Long kitchen waste run question

[jrhartley]

Hello

I am working out a new kitchen for someone who wants me to move the location of the sink. In its new position, the sink waste will need to turn 90' (L-shaped kitchen), but more importantly, its probably 4500mm from the stack. Gradient shouldn't be an issue as I am planning to fit an IKEA kitchen and run the waste pipe in a false compartment behind the Faktum units. The questions I would appreciate any thoughts on are:

a) That 4500mm-odd waste pipe run. I know the normal max is 3000mm - what options are there for me - I have heard people talk about putting a 40mm pipe into a 50mm pipe and also an anti-syphonic valve. There is no scope to put an air admittance valve in or a different waste stack as this is a first floor flat, concrete slab floors.

b) 90' turn in a waste pipe. Not great, I'm presuming? How much of an issue is this likely to be?

Other than not moving the sink as requested, I'm racking my brains to any other solutions to this. What would I need to worry about if I just ran the pipe from the U bend for 4500mm with a 90' turn?

Sorry for the naive post, this stuff is quite new to me.

 

[Bahco]

I would use an anti vac trap on it and ensure I had a 6 inch drop over that distance and sleep easy.

 

[Hugh Jaleak]

I would be inclined to use a 92.5deg swept bend as opposed to a 90deg 'knuckle' bend. Should allow for better flow, and probably easier to get a 'snake' round should worst happen and pipe block in future.

 

[tryitandsee]

Just to add, if and when the odd liquid fat is poured into the sink waste, it does tend to congeal over these long pipe runs as the 'hot' water flush cant get hot enough to melt it on it's way. In other words try and get a rodding point in somewhere.

 

[Agile]

At least you are thinking about it.

I dont see any problems but you could do it in 50 mm for a start.

The important thing is to ensure there are access points at regular intervals like midway and I would say there should be a straight in line access at the sink end.

Tony