Announcement

Collapse
No announcement yet.

maybe OT: Does anyone here use pvc air lines?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • maybe OT: Does anyone here use pvc air lines?

    I may have started a hornets nest on Practical Mach. Someone posted his new copper air lines and I casually mentioned my pvc air lines. Then the flurry of posts started.

    I use 3/4" schd 40 pvc for air lines at 120psi. I have had the system for about 13 years now. Does anyone else use them? I have already googled for air lines and pvc manufacturers specs. The pvc is impervious to most chemicals and oils according to the Charlotte site and good for 480psi. It said they will withstand extreme pressure beyond the rated pres. but to not use as air lines.
    It's only ink and paper

  • #2
    PVC is ok to use if it is shielded so it can't be bumped and if it blows the shrapnel is contained. Otherwise it is prohibited in many jurisdictions.
    Free software for calculating bolt circles and similar: Click Here

    Comment


    • #3
      The normal PVC Schedule 40 & 80 used for water piping if used for compressed air will at some time fail catastrophically. It is not a maybe, it will fail, and when it does, it usually bursts with needlelike shrapnel being the result.

      There may be some plastics suitable for shop air, but PVC is not permitted.
      Last edited by JCHannum; 09-18-2006, 10:09 PM.
      Jim H.

      Comment


      • #4
        The trouble with PVC is that it's easily cracked and when under pressure sends PVC scrapnel everywhere. I use copper both at home and at work. I had a guy hit a copper airline at work with a forklift, it bent and leaked no explosion. Copper is more expensive but cheaper IMHO. That said in a home shop with the PVC tucked out of the way of getting crushed I suppose it would be fine. I've seen shops with black iron pipe, to me it's even worse than PVC, it's difficult to replace, repair or add drops and it's seam welded so it ruptures if crushed.

        Comment


        • #5
          According to the Plastic Pipe and Fittings Association:

          PVC piping systems should not be used to store and/or convey compressed air or other gases. PVC piping systems should not be tested with compressed air or other gases either.
          Seems like they ought to know.
          Todd

          Comment


          • #6
            hey wait a minute...isnt black pipe used for natural gas and propane? what other kinds of metal pipe are there for air? galvanized i guess...

            <edit> i guess the keyword there was "iron" ? Not trying to be a jacka** or anything, just wondering!

            Comment


            • #7
              I too have had plastic installed for MANY years (prob 20?) and no problems. Few week ago I wanted another drop, so went to my local plastic pipe ONLY supplier to get the handful of ells, tees, etc and it came up that I was gonna run air....guy looks at me, kinda winks, says "you KNOW you aint supposed to use this for compressed air?", so I say, as usual, yep I sure do. We went ahead and talked a few mins and he says he sells a LOT of pipe for air. But, yeah, for some reason its not "approved"

              And then theres the cost..........terrible expensive, and HARD to work with...HAH!!! Love that plastic pipe......I think that extra drop cost me 8-9 bucks and took bout an hour.
              If everything seems to be going well, you have obviously overlooked something........

              Comment


              • #8
                If you have ever seen a failure, you would waste no time in removing the pipe.

                Standard copper pipe with sweat fittings is slightly more expensive, and installs just as easily. Compared to your vision, the few extra dollars is well worth it.

                Black iron pipe (which is not iron), galvanized pipe or copper will split of over pressured. PVC explodes. Believe it.
                Jim H.

                Comment


                • #9
                  pvc air line

                  spent 23 years in shop with pvc schedule 80 air line and use it in my own shop no problem.
                  Every Mans Work Is A Portrait of Him Self
                  http://sites.google.com/site/machinistsite/TWO-BUDDIES
                  http://s178.photobucket.com/user/lan...?sort=3&page=1

                  Comment


                  • #10
                    http://www.osha.gov/dts/hib/hib_data/hib19880520.html
                    Free software for calculating bolt circles and similar: Click Here

                    Comment


                    • #11
                      Go with 3/4 inch copper pipe and copper tubing for all of your air lines. Why? For heat dissipation. Cool air holds less moisture and your air tool and your plasma cutter will be much happier.

                      Comment


                      • #12
                        I have worked with several plant air systems and have been forced to use PVC on a couple of occasions when the bean counters or purchasing agents got involved with the cost aspect.

                        It can work, but it has to be well supported. I have had success with installations where the piping was installed in an obsolete piping run of a larger diameter. In these cases, the PVC was fully supported, and not subject to mechanical stress, only pressure.

                        I suspect some shops with piping under 1" or smaller may not experience the problems of larger diameter systems, especially if it is well supported. The installation is still a guessing game, and the stakes of guessing wrong are too high. I would never recommend it. I have seen many more failures than successes.
                        Jim H.

                        Comment


                        • #13
                          1980, my first job out of school, we had PVC piping for 120psi air. I thought nothing of it, I had also never seen an industrial accident at that time. I know a little more now, I would never go near a PVC air line again. A couple more bucks for the safety of everyone who enters the shop is money well spent.

                          Comment


                          • #14
                            I was in a woodworking facility in the mid 1980's when the PVC air line shattered. Nobody was hurt but it sure scared everybody. And this was a 20,000 sq ft building with PVC airline over the whole place....had to replace it all. Installation was 18 feet up, so nothing hit damaged it before the failure, but I don't remember the schedule or how well it was supported, which could have been a factor.

                            Humorously the same shop had PVC for their dust collection, and that didn't work longterm either due to major static electricity problems caused by wood dust flowing at high speed thru the piping !

                            Comment


                            • #15
                              I worked at one place where PVC was used for the air. It was a special kind, green color, schedule 80, and supposedly more resistant to oil. This particular PVC pipe was made exclusively for compressed air. There were no failures with the green pipe. One time a very old white sch 40 pipe broke at a threaded male fitting. That pipe was unsupported, putting a lot of stress on the fitting. There were no shards, it simply broke in two.

                              I used CPVC (because I had some left over from another project) at my old shop. Never had any problems. The CPVC was run over head, all the drops were flexible hose, so even if the overhead line had burst, it would not have been close enough to inflict damage (PVC projectiles would lose velocity very quickly).

                              My new shop has PVC running underground from the outdoor compressor to the shop. I used the PVC for corrosion resistance. I'm certainly not worried about the underground pipe hurting anyone. Galvanized iron will be used inside the shop.

                              Comment

                              Working...
                              X