Firestop- Mechanical Contractors

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.

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.

More on Compartmentation

In case you have not realized the importance of compartmentation or if you just want to know what it is, here is another great article by Richard Licht for you to read over. I love to share what I know, but its even better when I share what someone else knows because you hear a different voice as well.  So here it is.

As always if you need help with your passive fire protection please contact us.

What’s this firestop stuff?

On this blog the primary thing we talk about is firestop. Maybe because that is what I am passionate about, at least from a work perspective.  I guess I assume you know what I am talking about.  Recently it was brought to my attention that maybe that isn’t the case.  Not everyone knows what it is or why its important in construction so compliments of the International Firestop Council I will share this with you.

Why you should know more about how firestop is tested.

Understanding more about HOW firestop is tested will help you understand what is important when inspecting it. It will help you understand how firestop installations can fail when they are not installed properly. This series will address a wide array of issues while discussing how firestop is tested.

 

If you want to understand firestop and why certain requirements are important then you need to understand how firestop is tested. You could dig out the standards from ASTM or UL and read all about the process for firestop tests. But, that is a bit dry. So, this will be an attempt to explain how firestop is tested without getting dry and technical. There are a lot of pieces to this puzzle so bare with me as we discuss each one. Along the way you will also garner a better understanding for WHY all this stuff matters. This will be a series of interconnected posts that will loop back into each other and connect with former posts so you can skip what you already know or beef up on things you may want to know more about. Let’s get started.

 

WHY: Why do we test firestop? The basic answer is to ensure safe installations and to keep all the various manufactures on the same playing field and playing with the same rules.

 

If you want to create a firestop material and have any hope of selling it in the US, you have to first have it tested by a third party testing agency. There are a number of companies who will do the test, but the lions share of the through penetration tests are done at Underwriters Laboratories. There are more and they include such as Omega Point Labs, Warnock Hersey and others. Having a material tested by a third-party testing agency means that each manufactures material will be subject to the same type of critique and will have to meet the same expectations in the test burn.  This means that the end user can have the same expectations of any product installed according to the details in the tested and listed documentation. Understanding why certain elements of a test are important requires you to know more about HOW things are tested. Here is a start to the explanation:

 

Here are some basics:

Rated floor or wall– the assembly is built, allowed time to cure, set on the furnace. The assembly is peppered with thermocouples’ connected to computers so they can make sure the non-fire side of the assembly doesn’t get too hot. There are specific requirements to how they are placed. You can read more about if you wish by digging into the actual test requirements. We wont get into those specifics here other than to say that the edges of the assembly are not really considered important to this particular test because they are covered in the test for rated joints. This test assembly will be tested for an F rating and for a T rating.

 

The F rating is the time it takes for fire to breach the assembly. If you are testing a gypsum wall for 1 hour and fire breaches the wall before 60 minutes then you will fail the test. If it breaches at 61 minutes you have at least passed for a one-hour assembly. The T rating is a bit more complex, but still very important. We will save that for our next blog topic, so don’t forget to check in with us next week.

The technical term for this is to ensure that the F rating equals the T rating. There is a whole other topic that needs to be addressed which is the hose stream test, which is an important part of the test and again warrants its own blog post to come shortly.

 

Rated Joints– the test for the rated joints is basically the same as the test for the rated assemblies, but with a few additions. Now, we are dealing with two different assemblies. The way they are connected will provide the “code required” continuity of a rated assembly. So, if you have a floor joining a wall and they are both rated, we want to know that the joint between the two assemblies will be capable of withstanding the same rigors as the two assemblies independently. The tests are similar but there is one added dimension for many joint assemblies. (note we are not talking about Perimeter Containment/Edge of Slab firestop)

 

Joint assemblies can be either static (no expectation of movement) or they can be dynamic. Dynamic joints are subject to very specific movement criterion (another topic for later) the joints also require that the F rating and the T rating are the same, meaning that significant amounts of heat wont pass through the rated joint. This expectation will make more sense once we post the information on T ratings shortly.

 

Through Penetration- As you might expect, the test for through penetrations is very similar to the test for rated assemblies and rated joints. The differences are that we don’t have the T rating requirement. The T rating is a measure of thermal transfer (how much heat goes through the assembly). If you have a copper pipe running through a concrete floor the heat will be on the non-fire side of the assembly very quickly because copper is an excellent conductor. Therefor the T-rating requirement is not in the test standard but rather in the building code (you guessed it, a topic for later discussion). These through penetration tests often have a requirement that the penetrant be rigidly supported. This causes problems for the firestop installer in some cases, but causes even bigger problems for the long-term impact of the firestop if it is not complied with. This is a common deficiency in firestop installations.

 

If you have attended one of our training seminars or if you already know a bit about firestop you may be thinking…she didn’t even mention the hose stream test. This is critical to understanding why certain elements of the firestop listed assembly are so critical, such as sealant depth, annular space and other topics, but it also helps you understand how various drywall patch applications would not survive the laboratory test conditions AND you guessed it- it’s a topic for another blog post!

 

So we have basically set the groundwork for the next few months of posts. I hope you take the time to write in and let us know what you think and what else you think we should include. If you need help on a project don’t hesitate to contact us. We are happy to help you improve the level of life safety on your building.

 

 

Excellent video about firestop inspection

Happy Friday.  It is hot here in NJ, so I am making life a little easier for you (and me) and giving you a great video.  If you are responsible for firestop, whether you are an installer, inspector, architect, general contractor or ANYONE who should know what to look for  when looking at firestop, please watch this video.  It is a great start to learning a few things that are very important or refresh what you already know.  A big thank you to the IFC and STI for making this video available to everyone. Have a great weekend!

Watch the video here-

PLASTIC SLEEVES CAN’T BE FIRESTOPPED…OR CAN THEY? (Part 6)

The answer to this question depends entirely on your UL listed detail. Here is the verbiage pulled from a random UL listed detail that allows for a plastic sleeve.

Nonmetallic Sleeve – (Optional) – Nom 6 in. (152 mm) diam (or smaller) Schedule 40 polyvinyl chloride pipe sleeve cast or grouted into concrete flush with both surfaces of floor or wall.

So, clearly with this particular detail, it is possible to firestop to a plastic sleeve. The key is whether or not the detail you are using will allow it. It needs to. If it doesn’t then you either need to modify the field condition to match the detail, or you need to get a detail that matches the field condition; even if that means obtaining an engineering judgment.

Here are some things to think about if you have a project using plastic sleeves. For this discussion we are going to assume the sleeve is placed in a rated concrete assembly and not in a gypsum assembly. If you have questions about plastic sleeves in a gypsum assembly feel free to reach out to us for help.

More likely than not, the firestop detail will state that the sleeve MUST be flush with the surface of the concrete. If it isn’t, then it is likely the detail will require that the firestop must be recessed into the sleeve to the point that it is in the same plane as the concrete.

Why does this matter? If the plastic sleeve is not flush with the wall and the installer firestops to the outside edge of the sleeve, can you picture what will happen when the plastic pipe melts?

Depending on the type of plastic, it will begin to melt at temperatures between 200 and 500 F. Under the fire test conditions, this is fewer than 5 min into a 1 hour fire test, regardless of the type of plastic pipe you are talking about. The plastic pipe will melt away and take with it the firestop that is not secured in the opening of the rated wall.   This will leave a void in the rated assembly through which fire, smoke and toxic gasses can pass prematurely. If the firestop is installed in the same plane as the rated wall then, when the intumescent material begins to expand, it will be contained by the concrete and it will be able to maintain the integrity of the rated assembly.

One thing we often see on projects are the plastic sleeves used to hold the formwork together when concrete is poured. There are three different scenarios we have seen that have been used to resolve this breach in a rated wall. If you do something different on your projects, please let us know.

  1. Often times these are filled with grout and many inspectors are okay with this. The judgment is based on the fact that the code allows openings to be grouted back if they are less than a certain size (“shall not exceed 6” dia”…”shall not exceed 1 sq ft”*) and this application is well under that. However the section of code allowing this does not mention grouting inside a sleeve, let alone a plastic sleeve that would be combustible.*
  2. Other projects have required the plastic to be removed a certain depth and the remaining opening to be grouted in. The problem here (and above) is that the code requires that “the thickness of the concrete, grout or mortar shall be the full thickness of the assembly” and this is not going to be a viable solution if your inspector calls out this code section. If they do, contact us and we can help you navigate the code for a better solution*
  3. It is possible to get an engineering judgment or maybe even a tested assembly depending on the manufacturer being used on the project.

* NFPA 2012 8.3.5.1.1.3 similar verbiage can be found in the IBC as well section 714.4.1.1…Now please keep in mind that both sections of the code noted here are in areas where they discuss PENETRATIONS and in most jurisdictions the sleeve is considered a penetration and despite the fact that this section of code refers to metal penetrations the AHJ’s in my experience have tended to allow this section of code to be used despite the fact that there is no metal penetration. Check with your local building officials if you have any questions because they are the ones who can give you the answers to what will work in your area.

In the grand scheme of firestop problems this ranks lower on the list than many others but since we are having a discussion about sleeves and in particular plastic sleeves, we thought that this should be noted.

If you find we have missed something in the discussion of firestop sleeves please let us know and we will gladly add your voice to the discussion. If you have additional topics you want us to discuss, please let us know. If you have a project you want us to look at we are happy to help make your project better. We travel the world to help ensure projects get their firestop right. You will be hard pressed to find someone who enjoys THIS scope of work more than we do. Let us help make sure none of these problems, or a long list of other common problems do not crop up on your next project.

Firestop- It’s “good enough”… right?

This 20 minute video will help you see what happens when firestop is not installed properly.  Imagine being in the building, in the room right next to where the first started and the firestop installers did what they thought was “good enough”.  This is what would happen.