Venting question

[Coopatroopa]

Hi all,

I am planning to add a washing machine standpipe to a vertical run of pipe that vents through the roof. It already has a drain from the kitchen sink coming it at the upper section of the pipe (circled blue in image). The proposed standpipe location is circled in yellow.

my question is: do I need to connect a vent in between the two locations? My thought is that if both were running at the same time, the standpipe might not be able to vent sufficiently with water flowing down from the kitchen sink.

thanks!

 

[Reach4]

2 inch pipe already carrying the kitchen sink drainage?

Note there is a good chance that a clog could develop under the basement floor. Be alert for that. I had had that situation, but mine was only 1.5 inch. I set my drain pipe with access to use a medium Brasscraft drain bladder to clear that every several years. I am not there anymore.

For IPC today, you are supposed to have the standpipe and trap be 2 inch, but to expand to 3 inch when it joins anything else. So to join that kitchen waste, and to meet code, you could put in a laundry sink with or without an associated standpipe. The trap does need a vent, which could be with an AAV.

 

[Sponsor]

 

[Coopatroopa]

Thanks for the reply. It is 2” at and below the standpipe location and 1.5” from the kitchen waste to the standpipe.

The pipe just to the left in the first image I posted is a vent for the main drain..no waste currently goes into it. Would it be better to just shift the kitchen waste to that and leave the standpipe at the proposed location? That way they would each have dedicated drains and vents.

Alternatively I was thinking of venting the standpipe with a wye at the trap arm as shown in the picture below. I could easily tie that into the aforementioned Main line vent pipe on the left.

 

[Reach4]

The pipe just to the left in the first image I posted is a vent for the main drain..no waste currently goes into it. Would it be better to just shift the kitchen waste to that and leave the standpipe at the proposed location? That way they would each have dedicated drains and vents.

That line looks like 1.5 inch What would that vent line be venting I wonder-- a floor drain?

I am not sure you can bring adding just a standpipe here up to current code, but probably close enough to work. Which is a bigger violation... standpipe into 1.5? Standpipe+kitchen into a 2 inch? If just doing it, I think standpipe+kitchen into a 2 inch would be more likely to work. But add the laundry sink and you can meet current code I think. Bonus would be that if you did get that clog under the floor, the tub would fill with kitchen drainage, rather than that material coming out of the standpipe onto the floor.

 

[Coopatroopa]

The vent on the left is 2”. It was previously venting a floor drain but I opened up the floor to fix a broken pipe and replaced everything with pvc. At that time I removed the floor drain but added a 2” line from the main and tied it to the cast iron vent pipe in case I wanted to add anything down the road. Maybe I’ll just move the kitchen drain to that line, replace everything below the drain with new 2” pvc and keep the standpipe on a dedicated 2” drain (it would have a 1.5” vent, but I think that’s ok?)

 

[wwhitney]

Why is the blue circled fitting a san-tee instead of a quarter bend? What is happening above that fitting?

Cheers, Wayne

 

[Coopatroopa]

Why is the blue circled fitting a san-tee instead of a quarter bend? What is happening above that fitting?

Cheers, Wayne

Above the blue circled santee is vent through the roof. Not sure why it’s a santee, is a quarter bend more appropriate?

 

[wwhitney]

No, just questioning why there's a vent through the roof there, as any vent for the kitchen sink would need to at the elevation of the kitchen sink trap. So per your description, you have two unnecessary vents side by side.

As there is no reason to have a vent there, you just want to be certain that nothing else is draining down from above. If you swap the kitchen sink to the left hand line, and put the washer standpipe on the yellow connection, the standpipe will be depending on that stack for a vent. Which would prohibit any drainage from above.

Cheers, Wayne

 

[Coopatroopa]

No, just questioning why there's a vent through the roof there, as any vent for the kitchen sink would need to at the elevation of the kitchen sink trap. So per your description, you have two unnecessary vents side by side.

As there is no reason to have a vent there, you just want to be certain that nothing else is draining down from above. If you swap the kitchen sink to the left hand line, and put the washer standpipe on the yellow connection, the standpipe will be depending on that for a vent connection. Which would prohibit any drainage from above.

Cheers, Wayne

Ok gotcha. The kitchen sink was relocated and is vented with an AAV in the cabinet. the relocated sink drain was tied into the pipe from the old location (which is now a second vent of the blue circled connection) and the vent was left place since I figured it wouldn’t hurt. Nothing is coming from above on either line. It’s a hodgepodge of new and old plumbing.