Design & SizingQuestion 29 of 110
An individual vent serving a lavatory is 1-1/2 in. The vent sizing table limits a 1-1/2 in vent to a maximum developed length of 150 ft at the fixture-unit load carried. If the vent run is 90 ft, is the vent acceptable and why?
a.Yes, 90 ft is within the 150 ft limit
b.No, it exceeds the length limit
c.No, the vent must equal the drain size
d.Yes, vents have no length limit
Explanation
A 90 ft developed vent length is within the 150 ft maximum allowed for a 1-1/2 in vent at that load, so the vent is acceptable. Vent sizing depends on both the fixture-unit load and the total developed length; exceeding either forces a larger vent. Vents do have length limits, so the no-limit answer is wrong.
Law Reference: IPC §906.2Practice all 110 questions free — no signup required.
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