Required Fall On Horizontal Soil Pipe?

[thomp1983]

Hi all,

I need to run a soil pipe horizontally across the ceiling of my garage and need to know the required fall.

The run will be just over 6m horizontally and serve a full bathroom upstairs, everything will drop from a short vertical stack upstairs in the top left of the garage ceiling into the horizontal pipe then meet another vertical pipe the other side of the right hand garage wall down into the manhole.

Thanks
Chris.

 

[Exedon]

Rule of thumb was always 1 in 40 for a 4in/110mm drain
You can go shallower with plastic pipe check out approved document H for guidance.

 

[thomp1983]

Thanks so that means the right end should be 15cm lower than the left, that's going to be interesting with a 90 degree connector on each end.

 

[Exedon]

If you can get 150mm of fall over 6mts that will work well.

 

[Nige F]

Thanks so that means the right end should be 15cm lower than the left, that's going to be interesting with a 90 degree connector on each end.

they're not 90 degree, they're 87 1/2 (ish) to allow for a fall of 2 1/2 degrees