Best practice for ventilating toilet drain line

[Justin B]

We're redoing the plumbing in our house and we have a new toilet in a bathroom that is about 8 yards/meters from the primary drain stack. In the same bathroom, there is a sink, in between the stack and the toilet on the drain line.

I believe it is necessary to have a secondary ventilation for this toilet to avoid de-siphoning the sink, and to allow good flushing performance for the toilet (a US siphonic-flush toilet). My question is how this should be done. Attached is a picture of my question.

Would it be better for flushing performance to configure the vent to be on the upstream-side of the toilet as pictured on bottom? Or does this not really matter? What is best practice?

(The vent would be a one-way valve: https://www.necap.be/fr/knits)

Many thanks

 

[frodo]

no. the vent always is on the down stream side of the fixture,
it is configured in that manor so the base of the vent is washed,

if the distance between the sink and the terlet is...
oh crap....you ar in belgium
sorry I have no idea what you local codes are

but using the international plumbing code...if that is what you use

if the toilet is within 10' of the sink you can vent the toilet at the sink using a wet vent.

 

[Justin B]

I see, that makes sense. You wouldn't want crud building up in the vent.

The 10 foot to sink/vent rule: is that best practice? Would some codes be more strict than that? For some reason here in Belgium, there seem to be much less strict controls on plumbing than on electrical or gas, so I want to know what you'd do .

For the vent, I presume an air admittance valves (e.g. Studor) would work in either case?

Thanks again.

 

[frodo]

The 10' is the max allowable. Of course the closer you are the better
a typical bathroom is not 10' long
8' or 7' ?
AAV will work. I personally do not like to use them it is a personal preference thing
they can fail, and then the house stinks. or. if the sewer backs up ii have seen the house flood out of the aav
[mainly under a sink]
I guess I am old school. drill a hole in the roof !!!!!!!!!!!!!!!!

what i would do is this

 

[frodo]