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432 CHAPTER 23 : --ir : ,1948 Guide Equivalent Length of Run . All tables for. the flow of steam in pipes, based, on-pressure drop; must allow for the friction'offered- by the pipe as well as for the additional resistance of . :the fittings and valves. These: resistances generally are stated in-terms of straight pipe; in other words, a certain fitting will produce a drop in pressure equivalent to so many feet of straight run of the same size of pipe. : Table 4 gives the number of feet of straight pipe usually alI6iyd for the more common types of fittings and valves. In all pipe sizing; tables-in this chapter the length of run refers to the equivalent length of run.as distinguished from the actual length of pipe in feet. The Table 4. Length in Feet of Pipe to. be Added to ActUal' Length-of Run-- -Owing to Fittings--to Obtain Equivalent Length : Size op Pipe Inches ' Length in .Feet to be Added to Run Standard Elbow Side Outlet Tee Gate Valve* Globe Valve* Angle Valve M i m 2 m 3 3M 4 5 6 ... -8 10 12 14 1.3 1.8 2.2. 3.0 3.5 ; .4.3 5.0 6.5 8 9 11 13 17 21 27 30 3 4 5 -6 7 . ' -8 11 13 15 18 22 27 35 45 53 63 Valve in full open position. ; Example of length in feet of pipe to be added to actual length of,run. 0.3 14 7 0.4 18 10 0.5 23 . 12 0.6; 29 15 ; 0.8 34 18 : ' 1.0 7 46 22 1.1 54 27 1.4 66 34 1.6 80 40 1.9 ; 92 - 45 2.2 112 56 2.8 ' ' 136 . 67 3.7 180 , 92 4.6 230 112 - 5.5 270 132 6.4 310 152 'Measured Length " 132.0 ft. '4-in. Gate Valve- -- 1:9.ft ~ 0---4- --4 in-. Elbows . --__3_6_.0_ft ----v iEquivalent Length = 169.9'ft length ofriin 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 34 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. Steam Heating Systems and Piping 433, Table 5. Steam Pipe Capacities for Low Pressure Systems (Reference to this 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 op Heating and Ventilating Engineers. CAPACITIES OF STEAM MAINS AND RISERS FDirection or Condensate low in Pipe Line Special Capacity tor One-Pips Stbtkmb Onlt Pm Sro In. A With the Steam in One-Pipe and Two-Pipe Systems . or . MO. Drop' B /* psi or H Drop C !4mi . or 1 Os Drop D Mopr" 2 Os Drop B H psi or 4 Os . Drop - F Mpb or . SO* Drop . G Against the Steam Vertical Hori zontal H* / Radiator Supply Valves Radiator Risers and and. Up- Vertical Riser Feed Cbn- Run- nections outs' J* K Capacity Expressed in Square Feet E D R % 30 ' 30 25 1 39 46 56 79 in 157 56 '34 45 1M. . 87 100 122 173 . 245 346 122 75 98 m - ' 134 155 190 269 380 = 538 190 108 152 2 273 315 386 546 771 1,091 386 195 288 2J4 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 3J4 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 5,280 6,100 7.460 10,550 14,900 21,100 8 11,000 12.700 15.500 21,970 31,070 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 61.000 69.700 84,800 121,000 170.000 242.000 28 - 28 : 62 61 93 93 169 169 260 475 ^745 1,110 2,180 Capacity Expressed in Pounds per Hour Vi 8 86 1 , 10 12 14 1Vi 22 25 31 20 43 28 40 14 9 11 61 - ; . 87 31 19 20 iM . 34 2 68 39 79 48 97 67 ' 95 . 135 137 V 193 273 48 97 27 49 38 72 m 112 130 159 225 318 - 449 159 99 116 3 206 237 291 411 581 822 282 175 200 m 307 355 434 614 . 869 1,230 387 288 286 4 435 503 614 869 1,230 1,740 511 425 380 5 806 928 1,140 1,610 2,270 3,210 788 6 1,320 1,520 1,870 2,640 3,730 5,280 8 2,750 3,170 3,880 5,490 7,770 11,000 10 5,010 5,790 7,090 10,000 14,200 20,000 12 8,040 9,290 11,400 16,100 22,700 32,200 16 - 15,100 17,400 21,200 30,300 42,400 60,500 7 77 16 -- 16 23. v 23 42 42 65 119 186 : 278 545 All Horizontal Mains and Down-Feed Ross UpFeed Kisers Mains and Updripped Rub- outs Up. Feed Risers Radiator Con nections Runouta Not Dripped Note.--Steam at an average pressure.of 1 psi is used.as a basis for calculating capacities. All drops shown are m psi per 100 ft of equivalent run--based on pipe properly reamed. Do not use Column H for drops of V* or V psi; substitute Column C or Column B as required. bDo not use Column J for drop of */ Psi except on sizes 3 in. and over; below 3 in. substitute Column B. On radiator runouts over 8 ft long increase one pipe size over that shown in Table 4.