Kitchen sink and appliance wastes

[duotwr]

A question for any plumbers or experienced DIY'ers.

I'm plumbing in a double sink, washer and washing machine. Sink is from IKEA, but I want to bin the supplied wast trap.

I've got a single 40mm waste pipe going through the wall. There are various ways I could connect it up, but the basic question is whether 40mm is big enough to take all 3?

If it is, then rather than get some octopus-like trap with multiple spigots I was considering putting a standpipe in for the 2 appliances, which after a P-bend could connect into the 40mm waste from the sink, before exiting through the wall? Is this a sensible approach?

Thanks

Keith

 

[Hugh Jaleak]

40mm should be ok, if in any doubt then upgrade to 50mm to be certain. 40mm may struggle to cope with all 3 appliances discharging simultaneously, but the likelihood of that is probably remote.

http://www.mcalpineplumbing.com/traps/domestic-appliance-traps/1-189-twin-connector.html on top of the standpipe will take care of the washing machine and dishwasher.