Design & SizingQuestion 108 of 110
A demand of 62 gpm must be delivered with an available friction pressure of 24 psi over a 200 ft developed length. What is the allowable friction loss per 100 ft used to size the pipe?
a.4 psi/100 ft
b.8 psi/100 ft
c.24 psi/100 ft
d.12 psi/100 ft
Explanation
Allowable loss per 100 ft = (available pressure / developed length) x 100 = (24 / 200) x 100 = 12 psi per 100 ft. This uniform rate is read against the 62 gpm demand on the friction chart to choose the smallest adequate pipe. Spreading the full 24 psi over the whole run gives the per-100-ft design value.
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