# Natural Gas - Pipe Sizing

## Sizing pipes for natural gas - pressures above 5 psi (35 kPa)

The tables and diagrams below can be used to size natural gas pipes with pressures above 5 psi (35 kPa).

Capacity of 100 ft Steel Pipe Schedule 40 (MBH ≈ CFH)
Pressure
(psig)
Pipe Dimension (in)
UpstreamDownstream1/23/411 1/41 1/222 1/2345
10 9.5 355 745 1400 2880 4310 8305 13240 23400 47730 86350
9.0 515 1080 2030 4160 6240 12020 19150 33860 69060 124940
9 8.5 350 730 1370 2815 4210 8120 12940 22880 46600 84420
8.1 475 995 1875 3850 5770 11100 17700 31300 63840 115500
8 7.6 300 630 1190 2440 3650 7040 11215 19830 40440 76170
7.2 440 910 1720 3530 5290 10190 16240 28710 58560 105940
7 6.6 290 615 1160 2380 3565 6865 10940 19345 39460 71390
6.3 395 830 1560 3210 4810 9260 14760 26090 53210 96260
6 5.7 245 515 970 1990 2990 5730 9140 16160 32950 59620
5.4 355 745 1400 2880 4310 8310 13245 23415 47760 86400
5 4.7 240 500 940 1935 2900 5580 8895 15730 32080 58030
4.5 315 660 1240 2540 3810 7340 11695 20680 42170 76300
• inlet upstream pressure is more than 5 psig (35 kPa)
• fittings factor 1.2 - equivalent pipe length = pipe length + 20%
• steel pipes schedule 40

For natural gas the nominal BTU/cf varies from about 900 to 1100 BTU/cf. In general it is common to set

• 1 Cubic Foot (CF) = Approx 1,000 BTUs
• 1 CFH ≈ 1 MBH (MBH is thousands of BTUs per hour)
• 1 Btu/h = 0.293 W
• 1 lb = 0.4536 kg
• 1 ft (foot) = 0.3048 m
• 1 in water = 248.8 N/m2 (Pa) = 0.0361 lb/in2 (psi) = 25.4 kg/m2 = 0.0739 in mercury
• 1 psi (lb/in2) = 6,894.8 Pa (N/m2)

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