Waste Pipe Connections

[morningcloud]

Hi Guys

Can someone take a look at my sketch please, I’ve got a bath waste going into the stack at 180mm centres to the toilet waste plus the shower waste at 90 degrees to the toilet waste.

In the second picture it shows what is permissible.

Can someone confirm if I do it to my sketch it will be ok.

Thanks to anyone who can help.

 

[DGT plumbing]

I was lead to believe that you wont get cross flow if it's at 90 degrees to another inlet only happens when they are apposing each other.

 

[Riley]

Unless I’m misreading the attached docs it still has to fall outside a minimum dimension

 

[chris watkins]

The whole ideal of this regulations is to stop cross flow so when the toilet is flushed the discharge should not be able to enter the stack & cross over into a lower waste or soil connection. Therefore the only danger is from connections which enter below & behind the toilet connection in this case.
If I understand your draws & description correctly this will not happen in this case, so yes it meets part H requirements.

 

[chris watkins]

As a rule manufacturers make their fitting (boss connections & boss pipes) in such a way as that if put together you can't break the no connection zone.
It is only silly buggers who use strap-on bosses to make connections or anyone opening up a connections into a 4" lead or copper stack that could make the mistake.

 

[morningcloud]

Hi Fellas

Thanks for getting back to me, when I saw the cross hatching in the one photo, I just wanted to make sure I would be doing the job correctly and where better to ask but on this forum.
I didn't want to end up having to rod the bath or shower waste every few months to get rid of you know what

 

[morningcloud]

Hi Chris

I was just about to say, so the manufacturers have sorted it all out for us but then I came across this branch pipe photo.
If I used the boss marked in red wouldn't that be directly in line for cross flow.
What do you think?

 

[chris watkins]

Morning read the notes on the manufacturers guidance you first posted !!
It is fine because the water level when the toilet is flushed will not get any where near that level.

 

[Stigster]

Hi Chris
If I used the boss marked in red wouldn't that be directly in line for cross flow.

It's ok as according to the diagram posted above, the text say the smaller branch is acceptable if it is opposite but at or above the centreline of the larger branch (or at a right angle). The fitting you marked in red has the smaller branch at/above the centreline so all good.