DWV vacuum test

[BenjaminCoop]

Well this morning I finally got through to the inspector to ask a couple final questions for my rough-in inspection. He surprised me by saying they no longer allow the 5 PSI pressure test for DWV. Now it's 10ft head of water, or -2 PSI vacuum test. The water test would be extremely complicated and would require me to add a test tee or cleanout further downstream in the old cast iron in my basement, as I have already tied in all the new basement bathroom DWV.

Anybody have experience with the vacuum test? The inspector said something about a shop vac, but now I am wondering how that would actually work. Maybe a check valve of some sort screwed onto one of my test plugs? Would this one from Menards work? I'd need some adapters for what I'm currently using, Sioux Chief Test Titan plugs, with male garden hose thread. I could duct tape my shop vac hose to the valve and see what kind of vacuum it can create. I suppose I'll change out my pressure gauge for a vacuum gauge, like this one from Grainger.

I can't even find much info on this kind of DWV test by googling it, so I'd appreciate any input.

 

[John Gayewski]

An inflatable test ball won't work? I've not done a vacuum test, but a leak won't show itself very well at all. Water is gonna be way better.

Anyone who let anyone test PVC with air should get their brain checked. Very dangerous.

 

[Sponsor]

 

[Reach4]

It is going to be a lot easier to seal against a 5 ft head of water than a 2 psi vacuum. Air leaks in thru lot smaller holes than water leaks out of.

Of course the vacuum does not need cleaning up if there is a leak.

5 ft of water is only 2.17 psi...

 

[BenjaminCoop]

I had no trouble getting it to hold 5 PSI of air so the 2 PSI of vacuum should be no trouble. With the air test, I use a test tee in a cleanout just before the new plumbing ties into the old cast iron. There is no cleanout downstream of the new tie-in point, so how could I do the water test? I would somehow need to occlude the old cast iron downstream of all the new work. I could put a test balloon through my new cleanout and push it far enough downstream before inflating it, but then how would I be able to both seal the cleanout for the water test and release the test balloon to let the water drain through after the test? Sorry if I'm missing something...

 

[John Gayewski]

I had no trouble getting it to hold 5 PSI of air so the 2 PSI of vacuum should be no trouble. With the air test, I use a test tee in a cleanout just before the new plumbing ties into the old cast iron. There is no cleanout downstream of the new tie-in point, so how could I do the water test? I would somehow need to occlude the old cast iron downstream of all the new work. I could put a test balloon through my new cleanout and push it far enough downstream before inflating it, but then how would I be able to both seal the cleanout for the water test and release the test balloon to let the water drain through after the test? Sorry if I'm missing something...

The one time I saw someone silly enough to use air to test PVC. Literally the only time I've seen this, the guy had to get stitches above his eye. So there's that. Quit doing things that aren't safe.

I can't really figure out how to do your test for you without being there. When I've had to do this a two way cleanout is usually the best. Or we will skip one joint which would be the very first, as the test isn't for accessible joints right next to a cleanout which is easy to spot at any time. The hose can go inside of the pipe from the roof where the plug is tied off. These ideas aren't for me to implement. They are for you to figure out.

 

[Jeff H Young]

I've actually glued a cookie in the PVC at the cast iron to plastic junction then immediately above it at a santee or clean out tee put a temporary hose bib , both to fill and drain water down. that way I could pull band off and shop vac last gallon or less out.
Or just pull your no hub coupling and put a jim cap on end with a hose bib to drain out?
My method doesn't make sense unless you don't have a test weenie but I've done it once or twice .
I don't fully get the problem but maybe this helps.

 

[BenjaminCoop]

I passed my inspection last week and wanted to follow up here in case it might help someone in the future. Here's a few pictures.

Furthest upstream: from left to right, shower drain (with vacuum gauge), vent for shower (with AAV in bump out behind shower), toilet

Downstream from the toilet: washer standpipe vented independently, and laundry sink and lav with a double fixture fitting.

With all the vents and drains plugged, this is where I created the vacuum for the rough inspection. I used a shop vac which got me just past -2 PSI. I had initially screwed the PVC ball valve onto the threaded P-trap adapter, but in trying to make a good seal I overtightened it and broke the threads. So I tried again with a proper schedule 40 threaded fitting and it worked.

This is where I tied the new stuff into the old cast iron. The yellow is a Cherne Clean-seal test plug, so everything after that including the fernco couplings were not tested under vacuum. The inspector didn't have any problem with my setup and said I could simply cap the cleanout and bury it, as the toilet upstream provides the necessary cleanout.

I hope this helps somebody else. I'm in Columbus, Ohio which is under the 2017 Ohio Plumbing code, which I believe is 2015 IPC with amendments.

Thanks everybody for your input, both on this and on a couple other questions I posted over the past year.

Benjamin

 

[Terry]

Really nice work. I bet the inspector was very happy with your work.

 

[Jeff H Young]

I passed my inspection last week and wanted to follow up here in case it might help someone in the future. Here's a few pictures.

Furthest upstream: from left to right, shower drain (with vacuum gauge), vent for shower (with AAV in bump out behind shower), toilet
View attachment 87350
Downstream from the toilet: washer standpipe vented independently, and laundry sink and lav with a double fixture fitting.
View attachment 87351

With all the vents and drains plugged, this is where I created the vacuum for the rough inspection. I used a shop vac which got me just past -2 PSI. I had initially screwed the PVC ball valve onto the threaded P-trap adapter, but in trying to make a good seal I overtightened it and broke the threads. So I tried again with a proper schedule 40 threaded fitting and it worked.
View attachment 87352

This is where I tied the new stuff into the old cast iron. The yellow is a Cherne Clean-seal test plug, so everything after that including the fernco couplings were not tested under vacuum. The inspector didn't have any problem with my setup and said I could simply cap the cleanout and bury it, as the toilet upstream provides the necessary cleanout.

View attachment 87353

I hope this helps somebody else. I'm in Columbus, Ohio which is under the 2017 Ohio Plumbing code, which I believe is 2015 IPC with amendments.

Thanks everybody for your input, both on this and on a couple other questions I posted over the past year.

Benjamin

Good Job Ben!

 

[Brian Kehlmeier]

Wow. I am facing the exact same challenge Ben. How did you hook the shop-vac up to the ball valve? I also can't tell how you hooked up the vacuum gauge.

and kinda crazy. I am in Columbus as well.

 

[Jeff H Young]

Wow. I am facing the exact same challenge Ben. How did you hook the shop-vac up to the ball valve? I also can't tell how you hooked up the vacuum gauge.

and kinda crazy. I am in Columbus as well.

hopefully he is still around after nearly a year to answer for you Ive never do9ne a vacuum test understand theconcept but dont have a guage

 

[Brian Kehlmeier]

For those needing more guidance and the parts required, see my thread:

DWV Vacuum Test - How I did it.

This site has been incredible to me for years and here is my chance to contribute. Here in Columbus, OH, pressure testing is not available for rough inspection and in my case, I did not want to perform a test with water as failure would result in water damage to the existing interior (my...

terrylove.com

 

[Fitter30]

10' of head = 4.32lbs