Interpretation #6717

Published April 25, 2011

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Original Request

Code Version
2007
Code
PLUMBING
Code Description
Plumbing
Chapter
5
Section
308.7.1
Topic
Waste Stack Support

Question

Is it the intent of 308.7.1 to replace in a more general requirement section 308.9 of the 2001 FBC Plumbing in regard to support at the base of a waste stack.

Answer Published 04/25/2011 at 11:07 AM

The 2006 IPC commentary states "In drain pipes that are
large diameter, particularly 4 inches and larger, the flow
of drainage can create sizable forces in the system
resulting from the mass and velocity of the waste. To resist
such forces additional anchorage and supports would be
necessary.."

Commentary

It appears that this would require the same support at the base of a stack as was previously required in the Plumbing code.