Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Natural Gas - Pipe Sizing Calculator

Calculate capacities and dimensions of natural gas pipe lines.

Sponsored Links

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)


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

pipe inside diameter - d (in)

pressure drop - h (in WC)

pipe length - l (ft)

specific gravity of natural gas - SG

Natural Gas Pipe Calculator - Metric Units

pipe inside diameter - d (mm)

pressure drop - h (mm WC)

pipe length - l (m)

specific gravity - SG

Related Mobile Apps from The Engineering ToolBox Engineering Toolbox Apps

- free apps for offline use on mobile devices.

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse!

About the Engineering ToolBox!


We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.


This page can be cited as

  • Engineering ToolBox, (2008). Natural Gas - Pipe Sizing Calculator. [online] Available at: [Accessed Day Mo. Year].

Modify access date.

. .


3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Scientific Online Calculator

Scientific Calculator

3 10

Sponsored Links