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Discuss LDF masking gas Leaks in the Plumbing Forum area at

  1. richard978

    richard978 Member

    I work for a gas transport company as a FCO, been out to a SOG at meter and initial tightness test produced 11mb drop. I sniffed it out to a joint and sprayed with LDF which produced some spawn but then stopped.

    Second tightness held completely and failed to pick any readings from the same joint.

    Has anyone heard of LDF masking such a large leak because it’s the first time for me
  2. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    I’d be surprised if it masked 11mbar
    • Agree Agree x 2
  3. firemant

    firemant Plumber GSR

    Where was the reading in relation to the ECV? More likely to be intermittent escape on ECV. (opening and closing redistributes grease)
    • Like Like x 3
    • Informative Informative x 2
    • Agree Agree x 1
  4. richard978

    richard978 Member

    No checked ecv, it was definitely that jount. Left it to dry out and 47 LEL reading. Third test 11 mb drop.

    Ecv leak won't show on TT anyway think about it.

    I just not experienced anything like it
    • Like Like x 2
  5. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    11 mb drop is a fitting that hasnt been soldered so ldf wont make a seal / solve it

    wasnt a sunny day was it?
  6. CBW1982

    CBW1982 GSR Top Contributor!!

    How quick did it drop? Appliances off?
  7. firemant

    firemant Plumber GSR


    Yes, it can. On an old tap, and depending on the distribution of grease at that particular time.
    • Useful Useful x 1
  8. CBW1982

    CBW1982 GSR Top Contributor!!

    Thought about it for a while, I knew an engineer who had a massive drop. He sprayed every visible joint using a cheaper ldf. He called another engineer who had a more expensive brand, and found it on one of the joints he’d already sprayed, a hairline crack on an elbow.
  9. firemant

    firemant Plumber GSR

    Oh, for days of Fairly Liquid
    • Funny Funny x 2
  10. DGT plumbing

    DGT plumbing GSR

    They still make Fairy Liquid you know, they use it for washing pots now apparently.
    • Funny Funny x 3
    • Winner Winner x 1
  11. firemant

    firemant Plumber GSR


    Really? Does it not corrode the saucepans?
    • Funny Funny x 4
  12. richard978

    richard978 Member

    It was a poorly made joint, and LDF was enough to stop it .

    It goes to show the limitations of the tightness test and on low pressure gas.

    Thankfully we are given test equipment that is able to find these things.
    • Informative Informative x 1
  13. DGT plumbing

    DGT plumbing GSR

    Only copper ones.
    • Funny Funny x 1
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