Geometry & drainage
Round pipe water content
- where
- water content (m³; the calculator shows L)
- internal pipe diameter (m; any unit you pick is converted)
- developed pipe length (m)
Explain this equation
Works out the volume of water in a length of round pipe. Use it for system volume, inhibitor dosing, flushing or draining.
d is the internal bore. π × d² / 4 is the cross-sectional area. L is the length of pipe.
A pipe is a cylinder: volume is cross-sectional area times length. The calculator works in m³ and shows litres.
Sense check: 10 m of 20 mm bore holds about 3.1 L. Rough figures for copper: 15 mm about 0.15 L/m, 22 mm about 0.32 L/m, 28 mm about 0.54 L/m. Double the bore and the volume quadruples.
Watch out: use the internal bore, not the nominal or outside diameter.
Enter your values to see the result.
Good to know
Use internal diameter, not nominal or outside size.
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.