Related Resources: fluid flow

Flow Rate of Steam Schedule 40 Pipe

HVAC Systems and Components
Fluids Engineering and Design

Flow Rate of Steam in Schedule 40 Pipe Tables

Many heating systems for large industrial buildings use high pressure steam (15 to 150 psig). These systems usually have unit heaters or large built-up fan units with blast heating coils. Temperatures are controlled by a modulating or throttling thermostatic valve or by face or bypass dampers controlled by the room air temperature, fan inlet, or fan outlet.

Pressure Drop Steam per 100 ft of Length
Nominal
Pipe
Size, in.
1/16 psi
(1 oz/in2)
1/8 psi
(2 oz/in2)
1/4 psi
(4 oz/in2)
1/2 psi
(8 oz/in2)
Sat.
Press.
psig
Sat.
Press.
psig
Sat. Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
3.5
12
3.5
12
3.5
12
3.5
12
3/4
9
11
14
16
20
24
29
35
1
17
21
26
31
37
46
54
66
1-1/4
36
45
53
66
78
96
111
138
1-1/2
56
70
84
100
120
147
174
210
2
108
134
162
194
234
285
336
410
2-1/2
174
215
258
310
378
460
540
660
3
318
380
465
550
660
810
960
1,160
3-1/2
462
550
670
800
990
1,218
1,410
1,700
4
640
800
950
1,160
1,410
1,690
1,980
2,400
5
1,200
1,430
1,680
2,100
2,440
3,000
3,570
4,250
6
1,920
2,300
2,820
3,350
3,960
4,850
5,700
6,800
8
3,900
4,800
5,570
7,000
8,100
10,000
11,400
14,300
10
7,200
8,800
10,200
12,600
15,000
18,200
21,000
26,000
12
11,400
13,700
16,500
19,500
23,400
28,400
33,000
40,000

 

Pressure Drop Steam per 100 ft of Length
Nominal
Pipe
Size, in.
3/4 psi
(12 oz/in2)
1 psi
2 psi
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
Sat.
Press.
psig
3.5
12
3.5
12
3.5
12
3/4
36
43
42
50
60
73
1
68
82
81
95
114
137
1-1/4
140
170
162
200
232
280
1-1/2
218
260
246
304
360
430
2
420
510
480
590
710
850
2-1/2
680
820
780
950
1,150
1,370
3
1,190
1,430
1,380
1,670
1,950
2,400
3-1/2
1,740
2,100
2,000
2,420
2,950
3,450
4
2,450
3,000
2,880
3,460
4,200
4,900
5
4,380
5,250
5,100
6,100
7,500
8,600
6
7,000
8,600
8,400
10,000
11,900
14,200
8
14,500
17,700
16,500
20,500
24,000
29,500
10
26,200
32,000
30,000
37,000
42,700
52,000
12
41,000
49,500
48,000
57,500
67,800
81,000

Notes:
1. Flow rate is in lb/h at initial saturation pressures of 3.5 and 12 psig. Flow is based on Moody friction factor, where the flow of condensate does not inhibit the flow of steam.
2. The flow rates at 3.5 psig cover saturated pressure from 1 to 6 psig, and the rates at 12 psig cover saturated pressure from 8 to 16 psig with an error not exceeding 8%.

Related:

References

  • ASHRAE Handbook of Fundamentals, 2021 Inch-Pound Edition