These are devices incorporated in pipelines to control the flow into, through, and from them. Valves are also known as faucets, cocks, bibs, stops, and plugs. The term cock is generally used with an adjective indicating its use; for example, a sill cock (also called a hose bib) is a faucet used on the outside of a building for connection with a garden hose. A faucet is a valve installed on the end of a pipe to permit or stop withdrawal of water from the pipe. Valves usually are made of cast or malleable iron, brass, or bronze. Faucets in bathrooms or kitchens are usually faced with nickel-plated brass. The types of valves generally used in water-supply systems are gate, globe, angle, ball, and check valves. Gate valves control flow by sliding a disk perpendicular to the water flow to fit tightly against seat rings when a handwheel is turned. This type of valve is usually used in locations where it can be left completely open or closed for long periods of time. Globe valves control the flow by changing the size of the passage through which water can flow past the valves. Turning a handwheel moves a disk attached at the end of the valve stem to vary the passage area. When the valve is open, the water turns 90
to pass through an orifice enclosed by the seat and then turns 90
again past the disk, to continue in the original direction. Flow can be completely stopped by turning the handwheel to compress the disk or a gasket on it against the seat. This type of valve usually is used in faucets. Angle valves are similar to globe valves but eliminate one 90
turn of the water flow. Water is discharged from the valves perpendicular to the inflow direction. Check valves are used to prevent reversal of flow in a pipe. In the valves, water must flow through an opening with which is associated a movable plug (or flapper). When water flows in the desired direction, the plug automatically moves out of the way; however, a reverse flow forces the plug into the opening, to seal it. Ball valves are quick-closing (1/4 turn to close) valves, which consist of a drilled ball that swivels on its vertical axis. This type of valve creates little water turbulence owing to its straight-through flow design. 14.6.8 Pipe Supports When standard pipe is used for water supply in a building, stresses due to ordinary water pressure are well within the capacity of the pipe material. Unless the pipe is supported at short intervals, however, the weight of the pipe and its contents may overstress the pipe material. Generally, it is sufficient to support vertical pipes at their base and at every floor. Maximum support spacing for horizontal pipes depends on pipe diameter and material. The plumbing code should be consulted to determine maximum horizontal and vertical hanger spacings allowed. While the supports should be firmly attached to the building, they should permit pipe movement caused by thermal dimensional changes or differences in settlement of building and pipe. Risers should pass through floors preferably through sleeves and transfer their load to the floors through tight-fitting collars. Horizontal pipe runs may be carried on rings or hooks on metal hangers attached to the underside of floors. The hangers and anchors used for plumbing piping should be metal and strong enough to prevent vibration. Each hanger and anchor should be designed and installed to carry its share of the total weight of the pipe. All piping installed should be restrained according to the requirements specific to the exact earthquake zone where the building is located. The local code authorities should be consulted about these requirements. 14.6.9 Expansion and Contraction To provide for expansion and contraction, expansion joints should be incorporated in pipelines. Such joints should be spaced not more than 50 ft apart in hot-water pipe. While special fittings are available for the purpose, flexible connections are a common means of providing for expansion. Frequently, such connections consist of a simple U bend or a spiral coil, which permits springlike absorption of pipe

initial lamp output, lm  CU  LLF fc
(15.37) area of work plane, ft2 Factors contributing to LLF include ballast performance, voltage to luminaires, luminaire reflectance and transmission changes, lamp outages, luminaire ambient temperature, provisions for removal of heat from fixtures, lamp lumen depreciation with use, and luminaire dirt depreciation. The initial lamp output equals the product of the number of lamps by the rated initial lumens per lamp. Substitution in Eq. (15.37) and rearrangement of terms gives fc  area Number of lamps required
(15.38) initial lm per lamp  CU  LLF number of lamps required Number of luminaires required
(15.39) lamps per luminaire Layout of luminaires depends on architectural and decorative considerations, size of space, size and shape of fixtures, mounting height, and the effect of layout on quality of lighting. Different types of fixtures may be used in a space; for example, one type to provide general lighting, other types to provide supplementary local lighting, and still other types to produce accent or decorative lighting. Details of the lumen method of calculation are given in books on lighting (see Art. 15.20, Bibliography). Manufacturers list the maximum permissible spacing for each type of luminaire in photometric reports on their products. This spacing depends on the mounting height, relative to the work plane, for direct, semidirect, and general-diffuse luminaires, and relative to the ceiling height for indirect and semidirect luminaires. Spacings closer than the maximum improve uniformity of lighting and reduce shadows. Perimeter areas, however, require much closer spacing, depending on location of tasks and on the reflectance of the walls; generally, the distance between luminaires and the wall should not exceed half the distance between luminaires, and in some cases, supplementary lighting may have to be added. Computer programs are available for comparative analyses of different types and arrangements of luminaires. The objectives of and constraints on lighting systems and the interrelationship of lighting and other building systems are treated in this article. To design a lighting system for specific conditions, it is first necessary for the designer to determine the nature of and lighting requirements for the activities to be carried out in every space in the building. Also, the designer should cooperate with architects, interior designers, and structural, electrical, and HVAC engineers, as well as with the owners representatives, to establish conditions for optimization of the overall building system. For example, where feasible, reflectances for ceiling, walls, and floor for each space may be selected for high lighting efficiency and visual comfort. Also, HVAC may be designed to remove and utilize heat from luminaires. With tasks known, the designer should establish, for every space, criteria for illumination levels for task performance, safety, and visual comfort and also determine luminance ratios and light-loss factors. (For establishment of the light-loss factors, maintenance of the lighting system should be planned with the owners representatives.) Based on the criteria and the lighting objectives, the designer can then decide how best to use daylighting and artificial lighting and select lamps and fixtures, luminaire mounting and layout, and lighting controls, such as switches and dimming. Because quality, color rendering, and quantity of light are interrelated, they should be properly balanced. This should be checked in an appraisal of the lighting system, which also should include comparisons of alternatives and studies of life-cycle costs and energy consumption. The analysis should compare alternatives not only for the lighting system but also for the other building components that affect or are affected by the lighting system. Value analysis should examine illumination levels critically. A quantity of light that is sufficient for functional purposes is essential; but more light does not necessarily result in better lighting, higher productivity, or greater safety. Furthermore, higher illumination levels are undesirable, because they increase costs of lamps and fixtures, of lighting operation, of the electrical installation, and of HVAC installation and operation. Consequently, lighting should be provided, at the levels necessary, for visual tasks, with appropriate lower levels elsewhere, for example, for circulation areas, corridors, and storage spaces. Provision preferably should be made, however, for relocation or alteration of lighting equipment where changes in use of space can be expected. The various types of lamps differ in characteristics important in design, such as color rendering, life, size, and efficacy. For each application, the most efficient type of lamp appropriate to it should be chosen. Consequently, prime consideration should be given to fluorescent and high-intensity-discharge lamps, which are highly efficient. Also, consideration should be given to high-wattage lamps of the type chosen, because the higher the wattage rating, the higher the lumen output per watt. Furthermore, in selection of a lamp, much more weight should be placed on lifecycle costs than on initial purchase price. Cost of power consumed by a lamp during its life may be 30 or more times the lamp cost. Consequently, use of a more efficient, though more expensive, lamp can save money because of the reduction in power consumption. Similar consideration should also be given to luminaire selection. Efficient luminaires can produce more light on a task with less power consumption. Additional consideration, however, should be given to ease of cleaning and relamping, to prevention of direct glare and veiling reflections, and to removal of heat from the

Safe Building Materials. The technical specifications provided by the architect should be continually updated to eliminate any materials that are potential health hazards to occupants or construction workers, such as materials that give off gas within the occupied spaces. In addition, requirements in local, national, and international building codes to reduce fire and smoke hazards should be met. Occupational Health and Safety Issues. As discussed in the preceding, architects should exercise professional care in design and specification of all architectural and building systems to create a state-of-the-art building offering a safe, healthy environment for all occupants, visitors, and users. Recycled Materials. In todays environment, architects should understand that their designs must consider the impact on the ecological health of our society. With this in mind, architects should work together with the client to develop policies and innovative solutions that will reduce waste and promote the recycling of materials. During development of a project the client normally looks to the architect for construction cost estimates. It is advisable to provide a probable cost of construction at completion of the schematic design, design development, and construction document phases. A design contingency is usually carried in cost estimates. It can be reduced as the documents are further developed. At completion of the construction documents, the architect prepares, or has a consultant prepare, a final and most accurate estimate of construction cost, which can be used for comparison with the bids submitted to perform the work. Value engineering may be performed by consultants and construction managers during the development of the construction documents. (This is a misnomer for cost-reduction engineering, since value engineering should occur before a design has been finalized and construction documents have started. To be effective, value engineering should be undertaken prior to design of any building system. Value engineering should address operating and maintenance costs as well as first costs, to provide true life-cycle cost estimates for comparative analysis. This can be accomplished as early as the conceptual design phase of the project and should use the expertise of cost consultants, if such service is not offered directly by the architect or engineer. Cost analysis should be performed concurrently with technical evaluation of the systems proposed by the architects or engineers, to provide the client with proper information to make an informed decision. The architect and engineer should address cost without compromising the building program, building safety, or desired design and performance of the facility and respond to the client in a professional manner regarding cost estimating and value engineering. Specifications for a building project are written descriptions, and the drawings are a diagrammatic presentation of the construction work required for that project. The drawings and specifications are complementary. Specifications are addressed to the prime contractor. Presenting a written description of the project in an orderly and logical manner, they are organized into divisions and sections representing, in the opinion of the specification writer, the trades that will be involved in construction. Proper organization of the specifications facilitates cost estimating and aids in preparation of bids. The architect should coordinate the specification terminology with that shown on the drawings. 2.17.1 Content of Specifications It is not practical for an architect or engineer to include sufficient notes on the drawings to describe in complete detail all of the products and methods required of a construction project. Detailed descriptions should be incorporated in specifications. For example, workmanship required should be stated in the specifications. Contractors study specifications to determine details or materials required, sequence of work, quality of workmanship, and appearance of the end product. From this information, contractors can estimate costs of the various skills and labor re- quired. If workmanship is not determined properly, unrealistic costs will result and quality will suffer. Good specifications expand or clarify drawing notes, define quality of materials and workmanship, establish the scope of the work, and describe the responsibilities of the contractor. The terms of the contract documents should obligate each contractor to guarantee to the client and the architect or engineer that all labor and materials furnished and the work performed are in accordance with the requirements of the contract documents. In addition, a guarantee should also provide that if any defects develop from use of inferior materials, equipment, or workmanship during the guarantee period (1 year or more from the date of final completion of the contract or final occupancy of the building by the client, whichever is earlier), the contractor must, as required by the contract, restore all unsatisfactory work to a satisfactory condition or replace it with acceptable materials. Also, the contractor should repair or replace any damage resulting from the inferior work and should restore any work or equipment or contents disturbed in fulfilling the guarantee. Difficult and time-consuming to prepare, technical specifications supply a written description of the project, lacking only a portrayal of its physical shape and its dimensions. The specifications describe in detail the material, whether concealed or exposed, in the project and fixed equipment needed for the normal functioning of the project. If they are properly prepared, well-organized, comprehensive, and indexed, the applicable requirements for any type of work, kind of material, or piece of equipment in a project can be easily located. The technical specifications cover the major types of workarchitectural, civil, structural, mechanical, and electrical. Each of these types is further divided and subdivided in the technical specifications and given a general title that describes work performed by specific building trades or technicians, such as plasterers, tile setters, plumbers, carpenters, masons, and sheet-metal workers, to name a few. The prime contractor has the responsibility to perform all work, to furnish all materials, and to complete the project within a schedule. The contractor, therefore, has the right to select subcontractors or perform the work with the contractors own forces. In recognition of this, each specification should contain a statement either in the General Conditions or in the Special Conditions, that, regardless of the subdivision of the technical specifications, the contractor shall be responsible for allocation of the work to avoid delays due to conflict with local customs, rules, and union jurisdictional regulations and decisions. Standard forms for technical specifications can be obtained from the Construction Specifications Institute (CSI). The CSI publishes a Master List of Section Titles and Numbers, which is the generally accepted industry standard. In it, technical specifications are organized into 16 divisions, each with titles that identify a major class of work. Each division contains basic units of work, called sections, related to the work described by the division title. Following is the division format developed