Document NN0DKZBo2Rar4x52wKL527Row

American Society of Heating and Ventilating Engineers Guide, 1930 P t-- MOO *0 m 'O'ONOOO'O o OOOOO^h s woars'om^H oo cs ^ r oi cn r>-(N rS (fi 06 o H U < U. fc O tn 06 u o u 1 (h U. X z o 06 h oOMMMoom r* ^ oo 'O iO' 00 4* o doodoo 3 su o & Tf 1/5 NO t". OO \ 0. oooooo 5 Mu MO0MNMOO n >0 fO *-- v 00 O H T* to ' NOM 00 V *d oooooo' o Hoo'inrtNONin NW)OOOfONN nnatsinfoON SOtC>OCOfOtN .-H *H Qn'OnOfqoOfq OOOOhhhn K VI < U w. s06 > A o w H 3 w H < H K A A < JS ^OlNNO'O ts O'N' lo ^ CN ^'^"O'OMOO 4> o OOOOOO u oo cs oo *- t-- cn cO'pn*iosoo V OOOOOO 00 2 V fa. h OOOOOO IOONoOOiO mg 45 *-> Os w m c* .S s < 0* innoOirtfO^NfO SSSSSS-22 HN^noOlA-N OvO'O'OOOO*-' OOO -- noiMwjNOioO CSMMNMNNCS t^OOOOOOOOOOOs nvOMooO'OM^1 % M | V) a* >-- f- cn cn r-- tn ro Os in CN oo o td ^csm^tn'oooo ffl o - 278 a conductor operating under the indicated conditions. Chapter 16--Conductors & Convectors for Heating by Steam & by Hot Water tiplying its standard heat emission by the proper factor taken from Table 1. In estimating the size of heater required for a room under other than standard conditions divide the estimated heat loss from the room by the factor for the prevailing conditions as given in Table 1, and choose a heater which will supply this corrected heat loss when operating under standard conditions. Thus, if a room whose heat loss with 60 deg. air is 7,200 B.t.u. per hour, is to be heated to 60 deg. with steam at 200 deg., divide 7,200 by 0.955 giving 7,539, and pick a heater which will give 7,539 B.t.u. per hour when supplied with 215 deg. steam in a 70 deg. room. Effect of Humidity Fig. 1 shows the. effect of increasing the humidity upon the heat trans mission. It will be noted that with extreme change of humidity there is a slight change in the heat transmission. Heating the Conductor It' is often very important to know the maximum condensation that occurs in a heater when steam is turned on. Fig. 2 shows the conden sation rate in pounds per hour for the time elapsing after steam is turned into a column conductor. In practice the rate of steam supply to the conductor while heating up is, however, frequently retarded by controlled elimination of air through air valves or traps, and if sufficient time is allowed for the heating-up process, overload on the boiler may practically be eliminated. _ Effect of Paint Painting a conductor changes the emissivity constant of the radiating surface, but has practically no effect upon the heat lost by convection. It is, therefore, a surface effect and it makes no appreciable difference 279