I recall reading somewhere that "nail-in" or "hammer-set" anchors will come loose during a fire. In other words, you shouldn't use them to support electrical conduit and boxes to a concrete ceiling because they aren't rated for fire. But, everybody does. Anyone have the skoop about them?
Elzapper, I have not heard about that but it makes sense. Many moons ago when I was involved with the fire service we had major discussions about the metal plates used in truss rafters, seems in a fire they would char the wood around them and would give away with no warning. Most of the anchors are made of a lead-zinc alloy and do have a low melting point though.
Re: nail in anchors during fire#7726 02/20/0210:11 AM02/20/0210:11 AM
I've got a Powers catalog (couldn't use the link you provided because my Acrobat Reader 5.0 isn't working right..freezes my computer up!) and it says that standard Zamac Nailins AREN'T recommended for overhead use. Additionally they state that their Zamac Hammar-Screw can be used for overhead, but only if it is "designed by an engineer who will take the proper design considerations and safety factors into account." Well, nobody does that! What sort of design considerations? Fires?