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Low Pressure Gas Piping

Reference data and engineering information about low pressure gas piping for piping systems applications.

lowpressuregaspiping

Overview

Engineering reference data for Low Pressure Gas Piping in piping systems.

Key Formulas

Continuity

A1v1=A2v2A_1 v_1 = A_2 v_2

Mass conservation in pipe flow.

Pressure Drop

ΔP=fLDρv22\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}

Darcy-Weisbach equation.

Pipe Area

A=πD24A = \frac{\pi D^2}{4}

Cross-sectional area of a pipe.

Variables

SymbolDescriptionUnit
DDPipe diameterm
vvFlow velocitym/s
ΔP\Delta PPressure dropPa
ffFriction factor—

Low Pressure Gas Pipe Sizing Tables

The following tables provide recommended nominal pipe sizes for low-pressure gas service lines serving multiple apartments. These tables account for diversity in consumption across multiple consumers.

Pipe Sizing: 20–110 ft Service Lengths

11 rows
Nominal pipe size (inches) for low pressure gas service — Service lengths 20 to 110 ft
No. of Apartments
20(ft)
40(ft)
50(ft)
60(ft)
70(ft)
80(ft)
90(ft)
100(ft)
110(ft)
4222222222
8222222222
10222222222
12222222222.5
14222222.52.52.52.5
162222.52.52.52.52.52.5
202.52.52.52.52.52.52.52.52.5
242.52.52.52.52.52.52.52.53
302.52.52.52.533333
402.52.53333334
48333334444

Source: engineeringtoolbox.com

Pipe Sizing: 120–200 ft Service Lengths

11 rows
Nominal pipe size (inches) for low pressure gas service — Service lengths 120 to 200 ft
No. of Apartments
120(ft)
130(ft)
140(ft)
150(ft)
160(ft)
170(ft)
180(ft)
190(ft)
200(ft)
4222222222
8222222222
10222.52.52.52.52.52.52.5
122.52.52.52.52.52.52.52.52.5
142.52.52.52.52.52.52.52.52.5
162.52.52.52.52.52.52.52.52.5
202.52.52.5333333
24333333333
30333333333
40444444444
48444444444

Source: engineeringtoolbox.com

Design Conditions

These sizing tables are based on the following assumptions:

ParameterValue
Pipe typeSchedule 40 steel pipe
System pressureLow pressure service line
Pressure head6 inH₂O
Gas specific gravity0.6
Allowable pressure drop0.3 inH₂O

Note: The pipe sizes account for diversity in consumption when multiple consumers are supplied from a single service pipe. As the number of apartments increases, the probability that all consumers use gas simultaneously decreases, allowing for smaller pipe sizes relative to the total theoretical demand.

Interactive Charts

Gas pipes - capacity and number of apartments - diagram

Natural Gas Pipes - Low Pressure Capacities vs. Size

References

Source: engineeringtoolbox.com