Pipe Velocity and Erosion Check
Flow velocity (v = 0.4085*gpm/d^2) and the copper erosion-corrosion verdict, or the max flow for a velocity ceiling.
Example
You enter
- Mode velocity-from-flow
- Flow (gpm) 10
- Inside diameter (in, actual bore) 0.785
- Material copper
- Water service hot
You get
- Velocity (fps) 6.629
- Ceiling (fps) 5
Details, formula, and sources
Continuity: v (ft/s) = 0.4085 * gpm / d^2 (d = actual inside diameter, in); inverse gpm = v * d^2 / 0.4085.
Pipe-flow velocity from continuity (v = 0.4085*gpm/d^2) and the copper erosion-corrosion velocity limits (about 5 ft/s hot, 8 ft/s cold) per the Copper Development Association / ASTM and ASPE plumbing-design guidance, by name; first-principles.
Public first-principles continuity. Actual inside diameter (not nominal) governs; the material erosion-corrosion ceiling is the design limit.
Estimate. AHJ and licensed plumber / gas fitter govern. Verify against the IPC / IFGC edition adopted in your jurisdiction.
Field names used by the API: mode, flow_gpm, diameter_in, material, service, velocity_fps, ceiling_fps
- Inside diameter the actual bore for the material/size, not the nominal sizeASTM pipe dimension tables