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Flexible Gas Piping do's and dont's

jmholt Member Posts: 2
Had a question about when it is acceptable to use flexible gas piping and when it is not. One of my co-workers came across a commercial rooftop unit approximately 150,000 btuh on a job that was hard piped in 3/4 up to the gas-cock and then run in flex 3/4 to the gas valve (approximately 3 ft) and he wanted to know if it was up to code. Any suggestions or versions of the codes books to refer to?


    EBEBRATT-Ed Member Posts: 13,427
    That would be legal as far as I know. Did they use a flexible appliance connector or CCST?

    I would rater have it hard piped if it was mine
  • jmholt
    jmholt Member Posts: 2
    Here is a picture he sent me. When I looked closer I could see his model- looks like a Lennox KGA240 which would almost double the btuh I thought he was working with. Pipe size may be 1” looks to be CCST
  • BillyO
    BillyO Member Posts: 276
    Not in NYC
  • Ironman
    Ironman Member Posts: 7,119
    CSST tubing cannot be used as a connector, but a listed and approved (manufactured) CSST connector can be.

    In other words, it has to be a manufactured one, not field fabricated from tubing.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • unclejohn
    unclejohn Member Posts: 1,824
    That would have been one union two 90's and two 6" nipples. Whats the world coming to.
  • Henry
    Henry Member Posts: 996
    That is NOT an approved flexible connector. Also if you are in an area that has frost, drip pockets are prohibited because they can crack.
    EBEBRATT-Ed Member Posts: 13,427
    CSST can't be used as a connector which is why I asked about that in my first post.

    He should have hard piped it. It's close enough to do it with nipples wouldn't have needed a threader.

    Not sure if I have seen appliance connectors rated for outdoor use but they must be available
  • GroundUp
    GroundUp Member Posts: 1,572
    Where's the regulator? There should always be 2# gas to the roof, regulated down at each unit
  • mattmia2
    mattmia2 Member Posts: 7,721
    I thought that was a power steering hose for a second until I realized it was a short piece of the type of csst that has a metal braid and rubber on the outside to try to keep it from getting perforated in a lighting strike.
    EBEBRATT-Ed Member Posts: 13,427

    It's probably low pressure gas you can see the pipe coming up through the roof the main must be run indoors. Very common around here. A lot of cities and town don't have high pressure gas
  • rick in Alaska
    rick in Alaska Member Posts: 1,420
    Unless I remember wrong, you can run csst directly to an appliance if it not a portable unit. At least I have seen a few done this way, and the gas company allows it. The line also has to be protected from damage. I can not remember if it is a gas code that allows it, or if it is a manufacturers thing that allows it. I don't have access to either one of those codes right now.