rendering Initial efficacy, Im/W Lumen maintenance (mean lm) Rated average life, hr Degree of light control Input power required for equal light System operating cost for equal light Initial equipment cost for equal light Total owning and operating cost Relative rating of lamps Very important Important Unimportant Highest (80 up) Medium (5080) Lowest (1550) Highest (85% up) Medium (7585%) Fair (6575%) Shortest (5,000 or less) Intermediate (5,00015,000) Longest (15,00025,000) Highest Intermediate Lowest Highest High Intermediate Lowest Highest Intermediate Lowest Highest Intermediate Lowest Lowest Highest Intermediate Type of lamp Incadescent . . . . . . . .. Tungsten-halogen . .. . . . . .. Fluorescent . . . . . . . . . Clear mercury . . . .. . . . . Coated mercury . . . . . . . . . Clear metal halide . . . . . . . . . Coated metal halide . . . . . . . . . Clear high-pressure sodium Coated high-pressure sodium * Dot indicated that the light source exhibits the listed characteristics. Courtesy of Sylvania Lighting. FIGURE 15.14 Examples of ceiling-mounted fixtures: (a) opaque-side drum for direct diffuse lighting; (b) spotlighting with incandescent lamp; (c) direct, widespread lighting with an HID lamp; (d ) fluorescent fixture for direct diffuse lighting; (e) globe fixture with incandescent lamp for direct diffuse lighting; () small diffusing drum; (g) fluorescent fixture for semidirect diffuse lighting; (h) fluorescent fixture with diffusing lens for direct lighting. FIGURE 15.15 Examples of pendant fixtures: (a) globe fixture for direct diffuse light; (b) fluorescent fixture for general diffuse lighting; (c) exposed-lamp fixture for direct lighting; (d ) direct downlight fixture; (e) fluorescent fixture for semidirect lighting; () fixture for directindirect lighting; (g) fluorescent fixture for semiindirect lighting; (h) fixture with high-intensity discharge (HID) lamp for indirect lighting. scopic effect of the lamp output caused by the ac power supply and to keep the variation in current nearly in phase with the variation in voltage, thus maintaining a high power factor. Fluorescent lamps generally are available as linear, bent U, compact configuration, or circular tubes, and luminaires are designed to be compatible with the selected

x  0.22
16  0.45
40  21.52 ft Thus, the 20-kip lateral force has an eccentricity of 21.52  20  1.52 ft. The eccentric force may be resolved into a 20-kip force acting through the center of rigidity and not producing torque, and a couple producing a torque of 20
1.52  30.4 ft-kips. The nonrotational force is distributed to the shear walls in proportion to their rigidities: Wall A: 0.33
20  6.6 kips Wall B: 0.22
20  4.4 kips Wall C: 0.45
20  9.0 kips For distribution of the torque to the shear walls, the equivalent of moment of inertia must first be computed: Then, the torque is distributed in direct proportion to shear-wall rigidity and distance from center of rigidity and in inverse proportion to I. Wall A: 30.4
0.33
21.52/313  0.690 kips Wall B: 30.4
0.22
5.52/313  0.118 kips Wall C: 30.4
0.45
18.48/313  0.808 kips The torsional forces should be added to the nonrotational forces acting on walls A and B, whereas the torsional force on wall C acts in the opposite direction to the nonrotational force. For a conservative design, the torsional force on wall C should not be subtracted. Hence, the walls should be designed for the following forces: Wall A: 6.6  0.7  7.3 kips Wall B: 4.4  0.1  4.5 kips

In all cases, the architects or engineers legal responsibilities to the client remain firm. The prime professional is fully responsible for the services delivered. The consultants, in turn, are responsible to the architect or engineer with whom they contract. Following this principle, the architect or engineer is responsible to clients for performance of each consultant. Consequently, it is wise for architects and engineers to evaluate their expertise in supervising others before retaining consultants in other areas of responsibility. 2.4.2 Other Consultants A building team may require the assistance of specialists. These specialty consultants provide skills and expertise not normally found in an architectural or engi- neering firm. The prime professional should define the consultants required and assist the client in selecting those consultants. The architect or engineer should define and manage their services even if the specialty consultant contracts directly with the client for liability purposes, with the understanding that the client has the ultimate say in decision making. While several consultants may be required, depending on the complexity of the project, the cost for each may be minimal since their services are provided over short periods of time during the development process, and all consultants are usually not servicing the project at the same time. The following consultant services, most of which are not normally provided by architects and engineers, are provided by