Gas
Gas pressure loss from supplied table data
- where
- gas pressure loss (mbar)
- loss per metre from sizing table (mbar/m)
- developed pipe length (m)
- total fitting equivalent length (m)
Explain this equation
Works out the pressure drop along one section of gas pipe using a loss-per-metre figure from a sizing table. Use it to add up the drop from the meter to an appliance.
r is the pressure loss per metre read from the applicable table for that pipe size, gas and flow. L is the developed length of the run, measured along the pipe. L_eq is the extra length that the fittings in the section are worth, from the same method.
Friction loss builds up with length, so the drop is the rate per metre times the total effective length. Fittings are handled by converting their resistance into an equivalent length of straight pipe.
Sense check: 0.03 mbar/m over 10 m of pipe plus 5 m of fittings is 0.45 mbar. Double the run and the drop doubles.
Watch out: r changes with flow, so use the flow carried by that section. There is no built-in allowable drop. Add every section on the path to the appliance yourself.
Enter your values to see the result.
Good to know
Provide the correct rate for pipe, gas, size and downstream flow from the current approved method. No built-in allowable-drop limit or compliance verdict. Add all sections on the appliance path; this is not a complete gas-network sizing tool.
Sources
Results are arithmetic only. Worked examples are not recommended design settings. This library does not provide automatic gas pipe selection, live gas tightness tests, purging procedures, combustion acceptance limits, installation approval or commissioning certification. Manufacturer data and the applicable current method remain essential.