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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> WASTE PIPES https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1090910775 Message started by Dusty on Jul 27^th, 2004, 7:46am

Title: WASTE PIPES
Post by Dusty on Jul 27^th, 2004, 7:46am

I�m building a new kitchen and relocating the sink, washer & dish washer :o
Can anyone help with some guidance :-/
For the WM & DW what length of drop should each waste pipe have ::)
As the distance will be 3m, what angle should I have on the horizontal waste pipe going from the 2 machines to under the sink 8)
Do I need 2 U traps, one for the sink and one for the machines :)
Thanks
Dusty :D

Title: Re: WASTE PIPES
Post by billythekid on Jul 27^th, 2004, 1:23pm

i seem to remember for self-cleaning a drop of 1:20 is optimum(guys correct me if i'm wrong) this is quite steep for a waste. Any run is good in practice as long as it always drops, i.e no flat/level sections. You should have a seperate trap'U Bend' for each appliance.

Title: Re: WASTE PIPES
Post by PEDANTICVINDICTIVEMAN on Jul 27^th, 2004, 3:58pm

I know drains underground have to have whats called a self cleansing fall which I "think" is 1 in 40.

Title: Re: WASTE PIPES
Post by jasonB on Jul 27^th, 2004, 8:17pm

For soil pipes to domestic dwellings use Maguire's rule which is as follows:

Gradient = pipe diameter in mm divided by 2.5

Therefore 100mm pipe Div 2.5 = 1 in 40

for smaller waste pipes aime for 2.5 degrees thats why a waste elbow is actually 92.5 degrees and not 90 deg's. which using triganomitry gives approx 1 in 20.

Jason

Title: Re: WASTE PIPES
Post by thescruff on Jul 30^th, 2004, 8:36pm

For solids the recommended fall is 1-40, for liquids 1-20 is a minimum but no maximum.

scruff

Title: Re: WASTE PIPES
Post by scotspark on Aug 6^th, 2004, 9:18pm

thot the gradient would be steeper for solids

Title: Re: WASTE PIPES
Post by thescruff on Aug 7^th, 2004, 12:34am

No 1-40 is the ideal as any steeper and it leaves the solids behind.

scruff