Let’s talk about Prohibited Penetrations (part 5)

Just for this post I have unleashed the code geek. Be scared (no…not really- its painless I promise). After we talk about the code we will discuss the things to look for to ensure your team is conforming to the code.


First let’s clear up the difference between an opening and a penetration. An opening (IBC 2015 713.7) is a hole with a purpose such as a door or a window. Doors and windows are tested to their own standards when acceptable for use in a rated assembly. Note that there is a difference between the test for a horizontal and a vertical opening protection the same way as there is a difference between firestop assemblies. You cannot use a horizontal and a vertical assembly interchangeably. For instance, if you have an access door that you want to put in a mechanical shaft you cannot use that same door in a rated horizontal assembly, unless it is tested for that specific application. Its all about fire dynamics; they simply are not the same in each orientation.


IBC 2015 713.8.1 is on prohibited penetrations and basically says that any penetration in a shaft has to have something to do with the purpose of that shaft.

Here are a few things I have seen.

I was looking at a set of plans with an architect. I asked him if his fire extinguisher cabinets were surface mounted or recessed. Turns out they were semi-recessed and they created a code violation because they were located in the shaft wall assemblies. He relocated them outside of the shaft and all was well with the world (or at least with the extinguisher cabinets).

I mentioned this scenario in a class and someone asked if they could just use a rated extinguisher box. It is a great question, because this is a common misconception. Please remember that the rated extinguisher box or hose box allows you to have a giant hole in a rated wall and not have a code violation, except if that wall is a shaft…then it’s a prohibited penetration. If you have a hose box or an extinguisher box in a rated wall it must be a rated box as well. This is a whole different blog for another time though because there are a whole series of issues we need to talk about related to membrane penetrations. We will get to that later though.


What other things should you look for that are common prohibited penetrations?

Interestingly enough, most of these are membrane penetrations like the extinguisher cabinet. It could be corridor lighting, the magnetic hold open apparatus on smoke doors, exit signs and anything along these lines. These are not serving the purpose of the shaft, so they are prohibited in the wall assembly. This needs to be addressed early in a project or it can create serious headaches down the road.


Now if these same membrane penetrations are in your means of egress, they are relevant to the means of egress and therefore not a code violation. A mechanical shaft has to have mechanical pipes coming out of it to service the floors, it may need to have an access door and all of that is okay provided you are using a rated access door. The mechanical shaft does not have to have corridor sconce lighting and if it does, then you, my friend have a code violation.


Heads up gang, that prohibited penetrations section that we talked about with shafts relates to means of egress as well. If you have a duct or pipe that runs from one side of the corridor to the other side and doesn’t service that area then you have a code violation. In this case, however, the exit sign, mag hold and corridor lighting would not be a code violation because those things presumably serve a purpose in the corridor.


In our next post we will do an imaginary field walk and talk about what we might see.  If you would like some help pulling all of this together don’t hesitate to contact us so we can help on your project.