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534 CHAPTER 20 1958 Guide Table.8. .' Steam Pipe Capacities fob 30 Psig Steam Systems* Capacity Expressed in Pounds per. Hour (Steam and Condensate Flowing in Same Direction) Pipe Size Inches Drop in Pressure--Pounds per 100 Ft in Length HH M * 1 2 94 15 22 31 38 45 63 1 31 46 63 .77 89 125 m lU 69 100 141 172 199 ' 281 107 154 219 267 309 437 2 217 313 444 543 627 . 886 2*4 358 516 730 924 1,030 1,460 3 651 940 1,330 1,630 1,880 2,660 3*4 979 1,410 2,000 2,450 2,830 4,000 4 1,390 2,000 2,830 3,460 4,000 5,660 5 2,560 3,640 5,230 6,400 7,390 10,500 6 4,210 6,030 8,590 10,400 12,100 17.200 8 8,750 12,600 17,900 21,900 25,300 35,100 10 16,300 23,500 33,200 40,600 46,900 66,400 12 25,600 36,900 52.300 64,000 74,000 104,500 * Note: Steam at an average pressure of 30 psig is used as the basis for calculating the above table. are based on Babcock's formula, and have been used as the basis of design for a number of years. Return pipe capacities given in Tables 10 and 11 are based on the follow ing assumed pressures in the return piping: Pressure Drop Lb/100 Ft Pressure in Return Line (Psig) 30 psi System 150 psi System Pressure Drop Lb/100 Ft Pressure in Return Line (Paig) 30 psi System 150 psi System a am % 3 m A i 2A i 4 10 A 25 2 20 The pressure loss and line loss as given were substituted in the Babcock steam flow formula (see Table 2 of this chapter), and the resulting capacity was multiplied by 12 for 30-pound systems and by 16 for 150-pound sys tems to obtain the values given in Tables 10 and 11. The return line pressures used were found by observation of operating systems. Table 9. Steam Pipe Capacities for 150 Psig Steam Systems* Capacity Expressed in Pounds per Hour (Steam and Condensate Flowing in Same Direction) Drop in Press'dhe--Pbi per 100 Ft in Length Pips Sub Inches >4 K *4 X 1 2 5 H 1 1M 29 41 58 71 82 116 184 58 130 82 185 117 262 143 320 165 370 233 523 827 1*4 2 203 412 287 583 407 825 497 1,010 575 1,170 813 1,650 2,600 2*4 683 959 1,360 1,650 1,920 2,710 3 3*4 4 1,240 1,860 2,630 1,750 2,630 3,720 2,480 3,720 5,260 3,020 4,550 6,430 3,500 5,250 7,430 4,940 7,420 10,500 11,700 16,600 5 6 8 10 12 4,860 7,960 16,600 30,800 48,600 6,880 11,300 23,500 43,400 68,800 9,730 16,000 33,200 61,700 97,300 11,900 .19,500 40,600 75.600 119,000 13,800 22,600 47,000 87,300 138,000 19,500 31,900 66,400 123,000 194,000 50,400 105,000 195,000 307,500 * Note: Steam at an average pressure of 150 psig is used as the basis for calculating the above table. Steam Heating Systems 535 Table 10. Return Pipe Capacities fob 30 psig Steam Systems* ' Capacity Expressed in Pounds per Hour Pipe Size Inches K 1 iA 1A 2 2A 3 3A 4 5 6 X 115 230 485 790 1,580 2,650 4,850 7,200 10,200 19,000 31,000 Drop in Pressure--Pounds per 100 Ft in Length ... X .... . X 170 340 710 1,160 2,360 3,900 7,100 10,600 15,000 27.8QP 45,500 245 490 1,025 1,670 3,400 , 5,600 10,300 15,300 21,600 40,300 : 65,500 .X 303 615 1,290 2,100 4,300 7,100 12,900 19,200 27,000 55,500 83,000 . * Note: The above table is based on steam at pressures of 0 to 4 psig. 1 365 730 1,530 2,500 5,050 8,400 15,300 22,800 32,300 60,000 98,000 SIZING PIPING FOR ONE-PIPE GRAVITY SYSTEMS Gravity one-pipe air-vent systems, in which the equivalent length of run does not exceed 200 ft, should be sized by means of Tables 5, 6 and 7 as follows: _ 1- .For the steam main and dripped runouts to risers where the steam and condensate now m the same direction, use J<i6"psi drop (Column D). 2. Where the( riser runouts are not dripped and. the steam and condensate flow in opposite directions, and also in the radiator runouts where the same condition occurs, use Column L. Cohimn ee^ steam r^sers carrying condensate back from the radiators, use 4. For down-feed systems, the main risers of which do not carry any radiator con densate, use Column H. 5. For the radiator valve size and the stub connection, use Column K. 7 c dry-return main, .use Column U. 7. For the wet-return main, use Column T. ^ systems exceeding an equivalent length of 200 ft, it is suggested that e total drop be not over A psi. The return piping sizes should corre spond with the drop used on the steam side of the system. Thus, where %4-psi drop is being used, the steam main and dripped runouts would be Table 11. Retubn Pipe Capacities fob 150 psig Steam Systems* ______ Capacity Expressed in Pounds per Hour Pipe Size Drop in Pressure--Psi per 100 Ft in Length i* P 2A 3 3A 4 5 6 X 156 313 650 1,070 2,160 3.600 6,500 9.600 13,700 25,600 42,000 X 232 462 960 1,580 3,800 5,350 9,600 14,400 20.500 38,100 62.500 X 360 690 1,500 2,460 4,950 8,200 15.000 22,300 31,600 58,500 96.000 X 465 910 1,950 3,160 6,400 10.700 19.500 28.700 40.500 76,000 125,000 * Vr,*.. e... . The above table is based on steam at pressures of 1 to 20 psig. 1 560 1,120 2,330 3,800 7,700 12,800 23,300 34.500 49,200 91.500 150,000 2 890 1,780 3,700 6,100 12,300 20,400 37,200 55,000 78,500 146.000 238.000