Sorry - I can't find it (even though I found it before).
Anyone remember the figures for minimum gradient in 40mm and 50mm pipe for both baths and kitchen sinks? (3-5m lengths)
I thought it was in the Drainage Approved Doc, but I've been through that twice. Must be going blind...
Ta
Tim
There is a design curve for 32mm pipes tacked on the bottom of Diagram
3... The top of the digram shows the slope for 40mm and 50mm into a soil stack (18 to 90 mm/m)
I always use the addage 1" in every metre length, it's always worked for me.
Indeed - anything from 1 to 4" per meter is usually fine (and just about fits in with the approved doc anyway!)
Wouldn't 1" per yard be more sensible? ;-)
John Rumm coughed up some electrons that declared:
Ah got it.
Thanks John.
I've got a 5m run[1], so looks like I might have to upgrade that to 50mm pipe for better effect. Doesn't meet regs, but I'm not bothered for this - just means the bath won't drain so fast.
This takes it to a remote stack branch that's grey water only. I could dump it in with the local loo stack, but I don't think I can get the boss low enough for a bath drain - and it makes me a bit suspicious as any problems on that pipe and the bog might back up the bath (yuk). Rather a slow bath than a brown one!
Anyway - might just manage a 1:60 fall which is close enough to the 1:55 quoted. The kitchen is much easier - I've got quite a choice of gradients as sink drains are higher - so I was mostly looking for design figures on that.
Cheers
Tim
Ray coughed up some electrons that declared:
That's a good reckoner - I'll think I'll work to that for the kitchen.
Ta
Tim
I haven't read the approved Doc so apologies for ignorance. As a newly married DIY sprog back in the late 1960's ISTR some regulation regarding the length of waste run allowed before some means of air admittance was required. U bends were common then so this may not be relevant to P traps.
regards
>
On soil connections, the current rule is something like the new connection should be no more than 6m from a ventilation point. Otherwise you need to add a vent stack or a AAV.
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