Replies

1. 
   TLRice | Aug 30, 2002 03:19pm | #1

   You didn't say much about the structure, but I can tell you that in buildings with 2 hour fire walls, electrical cables not in conduit must be sleeved, with the sleeve sealed to the structure and the wire/cable caulked or firestopped inside the sleeve. BOCA is more restrictive than NFPA.

2. 
   BKCBUILDER | Aug 31, 2002 01:04am | #2

    Around here we don't have to specifically use fire caulking, but any type of caulking/foam to seal the hole. We call it draft stopping, since it's the draft that will feed the fire and provide a avenue for spread. That being said, an inspector will turn you down on one hole being missed. Then will call it improper firestopping. It's EASY to miss a few.

     I let the insulators do it when they insulate. They have a package called "sealant package" and is basically a deal where they caulk the bottom plate to subfloor, between double tops, all corners and ever joint where 2 studs or 2x's are nailed together(jacks, kings etc...) headers to kings, blah, blah, blah. After them, and right before the frame inspection, I get my can of foam out and walk the entire job and pick up the loose ends. There are always little problems(switches and rect. moved after sealant, etc) that never got sealed.

     I think I paid $100 for the foam gun and a can of foam is $12, but it goes a long way, and can lay down a real fine bead, or a huge one.

3. 
   r_ignacki | Sep 01, 2002 01:21am | #3

   every year, county comes up w/ a new "proper" way,

   the latest was rock wool, stuffed in the hole, as a backer, then caulk.

   no turn left unstoned  

1. 
   4Lorn1 | Sep 02, 2002 07:27am | #4

   On a commercial job the inspector required, on its face it seemed counter intuitive, that the holes, prior to caulking, allow 1/4" to 1/2", depending on the diameter of the cable or pipe, space around the cables. He explained that this allowed sufficient caulking surrounding the cable to expand to fill the gap left after the cable insulation melts and burns. A tight hole would not not contain enough fire stop material to seal the hole completely during a fire.

   I don't know that this is the problem but it is a concern that is noted in the literature that some inspectors are reading. At the time I was working in a hospital so fire stopping was a major deal.