New Bathroom Venting, One 3" Vent?

[Molo]

Hello,
Is it possible to vent a bathroom with one 3" vent and not have to tie the sink and shower in at a point other than the main 3" line?

The plan is to install a new bathroom and connect the sink and shower into the 3" line for the toilet, and take the vent off a point on the 3" line only.

Thanks for any help,
Bill

 

[Tom Sawyer]

Probably not.

 

[Sponsor]

 

[Terry]

I wouldn't be able to pass that here in Seattle either.

 

[Molo]

`1. What if the shower and bathroom sink were each within drained with a 3" line after their respective traps?

or

2. What about this?
http://www.jlconline.com/codes-and-standards/kitchen---bath--venting-with-air-admittance-valves.aspx

 

[hj]

If you want a "handyman" job, go with the AAVs, but if you want a properly functioning one, install proper vents. You are assuming AAVs are an approved device in your area, which may NOT be the case. It might also make a difference WHERE that "point" you take the 3" vent off is.

 

[Molo]

-Not sure, but the 3" vent would need to come off downstream of where the sink and tub connect to the 3" drain, correct?

-Again, I'm wondering if upsizing the sink and tub drains to 3" after their traps would be acceptable.

Thanks

 

[hj]

quote; Again, I'm wondering if upsizing the sink and tub drains to 3" after their traps would be acceptable.

That could be the "worst idea" you ever had because the larger pipes would lose their 'self scouring' function and could clog up, and once they did you would have NO WAY to insert the larger snake to clear them. With AAVs the 'single vent' in the system is supposed to be connected at the 'far end/highest point" in the system.

 

[Molo]

quote; Again, I'm wondering if upsizing the sink and tub drains to 3" after their traps would be acceptable.

That could be the "worst idea" you ever had because the larger pipes would lose their 'self scouring' function and could clog up, and once they did you would have NO WAY to insert the larger snake to clear them. With AAVs the 'single vent' in the system is supposed to be connected at the 'far end/highest point" in the system.

Good point HJ. Can an AAV be used on the tub? I'm assuming it can't be placed in the basement where it could freeze, and it would need to be accessible. Not sure what the maximum height above the trap would be...