Designing for Building Functions
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The earliest shelters probably provided only a bit of shade or protection from rain, and were warmed by afire and enclosed by one or more walls. Today we expect a lot from our buildings, beginning with the necessities for supporting human life. We must have clean air to breathe and clean water to drink, prepare food,clean our bodies and our belongings, and flush away wastes. We need facilities for food preparation and places to eat. Human body wastes, wash water, food wastes, and rubbish have to be removed or recycled.
As buildings become more complex, we expect less protection from our clothing and more from our shelters. We expect to control air temperatures and the temperatures of the surfaces and objects around us for thermal comfort. We control the humidity of the air and the flow of water vapor. We exclude rain, snow, and ground-water from the building, and circulate the air within it.
Once these basic physical needs are met, we turn to creating conditions for sensory comfort, efficiency, and privacy. We need illumination to see, and barriers for visual privacy. We seek spaces where we can hear clearly,yet which have acoustic privacy.
The next group of functions supports social needs.We try to control the entry or exit of other people and of animals. Buildings facilitate communication and connection with the world outside through windows, telephones, mailboxes, computer networks, and video cables. Our buildings support our activities by distributing concentrated energy to convenient locations, primarily through electrical systems.
The building’s structure gives stable support for all the people, objects, and architectural features of the building. The structure resists the forces of snow, wind,and earthquake. Buildings protect their own structure,surfaces, internal mechanical and electrical systems, and other architectural features from water and precipitation. They adjust to their own normal movements with-out damage to their structure or contents. They protect occupants, contents, and the building itself from fire.Buildings support our comfort, safety, and productive activity with floors, walls, stairs, shelves, countertops,and other built-in elements.
Finally, a building capable of accomplishing all of these complex functions must be built without excessive expense or difficulty. Once built, it must be able to be operated, maintained, and changed in a useful and economical manner.
THE BUILDING ENVELOPE
The building envelope is the transition between the out-doors and the inside, consisting of the windows, doors,floors, walls, and roofs of the building. The envelope encloses and shelters space. It furnishes a barrier to rain and protects from sun, wind, and harsh temperatures.Entries are the transition zone between the building’s interior and the outside world.
Traditionally, the building envelope was regarded as a barrier separating the interior from the outdoor environment. Architects created an isolated environment,and engineers equipped it with energy-using devices to control conditions. Because of the need to conserve energy, we now see the building envelope as a dynamic boundary, which interacts with the external natural energy forces and the internal building environment. The envelope is sensitively attuned to the resources of the site : sun, wind, and water. The boundary is manipulated to balance the energy flows between inside and outside.
This dynamic approach leads the architect to sup-port proper thermal and lighting conditions through the design of the building’s form and structure, supported by the mechanical and electrical systems. Engineers de-sign these support systems with passive control mechanisms that minimize energy consumption.
A building envelope can be an open frame or a closed shell. It can be dynamic and sensitive to changing conditions and needs, letting in or closing out the sun’s warmth and light, breezes and sounds. Openings and barriers may be static, like a wall; allow on–off operation, like a door; or offer adjustable control, like venetian blinds. The appropriate architectural solution depends upon the range of options you desire, the local materials available, and local style preferences. A dynamic envelope demands that the user understand how,why, and when to make adjustments. The designer must make sure the people using the building have this information.
BUILDING FORM
Energy conservation has major implications for the building’s form. The orientation of the building and its width and height determine how the building will be shielded from excess heat or cold or open to ventilation or light. For example, the desire to provide daylight and natural ventilation to each room limits the width of multistory hotels.
At the initial conceptual design stage, the architect and interior designer group similar functions and spaces with similar needs close to the resources they require,consolidating and minimizing distribution networks.The activities that attract the most frequent public participation belong at or near ground level. Closed offices and industrial activities with infrequent public contact can be located at higher levels and in remote locations.Spaces with isolated and closely controlled environments, like lecture halls, auditoriums, and operating rooms, are placed at interior or underground locations.Mechanical spaces that need acoustic isolation and restricted public access, or that require access to outside air, should be close to related outdoor equipment, like condensers and cooling towers, and must be accessible for repair and replacement of machinery.
Large buildings are broken into zones. Perimeter zones are immediately adjacent to the building envelope, usually extending 4.6 to 6 meters (15–20 ft) in-side. Perimeter zones are affected by changes in out side weather and sun. In small buildings, the perimeter zone conditions continue throughout the building. Interior zones are protected from the extremes of weather, and generally require less heating, as they retain a stable temperature. Generally, interior zones require cooling and ventilation.
BETWEEN FLOORS AND CEILINGS
A plenum is an enclosed portion of the building structure that is designed to allow the movement of air, forming part of an air distribution system. The term plenum is specifically used for the chamber at the top of a furnace, also called a bonnet, from which ducts emerge to conduct heated or conditioned air to the inhabited spaces of the building. It is also commonly used to refer to the open area between the bottom of a floor structure and the top of the ceiling assembly below. In some cases, air is carried through this space without ducting,a design called an open plenum.
Building codes limit where open plenum system scan run in a building, prohibit combustible materials in plenum spaces, and allow only certain types of wiring. Equipment in the plenum sometimes continues vertically down a structurally created shaft. The open plenum must be isolated from other spaces so that debris in the plenum and vertical shaft is not drawn into a return air intake.
The area between the floor above and ceiling below is usually full of electrical, plumbing, heating and cooling, lighting, fire suppression, and other equipment (Pic. 1). As an interior designer, you will often be concerned with how you can locate lighting or other design elements in relation to all the equipment in the plenum.
SERVICE CORES
In most multistory buildings, the stairs, elevators, toilet rooms, and supply closets are grouped together in ser-vice cores. The mechanical, plumbing, and electrical chases, which carry wires and pipes vertically from one floor to the next, also use the service cores, along with the electrical and telephone closets, service closets, and fire protection equipment. Often, the plan of these areas varies little, if at all, from one floor to the next.
Service cores may have different ceiling heights and layouts than the rest of the floor. Mechanical equipment rooms may need higher ceilings for big pipes and ducts.Some functions, such as toilets, stairs, and elevator waiting areas, benefit from daylight, fresh air, and views, so access to the building perimeter can be a priority.
Service cores can take up a considerable amount of space. Along with the entry lobby and loading docks,service areas may nearly fill the ground floor as well as the roof and basement. Their locations must be coordinated with the structural layout of the building. In addition, they must coordinate with patterns of space use and activity. The clarity and distance of the circulation path from the farthest rentable area to the ser-vice core have a direct impact on the building’s safety in a fire.
There are several common service core layouts (Pic. 2) Central cores are the most frequent type. In high-rise office buildings, a single service core provides the maximum amount of unobstructed rentable area. This allows for shorter electrical, mechanical, and plumbing runs and more efficient distribution paths. Some buildings locate the service core along one edge of the building, leaving more unobstructed floor space but occupying part of the perimeter and blocking daylight and views. Detached cores are located outside the body of the building to save usable floor space, but require long service runs. Using two symmetrically placed cores reduces service runs, but the remaining floor space loses some flexibility in layout and use.
Multiple cores are sometimes found in broad, low-rise buildings. Long horizontal runs are thus avoided,and mechanical equipment can serve zones with different requirements for heating and cooling. Multiple cores are used in apartment buildings and structures made of repetitive units, with the cores located between units along interior corridors.
BUILDING MATERIALS
The selection of building materials affects both the quality of the building itself and the environment beyond the building. When we look at the energy efficiency of a building, we should also consider the embodied energy used to manufacture and transport the materials from which the building is made.
Power plants that supply electricity for buildings use very large quantities of water, which is returned at a warmer temperature, or as vapor. Mechanical and electrical systems use metals and plastics, along with some clay. These materials are selected for their strength, durability, and fire resistance, as well as their electrical resistance or conductivity. Their environmental impact involves the energy cost to mine, fabricate,and transport them.
THE DESIGN TEAM
In the past, architects were directly responsible for the design of the entire building. Heating and ventilating consisted primarily of steam radiators and operable windows. Lighting and power systems were also relatively uncomplicated. Some parts of buildings, such as sinks, bathtubs, cooking ranges, and dishwashers, were considered separate items in the past, but are now less portable and more commonly viewed as fixed parts of the building. Portable oil lamps have been replaced by lighting fixtures that are an integral part of the building, tied into the electrical system.
Today, the architect typically serves as the leader and coordinator of a team of specialist consultants, including structural, mechanical, and electrical engineers,along with fire protection, acoustic, lighting, and elevator specialists. Interior designers work either directly for the architect as part of the architectural team, or serve as consultants to the architect. Energy-conscious design requires close coordination of the entire design team from the earliest design stages.
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