Document 8RXvm0X2k4QyxRdmm59db9X5d

American Society of Heating and Ventilating; Engineers Guide, 1924-25 TABLE 14. CLIMATIC CONDITIONS COMPILED FROM U. S. WEATHER BUREAU RECORDS (Continued) Col. A State NC mn Okla............. Pa R. I. SC. SD Utah Vt Va................ W. Va_____ Wis.............. Col. B City Col. C Col. D Col. E Col. F Average Temp., Oct. 1st-- May 1st Lowest Tempera ture Average Wind Vel ocity Dec., Jan., Feb., Miles per Hr: Direction of Prevail ing Wind, Dec.. Jan., Feb. 49.7 53.1 24.5 18.9 36.9 39.9 48.0 34.1 45.9 41.9 40.8 37.6 56.9 53.7 28.1 32.3 47.0 50.9 53.0 54.7 60.7 38.1 40.0 29.3' 49.1 45.2 47.4 45.3 37.5 38.8 41.9 28.6 31.2 33.0 31.0 28.9 -2 5 -45 -44 --17 -20 -17 -20 -2 -6 -20 -9 7 -2 -43 -34 -16 -9 -2 -8 4 -24 -20 -27 2 -7 -3 3 -30 -21 -27 . -36 -43 -25 -45 -36 7.3 sw 8.9 sw NW 11.4 w 14.5 sw 9.3 sw 12.0 N 6.0 ' SE 6.5 s 11.0 NW 13.7 NW 14.6 NW 11.0 N 8.0 NE 11.5 NW 7.5 W 6.5 sw 9.6 NW 10.5 NW 11.0 NW 8.2 N 8.9 W 4.9 SE 12.9 S 9.0 . N 5.2 NW 7.4 S 9.1 SE SW 4.8 W . 6.6 S 12.8 SW 5.6 NW 11.7 W 5.3 NW 3.0 NE The outside air temperature used in computing the heat loss from a building is seldom taken as the lowest temperature ever recorded in a given locality. Such temperatures are usually of short duration and are rarely repeated in successive years. It is therefore evident that a tempera ture somewhat higher than the lowest on record may be properly assumed in making the heat loss computations. The outside temperature to be assumed in the design of any heating system should not be more than 15 deg. fahr. above the lowest recorded temperature as reported by the U. S. Weather Bureau Table 14, during the preceding 10 years for the locality in which the heating system is to be installed. 20 American Society of Heating and Ventilating Engineers Guide, 1924-25 HEAT SOURCES The heat supplied by persons, lights, motors and machinery should always be ascertained in the case of theaters, assembly halls, and in dustrial plants, but allowances for such heat sources must be made only after careful consideration of all local conditions. In many cases, these heat sources should not be allowed to affect the size of the installation at all, although they may have a marked effect on the operation and con trol of the system later. In general, it is safe to say that where audiences are involved, the heating installation must have sufficient capacity to bring the building up to the stipulated inside temperature before the audience arrives. In industrial plants, quite a different condition exists, and heat sources, if they are always available during the period of human occupancy, may be substituted for a portion of the heating installation. In no case should the actual heating installation (exclusive of heat sources) be reduced below that required to maintain at least 40 deg. fahr. in the building. The following allowances may be made when required: TABLE 15. HEAT GIVEN UP BY PERSONS AND LIGHTS Persons : .Man at rest....................................................................................400 B.t.u. per hr. Man at work--............................................-.................................500 B.t.u. per hr. Lights: Electric lamps, B.t.u. per hr. equals watts per lamp X number of lamps X 3.415 Gas lighting: 1 cu. ft. producer gas................... 150 B.t.u. 1 cu. ft. illuminating gas..............................................................................700B.t.u. 1 cu. ft. natural gas.....................................................................................1000B.t.u. A Welsbach burner averages 3 cu. ft. of gas per hour and a fish tail burner 5 cu. ft. per hour. Motors and the machinery which they drive, if both are located in the room, convert all of the electrical energy supplied into heat, which is retained in the room if the product being manufactured is not removed until its temperature is the same as the room temperature. If power is transmitted to the machinery from the outside, then only the heat equivalent of the brake horsepower supplied is used. In the f..i.rst case th, e ^B.t.u. supplied, per hour = Moto.--r--h--o-r-s-ej-p--o--w---er wX 254.6., and, Efficiency of motor in the second case B.t.u. per hr. = b.hp. X 2546, in which 2546 is the B.t.u. equivalent of I hp. hour. In high-powered mills this is the chief source of heating and is frequently sufficient to overheat the building even in zero weather, thus requiring cooling by ventilation the year round. For intermittent heating allow 10 per cent additional for rooms heated in the day time only, and for longer intervals of several days or more, add 25 per cent in determining minimum heating requirements, and size of plant. ROOM TEMPERATURES USUALLY SPECIFIED In the accompanying Table 16 are the inside temperatures ordinarily specified for the many kinds of rooms, buildings, shops, factories and it 21