Design & SizingQuestion 10 of 110
A 4 in building drain is run at the code minimum slope of 1/8 in per foot over a developed length of 96 ft. What is the total fall from the upstream end to the downstream end?
a.6 in
b.12 in
c.9 in
d.24 in
Explanation
Fall = slope x length = 1/8 in/ft x 96 ft = 12 in, or 1 ft. Pipe 3 in and larger uses 1/8 in per foot as the minimum. Using 1/4 in per ft (which applies only to pipe 2-1/2 in and smaller) would wrongly double the answer to 24 in.
Law Reference: IPC §704.1Practice all 110 questions free — no signup required.
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