please help-bathroom waste with non return valve will this work?

[Loz7]

I am fitting a bathroom and I'm a bit stuck on the waste pipes-
I have a bath waste joined to a basin waste with 50mm pipe which goes to the soil pipe-
The shower has 40mm pipe that goes through the joists and then changes to 50mm once out of the joists and tees into the bath and basin 50mm pipe- I guess the water from the bath would come out of the shower without a non return valve, ( Like this one ) which is just before the tee to the soil stack. I am limited by the height of the joists which is only 145mm..

here is a drawing-

any help greatly appreciated.

 

[Hugh Jaleak]

Can shower waste be run separately? Non return valves gunge up, and are not a substitute for incorrect plumbing.

 

[Daveydub]

You could use a hepvo trap on the shower which also works as a non return valve
http://www.wavin.co.uk/web/solutions/waste-water/waterless-traps/waste-valve-hepvo.htm

 

[denso13]

I wouldn't run all the pipes into one before the soil pipe. Run them separately if at all possible.

 

[John D v2.0]

guess the water from the bath would come out of the shower without a non return valve,

It shouldn't as the bath trap is 40mm and the pipe where they join is 50mm so getting on for double the area. But as you say it doesn't confirm to regs.
In a standard system, as long as the falls are correct, the pipe should never be completely full of water, it should have an air gap above it. This would stop back flow via another trap.

Having said that improvements,- you'd still do well to eliminate flat right angles, if you can swap the flat 92.5 branch to a 45 and a 135 it would help.

Ideal and complying better with regs would be to bring all the pipes together into a 50mm stack then join that into the main stack, or one of those compact stack manifolds that looks like an elephant's foot. You can join about 4 pipes in without any crossflow.

 

[Hot&Cold]

if your shower tray is one of those very low level 40mm high type.then consider this will have the least gravity fall to the soil pipe and to ensure a good gravity flow it should take a priority route,ie straight with no restrictions. An nrv will be a restriction.

Where does the Wc enter the soil pipe

 

[Loz7]

Thanks for the replies, I could drill through the block wall and joist and put the drain through the cavity 400mm lower than the shower connection,

The toilet is at the top of the soil pipe is that a problem?
The soil pipe is on the other side of a cavity wall and exits through a flat roof to a stack, the toilet is teed to it just before it goes through the roof-

Alternatively I could lay a 50mm going down stairs to an outside drain?

 

[John D v2.0]

Toilet above is fine, you just have to avoid opposite and slightly below!
No need to have a complete separate stack, it's acceptable to have a short stack in 50mm and then discharge into another stack.
I think you'd benefit from reading through the drainage approved document as it has some useful principles hidden in there that are well explained in a way.

 

[Loz7]

I put the bath and basin waste through the wall into the cavity, now the soil connection for the toilet is 60cm above the boss strap for waste water instead of 5cm..It all works well thanks for the help