Long waste pipe runs

4 Apr 2010
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United Kingdom
If installing a waste pipe run that is outside the limits for 50mm for a 4 meter run. Would an aav on run help more than just an anti vac trap on the appliance? There is only one appliance on the run.
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4 metres in 2” is fine. What’s more important is the correct steady fall on the pipe & clipped correctly. Over time the issues will occur so as long as it’s accessible to clear build ups, all good. Anti vac traps are great but can have issues with blockages backing up & clogging the valve.
It's more like 9meters of 50mm. No other way of getting to the drains without major, major works
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I have 6m of 50mm serving a bath and basin with an AAV, no problems in 8 years.
There's an anti-vac waste on the basin and something like this at the start of the main pipe run:

Floplast a1 aavs are rated to be fit below flood level 200mm above the horizontal pipe section for 4inch and 100mm above the horizontal for the 1.5valve. Any one no if poly aavs are the same?
It doesn't make it too clear says 82 and 110mm need to be above spill over. I guess 50mm and 40mm are acceptable below as it doesn't mention them?


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Is it still a requirement for these to be fit above spill over level of the highest appliance?

With respect, the waste pipe diameter and length you are planning doesn't comply with the regs, therefore don't worry about the AAV height either. Fit it where you want.

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