HepvO valves or Air Admittance valves instead of open vent

[rosscoid]

Hello.

Having read lots of posts and gained plenty of information that's been of great use during my current bathroom refit - I now have a quick question!

Presently in our bathroom - our basin, bath and WC connect to a discharge stack that is boxed in and goes up through the ceiling and open vents through the roof. The 'boxing-in' is unsightly and I want to get rid of it.

Am I correct in thinking that this is possible by terminating the stack (above the height of the tallest overflow point - the basin?) either with an air admittance valve, or simply a bung in combination with HepvO valves on the basin and bath?

Does anyone have any preference between HepvO or air admittance? Are there any finer points that I am missing?

Many thanks for any help / information.

 

[Bahco]

You need to find out if you drains are vented elsewhere on your property. What you propose to do will be ok ONLY if you have a vent pipe to allow gases to escape.

Consult your BCO for advice.

 

[kevplumb]

this may be helpfull

 

[rosscoid]

Okay. Thanks for the advice.

I have now spoken with my local Building Control department at the council. In order to receive advice from them, I must submit a Building Notice application (£117.50) and I will then be entitled to a site visit and advice on the correct way to proceed - I gather they'll also visit afterwards to tell me it's all done correctly and give me a piece of paper confirming this.

With regard to my drains venting elsewhere on my property - no they don't. But I am fairly sure that I share the drain / sewer (not sure of correct terminology) with my neighbours and they've all got open vents - I believe this will suffice, obviously this is hopefully what BCO visit will confirm.

 

[Bahco]

They have shared vents on my estate with no problems.
If you are sure yours is the same ( have a look in your manhole) you may be able to go ahead. Maybe a plumber will have a look at it for you.

 

[Nige F]

I`ll have a look for £100.00 No VAT but I`ll give no bits of paper

 

[rosscoid]

Since initial post earlier today, I spoke with 'Institute of Plumbing & Heating Engineering', they have a public helpline which is nice of them.

The man on the phone said:

1) HepVo doesn't help at all with air admittance / ventilation they are basically just a waterless trap.

2) If I want to avoid an open vent I have to use an air admittance valve which must be 1 metre above the highest spill level, (ie. the basin).

So, point 1 contradicts what Hepworth told me and what their design guide suggests. And point 2 means that the stack will have to be so high that I might as well leave it through the ceiling.

Should I just give up on this idea - I thought it was going to be simple?!

 

[sdelasal]

Old thread I know ...but why does it have to be a metre above the huighest water level? Why not 3"?

Steve