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Thread: Adjacent Room Classification?

  1. #1
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    Adjacent Room Classification?

    I have a gas meter room that the architect has classified as Class I Div 2. There is an adjacent room that is not classified, and as far as I know there are no penetrations from the classified room into it. The edges of the doors are 4.63 ft apart. Must the second room share the same classification due to the proximity of the doors?

  2. #2
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    Quote Originally Posted by gadfly56 View Post
    I have a gas meter room that the architect has classified as Class I Div 2. There is an adjacent room that is not classified, and as far as I know there are no penetrations from the classified room into it. The edges of the doors are 4.63 ft apart. Must the second room share the same classification due to the proximity of the doors?
    Sure, why not? It sounds like the gas meter room was misclassified in the first place.

    Classifying a location isn't rocket science but it isn't trivial either.

    Whenever an enclosed space has a potential internal source, without sufficient additional information disclosed, it can only be Division 1. Division 2 isn't an option unless the space is properly purged or adequately ventilated. It may even be unclassified without purging or ventilation if the piping is totally closed with no intended openings to atmosphere such as pressure relief ports or spigots. However, possible valve leaks, without adequate ventilation would render the space Division 1 as I originally mentioned.

    If the meter room were properly classified, it is possible, depending on other piping geometry and process conditions, that the adjacent room, or part of it, could also be classified. Without full installation details I couldn't say.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  3. #3
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    I'm trying to get the particulars for this little cluster of rooms. Unfortunately I don't think I can upload snip of the PDF. The Port Authority of New York/New Jersey is a little touchy about that sort of thing. There is a separate gas regulator room within the gas meter room with cast-in-place concrete walls and a pre-cast lid that is 3-hour rated. My concern is that we have some detection and notification appliances in this "suite" and I want to make sure if they need to be XP rated or else removed.

  4. #4
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    Quote Originally Posted by gadfly56 View Post
    I'm trying to get the particulars for this little cluster of rooms. Unfortunately I don't think I can upload snip of the PDF. The Port Authority of New York/New Jersey is a little touchy about that sort of thing. There is a separate gas regulator room within the gas meter room with cast-in-place concrete walls and a pre-cast lid that is 3-hour rated. My concern is that we have some detection and notification appliances in this "suite" and I want to make sure if they need to be XP rated or else removed.
    This is definitely new, relevant information. See Section 500.7(K). Read the WHOLE Section including the INs very carefully.

    I confess I'm not a fan of gas detection schemes. They have very limited applications (actually only 3) and, where properly applied, most gas detection and associated equipment must be listed for Class I, Division 1. Other equipment may or may not be specifically required to be suitable [500.8(A)] for Division 2. They also have some fairly rigorous documentation and maintenance requirements in the Standards listed in the INs. While those Standards are in INs, the ANSI sanctioned ones are OSHA enforceable.

    The interior of the "regulator room" is almost certainly a case of Subsection 500.7(K)(1).
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

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