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### Appliance Gas Pipe Flow Rate Capacities

Appliance Natural Gas Pipe Flow Rate Capacities

Also see: Natural Gas Pipe Flow Rate Requirement Formulas and Calculator for pressure less than 1.5 psig

Piping for natural gas appliances should be of adequate size and installed so that it provides a supply of gas sufficient to meet the maximum demand without undue loss of pressure between the point of supply (the meter) and the appliance. The size of gas pipe required depends on:

(1) maximum gas consumption to be provided,
(2) length of pipe and number of fittings,
(3) allowable pressure loss from the outlet of the meter to the appliance,
(4) specific gravity of the gas.

Gas consumption in ft3/h is obtained by dividing the Btu input rate at which the appliance is operated by the average heating value of the gas in Btu/ft3. Insufficient gas flow in gas supply lines can cause inefficient operation of gas-fired appliances and sometimes create hazardous operations. Gas-fired appliances are normally equipped with a data plate giving information on maximum and/or minimum gas flow requirements or Btu input as well as inlet gas pressure requirements. The local gas utility can give the gas pressure available at the utility’s gas meter. Using this information, the required size of gas piping can be calculated for satisfactory operation of the appliance(s).

The data table given below provides recommended pipe capacities for gas flow for up to 200 ft of pipe based on a specific gravity of 0.60.

Maximum Capacity of Gas Pipe in Cubic Feet per Hour for pipe lengths 10 to 80 ft.

 Nominal Iron Pipe Size, in. Internal Diameter, in. Length of Pipe, ft 10 20 30 40 50 60 70 80 1/4 0.364 32 22 18 15 14 12 11 11 3/8 0.493 72 49 40 34 30 27 25 23 1/2 0.622 132 92 73 63 56 50 46 43 3/4 0.824 278 190 152 130 115 105 96 90 1 1.049 520 350 285 245 215 195 180 170 1-1/4 1.380 1,050 730 590 500 440 400 370 350 1-1/2 1.610 1,600 1,100 890 760 670 610 560 530 2 2.067 3,050 2,100 1,650 1,450 1,270 1,150 1,050 990 2-1/2 2.469 4,800 3,300 2,700 2,300 2,000 1,850 1,700 1,600 3 3.068 8,500 5,900 4,700 4,100 3,600 3,250 3,000 2,800 4 4.026 17,500 12,000 9,700 8,300 7,400 6,800 6,200 5,800

Maximum Capacity of Gas Pipe in Cubic Feet per Hour for pipe lengths 90 to 200 ft.

 Nominal Iron Pipe Size, in. Internal Diameter, in. Length of Pipe, ft 90 100 125 150 175 200 1/4 0.364 10 9 8 8 7 6 3/8 0.493 22 21 18 17 15 14 1/2 0.622 40 38 34 31 28 26 3/4 0.824 84 79 72 64 59 55 1 1.049 160 150 130 120 110 100 1-1/4 1.380 320 305 275 250 225 210 1-1/2 1.610 490 460 410 380 350 320 2 2.067 930 870 780 710 650 610 2-1/2 2.469 1,500 1,400 1,250 1,130 1,050 980 3 3.068 2,600 2,500 2,200 2,000 1,850 1,700 4 4.026 5,400 5,100 4,500 4,100 3,800 3,500

Note: Capacity is in cubic feet per hour at gas pressures of 0.5 psig or less and pressure drop of 0.3 in. of water; specific gravity = 0.60.

Related:

References:

American Gas Association and National Fire Protection Association.