Hot Water Piping Sizing Calculator

Size hot water piping based on flow rate and velocity limits per ASHRAE standards.

Hot water flow rate through the pipe.
GPM
Maximum allowable water velocity (typical 4-8 ft/s).
ft/s
Enter 1 for copper, 2 for steel, 3 for PEX.
type

Results

Minimum Pipe Diameter-inches
Recommended Nominal Size-inches
Actual Velocity-ft/s
References: ASHRAE Handbook - HVAC Systems and Equipment, Chapter 22 (Pipes, Tubes, and Fittings)