adding new section to toilet stack

[marsaday]

I am adding a new T to the stack and the soil pipe which comes into this is 3m long. What fall do i need to use here?

Do i need to add any release valves ? Not sure if this run is too long. The height of my stack is about 9m (3 levels)

 

[ChrisR]

Slope should be One in Forty, so about 3 inches
Don't go (much) steeper, or the solids get left behind.
You could use a bend with an access plate on it, otherwise no probs as it's only 3m..

 

[marsaday]

ok thanks. So that would be a fall of 75mm. I have now read 60mm will be fine. is this to shallow then ?