PVC and Compressed air

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by rockycmt, Oct 21, 2008.

  1. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    I am thinking of running a 1 inch PVC pipe from my garage to my basement from my compressor. Will PVC w/ glue joints support the 100psi? I jave a surplus of pipe and wanted to use this up before buying anything new?

    Chris
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    PVC is not recommended for compressed air applications by any manufacturer.
    The pipe can explode with great force!
    I have seen a hole punched in a block wall by PVC from an exploding pipe!:eek:
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,292
    Location:
    Cave Creek, Arizona
    air

    DO NOT use PVC for compressed air at any pressure. Either steel pipe, or copper tubing with soldered or brazed joints.
  4. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,308
    Location:
    Yakima WA
    With the price of copper and the hassle of using threaded steel pipe it is tempting to look at PVC isn't it. But as others have pointed out, PVC is not a safe material for compressed air. As it ages it becomes more and more brittle and therefore is subject to bursting. When it bursts, shards of plastic are shot out with great force. When I plumbed my shop's air, I used copper. Of course copper was much more affordable at that time, but if I had it to do over, I'd still use copper. I'd just modify my plan to use less material.
  5. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    I've had PVC in my residential garage for compressed air going on ten years. It's ASTM D1785 Schedule 40 and in 1/2" size rated for 600psi.
  6. msgale

    msgale New Member

    Messages:
    90
    Location:
    Ohio
    i have also seen the warning of no compressed air in PVC, but..

    granted, if the pipe explodes there is a problem. But,i cannot understand why water is safer, at the same pressure, than air?
  7. Terry

    Terry Administrator Staff Member

    Messages:
    14,794
    Location:
    Bothell, Washington
    It's because you haven't read what it can do, nor have you worked with it like the rest of us.
    Air is highly compressible, and therein lies the danger.
  8. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Water does not compress. It may be under pressure, but it doesn't compress.
    Because of that there is no stored energy.

    Compressed air on the other hand is just that... Air compressed and stored under pressure... There is a huge amount of stored energy!
  9. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    Read This!
    They don't even want you to test it with compressed air!


    http://www.charlottepipe.com/Default.aspx?Page=PVC40&type=PVCCPVC

    http://www.charlottepipe.com/Documents/PL_Tech_Man/ABS_PVC_pipe_fittings-TM.pdf

    Looks like you might want to repipe that compressed air system!
    Last edited: Oct 21, 2008
  10. Steve_P

    Steve_P New Member

    Messages:
    41
    Location:
    East TN
    all of the "don't do it" replies are correct and this is why pressure vessels, etc, are hydro-tested. Water is essentially not compressible and therefore does not have the potential energy that a compressed gas, like air, does. I know some people use plastic but I certainly would not.

    I did my shop with copper also, 175 psi is no problems on 3/4 cu tube and soldered joints.
  11. rockycmt

    rockycmt New Member

    Messages:
    129
    Location:
    New York
    Point well taken. I WILL NOT be doing this.
  12. Bill Arden

    Bill Arden Computer Programmer

    Messages:
    584
    Location:
    MN, USA
    Glued PVC is bad, but they do make plastic air hose.

    I use polyethylene tubing all the time for pneumatics.
  13. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,308
    Location:
    Yakima WA
    Polyethylene obviously is a totally different material than PVC. If the polyethylene hose bursts, you just have a hole in the hose and a whole lot of lost air.
  14. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    When PVC bursts chunks fly with a lot of force.
  15. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    Maybe I'll just cover it with chain mail. :D
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,292
    Location:
    Cave Creek, Arizona
    Pvc

    In that case copper might be cheaper.

    That makes as much sense as saying that you have had a male lion living in your house for 10 years and there is no way it will attack and kill you. What happened up until today, has no bearing on what could happen 10 minutes from now. And the older PVC pipes get the more fragile they become.
    Last edited by a moderator: Oct 22, 2008
  17. msgale

    msgale New Member

    Messages:
    90
    Location:
    Ohio
    aha, the compressed gas willexplode the pipe if it bursts,..

    whereas the water will just split it w. no major force .

    good point.

    thank you. now i feel better.
  18. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    The rating of the pipe is 600 psi. There is a safety factor on top of that; let's ignore that for now. My compressor shuts off at 80 psi, so the pipe is 7.5 times stronger than it has to be.

    For your analogy to make sense the lion has to be 1/7.5 times my size, or about 21 pounds. Lot of folks have cats that size. :)
  19. sjsmithjr

    sjsmithjr Geologist

    Messages:
    295
    Location:
    Knoxville, Tennessee
    The OP specifically stated an operating pressure of 100 psi.

    The American National Standards Institute/American Society of Mechanical Engineers limit the operating pressure of PVC to 100 psi and prohibit the installation of such systems unless the above ground portion is encased in conduit or casing.

    The Plastic Pipe Institute recommends against the use of PVC for compressed air (or other gas) in exposed piping.

    ASTM says no to the use of PVC for compressed air in exposed piping.

    OSHA says no to the use of PVC for compressed air in exposed piping. It's use for this purpose has resulted in serious injury.

    The industry as a whole says no to the use of PVC for compressed air in exposed piping. Anyone giving advice to the contrary is just plain wrong.
    Last edited: Oct 22, 2008
  20. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    600/100 = factor of safety = 6. But that ignores the factor of safety of the rating, which is probably 2, so that the actual FOS = 12. That big ol' lion in the house is now very small indeed. For a system used intermittently in a residence I see no problem.
Similar Threads: Compressed
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Compressed Air Piping Mar 26, 2009
Plumbing Forum, Professional & DIY Advice, Tips & leak testing new copper repipe with compressed air? Jan 5, 2008

Share This Page