Second plumbing test

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Tim F, Jun 5, 2006.

  1. Tim F

    Tim F New Member

    Jun 5, 2006
    I'm installing a half-bath (toilet, sink) on my second floor. I'm doing the work myself. Right after the rough-in was finished, the city inspector came in to inspect. At that point, I had to perform an air pressure test on the new lines. (Plug up vents and drains with test balls, which was a major pain since the balls kept slipping out and it was hard to fill them up and etc....). It passed.

    After I am done with the rest of the project (i.e. with sink and toilet in place and hooked up), the inspector will come back to have me perform a SECOND test. This second test will also be involve closing up the vents and drains, but will also involve putting a flexible plastic tube down into the trap of the toilet.

    Can anyone fill me in on the details of this test? I'm not really confident that I know what I'm supposed to do.

    The tube is supposed to be shaped into a U-shape. One end goes down into the toilet. The other end I blow on, to blow air into the system. Then, I supposedly read the level of the water in the tube? Okay, but how do I get the air into the system if I have water in the tube? Do I use two tubes, one to blow air into the system, and one to read the pressure?

    What is being tested with this test?

    Any help would be much appreciated.

    Tim F. Minneapolis,MN
  2. Master Plumber Mark

    Master Plumber Mark Master Plumber

    Feb 6, 2005
    Sensitivity trainer.. plumber of mens souls
    indianapolis indiana - land of the free, home of
    pressure test

    its a total pain in the butt.....

    what it is all about is they want to be sure that the
    pvc will hold a water teat for 15 minutes??

    Its more of a "make work for the inspector" than anything else...

    make the guy feel important ... all over nothing....

    usually you got to put a pump up test plug into the toilet and it pumps up
    with air, then you got to plug up the lav and bath line
    with smaller test balls and pump them up with air...

    then usually down stream in the basement you got to plug up the whole line
    again ---- usually at a clean out with another test ball

    a few times on bigger jobs we actally had to install a clean out in the stack
    just because of this rediculous stupid test....
    fora place to isolate the system
    to be able to just test out the new work...

    then you go up on the roof with a hose and fill up the whole syatem with water...

    if their are no leaks in youir pvc lines ----it passes.....

    thats all their is to it....

    this system will NEVER ever have to withstand that much pressusre

    but it keeps them busy and makes them feel useful....

    just BE CAREFUL when you take out the bottom test plug

    when the inspection is over....

    it will be under some weight and Ihave caught my hand--fingers

    in the pipe before trying to retreive that plug with water above it.....
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  4. tbplumbloco

    tbplumbloco New Member

    Jun 5, 2006
    2nd test

    I think you are confusing the second test with which is actually called the final plumbing test.According to your post you have already had your rough-in test w/air + passed,now your fixtures are set,the inspector wants that section of DWV capped at the vent and capped or plugged where the waste pipe ties into existing DWV.With that section isolated the water level in the toilet will be raised,locally we call this the "bowl test",if there are no leaks in your system the water level raised in the toilet bowl will maintain usually 1"of water column,if the water level cannot hold the 1"of water column your DWV has a leak,usually the leaks occur at the wax seal of the WC or the P-trap on the sink and yes sometimes by a screw or nail driven into that section of DWV.I hope this gives you a little more clarity,the inspector is a public servant (taxes,permit fees)with this knowledge confirm this with him or her and perform this test before he or she comes out for the final test so you know that your system is air tight.
  5. dubldare

    dubldare Plumber/Gasfitter

    Sep 14, 2005
    Here's another fine example of differing codes in different areas.

    What Tim is describing is MN's final air test, also known as a manometer test. In this test, all fixtures are connected and the building drain and vents are plugged. One end of a small tube is inserted through the trapway of a toilet, the other end is attatched to the manometer. The system is then checked to hold 1" of water column.

    This test subjects the low pressure air against trapseals, tubular piping after the trap's weir, the trapways of water closets, clean-out plugs and bowl waxes. This test virtually eliminates any issues of sewer gas.

    The pressure of 1" water column is used as the minimum trap depth is 2". This is also a higher pressure than what would result in a properly sized and installed DWV system.

    Now, on to your question, Tim. I generally use 2 small tubes, one for the manometer, the other to blow air in. As the pressure is met on the manometer, I pull out the tube I was using to blow the air in with. An alternate method would be installing the tube and manometer and then adding a slight amount of water.

    I do not recommend the water method for two reasons.

    1) Adding water to the system is rather slow to react on the manometer, and it is very easy to overfill the system, blowing air past a trap seal.

    2) Adding water to the system decreases it's air capacity. In this test air is your friend. Because air is compressible and water is not, a slight leak will show up much sooner with water in the system. Manometer tests are much simpler on large scale installations, because there is a larger reserve of air.

    Now, the amount of air you'll have to administer is very small, perhaps less than 1/2 of what you normally exhale. The inspector will want to see evidence of blowback, which is the administered air 'blowing' back out of the tube.

    Tim, make sure you mock this test up prior to calling the inspector. I've seen countless occasions where several hours, if not days, have been spent trying to get this type of test to pass, and that's with plumbers trying to do it. I've even had several new toilets with leaking trapways, which cause the test to fail.

    MN Plbg Code defines the test length as 'the duration of the inspection'. At times when I've failed after a minute of two and the inspector requires a retest, I'll spend hours on the system and get it to hold flawlessly for an hour or more. When the inpector returns, it's maybe a 15 second test, lol.

    If you find that the test is failing, look at any piping changes you've made since the rough-in air test. Closet collar, bowl wax, tubular piping, etc.

    Best of luck. If the inspector can make it a short visit, you'll have done good and he'll thank you. Mpls plumbing inspectors are all former plumbers, and put up with a lot of s***, so it's best to stay on their good side.

    Last edited: Jun 5, 2006
  6. Tim F

    Tim F New Member

    Jun 5, 2006
    should I just buy the test balls?

    Thanks Darren, and others. This is very helpful.

    One of the pains in the neck, which I'm sure you're aware of, is the fact that the average but experienced do-it-yourselfer like me doesn't own a nice set of test balls. For the first air test, I rented the balls (also had to rent the pressure gauge thing that you use to pump air in and measure it). Each ball rents for $6. One popped while I was using it. The whole thing required about 4 trips to the rental shop. Once I finally had the test successfully set up, I had to beg the inspector to come to my house and give me the okay before I racked up further rental charges. He made the trip. He's a good guy. But it sure was a major pain.

    Anyhow, do you think I should go ahead and just buy these balls? I need three of them: a 3", 2", and 1 1/2". I also need to use air-hose extender leader things (sorry, don't know what they are called) in order so that I can push the ball into the test tee and then down the pipe a ways and still be able to pump the air in. Without the extender things, I can't get the pump attached/un-attached to the balls, since they are around a sharp corner and down a pipe. Any opinions/advice on this?

    Thanks again for the help.

    Tim F.
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