AÉRATEUR À MEMBRANE PVC - where & how to fit?

[joidevie]

Hi all..

I'm just re-plumbing our bathroom & kitchen, and I'm considering adding some sort of odor vent into the 'evacuation'..

Can anyone enlighten me as to where & how to place this? (link with diagrams?). The bathroom is directly above the kitchen, with the 100mm loo pipe running along the outside wall into which all the waste will flow. There is also a loo on the ground floor adjacent to the kitchen, and this waste will also flow directly into the egout.

Is it simply a vertical extension of the 100mm outflow running on the outside wall which clears the roof height? Does it want to be 100mm or reduced to 40mm (much cheaper unit!)?

Do I really even want to fit one, or should I wait and see if there's any smell issues and then adapt the system?

As you can tell, I'm no plumber - and on my last project I didn't fit anything, but this time around I hope to improve my knowledge (and end product!)

Many thanks for any guidance..

[Anton Redman]

An AÉRATEUR À MEMBRANE allows air into a pipe but does not allow air and hence smells back out of the pipe. You use them to stop the fast moving plug of water produced when for instance you pull the plug on a basin dragging the water out of the trap. They also reduce glugging sounds for the same reason. Similar logic applies to WC with aereateurs. As they are in theory one way they can go anywhere though I would want on to be accessible in case the membrane fails.

If you want to vent you fosse with both air in and air out. You need to T off the WC pipe and go sufficient far upwards that the smells released clear the roof and do not reenter the house.

[sid]

The aerateur a membrane (sorry, the accents are missing!) is a device to allow air into the system but not let the smells out, so it's not a vent in the normal sense. There's a diagram here: http://www.pumplastiques.fr/fileadmin/cat/produit/pdf/Page%20219.pdf

The "valve" should be placed at the end of the pipe run (furthest from the sewer/fosse, with the pipe work extended if necessary, so that fresh air is drawn in from somewhere convenient like under the eaves or in the (unoccupied) grenier. The membrane "flap" prevents smells from being emitted in any case. The purpose of it is to allow air to be drawn into the system when a large amount of water is flushed away, as for example when the toilet is flushed or the bath is emptied. Without this vent there is a risk of the water in the U-bends of the other sinks/shower trays/washbasins etc being sucked out thus leaving the U-bend dry and allowing odours to come up the plug hole.

I've recently added a small WC (with broyer) and washbasin and I added a small version of the aerateur a membrane because I had created a new branch onto the main 100mm pipe. They come in sizes to fit the common waste pipes, 35, 40 and 100mm.

See also this thread: http://www.completefrance.com/cs/forums/2565055/ShowPost.aspx

I think it's a standard to install one of these devices.

EDIT I see that you beat me to it Anton while I was composing my reply!

[Chancer]

It sounds like you dont need one as you already have a vent pipe unless you want to do away with it as the smells from it are disturbing you.

The aerateur is designed to be fitted as described above, its a wise precaution to site it on a vertical leg that is higher than the overflow from any bath or basin, that way if things get blocked downstream there is no possibility of foul water coming out of the aerateur.

Air is much less dense than water and a columb of water in a down pipe does not need a full bore 100mm to allow it to fall (its the same principle when selecting jets for a carburettor) i only ever use 32mm or 40mm aerateurs and have never had a problem, they work just fine.

The extortionate prices demanded for larger aerateurs both sides of the channel bear no relation to the tiny incremental cost of the material, its exactly the same rip off used for serre joints, dont let them profit from you!!!

[joidevie]

Great, many thanks for the quick & well informed advice!