Below ground 110mm Double Branch

[LiamJones]

Hi,

 

I'm after a below ground 110mm double branch fitting like this, but can't find any in terracotta? 

 

Why? I want to connect in a soil stack upwards, and then go left to a bathroom and right to a utility room, all in 110mm under slab. I could stack two single branches on top of each other, but this costs valuable depth to keep them both below slab and makes the falls im working with very hard/impossible.

i could also use a single branch, then a 2 single branches off the horizontal branch, but i end up too far into the room at this point.

It seems the only workable solution is a double branch, like below, or i split the runs and have to go under the foundations twice!

 

 

https://www.floplast.co.uk/product/double-branch

[joe90]

The only problem with using black or grey pipe underground is it’s not as thick walled so in theory could crush if loaded a lot, personally I would use either and surround it in concrete (or not 🤷‍♂️)

[Mr Punter]

Would a bottom outlet chamber work?

 

https://www.drainageonline.co.uk/underground-drainage/drainage-pipe-and-fittings/marley-underground-drainage/250mm-diameter-double-bottom-outlet-chamber-body

[LiamJones]

9 minutes ago, Mr Punter said:

Would a bottom outlet chamber work?

 

https://www.drainageonline.co.uk/underground-drainage/drainage-pipe-and-fittings/marley-underground-drainage/250mm-diameter-double-bottom-outlet-chamber-body

Ooh, maybe. How does the stack connect into it? 

[Conor]

You need a small inspection chamber. The main stack will connect in via a long radius rest bend. All underground pipe and fittings must be orange.

[Russell griffiths]

How will you clear this if blocked. 
should be two separate runs outside the building to a chamber so they can be cleaned from the chamber back into the house. 
unless I’ve misunderstood what your trying to do. 
 

diagram would help. 

Edited February 5 by Russell griffiths

[LiamJones]

46 minutes ago, Russell griffiths said:

How will you clear this if blocked. 

It’s a good question. I don’t know. How would someone clear a single branch fitting, I’ve seen those used in loads of places, and presumably it’s the same problem, you can’t guarantee you’d be able to rod into the branch? 

[Temp]

I thought what you want isn't allowed in building regs? Don't they have to be staggered in height or is that only when one side is smaller than the other?

[LiamJones]

1 hour ago, Temp said:

I thought what you want isn't allowed in building regs? Don't they have to be staggered in height or is that only when one side is smaller than the other?

Double branch like this is fine because they’re swept in rather than in at 90. I think. So they’re not technically opposing.

[Russell griffiths]

12 hours ago, LiamJones said:

It’s a good question. I don’t know. How would someone clear a single branch fitting, I’ve seen those used in loads of places, and presumably it’s the same problem, you can’t guarantee you’d be able to rod into the branch? 

Nope, you shouldn’t have any branch line that does not have cleaning access from at least one end. 
so either an inspection chamber outside the build to clear inwards or an inspection point in the pipe as soon as it exits the floor. 
the second version is not recommended as a full stack of poo 3m vertically will be an unpleasant surprise when you take the cap off. 

removing a toilet to get to a pipe is not a recognised method of clearing a blockage. 
 

can this joint not be put in above floor height so access to clear. 
 

I think we need a drawing and a bit of a re design. 

Edited February 6 by Russell griffiths

[crispy_wafer]

If the works are open and no slab down, just make two runs to the ic outside, more pipe and a couple of fittings and an hour or two, but a batter solution that can be dealt with individually if the need ever arises.

[Jenki]

I Found this tech sheet helpful, although not cast in stone and building regulations per say, they will be accepted by Building control as proof of compliance. 

NHBC_TECH_SPEC.pdf

 

I used Diagram 6, to assist with invert levels.

Edited February 6 by Jenki
more detail

[Russell griffiths]

@LiamJones I’ve re read your original post, so if one of the junctions is just a utility room with no wc, then yes you can use a y junction as per @Jenki diagram. 
I originally thought you wanted two WC coming in from both directions. 
 

so you probably need two y junctions laying flat, not what you have in your first picture 

from the y junctions you would go left to the WC and soil stack and right to the utility room. 
 

you will need to put rest bends on the bottom of the pipes going vertical through the floor. 

[LiamJones]

Thanks all, i've decided to not complicate things and get the drainage out the build ASAP, rather than combining it all inside. I'm going to go over the foundations then drop to a lower level outside the building.