Membrane penetration

The building code says in section 714.3.2 that recessed fixtures shall be reduced. Is a toggle bolt really a fixture? My stance is that the term fixture is referring to things like time clocks and ice maker boxes or fire extinguisher cabinets and mag hold devices for fire doors. There is a LOOOOONG list of membrane penetrations, and the code looks at these in the exceptions that follow:

• Electrical boxes
• Boxes other than electrical
• Automatic sprinklers

It doesn’t say anything about toggle bolts.

So, let’s look at this another way, most of this code section is going to talk about the electrical outlets that can be in a fire rated wall and that you are allowed to have multiple in one wall provided that (and I am paraphrasing here- check the code for the literal wording)

You can have a box that is up to 16 sq inches with a gap of up to 1/8” around. Imagine the air flow through that box. I’m guessing it would exceed our little toggle bolt hole with a toggle bolt in it. What do you think?

Now let’s face it, you are going to have more than one toggle bolt in that wall, right? Well, the code allows you to have multiple openings as long as you don’t have more than 100 sq in of opening in 100 sq ft of wall. This is the line I would use to assess whether or not you need to firestop the toggle bolts. If you have so many toggle bolts that you are coming close to breaching the opening in the wall that you would get from this, then you may want to consider firestopping the holes. Don’t stop here because the code doesn’t stop here.

There is also a line that says if you have another box within 24 horizontal inches, all of a sudden you have to firestop both of them. So, if you have unprotected openings on the other side, then we need to re-evaluate this discussion.

Does that make sense? I would love to hear what you think about this, even if you disagree. Let me know what you think. But also…

Join us tomorrow for our next discussion which is Altitude vs Pressure.

For now, here is the code section referenced earlier.

714.3.2 Membrane Penetrations

Membrane penetrations shall comply with Section 714.3.1. Where walls or partitions are required to have a fire-resistance rating, recessed fixtures shall be installed such that the required fire resistance will not be reduced.

**Code sections pulled from the 2009 IBC. I’m expecting this to be the same in the future code cycles but please check to confirm.