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#7722 - 02/19/02 12:08 AM nail in anchors during fire  
Elzappr  Offline
Joined: Dec 2001
Posts: 270
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?

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#7723 - 02/19/02 08:15 AM Re: nail in anchors during fire  
Redsy  Offline
Joined: Mar 2001
Posts: 2,056
Bucks County PA
I know that some lead anchors have restrictions on their use due to the possibility of melting during a fire. But I believe steel is OK.

#7724 - 02/19/02 07:19 PM Re: nail in anchors during fire  
Elzappr  Offline
Joined: Dec 2001
Posts: 270
I don't think the anchors that I am referring to are made of steel..more like some sort of lead/zinc/? alloy..its pretty soft stuff.

#7725 - 02/19/02 11:22 PM Re: nail in anchors during fire  
spkjpr  Offline
Joined: Dec 2000
Posts: 218
Sedalia,MO, USA
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.

#7726 - 02/20/02 10:11 AM Re: nail in anchors during fire  
JBD  Offline
Joined: Jul 2001
Posts: 599
For technical information on fasteners go to Powers website at

#7727 - 02/20/02 06:06 PM Re: nail in anchors during fire  
Elzappr  Offline
Joined: Dec 2001
Posts: 270
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?

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