Document 0n0N7m1MdvZQ8Qoab3z5gxvb

American Society of Heating and Ventilating Engineers Guide, 1936 Ventilation (continued), openings skylights, 91 types of, 90 windows, 91 for public buildings, 359 purpose of, 95 quantity of air necessary for, 77, 531 . railway air conditioning, 257 by registers, 93 for schools, 72, 348 by stacks, 93 standards, 74, 790 for theaters, 348 Ventilator, ventilators, resistance of, 92 roof, 92, 779 ' unit, 218 (see also Unit Ventilators) Venturi chimney, 452 Vibration, insulation of, 333 Vitiation of air, 57 Volume, of air and saturated vapor, 10 conversion equations, 785 furnace, 779 specific. 3 of saturated steam, 27 of water, 30 W Wall, walls. air leakage through, 132 of chimneys. 465 fire. 379 heat transmission coefficients for, 105, 112, 114, 116, 118 radiators, output, 522 solar radiation on, 160, 161 sound transmission coefficients for, 331 surfaces, areas of, 104 time lag through, 162 Warm air heating systems, 782 gas-fired furnaces for, 502 gravity, 417 mechanical, 403 Washers, air, 201, 406, 772 capacity of, 203 specifications for, 204 types of, 201 Water, 41 boiling point of, 26 circulating, temperature of, 206, 663 from city mains, 180, 194 cooling, equipment, 204 efficiency of, 208 Quantity, 176, 206 temperature, 206 composition of, 26 density of, 26 domestic supply, 629 evaporation of, 211 factor of usage, 631 flow from fixtures, 630 freezing, 663 friction losses through pipes, 637 hammer, 560 heaters,.389, 645 heating, 629 hot, domestic supply, 643, 045 boilers, 279, 435 demand for, 649 electric heating of, 705 " pipe sizes for, 640 storage of, 648 heating systems, 587 (see also Bot Water Heat ing Systems) inches of water, 777 . Water (continued), line, in boilers, 445, 446, 533 in water supply systems, 636 make-up, 211 meters, disc, 635 pans, for humidification, 526 pressures, 26 properties of, 26, 30 removal of free, 732 replacement of, 211 supply piping, 629 temperature, maximum main, 180 thermal properties of, 30 vapor, 5, 9, 10 given off in combustion of gas, 482 heat content, 10, 22 mean specific heat of,- 3 weight of saturated, 10 Weather Bureau records, temperature, 148, 158 wind, 148, 158 Weatherstripping, 136 Weight, of air, 6 conversion equations, 785 of steam, 27 of vapor, 10 of water, 30 Welding, 607, 621 neck flanges, 623, 624 Wet-bulb temperature (see Temperature, Wet-bulb) Wet return, 782 Wind. in cities, 148, 158 effect on heating requirements, 147 forces in natural ventilation, 89, 95, 131 prevailing, direction of, 136, 158 records of velocity and direction, 148, 158 velocity on natural draft equipment, 210 average, 89, 136 147, 158 equivalent, in tall buildings, 138 used in calculations, 136 Window, windows, 91, 93 air leakage through, 135 area, 104 clearance of sash, 134 coefficients of transmission of, 125 comparison of various shades for, 163 crack, 134 measurement of, 134 solar radiation through, 163 storm sash, 134 Winter, comfort zone, 68, 69 conditioning, apparatus for, 170 cooling in, 157 humidification in, 171, 526 relative humidity in, 70 temperatures, 148 wind velocities and directions, 148 N Wood, woods. air speed for conveying, 380 heat transmission coefficients of, 110 'Z Zero, absolute, 771 Zone, zoning, for air conditioning systems, 172 automatic control, 281 - .comfort, 68, 72, 773 average, 68, 69 ' extreme, 68, 69 heat loss within, 82 control of steam heating systems, 548 for cooling of buildings, 164 for large heating systems, 603 neutral, 778 water supply systems, 629 XXII Chapter 1 FUNDAMENTALS OF HEATING AND AIR CONDITIONING Dalton's Late, Dry- and Wet-Bulb Temperatures, Properties of Air, Humidity, Relative Humidity, Specific Humidity, Relation of Dew Point to Relative Humidity, Adiabatic Saturation of Air, Total Heat and Heat Content, Enthalpy, Psychrometric Chart, Properties of Steam, Properties of Water, Rate of Evaporation A{ IR conditioning has for its objective the supplying and maintaining, in a room or other enclosure, of an atmosphere having a composition, temperature, humidity, and motion which will produce desired effects upon the occupants of the room or upon materials stored or handled in it. Dry air is a mechanical mixture of gases composed, in percentage of volume, as follows1: nitrogen 78.03, oxygen 20.99, argon 0.94,' carbon dioxide 0.03, and small amounts of hydrogen and other gases.' Atmospheric air at sea level is given in percentage by volume as: N2 77.08, O2 20.75, water vapor 1.2, A 0.93, CO2 0.03 and Hi 0.01. The amount of water vapor varies greatly under different conditions and is frequently one of the most important constituents since it affects bodily comfort and greatly affects all kinds of hygroscopic materials. LAW OF PARTIAL PRESSURES A mixture of dry gases and water vapor, such as atmospheric air, obeys Dalton's Law of Partial Pressures: each gas or vapor in a mixture, at a given temperature, contributes to the observed pressure the same amount that it would have exerted by itself at the same temperature had no other gas or vapor been present. If p = the observed pressure of the mixture and pi, pi, p%, etc. = the pressure of the gases or vapors corresponding to the observed temperature, then p = pi -f pi + pi, etc. (1) DRY- AND WET-BULR TEMPERATURES Air is said to be saturated at a given temperature when the water vapor mixed with the air is in the dry saturated condition or, what is the equiv alent, when the space occupied by the mixture holds the maximum pos sible weight of water vapor at that, temperature. If the water, vapor mixed with the dry air is superheated, i.e., if its temperature is above the temperature of saturation for the a,ctual water vapor partial pressure, the air is not saturated. international Critical Tables. 1