Document 961xNM9ZMEEqBngQvjvmw926

254 Chapter 14 _________ ' ~ __________ 1945 Guide direct radiation3 (abbreviated EDR) per hour. The drops indicated are drops in pressure per 100 ft of equivalent length of run., The pipe is assumed to be well reamed and without unusual or noticeable defects. .. Table 4 may be used for sizing piping for steam heating systems by pre-determining the allowable or desired pressure drop per 100 equivalent feet of rim and reading from the column for that particular pressure drop... This applies to all steam mains on both one-pipe and two-pipe systems, vapor systems, and vacuum systems. Columns B to G, inclusive, are used Table 4: Steam Pipe Capacities Capacity Expressed in Square Feet of Equivalent Direct Radiation (Reference to tills table will be by column letter A through L) This table is based on pipe size data developed through the research investiga tions of the American Society of Heating and Ventilating Engineers. CAPACITIES OF STEAM MAINS AND RISERS DmscnoN or Condensation Flow in Pipe Lins Pipe SlZB In. A With the Steam ia One-Pipe and Two-Pipe Systems 1/38 lb >/24 lb Vie lb Mlb Hib Hlb HO. HO* 1 Os Drop Drop Drop 20s Drop - 4 0s Drop 80s Drop BcD B F 0 Two-Pipe Only Vertical Hori zontal Ha / Special Capacities fob Onb-Pifb Systems Onlt Supply Risers Radiator Radiator and and UpFeed Con nections Run outs K Lb H 30 l 39 46 56 30 .25 79 in 157 56 34 45 1 Vs 87 100 122 ni 134 155 190 2 273 315 386 173 269 546 245 346 122 75 98 380 538 190 108 152 771 1,091 386 195 288 2H 449 518 635 898 1,270 1,800 635 395 464 3 822 948 1,160 1,650 2,330 3,290 1,130 700 3H 1,230 1,420 1,740 2,460 3,470 4,910 1,550 1,150 1,140 4 1,740 2,010 .2,460 3,480 4,910 6,950 2,040 1,700 1,520 5 3,210 3,710 4,550 6,430 9,090 12,900 3,150 6 8 5,280 6,100 7,460 10,550 11,000 12,700 15,500 21,970 14,900 31,070 21,100 43,900 __ __ 10 20,000 23,100 28,300 40,100 56,700 80,200 12 32,000 37,100 45,500 64,300 91,000 129,000 . . 16 61,000j69,700 84,800 121,000 170,000 242,000 -- -- -- 28 28 62 62 _ 93 93 169 169 260 475 745 1,110 2,180 -- AH Horizontal Mains and Down-Feed Rises UpFeed Risen Mains and Un dripped Run outs UpFeed Risen Radiator Con- nections Run outs Not Dripped Note.--All drops shown are in pounds per 100 ft of equivalent run--based on pipe properly reamed. Do not use Column 3 for drops of 1/24 or 1/32 lb; substitute Column C or Column B as required. bDo not use Column J for drop of l/32 lb except on sizes 3 in. and over; below 3 in. substitute Column B. cOn radiator runouts over 8 ft long increase one pipe size over that shown in Table 6. where the steam and condensation flow in the same direction, while Columns H and I are for cases where the steam and condensation flow in opposite directions, as in risers and runouts that are not dripped. Columns J, K, and L are for one-pipe systems and cover riser, radiator valve and vertical connection sizes, and radiator and runout sizes, all of which are based on the critical velocities of the steam to permit the counter flow of condensation without, noise. , As steam system designhas materially changed in recent years so that 240 Btu no longer expresses the heat of condensation from a square foot of radiator surface per hour, and as present day heating units have different characteristics from older forms of radiation, it is the purpose of The Guide to gradually eliminate the empirical expression square foot of equivalent direct radiation. EDR, and to substitute a logical unit-based on the Btu. The new terms to express the equivalent of 1000 Btu (Mb), and 1000 Btu per hour (Mbh), have been approved by the A.S.H.V.E. Steam. Heating Systems and Piping 255