Waste pipe length

zak410, Sep 22, 5:49pm
I am not sure but just to bump it, I think it should be OK if the 'slope' is sufficient.

trade4us2, Sep 23, 3:19pm
I have a single length of kitchen waste pipe of 10 metres, plus a few metres around the corner at each end. The plumber used plastic clips to hold it, and they eventually broke. I put galvanised steel clips instead.

pauldw, Sep 24, 4:18am
Check the Building Code, over a certain length (3.5m?) you need a vent or air admittance valve. The water in the trap can get siphoned out without one.

trade4us2, Sep 24, 10:00am
I have a vent in my long pipe.

tygertung, Sep 24, 11:06am
In my upstairs bathroom the suction from the bath draining is exceptionally violent. It is very hard to just let a small amount of water out. I would recommend doing something to avoid a situation like this. Perhaps one of those air admittance valves like previously suggested.

zak410, Sep 24, 11:53am
That can be VERY dangerous !

supernova2, Sep 24, 7:02pm
Will be about 8 meters in length.
I found some info on the use of Air Admittance Valves (AAV), then I thought about the new traps that contain an admittance valve.
Anyone know if they can be used instead of a stand alone valve. Looks like the Acceptable Solution requires the AAV to be 100mm above the water level in the trap. That would rule out the use of the trap with the built in valve.
Then I found a determination from the MBIE that says the Acceptable Solution documents are only suggestions. Got to wonder what the point of an acceptable solution doc is if it's only suggestions and has no legal standing.

The other thing I found in the Acceptable Solution doc is that 2 items (ie bath and basin) can have their waste pipes joined together (as long as they have AAVs) so that will cut down on the amount of pipe work considerably.

johotech, Sep 24, 8:02pm
Wouldn't your plumber be working all this out for you?

supernova2, Mar 20, 12:41am
Looking at reno options and getting conflicting answers.
Is there a maximum length for a 40mm bath waste pipe?
Trying to avoid having to install another gully trap which would mean digging up the drive etc.
TIA