Eclipse Engineering Guide

SIZING STEAM PIPING
Pipe Size, Lb/hr steam for piping pressure drop of 1 psi/100ft Lb/hr steam for piping drop of 5 psi/100 ft
Inches Steam Pressure, psig Steam Pressure, psig
(Schedule 40) 5 10 25 50 100 150 10 25 50 100 150
3/4 31 34 43 53 70 84 73 93 120 155 185
1 61 68 86 110 140 170 145 185 235 315 375
1-1/4 135 150 190 235 310 370 320 410 520 690 820
1-1/2 210 230 290 370 485 570 500 640 810 1,050 1,300
2 425 470 590 750 980 1,150 1,000 1,300 1,650 2,150 2,600
2-1/2 700 780 980 1,250 1,600 1,900 1,650 2,150 2,700 3,600 4,250
3 1,280 1,450 1,800 2,250 2,950 3,500 3,050 3,900 4,300 6,600 7,800
4 2,700 3,000 3,800 4,750 6,200 7,400 6,500 8,200 10,500 14,000 16,500
6 8,200 9,200 11,500 14,500 19,000 22,500 19,500 25,000 31,500 42,000 50,000
8 17,000 19,000 24,000 30,000 39,500 47,000 41,000 52,000 66,000 88,000 105,000
These flows were calculated from Babcock’s Equation,
Pd D5 where W = steam flow, lb/minute
P = pressure drop, psi
W = 87 (1 + 3.6 ) L D = inside diameter of pipe, inches
D d = density of steam, lb/cu ft
L = length of pipe run, feet
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