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Manifolds for Cryogenic Liquid Containers

  • Monday, February 19, 2018 9:11 PM
    Message # 5745938

    I need some clarification from the Forum group.

    I recently was performing a Verification of a new Source of supply, a Carbon Dioxide Manifold that included Cryogenic Liquid Containers and cylinder reserve.

    This manifold was supplied from a well known equipment supplier.

    During our review of the source manifold, I quickly noticed that this manufacturer does not include Local signals for "Reserve In Use" and "Reserve Pressure Low". They do include a "Local" signal for "Changeover".

    My concern is that a manifold in this category is required to include "Local Signals" that visibly indicates the operating status of the equipment. I reviewed this manufacturers installation information and their Operating and Maintenance Manual, and there is no mention of how they intend to display these required Local Signals.

    I spoke with their technical support department, and they kept describing the Master Alarm Signals. When I questioned about the Local Signals required at the source equipment site, they questioned what code reference I was referring, and than repeated the description of the Master Alarm Signals. I expressed my concern about their supplying a source supply that did not include all of the applicable code requirements. They were either not understanding what a Local Signal was, as far as the code reference, or they were hoping that I would accept their Master Alarm Signal answer. (As an interesting end to that conversation, the technical support person, obviously exhausted with their in ability to explain how the two missing Local Signals were to be displayed at the source equipment, they finally said "well we've been selling these for twenty years so it must be code compliant" and than they hung up.)

    In an effort to complete the verification for the facility, I labeled the header pressure gauge with a label that indicates the alarm point, and the reserve supply gauge with a label that indicates the pressure that the reserve supply will start to feed.

    Isn't it the manufacturers responsibility to provide a source equipment manifold that meets all code requirements, or at least describes in their supplied material how the installer is to display the missing Local Signals?

    Any input would be greatly appreciated.


    Bob Kroening (firebob1)

  • Tuesday, February 20, 2018 7:37 AM
    Reply # 5759487 on 5745938
    Al Moon (Administrator)

    YES / NO / MAYBE


    It's all about the code writer's ( NFPA 99 )  


    In the beginning ( like the bible ) or NFPA 99 2002 Edition

    NFPA 99 started with a new requirement for local signals.

    Their was some verbiage with the wording actuate a local signals, but as other editions were written, this was not as strongly noted.

    In 2002 & 2005: the wording flag indicator or light were used.

    In 2012: the wording flag indicator, light or other manifestation that allows you to know what conditions are present.

    So, these signals ( are to provide a visible indication only, of the operating status of the equipment.

    Yes a label and / or light is the only requirement.


    In your situation, I'm totally convinced that the suppler was lost in a phone conversation on this subject.


    But in the end, a label marker or black magic marker, is all you need to past NFPA 99 Code. ( take a survey of most the bulk oxygen sites around the USA and look at the final line regulator sets / the signals for reserve in use and reserve low cylinder pressure have a small label listing the local signals pressure settings )  



    ? question for you - was their a relief valve on each header piped to outside per code ? 



    Last modified: Tuesday, February 20, 2018 11:49 AM | Al Moon (Administrator)
  • Tuesday, February 20, 2018 10:37 AM
    Reply # 5766795 on 5745938

     I agree with Al and Bob I have seen your situation before,  you did the best thing. 

  • Tuesday, February 20, 2018 6:28 PM
    Reply # 5786059 on 5745938


    Yes there was a relief valve on the reserve line downstream of the reserve header regulator.

  • Wednesday, February 21, 2018 6:52 AM
    Reply # 5815767 on 5745938
    Al Moon (Administrator)

    Check Out Sections #'s

    for the code requirements

    for a pressure relief valve

    on each header of the manifold itself.

    This relief is to be located on each the header

    between the cryogenic vessel shutoff valve and the

    manifold cabinet shutoff valve. 



  part (9) & (10)

    plus part (4) 

    and part (2)


    Now the fun part / I have a secret ! 

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