Integrated Building Systems

CHAPTER 3 TOPICS

• Modes of Integration: Physical, Visual, and Performance

• Building Systems: Envelope, Structural, Mechanical, Interior, and Site

• Integration Potentials

T

his chapter proposes a framework for the integra­tion of building systems by identifying different modes of integration and delineating a classifica­tion of major building systems. These taxonomies are supplemented in Chapter 4 with an overview and exam­ple of how integration thinking is included in design activity.

Integration can be described by its intended result as effecting physical, visual, or performance benefits. Frequently, any combination of these three methods is employed to achieve compound results. The classification is nonetheless helpful in understanding the various approaches and outcomes.

The major designations of building systems are site, structure, envelope, mechanical, and interior. Within each of these macrosystems are subsystems. A forced-air ductwork distribution is a subsystem of the mechanical system; doors are a subsystem of the envelope, and so forth. Integrations occur with equal ease between major systems, between subsystems within major systems, and between subsystems of different major systems.

Modes of Integration: Physical, Visual, and Performance

The most fundamental goal of integrated building systems design is the elimination of redundant resources, usually achieved through strategic combinations of the systems that are deployed in concert with their shared mandates of space, image, or function. It is important that integration measures provide these and sufficient other tangible ben­efits to justify the effort involved. Exposing structure or mechanical systems components, for example, is a popular and often highly visible aspect of integration. But expo­sure itself is not inherently good, no matter what level of integration is attained. Some design intention or pro­grammatic goal must actually be served.

Physical Integration

Physical integration occurs wherever systems share archi­tectural space by occupying a common area or volume. This is the most fundamental of integration activities and must be considered for practically all building compo­nents. For an air-conditioning duct to pass through a steel bar joist system, for example, the structural system and the mechanical system must be physically integrated. This can be accomplished by comparing the size of the duct to the space available in the web of the joist. If the optimal size and shape of the duct is greater than the available space in the optimal joist, then one of the systems will have to be modi­fied if physical integration is to occur. This specific modifi­cation would more likely involve the duct system inasmuch as its dimensional characteristics are less critical than those of the structural supports. But because the air-conditioning duct has its own criteria of cross-sectional area for the vol­ume and velocity of air it carries, the modification to achieve physical integration would be limited to shape.

An interesting application of computer-aided design (CAD) drawing is its use in identifying physical integra­tion problems and opportunities. By its organizational nature, CAD separates different systems of a building into distinct layers of the drawing. Turning various layers of the drawing on and off allows the designer to examine the physical intersections of different systems and identify specific integration tasks. In the ductwork-to-structure example it may be found that the duct indeed does fit through the truss but will not pass under the solid steel beam located at the end of the structural bay. The same method can apply to lighting and air diffuser arrange­ments above furniture layouts, interference between light­ing and ductwork, and so forth.

Physical integration is also accomplished by the mesh­ing, layering, and folding together of space taken up by building systems. The aforementioned exercise of placing ductwork in the structural voids is only a crude example of meshed space. A more refined example can be seen in IKOY Architects’ design of the interior street of the Wallace Building in Winnipeg (see case study #5). Here, the corridor is left wide enough to double as a gathering place for class discussions, social meetings, and geology displays. Collecting the building’s four levels of circulation together in a central axis also forms an interior street that serves as the entryway from major parking lots to the cen­tral campus. Similar examples of physical integration of space are found at different scales in many buildings: Storage systems fold space into itself compactly; open rooms expand into one another, making small houses feel big; and so on.

Another mode of physical integration commonly occurs in every building wherever two systems or different materials connect; that is, in the details. The proper detail­ing of these connections assures permanence and security through the integrity of the joint as well as the intended finish condition of adjoining materials. Water – and air­tightness, water drainage, thermal expansion and contrac­tion cycles, differential movement, structural deflection, dissimilar metal separation, and a host of other pragmatic factors have a part in the physical integration of the joint. These joints are most pronounced where two macrosys­tems intersect, such as where structure and envelope sys­tems meet, but they occur as well at the level of subsystem or material interface. Detailing is also important to visual integration because it expresses design intentions, or at least an attitude about how a particular detail expresses the larger design concept.

Visual Integration

The expression of a system or combination of systems as a visual design element constitutes an act of visual integra­tion. For systems to be visually integrated, they must be either exposed and ordered in some compositional way or concealed behind layers of finish materials. Compositional techniques used in visual integration include modifica­tions of the color, size, shape, and placement of systems and their component pieces.

Exposure of commonly hidden structural or mechan­ical systems is an integration strategy that relies heavily on such visual modifications. This strategy of exposure can be traced to the precedent of Brutalism in the works of Le Corbusier or Alison and Peter Smithson. The concrete structure at Corbusier’s Unite d’Habitation in Marseilles is left exposed and unfinished to express the wooden form – work of fabrication, for example. As a design method, the notion of exposure has opened the architectural palette of materials to include the visual potential of previously for­eign and characteristically industrial elements. And as these elements are exposed, the essential nature of their function, materials, and detail connections necessarily become part of the architect’s concern and enthusiastic attention.

Separation of systems by the layering of materials is also a method of visual integration. This strategy com­monly employs a layer of finish material to cover and seg­regate unwanted systems from exterior or interior view. This is something of a negative approach to integration as compared with the gesture of exposure but is often an effective and economical way of solving the problems caused by the distribution of services and structural sys­tems in a building. Finish layers are often helpful, if not particularly inventive means of dealing with the problems of dirt accumulation and noisy equipment. They also can perform critical functions: sound-absorbent ceiling tiles in offices, acoustically reflective panels in auditoriums, light-reflective surfaces for daylighting, and so forth.

Performance Integration

Whenever building systems share functional mandates, performance integration is accomplished. In the case of Louis Kahn’s Kimbell Art Museum, the cycloidal vault of the concrete structure also forms the container of the building envelope and defines the interior space. Further, in concert with the narrow skylight and perforated reflec­tor at the ceiling level, the vault becomes an integral part of the daylighting system by washing the galleries with dif­fused and comfortably graduated levels of light.

A second mode of performance integration deals with the adaptive response of buildings to fluctuating demands. The ability to adjust and regulate building response to changing conditions through intelligent use of design elements constitutes “dynamic integration.” This sort of integrative and comprehensive design is what allows a building to respond appropriately to daily and seasonal changes in temperature, wind patterns, solar geometry and other environmental variations. Dynamic systems are integrative in the same multifunctional and shared mandate ways that hardware systems are integra­tive. Passive and sustainable buildings are generally good examples of integration through dynamic response. A basic example of dynamic integration is a roof overhang that allows sunlight to penetrate a window during under­heated seasons of the year when the sun is low and then provides shade from high sun in overheated periods. The overhang shading device is bimodal in that it differentiates according to the thermal needs of the building, even though it has no moving parts.

Bimodal sorts of dynamic integration are typical of buildings where aerodynamic response is tuned to winter winds versus summer breezes, or day versus night thermal response is controlled by the heat capacity of structural mass. Designs for adaptation to summer versus winter, day versus night, empty versus occupied are all examples of bimodal response. Such responses can be associated with factors of the thermal environment or any other per­formance function based on changing conditions. Norman Foster’s headquarters for Willis Faber Dumas in Ipswich, England, changes from dark glass, reflecting its historic surroundings by day, to an illuminated interior showcase at night (see case study #7). In this instance, the change in envelope mode is accomplished by employing the luminous properties of glass that make it reflective to the bright side and transparent from the dark side.

Automation technologies advance performance inte­gration as well. Computerized control systems have trans­formed buildings into intelligent robots that not only respond to changes and schedules, but actually anticipate, measure and learn from them. Replacing resources with measured responses provides such benefits as improved comfort, operational economy, and reduced capacity of servicing equipment. In other words, automation replaces brute strength with intelligence.

The Example of Exposed Ductwork

Consider an example of exposed ductwork in a building interior. This common treatment can be used to illustrate the thinking associated with all three modes of systems integration. First, of course, the motivation for visually exposing ductwork to occupied interior spaces must be considered. Such motivations may relate to the architec­tural character of the design in general or may simply be dictated by physically restricted space as in a low floor-to ceiling height that makes a dropped ceiling undesirable. The results of these motivations become the initial bene­fits of the integration. Other consequences of the integra­tion may provide additional positive results. In the final analysis, cumulative benefits will have to outweigh both the extra resources required and the negative trade-offs of the decision to expose the ductwork. In this example there are several compromises to consider, such as mechanical system noise and additional cleaning maintenance.

In terms of physical integration, exposed ductwork provides additional volume to the occupied space by elim­inating the ceiling layer and meshing the structural void of the space between the ceiling and the floor or roof above. These are issues of shared space that define physical inte­gration. Visual integration of the ducts is more complicat­ed, as the design will be exposing a hardware component that is normally configured and installed to maximize per­formance and economy without regard to visual appeal. The designer may take care to arrange the horizontal duct routing in overhead patterns that reinforce the order of the space, perhaps following the circulation paths between workstations, without sacrificing the ability of the duct system to deliver air efficiently to where it is needed. Other compositional techniques may then be applied through the material and finish selections for the ductwork. Consideration can also be given as to how the ductwork is supported by the structure, its connection to air register devices, and all manner of detailing.

Performance integration of ductwork adds consider­able sophistication to the idea. Ducts not only provide temperature relief and air motion in a space, they also play a role in the acoustical environment, specifically in the background noise level. Performance benefits may include energy savings by removing cooling air at 55°F from a nonconditioned attic at 140°F and thereby eliminating thermal duct losses. Acoustically, however, it may be nec­essary to use internally insulated ductwork with thicker wall construction to provide adequate noise isolation from air friction noise in the duct and low-frequency reflected fan rumble from the air handler.

When Louis Kahn decided to expose the mechanical systems at the Richards Medical Research Laboratory, he planned on weaving ducts and pipes into the open webbed concrete trusses of the floor-ceiling layer and maintaining a low 8 ft clear ceiling height below the trusses (see case study #1). Initially, this proved to be a problem of coordi­nation with building trades, which failed to realize that the systems would be left exposed and so installed them in the usual messy but convenient functional arrangements. Much of the initial work had to be redone. Eventually, Kahn realized that the exposed ducts, conduits, and pipes merely provided excessive areas for dust to collect and would thus be impractical in a biological research setting. Kahn used this experience at the Richards laboratories by providing 7 ft deep interstitial attics for all the mechanical services above each of the three laboratory floors of the Salk Institute for Biological Studies (see case study #2). The interstitial spaces at Salk are connected to the lab spaces via stainless steel access slots. This ensures complete freedom and flexibility of services, in keeping with the requirements of laboratory spaces. After Richards Medical, Kahn never employed exposed ductwork again.

A positive example of ductwork integration is found in IKOY Architects’ Wallace Earth Sciences Laboratory in Winnipeg (see case study #5). Ducts are painted in the color scheme of the interior street and provide scale and visual interest to the long corridor.