Document OznR11KKqzz3DpRYEDkJQ6DQw

American^ Society of Heating and Ventilating Engineers Guide, 1930 Trenches and Trench Covers 1. Furnished by whom. 2. Material, size, etc. 3. Provision for drainage. Railings, Machinery Guards, Bird Screens, Etc. 1. Material. 2. Method of fastening. Painting 1. What is to be painted. 2. Materials and workmanship. 3. Painting of insulation. 512 CHAPTER 33 PHYSICAL UNITS, WEIGHTS, MEASURES AND TABLES MODERN engineering practice depends upon the correct application of basic principles already developed. This chapter contains defini tions of fundamental units and tables of physical constants used by the heating and ventilating engineer. UNITS, WEIGHTS AND MEASURES One British thermal unit (B.t.u.) = ystt of the heat required to lou raise the temperature of 1 lb, of water from 32 deg. to 212 deg. fahr. This is substantially equal to the quantity of heat required to raise 1 lb. of water from 63 deg. to 64 deg. fahr. One mean calorie = of the heat required to raise 1 gram of water from 0 deg. to 100 deg. cent. This is substantially equal to the quantity of heat required to raise one gram of water from 17 deg. to 18 deg. cent. One mean calorie = 0.003968 B.t.u. = 3.085 ft. lb.. = 0.0011626 w.hr. Power, Work, Etc. 1 ton refrigeration Latent heat of ice 1 B.t.u. (British thermal unit) 1 watt hour (w.hr.) 1 kilowatt (1,000 watts) (kw) 1 horsepower (hp.) 1 mech. horsepower 1 boiler horsepower 199,038 B.t.u. per minute (approx.) 143.33 B.t.u. per pound. / 777.5 ft. lb. = 0.293 watt hours. \ 252.02 mean calories. 2,655.4 ft. lb. = 3.415 B.t.u. / 1.3405 horsepower = 56.89 B.t.u. per minute ( 44,236.5 ft. lb- per minute. 0.746 kilowatt / 42.44 B.t.u. per minute. \ 33,000 ft. lb. per minute. 33,523.7 B.t.u. per hour or evaporation of = 34.5 lb. of water per hour from and at 212 deg. fahr. Weights and Volume 1 gal. (U. S.) 1 British or Imperial gallon 1 cu. ft. 1 cu. ft. water at 60 deg. fahr. 1 cu. ft. water at 212 deg. fahr. 1 gal. water at 60<leg. fahr. 1 gal. water at 212 deg. fahr. 231 cu. in. = 0.13368 cu. ft. 277.274 cu. in. 7.4805 gal. = 1,728 cu. in. 62.37 lb. 59.76 lb. 8.34 1b. 7.99 lb. 513