Understanding Hose Stream Test- Part 3 Annular Space and Sealant Depth

Hose Stream part 3 annular space and sealant depth

Now that you understand the hose stream test a bit more, let’s look at why this information might change the way you inspect firestop. In this segment we will examine two very common errors we find on construction projects.   The first is a problem with sealant depth. The second is a problem with annular space, which may actually impact the sealant depth.


As Chad pointed out in his article we shared previously, a thin layer of sealant will not survive the hose stream test. This is why it is important to conduct destructive testing when evaluating firestop installations (both penetrations and rated joints). If the penetration firestop assembly is installed in concrete, there is a good chance that mineral wool is a required backing material. Often, if the installer is not careful how they pack the mineral wool, it will be lumpy. When the firestop is installed over the lumpy backing material the sealant depth will be irregular. It may be thicker than required in one area and to thin in another area. The area where it is too thin can easily be the very spot the hose stream test would fail, if your field assembly were subjected to the laboratory test. This happens both in penetrations and in joint applications where any form of backing material may be used. This is why destructive testing is so critical to ensuring installation conforms to the tested and listed systems. If you are in a jurisdiction where destructive testing is not allowed, I would challenge you to walk the site when the installer is working and check the way they pack the mineral wool before they install the sealant. If it is not compacted uniformly, then the sealant won’t be installed uniformly. If you are going to conduct destructive testing, this quick preliminary walk will give you some insight to what you can expect when you start your inspection.   If you are in a jurisdiction that prohibits destructive testing, this can be invaluable to identifying whether or not the installations might conform to the standards.


The next problem we often find is related to the annular space. Let’s revisit the scenario presented when we talked about annular space and continual point contact. We have a contractor who uses a 1” hole saw to make a hole for a 1” pipe. It may sound good, but it’s going to create a problem for a good firestop contractor. The firestop tested and listed assembly will call for a required sealant depth. The sealant needs to be installed in the annular space, which means the assembly into which the firestop is to be installed needs to actually HAVE annular space. Let’s paint a picture in your head of what would happen when a firestop contractor smears sealant around the edge of the pipe to make it look like there is sealant in the right place. Through the life of the building any movement of the penetration cause by pipe hammer, thermal expansion, pipe vibration or anything else would cause this thin layer of sealant to crack or pull away from the wall. Some firestop materials set up rather hard and would crack sooner than other more pliable materials but some form of failure would eventually happen to any material even before subjected to a fire scenario. Now if we take same installation that we have in your head and subject it to the test requirements even before the issues we previously noted have had a chance to occur, the picture you have in your mind should include water coming through the test assembly when it fails the hose stream test. But wait you say, the drywall would stop the water from going through, wouldn’t it? Sorry to say, its not likely. Let’s look at why!


The drywall on the fire side of the assembly is sacrificial and the only thing really stopping the fire is the drywall and the firestop on the non-fire side. Now let’s assume you have a metal pipe, it is going to draw heat through the wall. This will likely char the non-fire side drywall weakening it and creating a scenario where the assembly will fail the hose stream test, so sorry. If you think the drywall will stop the fire in this scenario you are mistaken. It will be brittle and will fail once exposed to the hose stream test.


Next post we will paint a picture that is even more bleak and we will look at how this simple error can create an even bigger problem.  If you want to be sure this is not happening on your project, check back and see where we go with this. Until then, keep learning and keep making buildings safer.



Understanding the Hose Stream Test- part 2

Hose Stream

Last post you read an excellent article from Chad Stroike of HIlti and this week I want to add a bit to it.


Imagine a room on fire. As the temperature mounts, the pressure inside the room will increase. We want to know that the integrity of the firestop system will be able to withstand the impact of this pressure increase. As the temperature grows metal elements through the walls and floors will expand and contract, twist and contort. They will be hot on one end and not on the other. Thin wires holding lights can snap, leaving the fixture to swing and slam into a rated wall. Furniture or heavy duct assemblies can crash into rated walls.   We want to know that the firestop installed in these rated assemblies will have the integrity to withstand these potential hazards without becoming dislodged. This is one more reason for this hose stream test on top of everything Chad mentioned in his article. If you haven’t read it yet, you can get it here.


Something I found interesting when I first learned about the hose stream test, is that it is done half way through the test. This means that a wall or floor is taken off the furnace half way through the duration of the test and immediately subjected to the hose stream test. Picture a concrete floor with pipes or ducts that are red hot. Now picture a 30-PSI stream of water hitting the red-hot pipes and smoking hot concrete assembly. You can imagine the steam engulfing the room and shrouding your vision, the steam hissing in your ear and the smell of smoke choking you. Then, after this segment of the test is completed, you would walk to the “non-fire” side of the assembly and look for signs of water breaching the concrete floor. If there is light coming through the assembly or any sign of water that may have penetrated the floor, then the test assembly has failed. If the assembly passes, this is just one step in the process because the assembly must be burned for the entire duration. This means that many rated wall, rated floor or floor ceiling assemblies are likely tested twice; once for the full duration of the fire test and then often a second time for the hose stream test. This may not be the case for concrete or block assemblies because they don’t degrade as rapidly in a fire and may survive the hose stream test even after the full duration on the furnace. Certainly for gypsum assemblies, the fire side is basically sacrificial. It won’t last long in a fire test, so UL’s requirement is that the hose stream test is conducted at the half way mark of the test (but not more than 1 hour). This means that a 1-hour fire test will have a hose stream test conducted after 30 minutes. A 2-hour test will have a hose stream test conducted after 60 minutes, as would a 3 or 4 hour test.


If you ever get the opportunity to witness the hose stream test, you should. If you are at all a geek like me, you will appreciate the impact it makes on the test assembly.


Next week, we talk more about scenarios where the hose stream can cause a test sample to fail.   Now that you have a better understanding of how firestop is tested, you can better understand why certain elements of the tested and listed details are critical to the performance of the assembly and critical elements to be inspected.

Happy Holidays

I want to wish you all a wonderful holiday season. However you may celebrate it I hope it is better than you could dream.  I will be back with you in the New Year to carry on this discussion about the importance of understanding the hose stream test and how this information impacts firestop installations and should impact inspections.

All the best to all of you,


Understanding the why behind whats important when inspecting firestop?- Part 1

When you look at a UL listed detail that has a 1-hour F rating, what does that tell you? At a very basic level you can expect the assembly was tested and didn’t let fire through for one hour. There is so much more to it than that and once you understand, it might change how you inspect firestop. Keep reading and let me know if it does.


F RATING- as defined on UL website

The F-rating criteria prohibits flame passage through the system and requires acceptable hose-stream test performance. Lets break this into two parts. First it is saying that fire doesn’t breach the assembly during the test period. Obviously, with firestop, we are trying to contain a fire; so we want to know that the rated assemblies will keep a fire at bay for the designated time period which is known as the F rating. A 1-hour rated wall is expected to contain a fire for 1 hour. F ratings for firestop are 1, 2, 3, and 4 hours. The temperature inside the furnace during the test will increase as the duration of the fire increases. For example in a 1 hour test the temperature will be at least 1700F (538C) at the 1-hour mark and 2000F at the 4-hour mark (1093C). Surviving these temperatures is still not enough to obtain an F rating for a rated assembly. There is one more critical element involved in the test procedure called the hose stream test.


HOSE STREAM TEST- what it is and isn’t

I have sat through too many classes on firestop, codes and what not, only to cringe when I hear the instructor tell the class that the hose stream test replicates impact of the fire fighting methods on the fire rated assembly. It is like nails on a chalkboard to me and I can feel it running down my spine. (Yes I am that much of a geek, that it bugs me to the core) By the time the fire fighters are on the scene with their hoses, any loss of life in that area has likely occurred. Property damage is done. Firestop serves no purpose at this point, because the integrity of the assembly has failed and fire has breached the wall or floor. Fire fighting methods are not part of the firestop test. I believe that understanding this critical element of the firestop testing process is integral to the proper inspection of firestop. We will get into this more shortly. In fact, a lot more, because this is a 5-part discussion about why the hose stream test needs to be better understood in order to improve firestop inspections. For now however, I would like to share this article by Chad Stroike of Hilti. Chad does an excellent job explaining the hose stream test, why it is part of the fire test standard and what it is intended to replicate.

Thanks to Chad and to the IFC for this great article.

Rutgers Professor

I am excited and proud to announce that I will be teaching at Rutgers in 2017. There will be two classes- one on Grease Duct Wrap Installation and Inspection and the other on Understanding the Requirements of Third Party Special Inspection of Firestop. They did not accept my 2 day class on Firestop Inspection and the Common Mistakes because there are other people who already train on firestop. If you are interested in joining one of the classes, please let me know and I will send you the schedule when it is pulled together. Have a great weekend everyone and when you get back to work Monday, be prepared to make a difference!

This may change the way you inspect firestop

ANNULAR SPACE- This is a term used only in a discussion of through penetration firestop not in rated joints. It is basically the gap. More specifically it is the distance from the inside edge of the opening to the outside edge of the penetrating item. It is actually a critical and often overlooked part of a firestop assembly.

When measuring the annular space, sometimes it gives a “nominal” measurement. If the detail says nominal ½”, then the tested and listed detail expects the field condition to have a pipe that is centered in the opening. That can happen, and it snows in Las Vegas…sometimes. More often the annular space will offer parameters defined by a minimum and maximum annular space. If the annular space lists 0” to 1” this means that the penetrating item does not need to be centered in the hole. It also means that its okay if the penetrating item makes contact on one side.

This does NOT mean that when an electrician runs a 1” conduit, they can use a 1” hole saw. Some contractors see the 0”-1” and think that the pipe can squeeze into the opening and the firestop contractor can firestop the application. This happens all the time, but that doesn’t make it right. It only makes it common.

When the opening is just barely big enough to allow the pipe through, this creates a condition known as CONTINUAL POINT CONTACT. Another time this can occur is when a 6” sleeve is run for a 4” pipe that will have 1” insulation on it. There is enough room to get everything through the sleeve, but there will not be enough room to install the firestop detail that should have been submitted.

There are very few tested and listed systems that allow CONTINUAL point of contact for a bare metal pipe, let alone for a combustible penetration such as insulation or even plastic. This gap is critical to the proper performance of the firestop assembly. If the tested and listed detail calls for 0”-1” then it assumes there will be some space into which the sealant can be installed. For a typical 1-hour gypsum wall the required sealant thickness will likely be 5/8”. If there isn’t at least ¼” gap, then the sealant depth cannot be achieved. This is critical to the performance of the firestop installation and we will talk more about this in our discussion on HOSE STREAM TEST. We will go into this in depth, but for now we are not finished with the discussion about annular space. How do you measure it?

If there is a square duct in a square hole, measuring the annular space is pretty simple. If it is a round pipe in a round hole, its simple again. What about when you have a round pipe in a square hole? Do you measure to the longest distance, which would be to the corner or do you measure from the edge? According to UL, the measurements should be made to the edge, so basically at a 90-degree angle from the edge of the opening to the side of the pipe.

That covers annular space pretty well for now, but there is more to consider. If you have any questions feel free to reach out to us and we are happy to help if we can. Next up we will talk about the hose stream test. This will help clarify why the annular space is such an important element to verify during a firestop inspection. You will know how a continual point contact installation will likely fail and much, much more. Thank you for taking the time to learn more about firestop.  If this information has not convinced you to take a closer look at the annular space requirements during our firestop inspections then the discussion on hose stream test certainly will. Till then…

New Definitions for a new understanding of firestop

You can Google all sorts of definitions you will need when you are talking about firestop. The problem is, now you now the meaning of the word, but you still may not understand the impact what that means in a fire scenario. This definitions section is going to focus on, not only the definition of the word, but also on the reason it may be important in a fire test condition. The hope is that this will help you take a closer look when you are inspecting these various elements of the firestop assemblies. We will give you a new word or a new concept every week and each one will be intended to change the way you may be inspecting firestop. If you know firestop it may not be a new word, but hopefully you will see the word in a new light. Let us know if we have changed the way you inspect.



Intumescent basically means to expand. So if you play rugby and catch an elbow in the mouth while getting tackled to the ground, your lip will intumesce and you will have earned your post game beer. (If you need to explain this to someone else, feel free to insert any sport analogy you wish as long. As it ends in some sort of facial contact and you will get the same image.) The difference with firestop is, that instead of a blow to the face as the catalyst for the expansion, we are looking at heat from a fire. Instead of blood rushing to the area to create swelling, we are dealing with a chemical reaction that causes the materials to enlarge, expand and fill any voids created by combustible materials or movement during a fire.


So intumescent material is all the same, right?



Different sealants will expand at different rates and at different temperatures because they are made with different chemical combinations. A basic intumescent sealant will not expand any where near as much as a wrap strip. Some wrap strips will perform differently than others. In fact, some manufacturers have different grades of wrap strip. These will perform dramatically different. Some will require more material some will require less. Some will cost more and some are considerably cheaper.


When inspecting firestop it is critical that you make sure that the material shown on the tested and listed detail that was submitted and approved for the project, is the same thing that is being installed.


If you are the inspector you may think I’m crazy or you may be cringing thinking of all the paperwork you would have to carry. When I train installers I tell them flat out, that if they want to look better than their competition, they should post a copy of the submittal on every floor. Then when the inspector had a question, the answers were right there for them. When the installer had a question, they knew where to do for the answers as well.   Here is a hint- if your firestop installer doesn’t have a copy of the submittals on the floor where they are working, then this means they are not looking at the details. If they are not looking at the firestop details, how do you expect them to be installing something that conforms to these same missing details?


Next week we will discuss annular space- we will talk about the gap and when we are done you may have another reason to change the way you inspect.  If this was useful, let us know.

Modern building codes made firestop more important, but no one noticed.

The International Building Code(IBC) is the model building code for all codes in the US and possibly in international jurisdictions as well.  There are some regional changes based on unique needs of certain areas such as weather, seismic, wind and various other regional concerns, but other than this, the requirements are generally universal.  Before this, the US had at a minimum 4 different codes that any construction team or architect needed to know in order to  work in any specific jurisdiction.  The IBC made it easier for designers and builders to cross boarders with the same set of skills being required across the US.  One of the most recent changes in this new code had to do with the “compartments”.  This is the concept of building walls and floors specifically to contain fire.  This is one of the means of life safety, and how fires are prevented from impacting large sections of the building unfettered.  The IBC allowed compartmentation to be larger than before.  This means that there is a heavier reliance on fire sprinklers.  This also means that the areas that create the boarders on these various compartments suddenly are that much more important because if anything interferes with the sprinkler systems, the passive fire protection is the last line of defense.  This article does an excellent job of outlining the importance, so rather than try to recreate it, I will just share it with you here.

If you would like help on your project, ensuring that your compartmentation will work as expected contact us for a complimentary review.

Common Firestop Problems

Here is an excellent article from the International Firestop Council discussing the common firestop deficiencies.  There is so much more to add to this, but it is a great start.  If you can stope these things from happening on your projects you have gotten off to a great start. It is 10 years old, but sadly not much has change with regard to this topic.  Here is the article.    You can always check out our classic mistakes tab as well.  As the posts continue we will delve into WHY all of these issues are such a problem.  Its not just because “its not right”, its because it will fail and a fire may be allowed to spread prematurely.  The more you understand about how firestop is tested the easier it will be to remember these critical elements.  As these posts continue we will get into that as well. Stay tuned friends and together we can make a colossal impact on the level of life safety of your projects as well as mine! If you have any questions along the way, don’t hesitate to ask.

Who can be a Firestop Special Inspector?

Are you responsible for evaluating a potential Firestop Third Party Special Inspector?  If you have been following this blog series, you know why special inspection is now required.  You also know the types of buildings that are required to have a Firestop Third Party Special Inspector. (You can click the underlined sections to find the related blog sections.)

Do you know HOW to evaluate the potential individual?  We are in the middle of creating this very document.  In the meantime, we have completed a paper that combines the requirements of the IBC as well as the ASTM E2174 and ASTM E2393; which are the two standards on inspecting through penetrations and rated joints respectively.  This paper tells you WHO is allowed to be a third party special inspector.  Hang tight and we will give you another paper on how to evaluate an inspector and as a bonus we will include an evaluation of the ASTM E3038 which is the test standard for evaluating an inspector that just came out this summer.

Did you know, that just because someone is a jurisdictional inspector does not automatically mean they can be a third party special inspector?  That is because juridictional inspectors are expected to know a broad general range of things to perform their job.  The level of education they need is never ending as they can specialize in more and more things.  As a firestop inspector, I concede that they know a lot more than me about construction in general and maybe even about the building codes too. (Which is impressive from a self-professed code geek.)

Firestop third party inspectors need to know a very general range of information about the various trades, so they know the difference between a cable and an innerduct, they can identify various insulation types, understand metal gauges and a handful of things that would seem simplistic to your typical jurisdictional building inspector.  However a firestop inspector should be able to take all of these different elements and know exactly how they relate to firestop.  For example, they need to understand how sheet metal gauges relate to firestop when they are being used in sleeves (we did a whole series on sleeves) or when they are being used for angle on ducts(and, you guessed it we have another series another one on ducts).  A specialty firestop contractor would need to know all this and much, much more.  Where most jurisdictional inspectors are not expected to know how all these things relate to firestop.

So, if you want to know WHO can be a third party special inspector, click here to get the white paper.  If you have any questions feel free to contact us.  In the meantime, go out and keep your firestop installers on their toes!  Together, we will make buildings safer for the building occupants and for the first responders who would be dealing with these buildings in any emergency.