Results 1 to 10 of 10

Thread: Interior Wiring method in Assembly Occupancy - Fire Rated Exterior only -- 518.4

  1. #1
    Join Date
    Jan 2011
    Location
    Pennsylvania, USA
    Posts
    48

    Interior Wiring method in Assembly Occupancy - Fire Rated Exterior only -- 518.4

    There is a church project that a friend of a friend of mine is working on and the electrical contractor is saying that he needs to use fire rated wire by code, citing 518.4(A), which deals with wiring. The construction type of the building is 3B, which only requires the exterior wall to be 2-hour rated.

    Are the "fire rated" wiring methods required for interior work in a building that is type 3B?

    I'm also digesting this portion of the NEC now - but need your expertise...

    Thanks for all input!

  2. #2
    Join Date
    Jan 2011
    Location
    Pennsylvania, USA
    Posts
    48

    Location: MD

    Note - project is in Maryland. Thus 2014 NEC applies.

    The 2014 handbook has some good notes (pages 706-707) - but I need some aid digesting this, relevant to the original posted question.

    Thanks again.

  3. #3
    Join Date
    Jan 2011
    Location
    Pennsylvania, USA
    Posts
    48

    Follow-up

    Well...hearing no responses, here was my response to my friend:

    "The 2014 handbook has a great explanation in this section. Exhibit 518.2 there shows a very similar situation to the one that your friend has posed.

    My initial take is that yes, the interior work needs to comply with section 518.4(A). The handbook notes state that these wiring methods apply to “any wall, floor, or ceiling within an assembly occupancy, as classified in 518.2.” Wiring methods for areas that are not within assembly occupancies are covered in section (B). Section (C) gives some additional relief, for areas including “places of religious worship” “provided these wiring methods are installed behind a surface that has a 15-minute finish rating."

    I'd appreciate anyone's more in depth experience clarifying or expanding on this. Thanks again.

  4. #4
    Join Date
    Oct 2007
    Location
    New Jersey
    Posts
    5,846
    Quote Originally Posted by jonathankpa View Post
    Well...hearing no responses, here was my response to my friend:

    "The 2014 handbook has a great explanation in this section. Exhibit 518.2 there shows a very similar situation to the one that your friend has posed.

    My initial take is that yes, the interior work needs to comply with section 518.4(A). The handbook notes state that these wiring methods apply to “any wall, floor, or ceiling within an assembly occupancy, as classified in 518.2.” Wiring methods for areas that are not within assembly occupancies are covered in section (B). Section (C) gives some additional relief, for areas including “places of religious worship” “provided these wiring methods are installed behind a surface that has a 15-minute finish rating."

    I'd appreciate anyone's more in depth experience clarifying or expanding on this. Thanks again.
    That "15 minute finish rating" is basically 1/2" gyp-board that's properly taped.

  5. #5
    Join Date
    Apr 2006
    Location
    Simi Valley, CA
    Posts
    8,357
    I highly doubt that a church is a 3B Occupancy. Most churches are an A occupancy.
    I can build anything you want if you draw a picture of it on the back of a big enough check.

    There's no substitute for hard work....but that doesn't mean I'm going to give up trying to find one.

    John Childress
    Electrical Inspector
    IAEI / CEI / C10
    Certified Electrical Inspector

  6. #6
    Join Date
    Oct 2007
    Location
    New Jersey
    Posts
    5,846
    Quote Originally Posted by cowboyjwc View Post
    I highly doubt that a church is a 3B Occupancy. Most churches are an A occupancy.
    3B is the construction type, which is not the same as, say, a "B" occupancy.

  7. #7
    Join Date
    Feb 2013
    Location
    Aspen, Colo
    Posts
    1,993
    He could be talking about IIIB as the 2hr exterior wall is the only rated assembly for IIIB -- but remember 518 article covers all buildings or portions of buildings or structures designed or intended for the gathering together of 100 or more persons for such purposes as deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar purposes.

    there may be some building area's not considered an assembly -- & 15 min finish rating is generally 1/2" drywall
    CircuitRyder --- Unfortunately not all good ideas are code enforceable.

  8. #8
    Join Date
    Jan 2011
    Location
    Pennsylvania, USA
    Posts
    48

    Merci

    Thanks, everyone, for the help. I greatly appreciate your time to assist. This forum is a great resource.

  9. #9
    Join Date
    Apr 2006
    Location
    Simi Valley, CA
    Posts
    8,357
    Quote Originally Posted by mwm1752 View Post
    He could be talking about IIIB as the 2hr exterior wall is the only rated assembly for IIIB -- but remember 518 article covers all buildings or portions of buildings or structures designed or intended for the gathering together of 100 or more persons for such purposes as deliberation, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar purposes.

    there may be some building area's not considered an assembly -- & 15 min finish rating is generally 1/2" drywall
    That is true, but depending on the layout, which we haven't seen, the exterior may not be the only rated walls. I can't tell you how many engineers miss rated walls at plan check.
    I can build anything you want if you draw a picture of it on the back of a big enough check.

    There's no substitute for hard work....but that doesn't mean I'm going to give up trying to find one.

    John Childress
    Electrical Inspector
    IAEI / CEI / C10
    Certified Electrical Inspector

  10. #10
    Join Date
    Feb 2013
    Location
    Aspen, Colo
    Posts
    1,993
    Quote Originally Posted by cowboyjwc View Post
    That is true, but depending on the layout, which we haven't seen, the exterior may not be the only rated walls. I can't tell you how many engineers miss rated walls at plan check.

    The most common in B's is an occupancy separation -
    CircuitRyder --- Unfortunately not all good ideas are code enforceable.

Posting Permissions

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