Arranging and venting a waste pipe branch

[phloaw]

I recently got ground floor piping extended to have drain (40mm leading to the stack as in the figure), hot and cold in a first floor room. Only the pipes are there, but I'd like to install a sink and a washing machine as from the (quite schematic) diagram.

Note that the washing machine will be at a higher level, because it will be placed on a riser about 1m higher than the floor level.
The drain pipe distance between the new sink and the lower floor sink is about 7-8 metres, while that between the new washing machine and the new sink would be about one metre.

Questions:

1) How do I arrange traps? I plan to place one under the new sink, but should it also serve the washing machine or the latter would need a separate one? And would it be wiser to buy resealing ones?

2) Should I add an aav valve, given that the branch is now pretty long (around 10 metres)? If yes, where to place it?

3) Do you see any foreseeable problem with this setup, either practical or regulation-wise? (I'm in Scotland)

Thanks!

 

[Newboy]

You haven't mentioned what size your waste pipework is - I'm not familiar with Scottish Regs. but English regs. would allow a maximum length of 4 m with a 50 mm unvented branch.

 

[phloaw]

You haven't mentioned what size your waste pipework is - I'm not familiar with Scottish Regs. but English regs. would allow a maximum length of 4 m with a 50 mm unvented branch.

Thank you for replying. Sorry, that's 40mm waste pipe diameter. I also amended my post. Scottish Regs seem to embrace English ones in this respect, and I know about the 4m meter.

That's why I was mentioning to install aav valves: do you think this would eliminate the 4m limit? Reading Approved Document H I couldn't get clarity on this point.

 

[Newboy]

Try H1.20

Personally I wouldn't use 50 mm pipework over the distances you're planning.

If I understand your post correctly, you're dropping one storey in 50 mm pipe - this diameter of waste isn't appropriate for effectively forming a stack.