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American Society of Heating and Ventilating Engineers Guide, 1925-26 proper amount for exposure add 40 per cent and refer to Tables 18-24 to find the proper size radiator. Example.--The heat losses including allowance for exposure for a given size room is 17,200 B.t.u., + 40 per cent or 24,080 B.t.u., requiring a 19-section 45 in. 3-col. semi-indirect radiator. Pipe coils should be of the header type, with provision made for ex pansion by a mitre piece. The steam supply should be at the mitre end and all coils should be securely anchored at the return header so as to throw the expansion toward the mitre end. The coils should be made of l]4, or 1J4 >n. pipe and not over 60 ft. in length, not including the mitre, which should be at least one-tenth the length of the coil, SELECTION OF RADIATION It is usually necessary to select the type and location of radiation to conform to the conditions and space available in the room. In general it is usually most convenient and practical to locate the radiation on the exposed side of the room. The size of the radiator to take care of any particular heat, loss can be best selected from the sheets compiled by the Society's Research Laboratory in cooperation with the U. S. Bureau of Mines Experiment Station, which are based on experiments by the late Director John R. Allen, and F. B. Rowley. As the heat emitted per square foot of radiation varies in radiators of different heights, widths and lengths, and also with the steam pressure and the temperature of the room, errors will occur if the same factor is used for all radiators. Examples for the Use of Tables.--Assume that the heat loss from a room is 15,497 B.t.u. per hr., to heat the room to 70 deg. fahr. Two-column 38-in. radiators have been selected using steam at 1-lb. gage or approxi mately 215 deg. fahr. . Solution.--Ii>Table 19 for two-column radiators, under 38 in., it will be found that a 17-section radiator will emit 15,960 B.t.u. There fore a 17-section two-column 38-in. radiator will be required with a rated surface of 68 sq. ft. If in the same example steam at 5-lb. pressure or approximately 227 deg. fahr. was used and the room was heated to only 60 deg. fahr. re quiring 13,300 B.t.u. and three-column 26-in. radiators are selected the radiation would be estimated as follows: Solution.--In Table 25 following down the first column to 5-lb. gage pressure and then over horizontally to 60 deg. fahr. room temperature the conversion factor 0.864 will be found. The heat loss 13,300 X 0.864 (the equivalent, heat loss) =? 11,480 B.t.u. In Table 20 for three-column radiators under the heading 26 in. it will be found that a 13-section radiator will supply 11,242 B.t.u. under standard conditions which is the closest to the amount required. Therefore a 13-section three-column 26-in. radiator will be required. 32 American Society of-Heating and- Ventilating Engineers Guide, 1925-26 z o' 1 Total B.t.u. per hr. , to cm t-* cm oo oo r-- I-**.' CsMo fto- troo OO CO CM CM ro to Tf lOrTOoO* OCr*oM*'CftCo-MOrCtNooM rOtHO OO^1 00 T* t^oO'rtof. aoo ttoo lOO'OO'O to to i O CM ro to to to to OO O' C--M CCMM to' to Cr*M* tCoM rCM- oCMo Oto SSuQr.f fatc.e Rated 7309 7752 8193 8635 . 9080 26.66 28.33 ' 30.00 31.66 33.33 zo. HHE? Q ! li as >2- DC/) .uOJ Z <C zg cjozd a (S) XwfcXl sj zoHI l5 < z< ga o2 26 In . 2 3 n .I Rated Surface sq. ft. Total B.t.u. per hr. Rated Surface sq. ft. 1.66 3.33 5.00 6.66 8.33 Total f B.t.u. [` per hr. 654 1112 1555 1997 2440 OoCcMmo0 CrrooM t-- ro i cTmf et<toMJ< ttooi OrttoooO otoo Ce^MM* to co 18.33 20.00 21.66 23.33 25.00 10.00 11.66 13.33 15.00 16.66 ro r- -- to Nr-OeMiOooNtoCoOo cm cm OO rroo OtrooO ftrt*o--*** OO--<O**' ^to COMt^O"j< n Tj* \ V to'Or*r* cm 'oo O CM ^* OO CCMM rCMf CM OCMO ro CtoM ro co 0to0 S' A* Q s \\ Cd t S Hu> g 1? H(<d rfw* 2*> , oo 00 32 In . Rated Total Surface B.t.u. s q . ft. i per hr. to --< CCMM OCMO CO CO ^ tlCrOt"M<. trtrooof COMO to O >0 rtC--oM OO''CT--Mt CCtMMot0CroM0* o to to cm to e-* CM to to to r-- -- oCM cCMm tCoM to to to rC--M OroCroMriooiC-O. to to O M^ ionOto . tooioot^to CM -- OO fto- oro to tTot*OTTtffo' fCCOMM*toO--O Oo^OorfO-*hroTo .toicrC*M--oM' 12053 12781 13511 14239 . .14964 Total | B.t.u. ; , per hr. z CO I-Ssi- 31 g C/J " ro CM to oo Tt* t-- --i CM CM CM CO CO O' CM to OO -H'Tt* r-T o ro to tO tJ* to to to ' .. . O b. 22** o Hu u C/1 . v-i cm ro to' t-OO" *-< CM ro to t-- 00 V H-HH-lfS. o ro to to Tjt to 15 20 '25 i L e n g t hI nches 5 10 33 7236 7863 8489 ' 9117 9744 626 250 8489 9000 9515 10028 10544 514 257 385 B.t.u. per Intermed. Section 728 443 243 . 375 .CM oroo- 3 3 fcu & cn 3 " " " End Surface 394 263 395 .