Re: Question for Sylvan, what size pipe for toilet waste line?
Posted by Sylvan Tieger on April 19, 2004 at 15:48:28:
In response to Re: Question for Sylvan, what size pipe for toilet waste line?

Hi Jim I am so sorry I just got back (I was an expert witness)

Personally I think the 3" piping should be used in lieu of 2 1/2 reasoning is Cast Iron comes in 2 or 3 or 4 Inch diameter

Also why figure exact FU's and not consider the very real posibility of someone adding more fixtures are a later date?

The scouring action of the 3 would be acceptable with 1.6 GPF plus and if someone had a set up with a back to back bathroom and kitchen I would much rather opt for the 3" piping under ground as the radius would be easier to rod or water jet.

2 1/2 I encountered ONCE in an older building for drainage rather then heating applications.

If a sewerage ejector is used the volume being pumped may over load 21/2 design down stream where more fixtures maybe added on.

In reality may folks have to flush twice to remove heavy matter thus the 1.6 GPF is mute.

The cost savings would take years to recoup if manufactures had to start making 2 1/2" CI or plastic.

Everyone preached gloom and doom with the 1.6 GPF flowing through a 5 or 6" waste line ALL the stoppages I read about just did not happen WHEN the origional piping was properly sized and installed.

Also if you are talking main sewers also 2 1/2" I would be very hard pressed to run a 3/4" wire (snake) if roots were in this line AS it is a 3/4 wire is not suggested even for 3" lines where your going through a trap.

People add on to buildings very seldom remove fixtures


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