volume discharge

What Is Volume Discharge in Pumping?

Volume discharge refers to the amount of fluid a pump moves over time, commonly measured in litres per second (L/s), gallons per minute (GPM), or cubic metres per hour (m³/h). It’s a key factor in ensuring the right pump is selected and your system performs efficiently.

At National Pump & Energy, we provide practical tools and charts to help you calculate flow rates and understand fluid movement in dewatering and transfer systems. Visit our Pump Hire page to explore equipment suited to your site’s needs.

For global equipment standards, see our parent company, the Atlas Copco Group—a leader in sustainable industrial solutions.

Flow Estimation Calculators

Estimate flow rates based on discharge measurements.

Full Pipe Flow Calculator

Discharge Distance (mm)

Pipe Inside Diameter (mm)

Estimated Flow

0.00 L/s

Partial Pipe Flow Calculator

Discharge Distance (mm)

Pipe Inside Diameter (mm)

Empty Height Above Flow (mm)

Estimated Flow

0.00 L/s

Disclaimer: Results are estimates only and should not be relied upon as engineering design data. Actual flow rates may vary depending on installation conditions, pipe condition, turbulence, and measurement accuracy.

The following table may be used to estimate the volume discharge from a level pipe.

Full Pipe – Measure horizontal distance ‘X’ for water to fall 305mm. Consult table for approximate flow.

Partial Flow – Proceed as above to get approximate flow. Measure height ‘Y’ of water in pipe. Calculate 300 ‘Y/D’ to get percentage of full pipe flow.