Durgo at end of run or not?

[saveasteading]

The Scottish Standards appear to accept an air admittance valve at the end of the sewer run.

This is so much tidier and easier than an open stack, that I would like to alter our design to suit.

Currently a very visible pipe is intended either outside the last installation (up the wall, client says too ugly), or in the room and through the roof (I say even uglier, and why put a hole through a good roof)).

 

I ask because the regulations appear to allow a Durgo (or eq), but I  have seen comments suggesting the opposite.

 

Second question.  Is there an AAV that can be located outside, by extending the pipe run to a discrete position?

I guess we could alternatively have the open stack in such a location.

 

Air admittance valves are another method of ventilating a drainage system as they allow air to enter the drainage system, but not to escape, thus limiting pressure fluctuations within the system. Care should be taken when installing these valves that they are located where they will operate effectively. Air admittance valves should be installed:

1. in accordance with the recommendations in BS EN 12380: 2002, or

2. in compliance with the conditions of certification of a notified body.

[Temp]

Building Control Officers in England tend to want one open vent at the furthest point from the sewer in the road. They tend to accept AAV on any other vents.  I'm not sure this is a hard and fast rule.

 

Some time ago I found this reference to only needing one open vent pipe per every 5th house on an estate...

 

https://books.google.co.uk/books?id=7eAhNzZW1goC&pg=PA846&lpg=PA846&dq=one+open+vented+stack+ever+four+dwellings&source=bl&ots=tK13FKNupg&sig=ACfU3U1pU0TMwSQa0xcSaUFx9tnojD06AA&hl=en&sa=X&ved=2ahUKEwjUto7_0qDlAhXSbsAKHfjgD10Q6AEwDnoECAcQAQ#v=onepage&q=one open vented stack ever four dwellings&f=false

 

However it also says this isn't suitable where there are interceptor traps on the drain to each house (which I thing might be the case in Scotland?)

 

 

 

 

[Temp]

I forgot... I think the English regs allow the vent part of a stack to be 75mm ID/82mm OD eg doesn't need to be 110mm. Not sure if that helps much.

[Faz]

Durgos fail after around 10 years - make sure it is accessible if you are going to put one in (unlike an idiot main contractor I had in 2016 putting them in sealed partitions between flats....)