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.

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Formula and source

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.

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