Smooth-Bore Tip Diameter for a Target Flow
The inverse of the smooth-bore-flow tile: the tip (bore) diameter a target flow needs at a nozzle pressure, d = sqrt( gpm / (29.7 x sqrt(NP)) ). 250 gpm at 50 psi wants a 1.09 in tip (round up to a stocked 1-1/8 in), which handles about 93 lb of reaction. Answers 'what tip for this flow' instead of the flow from a set tip. Round to a stocked size; incident command and the pump operator govern.
Formula and source
bore_in = sqrt( target_gpm / (29.7 x sqrt(nozzle_pressure_psi)) ), the inverse of gpm = 29.7 x bore_in^2 x sqrt(NP); companion nozzle reaction = 1.57 x bore_in^2 x NP.
IFSTA Pumping Apparatus Driver/Operator Handbook smooth-bore discharge form (by name), solved for the diameter; classical orifice discharge, no edition cycle.
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