Natural Gas - Pipe Sizing Calculator
The capacity of a low pressure natural gas (less than 1 psi, 6.9 kPa) pipe line with a small pressure loss can be calculated with the Spitzglass formula
q = 3550 k ( h / (l SG))1/2 (1)
where
q = natural gas volume flow (cfh)
h = pressure drop (in Water Column)
l = length of pipe (ft)
k = [d5 / (1 + 3.6 / d + 0.03 d)]1/2
d = inside diameter pipe (in)
SG = specific gravity of natural gas
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 1000 BTUs
- 1 CFH = 1 MBH
The specific gravity of natural gas varies from 0.55 to 1.0. Typical values are in the range 0.6 - 0.7.
The downstream pressure in a houseline after the meter/regulator is in general in the range of 7 to 11 inches Water Column, or about 1/4 psi.
Example - Natural Gas Pipe Capacity
The capacity of a 100 ft natural gas pipe with a nominal diameter 0.5 inches (actual ID 0.622 in) and 0.5 inches WC pressure drop can be calculated as
k = [((0.622 in))5/(1 + 3.6 / (0.622 in) + 0.03 (0.622 in))]1/2
= 0.117
q = 3550 0.117 ((0.5 in) / ((100 ft) 0.60) )1/2
= 37.9 (cfh)
Specific gravity of natural gas is set to 0.60.
Natural Gas Pipe Calculator - Imperial Units
Natural Gas Pipe Calculator - Metric Units
Related Mobile Apps from The Engineering ToolBox
- free apps for offline use on mobile devices.
Related Topics
• Gases and Compressed Air
Air, LNG, LPG and other common gas properties, pipeline capacities, sizing of relief valves.
Related Documents
Density vs. Specific Weight and Specific Gravity
An introduction to density, specific weight and specific gravity.
Gas Pipes - Approved Materials
Materials approved for gas pipes.
Gas Pipes - Low Pressure Sizing
Sizing gas pipes for apartment service lines.
House Gas Pipes - Capacities vs. Dimensions
Carrying capacity of house gas pipes - in imperial and metric units.
Natural Gas - Meter Capacities
Types of natural gas meters and their capacities.
Natural Gas Apartment Consumption vs. no. of Apartments
Multiple apartments and natural gas demand.
Natural Gas Laboratory Consumption vs. no. of Outlets
Natural gas consumption in laboratory outlets.
Natural Gas Pipes - Low Pressure Capacities vs. Size
Sizing low pressure natural gas pipe lines - Imperial units.
Natural Gas Piping - Sizing of Low Pressure Pipes vs. Capacity
Sizing low pressure natural gas pipe lines - Metric units.
Orifices - Natural Gas Capacity
Capacity of natural gas orifices.
Pipes - Relative Capacity
Relative capacity between larger and smaller pipes.