Gas Pipe Sizing Calculator

Gas Pipe Sizing Calculator

1,000 - 5,000 downloads

Add this app to your lists
A study carried out by Worcester Bosch Group's technical support team found that the most common cause of a boiler installation problem was from incorrectly sized gas pipes. When fitting a new boiler, often the existing pipes should be replace for larger ones due to the increased output. Smaller pipes will mean the boiler is running at a lower power and can cause an increase in carbon monoxide levels.

The Gas Pipe Sizing Calculator is an extremely easy to use app that will help you to select the right size pipe for a domestic installation using copper (BS EN 1057) and steel (BS 7838) pipes of 8, 10, 12, 15, 22, 28 and 35mm. It will calculate the right pipe diameter for sections up to 30m (98ft) in length.

To carry out a calculation simply enter the appliance heat input, enter the pipe length, the number of elbows, tees and bends and then press the 'Calculate' button. The results will show the total equivalent length, the minimum pipe diameter that should be used and the pressure drop for that section of pipe.

For multiple appliances each section should be calculated in turn and the kW inputs for the appliances in each section added together for each calculation.

The maximum pressure drop from each appliance to the meter should be no more than 1 mbar. Adding all drops together using the minimum pipe diameters may cause this to be exceeded. Where possible, the results will also calculate the drop if the next larger size pipe diameter is selected on a section, this should help to ensure the right sizes are used throughout the whole circuit.

The calorific value of natural gas in your area can be saved in the Settings page to improve the accuracy of the results.

***Mr Combi Training would love your feedback on this app and suggestions for other apps that Heating Engineers would find useful. Please contact us at

Tags: gas piping sizing in mbar, commercial gas ventilation calculator, gas pipe sizing calculator, commercial gas pipe sizing, gas pipe sizing, gas pipe size calculator, free gas piping calculation book s, sizing calculator medical gas pipe, pipe diameter, pipe tools.

Recently changed in this version

v1.1 - Heat input can now be entered in MJ/h and BTU/h

v1.2 - Gas rate added to result screen

Comments and ratings for Gas Pipe Sizing Calculator
  • (66 stars)

    by Craig Dabbs on 03/10/2013

    Will be handy to have Lpg options.

  • (66 stars)

    by Ian Briggs on 31/05/2013

    It is a good app to help you make decisions about the gas pipe size you need. It works best in domestic properties as it has a maximum length of 30m. So if you use your knowledge and this app together you will be happy. Also, i contacted mr combi training