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gas piping.

Gerry1 Member Posts: 3
Hi , i have installed a new gas line from new Gas meter at my house, when the air pressure test is say. at 20 on the guage should that hold indefinetly or will it gradually bleed down.I ran 60 feet of 1 inch black steel and to new water heater location and some three quarter to a new fire insert location,. I notice that the air pressure test wil fall off some over a couple of days and then hold up. does this mean i have to leak test the run ?? Thanks Gerry


  • icesailor
    icesailor Member Posts: 7,265
    Air test:

    I was told by an inspector that I couldn't test gas piping at more than 5# with a special 5# gas test gauge.

    That said, I always tested first to 100# (with no appliances or regulators connected) and if tight, I put the 5# gauge on. My inspectors wouldn't pass anything that didn't have the special 5# gas gauge on it for the inspection.

    As far as the drop in pressure, I have never seen it stated, but I always attributed it to the temperature of the piping and them temperature of the compressed air reaching an equilibrium from the environment.
  • Steamhead
    Steamhead Member Posts: 15,509
    In Baltimore

    the piping must hold 30 PSI for 24 hours, and we must use a 60-PSI gauge for the test. The inspector will bleed the air charge when he arrives, to make sure the gauge actually drops when the pressure drops. Yes, people do try to fake it..... which I believe will result in criminal charges.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • RobG
    RobG Member Posts: 1,850

    Every county in my neck of the woods have their own rules and inspectors. Typically it's a 24 hour low pressure test on gas and a high pressure test on water. In winter in lieu of water testing waste and water lines you may use air. When you put air in the pipes you mark the gauge to ensure it is holding. There are sometimes a small change in pressure due to expansion / contraction but the inspectors usually take it into account. I have had inspectors where I used nitrogen to avoid the exp /con issue. They always release the air at the time of inspection to assure that the system was full of air (or nitrogen). I did have a helper who aired up a house and did not open the petcock on the gauge. I was not watching so I assume it took him about 1/10 of a second to air up the lines. (you can't fix stupid). The inspector did not hold it against me and came back the next day, however my helper did not.

  • jonny88
    jonny88 Member Posts: 1,139
    24 hr test?

    In new York 20 minutes at 3psi does it.If you come across a gasline that has been painted it has to hold 90 psi.
  • ChrisJ
    ChrisJ Member Posts: 13,230
    edited August 2014

    When I ran the gas piping in my house my pressure kept dropping slowly over a few days. We found a leak at one of the few Chinese fittings I used which is the reason I only use Ward fittings now unless I have no choice. After that the line held 40 psi for weeks with very little change due to temperature fluctuation

    Make sure all of the valves to the appliances are shut off as you don't want that pressure damaging the regulators..

    If you can't find the leak, increasing the pressure to 50 or even 100 psi should make it a lot easier. Use dish soap mixed with some water. As others have said the inspector will bleed some air to check the gauge, mine even made the comment "does this thing even work" while doing it. Interestingly, he had no idea I had done all the work my self until I told him at the end. I suppose that's a good thing.

    Please understand I'm a homeowner, not a pro but this is what has worked for me in the past and I believe it to be good advice.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • icesailor
    icesailor Member Posts: 7,265
    Leak Detecting:

     ""Use dish soap mixed with some water. ""

    There are available commercial liquid leak detecting products that are FAR better than dish soap and water. Some make great big bubbles in a fraction of the time that dish soap will make little tiny bubbles.

    Be sure to wipe it all of so it doesn't leave the work looking like a Hackaroo piped it when all the bare steep parts get covered in rust.
  • jonny88
    jonny88 Member Posts: 1,139
    I am all about American fittings but twice recently I had pin hole leaks on ward fittings sorry to go of topic.
  • j a_2
    j a_2 Member Posts: 1,801
    Jonny88 I had the same issue awhile back with ward fittings…One was cast on a steamer, the other was a malleable fitting for a gas line…..I to am all about American fittings…Contacted ward thru my wholesaler, never got a response…..I was disappointed...
  • j a_2
    j a_2 Member Posts: 1,801
    Someone mentioned air test on waste pipe...
    Testing with or use of compressed air or gas in PVC / ABS / CPVC / Cast Iron pipe or fittings can result in explosive failures and cause severe injury or death.
    • NEVER test with or transport/store compressed air or gas in PVC / ABS / CPVC / Cast Iron pipe or fittings.
    • NEVER test PVC / ABS / CPVC / Cast Iron pipe or fittings with compressed air or gas, or air over water boosters.
    • ONLYusePVC/ABS/CPVC/CastIron pipe or fittings for water or approved chemicals.
    • Refer to warnings in PPFA User Bulletin 4-80 and ASTM D 1785.
  • icesailor
    icesailor Member Posts: 7,265
    Its really hard to do a water test on any waste piping when it is 10 degrees F outside.

    Sometimes, you can't get enough water on a job. If you HAVE to test with air, you MUST NOT go over 5# PSI.

    You don't test drainage systems with 125# air, even if it is copper.
  • j a_2
    j a_2 Member Posts: 1,801
    My point was, Charlotte says no air at all…ref ,above copied and pasted warnings….What we think and what we do out here in the field is another story….Who would ever test soil/waste pipe to 125 lbs. thats just plain stupid
  • j a_2
    j a_2 Member Posts: 1,801
    I would not want to be the owner of a company, who instructed an employee to do an air test and got his hand blown off...
  • Gordy
    Gordy Member Posts: 9,514
    Damn so much for the potatoe launcher
  • icesailor
    icesailor Member Posts: 7,265
    j a said:

    My point was, Charlotte says no air at all…ref ,above copied and pasted warnings….What we think and what we do out here in the field is another story….Who would ever test soil/waste pipe to 125 lbs. thats just plain stupid

    Why do you think they offer "Darwin Awards"?

    I once saw a photo of a couple of Darwin Award recipients where they tried to steal a 60,000 volt primary droop on a pole with a saw, to get it out of the conduit. There were two plack masses on the ground. That's not the color of their skin when they were born, it's the color of their clothes and their bodies after the 60,000 volts traveled through them while getting to ground.

    Battery powered Sawzalls are a wonderful thing.