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Passed Rough, Need Firestopping?

Tbakes | Posted in General Discussion on July 10, 2006 11:05am

So I just passed rough inspection and elect inspection on a reno I am doing myself.  The building inspector wass nice and passed, but said I need firestopping for all of my penetrations into the attic / basement where I ran wiring.

Doesn’t seem unreasonable, but buildings have been fine for years without it.  I know in the industrial side where I work firestopping is done, but didn’t know it was a requirement for residential.

So, the question is, do I just run down to the BORG and buya few tubes of the red 3m chaulk?  Any tips? I am only going to do the penetrations that I can get to from the rennovation, so half the house will not have it… 

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  1. firedude | Jul 10, 2006 11:59pm | #1

    while you won't have it in the old part of the house, the newer part will be that much safer for having it - one thing to realize is the material for doing firestopping probably didn't exist when the old part was built - kind of like bike helmets, "when I was young, we didn't need helmets" - truth is when I was young, they didn't make bike helmets, so we didn't have them - was that "good"?, doesn't matter, no helmets back then
    okay, to actually answer your question - 3M and Hilty make various fire caulks and fire stopping mechanisms - check them out and you should find something that works - there are "chokes or collars" for plumbing penetrations - they're fastened to the flooring around the plastic pipe and when it gets too hot, they expand to seal the opening
    hope this helps

  2. User avater
    dieselpig | Jul 11, 2006 01:39am | #2

    Yep... dats da code.  All the small stuff gets caulked with 'fire stop' caulking or mortar.  Larger holes get plugged with rockwool or that green firestop insulation. 

    View Image
  3. BryanSayer | Jul 11, 2006 01:52am | #3

    An alternative is the gray/green clay stuff, at least it used to be. Should be in the electrical department.

  4. Oak River Mike | Jul 11, 2006 02:03am | #4

    Although it does sound extreme, it is a good idea.  I know some will say its overkill but I have my CBO and was formelry on the inspector side and after speaking with some of the local fire department guys, I've seen alot of the "if they only had done this..." while they are examining a residential fire.

    For the price of a few good tubes of 3M caulk (what $10 a tube?) I think its good peace of mind.

    BTW, watch what kind of fire caulk you get as each is rated differently and some will not adhere to certain materials.  If I recall, the green (or is it blue?) does not stick to steel very well...

    Mike

    1. mclaren | Jul 11, 2006 05:12am | #7

      Hi,

      Mclaren here from Baltimore....

      Thought I'd chime in on the subject.

      There are two basic types of fire caulking.

      Elastomeric and Endothermic.

      Elastomeric for caulking/sealing around wires and small

      penetrations, metal pipe etc.  It stays flexible.  Relatively inexpensive.

      Endothermic for caulking around Pvc pipe or anything which may

      combust, it swells in the presence of heat to seal the void.

      costs a little more, but could be the difference of getting you and

      your family out of the house!  Larger openings require the mineral

      wool previously mentioned for backup.

      Here in Baltimore we see a good bit of WR Grace Flame Safe as

      well as the Hilti.

      Mclaren

  5. renosteinke | Jul 11, 2006 02:31am | #5

    The requirement is that penetrations be sealed, in a manner that maintains the fire rating of the wall or ceiling.

    In other words, a perfectly acceptable job might be done with joint compound and tape. The fancy caulks are more for convenience and versatility than anything else.
    The simple rule is to patch with a like method. 5/8 drywall needs 5/8 of joint compound in the space. Block and brick need a masonry patch, Etc.

    Now, that's FIRE-stopping. DRAFT-stopping is another matter entirely. That can be most anything to seal- in our walls, that's what those wood blocks are for. In a non-fire rated floor or ceiling, one could plug the holes with expanding foam.

    Code issues aside, such attention to detail might help limit future damage by vermin or water leaks.

    1. Tbakes | Jul 11, 2006 05:34am | #8

      Thanks for all the replies - just got back from the borg with 3 tubes of 3m yellow 2 hour chaulk.

      I have no problem with doing it - should be pretty easy.  I agree that this half of the building should be a bit safer for it and in the grand scheme of this remodel, this is nothing!!

       

    2. firedude | Jul 13, 2006 02:26am | #10

      have to disagree with the idea of 5/8 mud is the same as fire caulk - mud will dry and fail under fire conditions and shouldn't be "code" acceptable - heard about a guy who dyed the mud red to pass inspection but still got "caught" - easier to fill the penetrations when you're making them than to go back - can't seem to get the plumbers and electricians to understand......

      1. renosteinke | Jul 13, 2006 03:09am | #13

        A former chief engineer at Ford was famous for saying "Everyone has an opinion.... it's data that makes one stand out from the pack. There are standard fire tests for fire assemblies. These tests are also used to evaluate sealants, penetrations, etc. UL, together with some trade associations, has conducted a number of tests, evaluating "trade practices," as well as specific materials. Their publicly available studies document that the methods I outlined do, in fact, maintain the integrity of the fire wall. There is one qualification- the UL protocol also followed industry standard techniques. For example, larger patcches getting the specified reinforcement, etc. As for the fiberglass / mineral wool issue, again, this is a distinction without a difference. Both materials, whatever the technical differences between them may be, perform identically in the fire tests. Now, if you are following a specification, then of course you ought to follow the spec. For the curious, the fire tests I refer to are full scale tests of completed assemblies, with a massive gas fire on one side, and numerous temperature measurements on the unexposed side. This is the test to determine if a wall (or ceiling) gets a 20 min, 30 min, or whatever rating. It's not the sort of thing you can replicate on your BBQ.

        1. firedude | Jul 13, 2006 04:10am | #14

          Guess UL has changed things - used to be only rated materials were accepted for sealing penetrations in rated assemblies - understand that UL has started looking at performance based assemblies rather than design/tested - if the assembly meets the performance criteria, then it gets accepted
          better providing something for firestopping than have the opening for a "chimney"

          1. Jer | Jul 13, 2006 04:30am | #15

            Well, I for one believe that you're right.  I've talked to many inspectors about this very thing and they listed the products and said that rotten wool (mineral fiber) was to be used and not fiberglass.  Well, maybe it goes by area.

          2. User avater
            dieselpig | Jul 13, 2006 05:04am | #16

            FWIW, the inspectors in my area, and myself agree with your interpretation of the code.  The 'pink stuff' will not fly here.  Nor will mud.  Fire rated caulk, and mineral wool or green firestop insulation at any and all penetrations or you flunk.View Image

          3. User avater
            Taylor | Jul 13, 2006 02:00pm | #17

            FWIW Great Stuff Pro foam (in the orange can) is rated for fire-blocking.

          4. renosteinke | Jul 13, 2006 05:18pm | #18

            It was not so much a matter of UL "changing" things as it was specific research documenting what was already "known." It may be hard to believe, but there were wall, fire tests, and fire stopping well before the Browns' Ferry Nuclear Power Plant fire (1972?).
            (For those who don't remember: this was a fire that started whan a plumber used a candle to test the expanding foam he had used to seal openings around pipes. It grew to a major fire, nearly destroying the plant.) This fire brought the spotlight on sealing methods- and led to the development of the assorted caulks. Likewise, UL publishes a number of "Fire Resistance Directories," detailing construction methods. Many of the "sealants" used are nothing more than everyday mortar and joint compound. Again, the research study allowed UL to say this plainly, rather be limited to ststing a particular manufacturers' part number. (It all comes down to 'who paid for the test.') As I mentioned in my first post, it does make a difference if we are talking about a rated assembly- or not. The usual penetrations in, say, the top plate of a home's wall are not going throug a "fire barrier", and thus call for 'draft stopping", rather than "fire stopping. There is absolutely no standard, no listed product, for 'draft stopping." You're on your own as to how you fill the gap.

          5. pgproject | Jul 13, 2006 09:58pm | #19

            Sorry, I have to jump in---What's "chaulk"?Surely you mean "caulk"?Apologies for being pedantic.Bill

  6. User avater
    trout | Jul 11, 2006 05:02am | #6

    In our neck of the woods many of the oddball fireblocking tasks are plugged with tightly packed fiberglass insulation.  Holes are sealed with foam.  I was resistant at first, but now it makes good sense.

    While it doesn't provide a completely airtight seal, fiberglass is readily available, plugs big holes if needed, is easy to install and most people seem to know how to stuff it.

    While remodeling, any cavity that is opened up, gets firmly stuffed with fiberglass for fire stopping since it's easy and it's often too hard to determine if the cavity is properly sealed top and bottom.  In the course of making four dozen holes of various sizes we go through a lot of insulation.

    The exception is around chimneys and other high temp areas, which are sealed air tight with fireblocking caulk.

    In the good old days before fireblocking, when a chimney fire occured the house simply burned down.  At least with a well sealed chase a fire has to smolder for much longer before moving to other parts of the house.

    1. Tbakes | Jul 11, 2006 03:38pm | #9

      Ok, so before I apply the chaulk, can I confirm the procedure - lets say for a top plate with 1" hole for wiring - apply a bit of the chaulk flush to the top and thats it?  Or should I shove a wad of fiberglass in first?

       

      1. firedude | Jul 13, 2006 02:33am | #11

        fiberglass not usually code acceptable for fire stopping - lot of people get fiberglass confused with mineral wool - both are insulation, but mineral wool is usually spec'd for fire stopping - check the link for the choices from Hilti - might want to check with the guy signing off and see what he's going to require, and also have him "point" to the part of the code that applies - easier to do it right than to do it againhttp://www.us.hilti.com/holus/modules/prcat/prca_navigation.jsp?OID=-12266

        1. Tbakes | Jul 13, 2006 03:05am | #12

          Funny thing is he already signed off - said - "I'll trust you to do it..."  Well, I went ahead and did it.  Stuffed the holes half full with fiberglass and then put about an inch thick blob of 3M 15IWC yellow chaulk.  I doubt he will crawl into my attic at the final to check, but I made sure that all the holes nearest the attic were done very obviously.

          He didn't site a code section, and from what I can tell, the 2003 IRC that my town follows doesn't require fireblocking for single family.  I don't have a code book to check though.

          Ohwell.  About half the house is now "fireblocked" to the best of my abilities.  with 90 degree / 100% humidity, I feel proud I managed to finish!

          Thanks for all the tips!

      2. User avater
        trout | Jul 14, 2006 04:15am | #20

        Ok, so before I apply the chaulk, can I confirm the procedure - lets say for a top plate with 1" hole for wiring - apply a bit of the chaulk flush to the top and thats it?  Or should I shove a wad of fiberglass in first?

        Personally, I'd just caulk it full.  Adding fiberglass would take enough extra time, and be messy enough that it wouldn't be all that cost/time effective for me.

        Good caulking

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