Miscellaneous Sources of Heat Gain. In an air-conditioning unit, the fan used to circulate the air requires a certain amount of brake horsepower depending on the air quantity and the total resistance in the ductwork, coils, filters, etc. This horse- TABLE 13.9 Rates of Heat Gain from Occupants of Conditioned Spaces* Degree of activity Typical application Total heat adults, male, Btu/hr Total heat adjusted, Btu/ hr Sensible heat, Btu/hr Latent heat, Btu/hr Seated at theater Theatermatinee 390 330 225 105 Seated at theater Theaterevening 390 350 245 105 Seated, very light work Offices, hotels, apartments 450 400 245 155 Moderately active office work Offices, hotels, apartments 475 450 250 200 Standing, light work; walking Department store, retail store 550 450 250 200 Walking; standing Drugstore, bank 550 500 250 250 Sedentary work Restaurant 490 550 275 275 Light bench work Factory 800 750 275 475 Moderate dancing Dance hall 900 850 305 545 Walking 3 mph; light machine work Factory 1000 1000 375 625 Bowling Bowling alley 1500 1450 580 870 Heavy work Factory 1500 1450 580 870 Heavy machine work; lifting Factory 1600 1600 635 965 Athletics Gymnasium 2000 1800 710 1090 *Tabulated values are based on 78
F room dry-bulb temperature. For 80
F room dry bulb, the total heat remains the same, but the sensible-heat value should be decreased by approximately 20% and the latent heat values increased accordingly. All values are rounded to the nearest 5 Btu / hr. Adjusted total heat gain is based on normal percentage of men, women, and children for the application listed, with the postulate that the gain from an adult female is 85% of that for an adult male, and that the gain from a child is 75% of that for an adult male. Adjusted total heat value for eating in a restaurant includes 60 Btu / hr for food per individual (30 Btu sensible and 30 Btu latent). For bowling, figure one person per alley actually bowling, and all others as sitting (400 Btu / hr) or standing and walking slowly (550 Btu / hr). Reprinted by permission of ASHRAE from ASHRAE HandbookFundamentals, 1989, American Society of Heating, Refrigerating and Air-Conditioning Engineers. power will dissipate itself in the conditioned air and will show up as a temperature rise. Therefore, we must include the fan brake horsepower in the air-conditioning load. For most low-pressure air-distribution duct systems, the heat from this source varies from 5% of the sensible load for smaller systems to 31/2% of the sensible load in the larger systems. Where the air-conditioning ducts pass through nonconditioned spaces, the ducts must be insulated. The amount of the heat transmitted to the conditioned air through the insulation may be calculated from the duct area and the insulation heat-transfer

Preliminary Estimates. These reflect the basic design parameters. For this purpose, a site plan and a schematic design are required. The schematic should show plans and elevations plus a few sections through the building. For buildings such as power plants and chemical refineries, it should also contain a process diagram, major equipment list, and an equipment arrangement diagram. Preliminary estimates can reflect solutions, identify unique construction conditions, and take into account construction alternatives. Usually, this type of estimate does not reveal design interferences. Generally prepared by the designer, preliminary estimates are made after about 5 to 10% of the design has been completed. Several preliminary estimates may be made for a project as the design progresses. Baseline Estimates. These are final preliminary estimates. For most buildings, requirements for preparation of an estimate include plans, elevations, and sections. For process plants, also necessary are complete flow diagrams, process and instrumentation diagrams (P&ID) in outline form, and a list of equipment selected and the location of the equipment. Subsequent changes in the estimate are measured with respect to the baseline estimate. Identifying all cost components, the estimate provides enough detail to permit price comparisons of material options and is sufficiently detailed to allow equipment quotations to be obtained. The baseline estimate is generally prepared by the designer. It is made after about 10 to 50% of the design has been completed. Definitive Estimates. From a definitive estimate, the client learns what the total project cost should be and the designers overall intent. The estimate is based on plans, elevations, and sections; flow diagrams, P&IDs, and equipment and instrument lists (for process plants); design segments for each discipline; and outline specifications. It identifies all costs. It is sufficiently detailed to allow quotes to be obtained for materials, to order equipment, and to commit to material prices for approximate quantities. This type of estimate is generally prepared by the designer and represents the end of the designers responsibility for cost estimates. It is made after about 30 to 100% of the design has been completed. Fixed-Price Estimates. Prepared by a general contractor, a fixed-price estimate, or bid, represents a firm commitment by the contractor to build the project. It is based on the contractors interpretation of the design documents. It requires detailed drawings for each discipline, equipment lists, P&IDs, wiring diagrams, and specifications. A fixed-price estimate is highly accurate. It should be in sufficient detail to enable the contractor to obtain quotes from suppliers and to identify possible substitutes for specific items. It is made after 70 to 100% of the design has been

Information on passenger capacity of a moving walk or powered ramp should be obtained from the manufacturer. The capacity depends on treadway width and speed. Standard widths are 24, 32, and 40 in. With level entry and exit, ramp speeds generally are a maximum of 180 ft /min for slopes up to 8
and 140 ft /min for slopes between 8
and 15
. (Life Safety Code, National Fire Protection Association, Batterymarch Park, Quincy, MA 02269; American National Standard Safety Code for Elevators, Dumbwaiters, Escalators and Moving Walks, A17.1, and Making Buildings and FIGURE 16.2 Arrangement of straight stairs: (a) a single flight between floors; (b) a series of flights without change in direction; (c) parallel stairs; (d ) angle stairs; (e) scissors stairs. Facilities Accessible to and Usable by the Physically Handicapped, A117.1, American National Standards Institute, New York, NY 10018.) Less space is required for stairs than for ramps, because steeper slopes can be used. Maximum slope of stairs for comfort is estimated to be about 1 on 2 (27
), but this angle frequently is exceeded for practical reasons. Exterior stairs generally range in slope from 20
to 30
, interior stairs from 30
to 35
. 16.3.1 Types of Stairs Generally, stairs are of the following types: straight, circular, curved, or spiral, or