Drainage, Waste & VentQuestion 31 of 120
An 8 in building drain is proposed at 1/16 in per ft over a 200 ft run. What is the fall, and is that slope permitted?
a.6-1/4 in, and the slope is never permitted
b.12-1/2 in, and the slope may be permitted for 8 in and larger pipe where approved
c.25 in, and the slope may be permitted for 8 in and larger pipe where approved
d.50 in, and the slope is never permitted
Explanation
At 1/16 in per ft, 200 ft x 1/16 in = 12-1/2 in of fall, and slopes as flat as 1/16 in per ft may be approved for pipe 8 in and larger where the resulting velocity is adequate. The 25 in and 50 in figures come from applying the 1/8 in and 1/4 in rates, and 6-1/4 in halves the correct fall.
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