Re: proper slope for dwv in new construction
Posted by hj on June 05, 2003 at 17:08:35:
In response to Re: proper slope for dwv in new construction
University data has been reported in trade journals for years that this "old wives" tale is false. If it were true then vertical drains would have continual stoppages. I have been installing sewer lines using whatever grade is necessary for a lot of years and have never had the problem you refer to.

: : It is an "old wive's" tale. Research has found that it does not happen.

: : : : Minimum 1/4" per foot for 3" and smaller.

: : :
: : : May I add that one does not want to exceed a slope of 1/2" per foot on these same size pipes.
: : : Otherwise, a situation could develop where the liquid waste flows past or first down the drain, potentially allowing the solid waste to get stuck and accumulate, eventually causing a blockage.

: : : If you slope at 1/4" per foot the wastes will travel together and help to prevent drain blockages.

: : : : : what is the recommended slope for drain line, main & branches

: A fast waste will allow the water to outrun and leave the solids. This testing is performed by organizations like IAPMO and ANSI in addition to the toilet manufacturers. hj's calling this code standard a old wives tale is wrong. What is the research you refer to hj? LonnythePlumber

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