Insulation that you SHOULD NOT Fire stop Make sure your firestop installers are aware of the difference in insulation. They are NOT the same!

When you are done with this presentation you will have a better idea of some basic things to look for regarding firestop around pipe insulation and when, as an installer or an inspector, you may need to stop and take a closer look.

Whether you are reviewing submittals, installing or inspecting firestop or any of the steps in between, you need to know NOT ONLY the different insulation types and how to identify them, but also how these differences impact firestopping and potentially your companies liability on projects. Let's keep it simple to start with. If your project has fiberglass insulation and AB/PVC insulation, there is a good chance you will need a different UL listed assembly for each of these. Why? Because they behave differently in fire scenarios, so the firestop requirements may be different. There are many different insulation types you can find on various projects so always be sure that you have a UL Listed assembly showing how to firestop that particular insulation assuming it penetrates a rated assesmbly. For the purpose of this discussion, we will be looking at four specific types of very common pipe insulation, two of which will open your project up to some serious liability if you firestop them for the simple fact that you won't have a UL listed assembly to support any installation. This means that there is a potential for a position of liability for the firestop installer, the company who hired the installer, the building owner, the third party special inspector (if there is one on the project) and others as well. The firestop manufacturer will not bear any liability because the material was used in a way other than what they recommend, so they are off the hook.

First, we will talk about some basic fiberglass pipe insulation and some common ways that the firestop may be installed wrong.

Before we can start this discussion however; we need to be on the same page with some things. First two are terms common in firestop and third is secret about firestop. The first term is "intumescent". This means that something expands or swells, for firestop the catalyst for this expansion is the heat from a fire. This is particularly important when firestopping to a combustible material. In this discussion, our combustible material is pipe insulation. The second term is annular space. This is defined as the distance from the outside edge of a penetrating item to the inside edge of the hole the pipe is running through. We will have an entire discussion on annular space at a later time, stay tuned. The secret I promised to tell you about firestop, "IT IS LAZY". It will intumesce or expand in the area of least resistance. Okay, so it's not lazy; it is just the nature of things really. The reason I'm stating the obvious in a ridiculous manner is to get your attention. Firestop needs to be placed in the annular space- the area between the edge of the opening (in the rated floor or wall) and the pipe insulation. This will force the intumescing sealant to push against the edge of the opening and compress the insulation against the pipe in order to close the space; preventing fire, smoke and toxic gases from getting through the rated assembly. Am I stating the obvious? Keep this in mind with these next two pictures you are about to see.

This is a cast iron pipe insulated with fiberglass insulation. The mason grouted back to the pipe insulation so there was no annular space in which to install the firestop. The firestop installers knew the inspector would notice it was missing, so they effectively "painted" sealant around the penetration. If there is a fire, the intumescent material will expand in the area of least resistance, which means it will expand away from the wall. Nothing will prevent the fire and smoke from coming through the rated wall prematurely. You will encounter similar issues any time the opening through the rated assembly is to small to accommodate both the insulation and the required firestop. This can happen when a sleeve is sized only large enough to accommodate the pipe and the required insulation, but not enough annular space in which to install the intumescent firestop sealant. This same issue can arise on a gypsum wall when holes are undersized. If you have these issues on your project, there are two solutions we can suggest.

This is an insulated pipe with a pipe saddle that is intended to prevent the insulation from being crushed by the hanger because it disperses the pressure caused by the weight of the pipe and its contents. The problem, in this case, is that the saddle is penetrating the rated wall; so if there were a fire, the intumescent firestop would not be able to adequately compress the fiberglass insulation against the pipe because the saddle is between the insulation and the firestop. If you see this problem on your project, just have the saddle relocated. In this condition however its not quite that simple. The pipe is going through a shaft, so remediation is going to be either incomplete or complex and expensive. This is why a pre-construction meeting from HLS can be a huge benefit to your project because we can outline all the problems we typically see on projects and help your construction team avoid them.

The next two types of insulation in our discussion are AB/PVC insulation and Polyethylene insulation. Your insulators are going to tell you they are the same. If they are referring to the R value, then they are not wrong. If they are talking about how to firestop these different insulations then they are VERY wrong!

This is AB/PVC insulation, acrylonitrile butadiene/polyvinyl chloride. It is a flexible foam insulation often called rubber. It has a flat black finish and is rather soft with a smooth textured finish. You CAN firestop to this material with an intumescent firestop. Make sure your UL detail lists AB/PVC as the insulation type and pay attention to the insulation thickness because that may change the firestop requirements. This is typically listed either in line three or line four of your UL detail. If your firestop submittals only allow for 3/4" insulation but the installation is using 1-1/2" the firestop requirements may be different. Double check the details to make sure your project is not being compromised.

This is Polyethylene insulation. When new, it has a shiny finish and it has the same texture as a lemon. So, it looks and feels different from AB/PVC if you look at them. The big difference is that this insulation is in the polyolefin family of plastics, so it will melt at temperatures under 200F. This makes it very difficult to firestop properly, because most intumescent firestop materials need temperatures between 300F and 600F before they start to expand. When testing for a UL Listed system the temperature inside the test furnace is at 1000F after only 5 minutes. Additionally,, it is unlikely that your firestop submittals will have a listed detail that will allow THIS material. Make sure your insulators understand the difference so you are not exposed to this liability. If you see this running through a rated assembly, make someone take it out and replace it with an appropriate material.

The last one is Polyiso-cyanurate. This is the hard casing insulation that is used on mechanical piping. You can not firestop to this material unless you have a UL listed firestop detail that will allow this type of insulation. While new tests are conducted regularly, on last review we did not see any for this material. This means, similar to Polyethylene insulation, you can not firestop to it.

This type of insulation has three problems that cause complications.

  1. A low melting point (around 400 F)
  2. The insulation is thick and leaves a large gap once it has melted
  3. The various jackets that encapsulate and protect the insulation from damage may pose the same problems the saddle caused with the fiberglass insulation noted earlier

These are the various types of covers that can be found on this type of insulation. The heavier shields will obviously cause more of a problem for the intumescent firestop.

So, if this insulation happens to penetrate a rated wall, please be certain it is removed and replaced with an appropriate material. This needs to be done at least in the section that encroaches on a rated assembly.

This information should help you limit your liability on projects a little bit. Keep in mind that these are just a few examples of things to look for. You need to do this when conducting a specification review, when you are walking the site before firestopping starts, when the inspectors are reviewing and hopefully well before you are going for TCO. There are so many more things you can do to be proactive early on in your project that will reduce complications, increase the level of life safety and mitigate liability.

Want to learn more?

Want our help on your project?


Follow us on Twitter, Friend us on Facebook and connect on Linked In so you can stay informed of all of our educational sessions, blogs and commentary.

Made with Adobe Slate

Make your words and images move.

Get Slate

Report Abuse

If you feel that this video content violates the Adobe Terms of Use, you may report this content by filling out this quick form.

To report a Copyright Violation, please follow Section 17 in the Terms of Use.