Durgo size and height ??

[plumbtastic]

I am confused.
There are new housing schemes being built that build 4-5 houses sharing one open vent. The rest have durgos. the reason for this is to minimise work at heights and also maintain the thermal integrity of the roof. There seems to be a conflict in 'theory' here between seasoned plumbers and what the industry does.

Is your main beef that you do not trust durgos to do their job properly ?

 

[snowhead]

In no particular order.

Air admittamce valves, aka Durgos, do just that.
They let air in to prevent syphoning, when required, they don't vent the system.

Open vents are most effective at the head of the system, that way they guarantee to vent the whole system.

Just because others use 1 vent per system doesn't mean it's laid out in the same manner as your proposal.

Search on here for issues with AAVs failing and causing smells.

An open vent has no moving parts.

You'd need to consider how a potential buyer and or their surveyor will respond to the reliance on Durgos.

If it was my property I wouldn't have one in the place.
If I was installing for others and Durgos were the most economic and suitable way, I'd make sure they were fitted so they were accessible and would not cause too much nuisance when they fail.

 

[Sharp Point]

I am confused.
There are new housing schemes being built that build 4-5 houses sharing one open vent.

And I will pretty wager, that a lot of the above ground drainage that serves these houses are wrong, as a lot of plumbers don’t know what they’re doing. Yes a single vent could be used to serve multiple houses, as long as the configuration is correct. But nowadays these rabbit warren type estates that have drains going all over, that throws the multiple house method out of the window.
AAV are a get out of jail method and not good practice,

 

[Welder]

I am confused.
There are new housing schemes being built that build 4-5 houses sharing one open vent. The rest have durgos. the reason for this is to minimise work at heights and also maintain the thermal integrity of the roof. There seems to be a conflict in 'theory' here between seasoned plumbers and what the industry does.

Is your main beef that you do not trust durgos to do their job properly ?

The ONLY reason they install them is to reduce costs. End of.

 

[king of pipes]

I genuinely respect your experience KOP, however I'm going to vehemently disagree with you on this one 🙁

There is no evidence that a single vent at the tank is even viable. The OP has been asked for a drawing but has not provided it. As the septic tank has to be a min distance from the property AND the property has multiple bathrooms an AAV cannot be classed as even a borderline 'acceptable' solution.

If you wish to advise it is, and of course the OP will jump on anything that reinforces his thought process, then that is your prerogative.

My, purely personal view, is that we have a poor enough reputation as an industry already so we can hardly complain about it in our own day to day dealing with customers if we sanction poor practice here. 😉

I agree with you Davy boi if you read again what I said the drains need a open vent not just one on the run I wouldn't do it . Kop