Connecting sink into toilet pan pipe

[Danzka]

I have a steel beam that prevents me from getting my ensuite 32/40mm waste below floor so am considering running 1m in the wall to the inwall toilet pan connector (90mm diameter) before it goes below floor.

I know a branch T is better (as it cannot block) but I cannot fit it in, so would it be a bad idea to fit a 90mm/40mm reducing T (pic below) with a 32mm reducer? Would the reducing T incur blockages from the soil waste streaming past? My thoughts are that it is only a 32mm hole and the angled side of the reducer (see pic) should deflect it onwards rather than 'catch it'.

Any thoughts/advice on this would be welcome.

 

[ShaunCorbs]

Picture of said toilet pipe please

 

[Danzka]

Picture of said toilet pipe please

Thank for taking a look 🙂.

Proposing to put reducing T in here (as per finger point) with 32mm pipe entering from right to left

 

[ShaunCorbs]

Where does the soil pipe run from there as I wouldn’t tee there will cause vacuum issue / pull the basin trap

 

[Danzka]

Where does the soil pipe run from there as I wouldn’t tee there will cause vacuum issue / pull the basin trap

It runs down about 180mm below floor level then turns 90 degrees to the left and continues at a slight fall for about 1.5m to the outside wall.

Interesting that you don’t think blockages will be an issue, just the vacuum sucking and subsequent smell in the toilet - which should be negated by people washing their hands after flushing the toilet (theoretically 🙂).

You raise a good point though, which makes me wonder what stops it sucking any pipe that is bossed into it along its journey to the sewer? Or is it only an issue near the source of the flush due to the concentrated volume there and the reduced size of the pan pipe (90mm v normal 110mm).