Is this sensible or daft or worse

[MikeSharp01]

I need to connect the bath and sink outflows into the soil pipe and I am thinking something like this - ots only clipped on. I worry that its too close to and on the outside of the bend and that it will cause a 'catch point' for solids etc from the WC which is about 2m away from the bend. The blue arrow shows the flow direction. I can go through the I beam just behind and perhaps move the entry point 3-400mm downstream. I can also reduce the incoming pipe size but if I go much smaller the bath may take time to empty - not that that is a problem.

 

Any thoughts?

[Mr Punter]

Can you rotate to get the fitting nearer to the top of the soil pipe?  Maybe a bend with a spigot and socket would help?  Hopefully someone who is decent at plumbing can make a more useful comment.

[joe90]

9 minutes ago, Mr Punter said:

Can you rotate to get the fitting nearer to the top of the soil pipe? 

I agree, I did similar in my build but rotated a bit to be higher within the main soil pipe (might be difficult to get a hole cutter in there if the floor is fixed!).yes moving it downstream a little may help in that water/solids are not washing up the wall of the soil pipe as much as nearer the bend.

[ProDave]

Can you post a plan of what pipes you have and where in relation to that the new pipe has to finish?

 

Only with that can I tell if there is a better way.  e.g going into the top of the soil pipe where you are suggesting means you can't then run your new pipe through the joists.  That may or may not be a problem.

[MikeSharp01]

Thanks all - I will post a drawing later to show the whole layout. This is all due to change in the room layout which means we have very restricted height above the pipe. The soil pipe is not yet fixed, only dry fixed, so it can all come out to play.

 

I can get the pipe up a little  but because it runs about a meter further in the direction of the open end I still need a fall and I cannot cut the flanges although the webs are fair game for 50mm holes given the span and loading. 

[Conor]

It's too close to the bend. Can you bring the small waste pipe through the I joist and connect in about 500mm down from the bend? My general rule is leaving 3-5x pipe diameters between connections, bends etc. Might need to do some reinforcing of the joist.

[MikeSharp01]

@ProDaveOk finally got time to pull the drawing:

 

 

 

So the challenge is to get the two inflows from the from the sink and bath into the main pipe which turns to the right under sink as shown in my OP. We won't want the pipe to go into the floor under the sink so we are taking it along in the wall and bringing it out under the bath then down through the floor and along through the joists to the point I modeled in the OP. We are prevented from going through the floor below the wall as the gluelam beam is there and we cannot drill through the twin Kerto beams, in the pic, that runs under the shower and butts onto the gluelam beam because the SE, who signed off the holes we already have in it won't sign any more holes off.  We cannot run in the wall all the way to the lower right corner, and drop down into the I-beam zone in a boxed in corner, from the bath as there won't be enough drop. 

 

I think I have to go through the next I-beam and then into the pipe but I will probably have to strengthen the I beams so broadly what @Conor suggests. What is the shallowest slope I can allow on the water outflows from the sink and the bath - not usual solids at least! 

[ProDave]

Still not understanding fully.

 

Where it says "exits wall low then through floor" i take it that is 110 between joists under the bath almost to the end, turns right, through 2 joists to WC?

 

If I have got that bit wrong no point continuing until I understand it.

[MikeSharp01]

Here is a bit more detail. Hope it helps.