be easily connected to the water heater or washing machine from the pipes in the nearby vertical shafts (Figure 1.18). Finally, the pipes in the vertical shafts, the trenched floor, and pre-wall installation are all easily accessible, thus the inspection and maintenance of piping elements are facilitated (Figure 1.18). Figure 1.18 The 60cm wide buffer zone provides additional functional uses such as planting,
clothes line dry, equipment accommodation, a access to pipes underneath. nd easy
Trenched floor
Cover
Outer envelope
Railing
Planting
Aluminum window
Structure
A/C unit
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5. CONCLUSIONS
Theories, concepts, and technologies of open building, systems integration, and double façade were applied to develop the Integrated Façade System as a domestic and integral solution to the façade problems often seen in apartment buildings in Taiwan. By integrating the open RC frame structure, the adjustable outer envelope, the insulating inner envelope, the relocatable interior partition, and the accessible piping distribution systems, the IFS is expected to deliver the benefits of spatial flexibility, sustainability, effective climatic control and security, uncluttered and diverse façade appearance, improved functionality and facilitated maintenance. In order to test the IFS’s applicability to domestic typical apartment building design and construction in Taiwan, an IFS prototype has been further developed and a mock-up built. The comparative analyses of the construction costs, process, time, quality, and technical problems between the IFS and conventional construction system are progressing and will be reported later. In general, it’s felt that the IFS needs modifications, but is yet promising and feasible for use in Taiwan. The newly developed IFS offers two distinct contributions. One is serving as an exemplar in improving performance and quality of housing products in Taiwan. The other is presenting a new ‘open building’ concept and method to maximized spatial flexibility in housing design. Two research efforts are to be further pursued: (1) to conduct a refurbishment experiment on the mock-up to examine the construction effectiveness (cost, time, quality, and process), reconfigurability (demountability, relocatability, reassembly of envelopes, partitions, pipes), and sustainability (reusability and construction waste) of the IFS during remodelling; and (2) to monitor the building performance (thermal, acoustic, lighting, ventilation) of the mock-up to examine the effectiveness of thermal and sound insulation, water- and fire-proofing of the elements of the outer and inner envelope systems. At last, the authors would like to acknowledge the Architectural Building and Research Institute for sponsoring the development of the Integrated Façade System and its prototype, the construction of the mock-up, and the subsequent analyses and experiments.
6. REFERENCES
Blum, H.J., 2001, Doppelfassaden (Berlin: Ernst). Ehrenkrantz, E., 1989, Architectural systems (New York: Mcgraw-Hill). Habraken, N.J., 1976, Variations: the systematic design of supports (Cambridge: MIT press). Kähler, G., 2002, Die klima-aktive Fassade, AIT-Edition Intelligente Architektur (Leinfelden-Echterdingen: Koch). Kendall, S. and Teicher, J., 2000, Residential open building (New York: E&FN Spon). Oesterle, E., 1999, Doppelschalige Fassaden (München: Callwey).
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Rush, R.D., 1986, The Building system Integration Handbook (New York: John Wiley & Sons). Tu, K.J., 2003, Building Systems integration for flexible configuration, easy maintenance, and sustainable construction: Open building Implementation in the CMLF Project in Taiwan, in Proceedings of International Conference on Open Building: Dense Living Urban Structures, Hong Kong, 276-286. Tu, K.J., 2002a, The characteristics of housing renovation needs in
Taiwan. Journal of Architecture, 39, 87-100. Tu, K.J., 2002b, The restricted double deck method: A sustainable method to increase spatial flexibility and facilitate pipe repair work in apartment buildings in Taiwan, in Proceedings of International Conference of Sustainable Building 2002, Oslo, Norway. Wei, H.Y. and Tu, K.J., 2006, Construction of a full-scale integrated façade- system for domestic open building in Taiwan. Research project report, Architectural and Building Research Institute, Ministry of Interior, Taiwan. Wei, H.Y. and Tu, K.J., 2005, Development of critical interface system for open building. Research project report, Architectural and Building Research Institute, Ministry of Interior, Taiwan. Wei, H.Y. and Tu, K.J., 2003, Development of an interior movable partition system. Research project report, Architectural and Building Research Institute, Ministry of Interior, Taiwan.
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