Using horizontal (dead flat) soil pipe

[nicglee]

Due to restrictions I want to run a soil pipe from a washing machine for about 4 metres dead horizontal with a couple of bends (and then slope to join a bath waste) in probably no more than 2 inch pipe. Can any one advise if I can get away with this? Perhaps only using washing liquid and not powder? And if I'm able to access the pipe to clean out every now and again (how often is advisable)?

 

[Simon F]

are you sure you can't get any fall on the pipe?
the building regs requirement is a fall of 18-90mm per m on a 40mm pipe, that's not a lot.
also the run of 4m would require some means of venting to avoid negative pressure in the pipe.
can the run not go a different route?
best not to join pipes, again because of issues with trap seal loss.

 

[nicglee]

Thinking again I could acheive this drop by running the pipe initially through the back of a cupboard (not ideal but may have to be). Would I still need the venting you suggest? Clearly I would have a U-bend trap immediately at the outlet of the washing machine. Would I need more than this and what would it consist of (note: I am an amateur)? Do you have a link that would explain simply?

 

[Simon F]

you need a anti vac trap / hepvo valve, something that allows air into the pipe to avoid issues with negative pressure, trap seal loss because of the pipe length

 

[Simon F]

hope this helps
www.draincenter.co.uk/docs/2741_HepvO_PG_WEB.pdf

 

[nicglee]

Thanks again Simon. I read elsewhere that I can use a Hep vO instead of a U-bend at the outlet of the washing machine. Would this be sufficient venting for what I now estimate to be about 6 metres of piping with 4 x 90 degree bends, or would I need to insert another vent somewhere else (where)?

Also (again due to restrictions) I plan to start the 'horizontal' run at about 80-85cm from the ground (base of washing machine). Is there a minimum vertical drop from the outlet hose of the washing machine, and/or what is the maximum height to which the machine pump will push the water the enter the vertical pipe?

 

[nicglee]

Sorry, this was not meant only for Simon to answer (just to thank him) but for anyone who can help.
To add to the previous message: I had been thinking that I might have to build something to raise the washing machine, but if the machine pump can pump to a sufficient level above the machine and/or the vertical drop required from the outlet hose is minimal then this may not be necessary? Should the connections in the waste pipe be with ring-seals or sealant welded (or even glued)?

 

[Simon F]

probably easiest for you to use push fit or compression pipe and fittings

 

[nicglee]

Are push fit better than ring seals (can push fit be taken apart if they fail)?

What about the outlet height and trap issues I raised in the previous post?