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Thread: firewall penetrations

  1. #1
    Join Date
    Jul 2008
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    firewall penetrations

    We are dealing with a 4 hour CMU firewall construction. Other than fire sealing/flame stopping does the UL or NEC speak to any restrictions on electrical penetrations or conduits run in the firewall? We are going through final inspections and the fire marshall is now questioning it...
    thanks

  2. #2
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    You will need to look into your local building codes and then the UL Orange Books, AKA, Fire Resistive Directory.

    You can go to the UL web site but it is not very easy to use.

    Roger
    Moderator

  3. #3
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    Jul 2008
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    Quote Originally Posted by rickysib
    We are dealing with a 4 hour CMU firewall construction. Other than fire sealing/flame stopping does the UL or NEC speak to any restrictions on electrical penetrations or conduits run in the firewall? We are going through final inspections and the fire marshall is now questioning it...
    thanks
    Thanks, yes we have consulted the UL books, but there isn't anything there that prevents it. Not sure where this guy is coming from. Again, thanks for your confirmation.

  4. #4
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    UL has to do with product ratings, not installations (except indirectly in that a UL listed product must be correctly installed). The UBC and NFPA Code are what dictates the requirements at the installation and IIRC, does address firewall penetrations of conduit. This presentation outlines it well, specifically page 14 addresses your issue.

    http://www.thomasjdonnellyinc.com/st...conditions.ppt

    So essentially, if your conduit has a fire rating equal to or greater than the fire wall it penetrates, then all you need to do is seal the edges with an approved material.

  5. #5
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    Smile

    Quote Originally Posted by rickysib
    . . . 4 hour CMU firewall construction. . .
    As far as I know, CMU (concrete masonry units) construction needs only grout or intumescent material for the penetrations. I have never heard of the need for internal blocking or fire stopping of the conduit runs. :smile:
    Charlie Eldridge, Indianapolis, Utility Power Guy
    Responses based on the 2011 NEC, unless stated otherwise.

  6. #6
    For information on dealing with fire rated walls read Chapter 7 of the 2006 International Building Code (IBC). If you need specific info on how to seal a penetration 3M has a great site and they even offer free tech support.

    http://solutions.3m.com/wps/portal/3...beS02HSH6W0Mgl

  7. #7
    Join Date
    Oct 2003
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    The fire resistive rating of the wall is only part of the story.

    You have to consider what the wall is being used for. A good example is a Vertical Exit Enclosure, better known as a stairwell. In a High Rise bldg these are two hour fire resistive construction.

    The rest of the story is that penetrations through these wall are NOT permitted unless the item serves the stairwell. Such as electrical for lighting or fire sprinklers.
    I'm an Inspector, what do I know?

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