Washer drain , where to put AAV

[henryccca]

in ohio,

Currently working on a bathroom remodel where a 1 1/2" washer drain comes from about 7' away through the studs walls. The drain has another 4' and a 90deg and another 4' to get to 4" drain with a vent to the roof. I am thinking of putting a AAV in the drain and keep it accessible to change out when needed. the only location that can happen is just after the 90deg bend that I mentioned above. is that too far of a straight horizontal line to put a trap and that valve. I realize that I need to put the valve above the water level that would be in the washer. There will also be a shower drain, bathroom kitchen sinks and toilet draining into the same 4" line as well via a 2" piece of PVC.

There is no place install a outdoor vent as it is the middle of the home on the 1st floor.

thanks for all your help

 

[Zanne]

In Ohio, according to my notes, you are under IPC so the trap arm rules apply.

Pictures or sketches of what you are describing might help us to visualize the situation.

Also, 1-1/2" is insufficient for current washing machines. The current standard is 2". With a 2" standpipe, the developed length of the trap arm must be a minimum of 4" (it must be no shorter than 2 pipe diameters) and no longer than 8' (slope must be no greater than 1 pipe diameter). Shorter than that and it creates a crown vent which allows siphoning. Longer and water will block the trap weir and prevent air from pushing the water-- creating a vacuum and trapping water in the pipe. Keep in mind that the "straight horizontal line" must actually have a downward slope of 1/4" per ft to allow gravity to pull the water and any debris out.

I've seen online sites selling special boxes for AAVs that are placed in walls-- although, you can probably make your own for about $1 if you get a plastic box with lid from a dollar store-- cut the hole for the pipe and put vent slits in the lid.
Here is an example at HD: http://www.homedepot.com/p/Oatey-Sure-Vent-Wall-Box-with-Grill-Faceplate-39010/203309148

For the standpipe it should look something like this and you would just have the AAV on top-- I believe it must be a minimum of 4" above the trap, but I would go higher if possible.

From IPC
802.4 Standpipes.
Standpipes shall be individually trapped.
Standpipes shall extend a minimum of 18 inches (457 mm) and a maximum of 42 inches (1066 mm) above the trap weir.
Access shall be provided to all standpipes and drains for rodding.

I believe Frodo or one of the actual plumbers here could give advice on recommended cleanout location.

I apologize if this isn't the info you are seeking, but I'm hoping it can be helpful. Any additional info (like I said, pictures/drawings, etc) would be good.

Does the 90 degree bend go up, down, or sideways? Is it part of the drain? If so, is it being plumbed with a long sweep 90 ell or a short 90? (short 90s are not allowed for drains).

Another thing to keep in mind is that the drain does not have to go down at the same spot as the vent. The vent just has to be placed within the specified parameters at the same place as OR before the drain goes vertical.
Something like this (although this is for a sink):

 

[henryccca]

Very quick and detailed reply thank you so much.

The 90 bend will be sideways and it is part of the drain and I will be putting a sweeping 90 in that location, the horizontal line does have a slope.


I have seen those boxes but the only way to that in is if I take out the drywall between the studs in wall and install inside of wall, just hoping to do the trap and aav with the 16" centerlines of studs, do you know if there is glue pvc fitings to replicate a trap instead of the compression threaded fittings that you see under all sink drains.

 

[frodo]

1.5'' is not allowed for a washer drain. minimum size pipe is 2''

 

[Zanne]

Very quick and detailed reply thank you so much.

The 90 bend will be sideways and it is part of the drain and I will be putting a sweeping 90 in that location, the horizontal line does have a slope.


I have seen those boxes but the only way to that in is if I take out the drywall between the studs in wall and install inside of wall, just hoping to do the trap and aav with the 16" centerlines of studs, do you know if there is glue pvc fitings to replicate a trap instead of the compression threaded fittings that you see under all sink drains.

I don't know if they have the AAV kit like that, but I do know they have 2" P-traps. Like this: http://www.homedepot.com/p/2-in-PVC-DWV-Hub-x-Hub-P-Trap-C4885HD2/100342868

And one that has a little cleanout in the bottom. http://www.homedepot.com/p/2-in-PVC-DWV-Hub-x-Hub-x-Cleanout-P-Trap-C4884HD2/100343824

I *think* this AAV will fit 2" pipe: http://www.homedepot.com/p/Sure-Vent-1-1-2-in-x-2-in-PVC-Air-Admittance-Valve-39016/100201861 If it doesn't or you want to get a cheaper one, on the tee you could use a reducer to go from 2" to 1-1/2" then have some 1-1/2" straight PVC capped with the AAV.

If your drain is in a different spot than the vent I believe you could use something like this fitting for the vent: http://www.homedepot.com/p/2-in-PVC-DWV-Hub-x-Hub-x-FIPT-Test-Tee-C481114VHD2/100344901 with the

And the long sweep for where it goes down. Where the vertical drain pipe hooks to horizontal you must connect with a sanitary wye (depending on angle you may need a combo wye or a wye + 1/8 bend).

I believe the vent for the washer can be 1-1/2" while the drain/trap/arm must be 2".

If you make your own little box and just cut a hole large enough in the drywall to fit the box in, you don't need to secure it to studs underneath the drywall. You could get something like this box from Dollar Tree (if you have that locally) put the pipe against one of the short sides, trace the size/shape, cut the hole out, push the pipe through, put the AAV on it. put the lid on, and cut vent slits in the lid and maybe secure the box with some hidden screws (under the lid) or with caulk/silicone. You could even just put one of the long sides against a stud and screw it in.

I imagine you could also buy the fancier one specifically designed for the job and screw through the side to secure it to the stud without removing the drywall-- and maybe just cut large enough that the vent cover would sit flush.

I hope I'm making sense.

 

[Zanne]

I'd like to add that even though the rule about not exceeding one pipe diameter in slope-- which sounds like it would allow up to 8ft in length for trap arm, IPC limits 2" trap arms to 6ft. Some jurisdictions limit them to 5ft.