kitchen sink drainage

[sasha]

I am modernising a very old kitchen/living room. This mainly involves moving the kitchen area from one side of the room to the other - 6 metres away from the waste stack. The flat is on the 3rd floor so space between the floor and my downstairs neighbours ceiling is limited. Can anyone confirm the degree of the slope required please and recommend diameter for the drainage pipe? And any other relevant info or tips if youve heard of this or been involved in this type of work before. [Local Building Control will not allow Sanivite use.]

 

[kevplumb]

use 1/1/2"" or 2"" solvent fall depends on pipe dia
general guide 1 in 40

 

[brumylad]

at 6 m I'd say you will have to include an air admitance valve in the pipe run, (u might get away with anti-syphon traps) and if they want a washing machine and/or dish washer go for 50mm.

 

[kevplumb]

scuse me 2 ""

 

[brumylad]

sorry old timer,.....2" it is then,

 

[felix]

Here's a trick I've used to avoid problems with long pipe runs - and 6m is certainly a long run. Start with a modest length, say 2m, of standard 1.5" (40mm) pipe then increase to 2" for the rest. The increase in pipe diameter prevents the larger pipe from running full so air from the stack can always get to the end of the smaller pipe.

If you use solvent weld on such a long run you'll have to include at least one push fit joint to allow for expansion. Plastic pipe has a very high coefficient of thermal expansion. Why not use push fit all the way. Do take care with your slopes and use plenty of supports to keep the pipe running in a straight line. One in forty is fine. Let's hope you have room for a 15cm drop.

 

[sasha]

Thanks for the responses. I've managed to clear out all the rubble under the floorboards nearest the draining pipe to see if I've got enough depth. It looks OK! Might be able to get this project moving after all. CHEERS.[/b]