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Question: 08-11 Code Section: 7 Date: 22 March 2008

OBC 2006 Reference: 7.2.1.5.

 

Question: Piping, fittings and joints used in pressure sewer, forcemain or sump pump discharge applications shall be capable of withstanding at least one and one-half times the maximum potential pressure. Well, it has been my common practice and I'm quite sure majority of others, to install ABS Drainage Pipe and Fittings for this application, but to my knowledge according to the manufacturer of ABS they have no pressure rating. Am I reading this wrong? If not, then there are a few of us not completing their work according to Codes.

Interpretation: There should be very little pressure in the piping because the discharge from the pump is free flowing unless there is a blockage. Head pressure would be the greatest amount of pressure exerted on the piping (.434 x height). Sump pumps or sewage pumps don't appear to be rated by pressure (psi) but rather by flow (gpm) so the "maximum potential pressure" is very hard to determine. ABS pipe manufacturers don't list a working pressure, again very hard to determine. It just has to be "capable of withstanding". Remembering that either a sanitary forcemain or sump pump (storm forcemain) discharge are all different. When in doubt ask for pressure pipe.

Interpretation: Approved at AMES 2008 

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