Div. B › Part 7 › 7.5 › 7.5.7 — Minimum Size of Vent Pipes

7.5.7.2 — Size Restriction

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(1) The size of a branch vent, stack vent, vent stack or header shall be not less than the size of the vent pipe to which it is connected.
(2) Every sanitary building drain shall terminate at its upstream end in a stack of at least 3 in. size.
(3) A stack referred to in Sentence (2) shall be a soil stack if one is available and may be a vent stack or waste stack that provides at least 3 in. stack vent and that goes to open air above the roof, either directly or through a header.
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