Wisdom of combined waste for kitchen sink and appliances?

[tomsavage]

Please excuse newbie ignorance as far as terminology, etc goes... Currently my washing machine discharges into a stand waste which exits the external wall separately to the kitchen sink waste. I am about to add a dishwasher, and replace sink and will be re-plumbing all the wastes. I would like to combine the three wastes somehow so that there is just one waste pipe emerging outside, low on the wall just before entering the gulley. Can I add a stand waste for the D/W then join this and the W/M waste into the sink waste just before it exits the house (using T-junctions, or a manifold - if such a think exists)? Thanks

[Fluffster]

Yes seperate stand pipes is the best way to do it if you have the space.
Make sure when you attach the tees you have the sweep going in the right direction.
You could always attach the waste pipes into the sink trap but I find them noisy.
Good luck
Pete

[tomsavage]

Thanks very much for your help! When you refer to the angle of the tee, I assume you are talking about some kind of swept tee? Would it be important to use these rather than a 90 degree tee? Also, (not sure if this is answerable but...) should there be room behind the average dishwasher and washing machine to have a stand waste without making the machine stick out beyond the worktop? I am hoping that horizontal stretch of pipe (from the W/M and D/W trap) will run under the kitchen cabinets (they clear the floor by 16cm). Thanks again.

[Fluffster]

If you look at the tee it will have one outlet swept in a direction of flow.
As for gaps behind the appliances I have seen some that have and not.

The flexible waste pipe should reach somewhere you can place the stand pipes.
Pete

[tomsavage]

Thanks very much for those tips, cheers!

[lcgs]

If you intend to combine all 3 into one, our local building inspector demands that the waste pipe be run in 2inch, which when calculated by discharge units is correct and not 1.5inch.