Drainage regs

[ChilliChowder]

Hi everyone

This weekend I am re-siting the connection from the soil stack to the sewer via a new manhole to make way for an extension at the back of my house. One question - I know that there is a minimum gradient for the 100mm pipe, but is there a MAXIMUM gradient? I know for instance that a lower gradient is favourable to help suspend the 'solids', where a steep gradient might leave them stranded. But is a max gradient in the regs at all?

All answers (even facetious ones) welcome

Cheers

 

[Fluffster]

Go as close as you can to the 1 in 40 gradient too steep tends believe it or not to cause blockages as the crap hits a level at speed it splashes onto the walls of the pipe and so builds up until it blocks.
Pete

 

[ChilliChowder]

Cheers for the reply fluffster... in this instance I have very little choice but to fall ~1.5m over a distance of ~4m. Not ideal.

 

[marshman]

put in a drop chamber if your are going to a plastic chamber its easy and the right way
put a single socket 90 at base of chamber short up stand pipe to a T fitting
core drill a 110mm hole through chamber riser at this height insert short piece of pipe
through chamber wall into end of T over hang 50mm into chamber
T fitting is set a the right height for your fall.

 

[ChilliChowder]

put in a drop chamber if your are going to a plastic chamber its easy and the right way
put a single socket 90 at base of chamber short up stand pipe to a T fitting
core drill a 110mm hole through chamber riser at this height insert short piece of pipe
through chamber wall into end of T over hang 50mm into chamber
T fitting is set a the right height for your fall.

Awesome, cheers. I looked this up further here

http://www.pavingexpert.com/drain05.htm

Do I have to surround this in concrete? I was only planning on basing the IC on 100mm concrete not surounding it... ?

 

[marshman]

not unless its in your drive and then that's not always needed
you don't need concrete under it.
bed it on pea shingle packing the shingle under it when its at the right level
bed your pipes on the shingle to set the falls
when your happy with the fall chop the shingle in tight around the pipe with a shovel
don't over do this and raise your pipe, stand on the bit you have just done then walk along it
chopping each side as you go,
then cover your pipe with 50mm shingle cover the base of IC above all ports you can even
back fill to about 100mm from top of IC then concrete a plinth around your lid
it really depend where your IC is as to how you finish the top.