Membrane Penetrations- how to avoid firestopping them Part 1

This week we are going to talk about firestopping membrane penetrations, or rather how to avoid firestopping them in some cases.  

I was on site explaining to an electrician the various requirements for firestopping electrical boxes.   I was explaining to him that if the box is metal and it is 16 sq inches it has to be firestopped if it hits there other criteria (code stuff, right).  The next thing I said got this guy all jazzed up and the lightbulb went off and he realized how he could avoid needing to put putty pads on boxes.  He said “If I change this one thing, I don’t have to put these putty pads on? Dang, I’m never using these boxes again I will string three boxes together if I have to just to avoid putty pads!” He was so excited!  He just learned a trick that was going to change how he planned out his projects. 

What was that trick you ask? 

He was using boxes that were just a bit larger than 16 sq inches, so that meant that every one of them required a putty pad (or some other protection).   By just changing out to a slightly smaller box, he could eliminate this… weeeelllll… Not eliminate 100% of the time, but enough that he was all excited. You see when the box is over 16 sq in, they always required protection, but when they were 16 sq in or smaller you had to hit a different trigger before you needed any form of protection.