Hydrant Flow

GPM from Pitot pressure and outlet diameter.

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Formula and source

Flow GPM = 29.83 × c × d² × sqrt(P_pitot). c = coefficient of discharge (0.90 typical for rounded outlets, 0.80 for square outlets, 0.70 for cocked-back outlets).

AWWA M17 (Installation, Field Testing, and Maintenance of Fire Hydrants) by name; ISO Public Protection Classification fire-flow methodology.

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