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General Plumbing and Gasfitting Talk => Plumbing => Ask Plumbers (Trade) => Topic started by: spud on September 15, 2015, 06:38:57 AM

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Title: Toilet venting question
Post by: spud on September 15, 2015, 06:38:57 AM

Does anyone have a definitive answer about when toilets need to be vented? I always thought that if drain is in 100mm and laid at 1:60 grade then a toilet only needed venting if it was more than 6 m away from main drain.
I see a lot of houses where drainlayers put junctions on outside walls for AAVs when really the toilet doesn't need them.

Am I wrong?

Title: Re: Toilet venting question
Post by: robbo on September 15, 2015, 08:40:58 AM

hi guys, Spud my understanding is that if w.c. is no more that 6mtrs from the terminal vent then no aav is required, cheers

Title: Re: Toilet venting question
Post by: spud on September 15, 2015, 05:20:49 PM

yeah that's what I thought Robbo, as long as everythings at 1:60 which is about 17mm per meter of fall, which is quite a bit really in my opinion.
The number of times I look at a plan and the architect wants vents on toilets which don't require it makes me laugh. I just read one which wants laundry tub run at 1:30 fall! Why?

Title: Re: Toilet venting question
Post by: robbo on September 15, 2015, 09:44:49 PM

hi guys, yes Spud 16.666666666mm to be exact. Divide 1000 by the required gradient =answer,cheers