Document 5bdQqb4QGB3LYEGkKy4nGrEr5

530 CHAPTER 20 ' 1958 Guide Table 5. Steam Pipe Capacities fob Low Pressure Systems (Reference to this table will be by column letter A through L) This table is based on pipe sise data developed through the research investigations.ofr The American Society or Heating and Air-Conditioning Engineers. . Pipe Size In. A CAPACITIES OF STEAM MAINS AND RISERS Special Capacities eoh Oke-Pxpb Systems Oklt Direction or Condensate Flow in Pipe Line Radi With the Steam in One-Pipe and Two-Pipe Systems > Against the ator Radi Supply Valves ator A psi or AoPr si Aoprsi *Os Drop iSp 1 Os Drop 1 PSI or 2 Oz Drop J psi or 4 Oz Drop Jps or 8 0s Drop Two-Pij>e Only Vertical Hori zontal Risers and and Up- Vertical Riser Feed Con Run nec outs tions BcD E F :: Q /e /b K Z.' Capacity Expressed in Square Feet EDR i_ _ 30 _ * __ __ 30 __ 25 _ i 39 46 56 79 in 157 56 34 .. - 45 28 h 87 100 122 173 245 346 122 -75 98 62 ti 134 155 190 269 380 538 190 108 152 93 2 273 315 386 546 771 1,091 386 195 288 169 21 449 518 635 898 1,270 1,800 635 395 464 -- 3 822 948 1,160 1,650 2,330 3,290 1,130 700 800 -- 31 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 4,200 3,150 -- -- 6 5,280 6,100 7,460 10,550 14,900 21,100 7,200 5,600 -- -- 8 11,000 12,700 15,500 21,970 31,070 43,900 15,000 12,000 -- 10 20,000 23,100 28,300 40,100 56,700 80,200 28,000 23,000 -- -- -- 12 32,000 37,100 45,500 64,300 91,000 129,000 46,000 38,000 -- -- 16 61,000 69,700 84,800 121,000 170,000 242,000 88,000 76,000 -- -- _ 28 62 93 169 260 475 745 1,110 2,180 -- -- -- -- -- Capacity Expressed in Pounds per Hour _a 8 __ _ _ 8_ 6_ i 10 12 .14 20 28 40 14 9 11 7 li 22 25 31 43 61 87 31 19 2C 16 ii 34 39 48 67 95 135 48 27 38 23 2 68 79 97 137 .193 273 97 49 72 42 21 3 112 13C 159 225 318 449 159 99 116 -- 206 237 291 411 581 822 282 175 2a -- 31 307 355 434 614 869 1,23C 387 288 286 -- 4 435 503 614 861 1,23C 1,74C 511 425 381 5 806 928 1,14( 1,61( 2,27C 3,21( 1,05C 788 -- -- 6 1,320 1,52( 1,87( 2,64( 3,730 5,28( a.sa 1,4a -- 8 2,750 3,17( 3,88C 5,49( 7,77( n,oa 3,75( 3,oa -- -- 10 5,010 5,79( 7,09< 10,000 14,200 20,000 7,000 5,7a -- -- 12 8,040 9,29( 11,4a 16, ia 22,7a 32,2a u,sa 9,5a -- -- 16 15,100 17,400 21,200 30,300 42,400 60,500 22,000 19,000 -- -- 7 7 16 23 42 65 119 186 278 545 -- -- -- -- -- AQ Horizontal Mains and Down-Feed Risers UpFeed Risers and Un dripped Run outs UpFeed Risers Radi ator Con nec tions Run*: outs Not Dripp*" - Note.--Steam at an average preesure of 1 peig is used as a basis for calculating capacities. All drops shown are in pei per,100 ft of equivalent run--based on pipe properly roamed. * Do not use Column H for drops of 1/24 or 1/32 psi; substitute Column C or Column B as required. ' : b Do not use Column J for drop 1/32 pei except on siaes 3 in. and over; below 3 in. substitute Column B. Pitch of horisontal runouts to risers and radiators should be not less than 1/2 in. per ft. Where this pit*"1 cannot be obtained, runouts over 8 ft in length should be one pipe size larger than called for in Table 5. Steam Heating Systems 531 length of run is not usually known at the outset; hence, it may be necessary to assume some pipe size at the start. Such an assumption frequently is considerably in error, and a more common and practical method is to assume the length of run and to check this assumption after the pipes are sized. For this purpose the length of run usually is taken as double the actual length of pipe. TABLES FOR PIPE SIZING FOR LOW PRESSURE SYSTEMS2 Tables 5, 6, and 7 are based on the actual inside diameters of the pipe and the condensation of lb (4 oz) of steam per square foot of equivalent direct radiation (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 5 may be used for sizing piping for steam heating systems by pre-determining the allowable or desired pressure drop per 100 equivalent feet of run, 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 BtoG, inclusive, are used where the steam and condensate flow in the same direction, while Columns H and I are for cases where the steam and condensate 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 condensate without noise. Return piping may be sized with the aid of Tables 6 and 7 where pipe capacities for wet, dry, and vacuum return lines are shown for the pres sure drops per 100 ft corresponding to the drops in Table 5. It is cus tomary to use Ike same pressure drop on both the steam and return sides of a system. Example 2: What pressure drop should be used for the steam piping of a system if the measured length of the longest run is 500 ft, and the initial pressure is not to be over 2-psig? , Solution: It will be assumed, if the measured length of the longest run is 500 ft., that when the allowance for fittings is added, the equivalent length of run will not ?ce(* 1.000 ft. Then, with the pressure drop not over one-half of the initial pressure, he 1 psi or less. With a pressure drop of 1 psi and a length of run of n inn drop per 100 ft would be Ho psi, while if the total drop were H psi, the drop per luo ft would be Ho psi. In the first instance the pipe could be sized according to i^oiumn D for H6 psi per 100 ft, and in the second case, the pipe could be sized accord- jng to Column C for H4 psi. On completion of the sizing, the drop could be checked y taking the longest line and actually calculating the equivalentlength of run from P'Pe sizes determined. If the calculated drop is less than that assumed, the pipe involS ; jf it is more, it is probable that there are an unusual number of fittings j lved> either the lines must be straightened or the column for the next lower p must be used, and the lines resized. Ordinarily, resizing will be unnecessary. TABLES FOR PIPE SIZING FOR HIGH PRESSURE SYSTEMS ^ Many of the recent installations of heating systems for large industrial ype buildings have been designed for the use of high pressure steam, Vs' tyRhout the use of pressure reducing valves. Such systems usually coilv Vp TMe Use urL*t heaters or large built-up fan units with blast heating are e ;es?lres 011 these systems vary from 30 to 150 psi. Temperatures tmllu L ky a modulating or throttling type thermostatic valve con- T hia'r temperature in the room, fan inlet or outlet, system ^ f o ^ may he used for the sizing of steam and return piping for "fs of 30 and 150 psi pressure at various pressure drops. These tables