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476 CHAPTER 25 1948 Guide Table 3. Correction Factors for Direct Cast-Iron Radiators and Convectors, Steam Press. Heating Medium ' Factors fob'Dibbct * Cast-Iron Radiators Factors tor Convectors Approx. Gage Abe. Temp F Steam ROOmT ATUKB F Inlbt Air Temperature F . Vacuum lit Hg. Lb per Sq In. Water 80 75 70 ' 65 60 55 50 80 75 70 65 60 55 50 .22.4 "20-3 17.7 14.6. _ 109 6.5LbperSqln. -1 6 15 27 52 3.7 4.7 6.0 . 7.5 - 9-3, UJ. .150 160 170 180 190 200 15.6 21 30 42 67 215 230 250 * 270 - 300 2.58 2.36 2.17 2.00 1.86 1.73 1.62 3.14* 2.83 2.57 2.35 2.15 1.98 1.84 2.17 2.00 1.86 1.73 1.62 U2 1.44 2.57 U5 2.15 1.98 L84 1.71 1.59 1.86 1.73 1.62 1.52 1.44 US 1.28 2.15= 1.98 1.84 1.71 1.59 1:49` 1.40' 1.62 U2 1.44 1.3S. -1.28 1.21 1.15 IM t.71 U9 1.49 1.40 U2: 124. 1.44 US 1.28 1.21 1.15 1.10 1.05 1.59 1.49 1.40 U2 1.24 -1.17, 1.11 .1.28 1.21 1.15 1.10 1.05 1.00 0.96 1.40 U2 1.24 1.17 1.11 1.05 1.00 1.10- 1.05 1.00 0.96 0.92 088 0.85 1.17 1.11 1.05 1.00 0.95 0.91 0.87 ' 0.96 0.92 0.88 0.85 0.81 0.78 0.76 1.00 0.95 ;0.91 0.87 083 079 076. 0.81 0.78 0.76 0.73 0.70 0.68 066 0.83 0.79 0.76 0.73 0.70 0.68 0.65 0.70 0.68 0.66 0.64 0.62 0.60 0^58 070 0.^8 065 0.63 060 0.58 0.56 0.58 '0.57 0.55 0.53 0.52 0.51 0.49 0.56 0.54 0.53 0.51 0.49 0.48* 0.47 . aTo determine the size of a radiator or a convector for a given space, divide the heat loss in Btu per hour by.240 and multiply the result by the proper factor from the above table. To determine the heating capacity of a radiator or a convector under conditions,other than the basicones with the heating medium at a temperature of 215 F. and the room temperature at 70 F in the case of a radiator,.and the inlet air temperature at 05 F in the case of a convector, dhride the heating capacities at the. basic conditions by the proper factor from the above table. rating-test conditions to output under other operating conditions. Such factors are. given in Table 3. When it is desired to change the output under any test conditions to the corresponding; output under standard Code test conditions, the reciprocal form of correction factor may be derived. The equations for steam units are:. : For radiators: 215 - 70\i-3 C,, A - W For convectors: (i) ,, Y215 - 65V-5 Cs " V A - ti ) m The output under standard conditions will be: where lh = C,, Ht correction factor. ' steam temperature during test, Fahrenheit degrees, room'temperature during test, Fahrenheit degrees. inlet air temperature during test, Fahrenheit degrees- heat emission rating under standard conditions, Btu per hour. heat output under, test conditions, Btu per hour..: '' : (3) ......... .The relation.between the size of the radiator or convector andthesize of the test room will affect the results obtained in a capacityrrating test:? The height and location of the radiator and the insulation of the test room are other important factors that are not specifically regulated by the Code. For a radiator, the finish coat of paint affects the heat output. Oil paints pf any color, will give about the same results as. unpainted black or rusty surfaces, but an aluminum or a bronze paint will reduce ;the heat emitted by radiation. The net effect may be a reduction of 10 per cent or more in the total heat output of the radiator t'5,r. ; Radiator enclosures and convector casings affect the heat distribution within the room as well as the total amount of heat supplied by the steam or hot water.8 , -. Radiators, Convectors, Coils 477 Heating Effect 1 For several years the term heating effect has been used to designate the : relation between the useful output of a radiator* in the comfort zone of a room, and the total input as measured by steam condensation, or water temperatures " ". The application of such a heating effect factor is a recog nition that some radiators and convectors use less steam than others for producing equal comfort heating results in the room. No standard method for evaluating the heating effect of radiators and convectors and correlating it with comfort has yet been accepted;- One method, with test data11 on radiators and convectors, and making use of the eupatheoscope for evaluating the environment produced, has been suggested by the University of Illinois. The,principle.underlying the eupatheoscope involves the measurement of the heat loss from a sizable [ErrmTTTTTT d room t emp in deg F | III 1111 j Tn ,11.1.1.. 111- 111 ill ML 5.60 ib convector No. 1 5.84 ib convector No. 22 6.12 (b convector No. 6 6.32 ib 5-tube radiator Temperature in deg F Position No. 3 Position No. 1 30" level Eauhr Dtft 30- level Equiv Di(f 67.7, 66-2 *t.5 67.4 65.9 1.5 682 643 *3.9 63.0 66.6 *1.4 68.0 65.1 *23 679 67.9 0.0 6&2- 66.4 IB 56 7 HDGHT ABOVE FLOOR IN FEET Fig. 2. Temperature Gradients and Equivalent Temperatures for Radiator body by radiation and convection, when the surface is maintained at some constant temperature. Through the use of this instrument and its calibration curve, non-uniform environments may be referred to uniform environments in which the air and all surrounding surfaces are" at the same temperature. The temperatures of the uniform environments are referred to as equivalent temperatures. 'r , .. 7 The Kata thermometer12; the thermo-integrator u-14, and the globe15 thermometer are other instruments which have been used, to measure the influence of air temperature, air movement and radiation; in,.an environment. Data given in Fig. 2 show that while the air temperature.at^the 30-in. level is the same for the three convectors and the one large-tuhe cast-iron radiator, in position No. 3 in the test room, the equivalent temperature is 1.5 F lower than the air temperature in the case of the three convectors,. and the same as the air temperature in the case of the radiator. The difference between the minimum and the maximum amount of heat