Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14

Thread: Boundary distances for class 1 div 2 room

  1. #11
    Join Date
    Apr 2004
    Location
    Mission Viejo, CA
    Posts
    4,878
    Quote Originally Posted by martnr View Post
    Is there an amount of gas that needs to be used in the room to make it Class I Div 2? Or does any amount of gas being used in a closed loop process constitute a hazardous classification for the area? And if there is an amount that would be below the threshold where will that amount be found?
    The OP indicated that the classification had already been evaluated; presumably by someone qualified to do so. If no qualified person has been involved so far, I suggest getting one. Otherwise, this is essentially a DIY, which this site frowns on.

    To answer this particular post, there is no set amount of volatiles; however, it's obvious that there must be some limits. API RP 500 makes some suggestions in its Appendix D. For gases and fluids, vapor pressures, process flow rates, process temperatures and potential leaks or other releases (such as relief plates or valves or collection spigots) to the surrounding atmosphere all play part in the evaluation. Add to that means and methods of ventilation and you have a start. Appendix E outlines the evaluation methodology.

    NFPA 30 is the typical Standard for evaluating adequate ventilation. Beyond flow rates, evaluating the location for potential "dead spaces" where volatiles could collect is also important.

    It should be noted that NFPA 30 is a "Code", intended for enforcement even if it isn't locally adopted. API RP 500 is only a "Recommended Practice" but it is ANSI sanctioned, so both Standards are enforceable by FedOSHA and most State OSHAs (including Alaska) under their various General Duty Clauses. Like NEC Appendices, API RP 500 Appendices aren't technically part of the Standard, but ignoring them without a damn good reason is still an OSHA no-no.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  2. #12
    Join Date
    Feb 2017
    Location
    fairbanks alaska
    Posts
    5
    There will be only 24 gallons of butane in the entire system. I am wondering if this is low enough to avoid the Class I Div. 2 classification.

  3. #13
    Join Date
    Apr 2004
    Location
    Mission Viejo, CA
    Posts
    4,878
    Quote Originally Posted by martnr View Post
    There will be only 24 gallons of butane in the entire system. I am wondering if this is low enough to avoid the Class I Div. 2 classification.
    If you dumped it all out, would it avoid classifying the location?
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  4. #14
    Join Date
    Jun 2014
    Location
    Denver
    Posts
    18
    Quote Originally Posted by Dale001289 View Post
    Yep, also used by the American Petroleum Institute: API 500 and 540
    Per API RP 500, the division of the CID2 boundary would be depicted by the construction of the building. Are the walls of vapor tight or non-vaportight construction? 3' feet listed above per NEC may grow to 10' (figure 54a). Also, pressures may have an impact on your extents. What pressure class are you operating under within your extraction process? Be aware of Table 1.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •