In our last blog post we talked a little about shaft walls, what they are made of and some things to keep an eye out for. We will build on that as we go.
Today we are going to look at firestop submittals as they relate to shaft wall assemblies, so the next time you are reviewing project documents you will have a better idea if something is missing. The easiest way to understand this discussion is to quickly review the UL nomenclature post found here so this will be easier to follow. If you do not know this nomenclature its much more difficult to conduct this exercise.
First let’s think about the RATED JOINTS. Let’s assume that the project has both block shafts and gypsum shafts. As you look at the firestop submittals pull out the HW (head of wall) details and look for the types of shaft walls you have on your project. For this discussion we will assume you have both gypsum and block shaft walls.
You will likely have a handful of HW details but if you have gypsum shafts you need to be sure the project has a detail for firestopping this gypsum shaft. When you look at the WL details for gypsum walls, you will notice it is not like the standard gypsum wall details, namely because the shaft walls are built differently so they need to be firestopped differently as well. This will require sealant at the shaft liner as well as on the outer layers of drywall. If you allow this wall type to be firestopped when the wall construction is complete, you will not have a compliant system because you will only have protection from one side of the wall. This would create a major liability for the installer as well as the GC, building owner and building occupants. If you are looking at a WL2000 series detail for plastic pipes, be sure to take a closer look, but do the same for all your penetration types.
If you have access to both sides of the wall, as you would in an elevator shaft, then it is easy to firestop the head of wall joint on a block wall from either side of the wall. Likewise you can firestop your through penetrations with either a CAJ or WJ detail. If you only have access to one side of the wall, you will need what is commonly referred to as a sandwiched detail and my guess is that it will likely be a WJ detail or possibly an engineering judgement. This would allow for firestop to be installed in four steps. Typically there would be installation of mineral wool recessed maybe 4-1/2” into the joint, then firestop sealant (let’s say it calls for ½” of sealant) then another layer of 3-1/2” of mineral wool followed by another ½” of sealant. There are 4 steps to this installation, which means 4 steps to any firestop inspection as well, unless the inspector wants to try to cut into this kind of joint application, which is going to be a challenge in and of itself. This also means that the firestop detail needs to show installation from one side if this is what the installers are doing.
That is what you expect to see when you are in the field, but when looking at the firestop submittals you need to be sure that the block wall detail that is provided can actually be installed on the project. Is it physically possible? You need to be sure there is a head of wall, bottom of wall and possibly a wall to wall detail for the gypsum assembly. It is not uncommon for a contractor to miss these details, so be on the lookout for them.
Next, think about what penetrations will be going through your shaft walls. The block and concrete walls often will not have access from the inside of the shaft so a sandwiched application needs to be used in many cases, though there are devices that can be used and installed from one side. If we are working on a project with you then we can help you determine which different manufacturers products would be best for various scenarios. Let’s say your stairwell walls are block or concrete. This means the firestop details you will need will start with either a CAJ or a WJ (potentially WK for thicker walls). You will need a 1000 series detail for your sprinkler pipes and conduits, unless you have plastic sprinkler pipes then you will need a 2000 series detail as well as a 3000 series for your MC cables. You won’t need a 7000 series detail for your ducts because they are going through a 2 hour wall and will require dampers. Pull out these details and be sure that if you only have one side access that the details will allow one sided access for the installation requirements. If not, you will need an Engineering Judgment. If you are in NJ, remember DCA does not allow EJ’s- sorry NJ.
Typically firestop installers will submit details for the various penetrations through a standard wall. These may be okay if the shaft wall type is included in what is allowed in the listed detail. If it is included, then you are fine, and if not then they need to submit a new detail. This will be found in item 1 of all details. These details will start with WL for gypsum framed walls and if it is a mechanical shaft you will likely have WL 1000 for metal pipes, WL 5000 for insulated pipes, maybe WL 2000 for plastic pipes. When doing the installation or inspection of these walls you will want to be sure to check annular space and sealant depth to be sure it conforms with the details. You will also want to be sure the installer firestops the shaft liner side before the outer two layers of drywall go up as you will see in one of the later posts.
We have given you a few things to be cautious about, but in our next post we will dig deeper into this and the building code. If you have questions about a recent firestop submittal please contact us for help.
It’s a New Year, so I thought I would play around with a new medium. I have pulled up a few old videos from various training segments I’ve recorded in the past 5 years. Here is a brief general discussion about how rated assemblies are tested. There is so much more I want you to know about this, but this is not a bad start and it segues into some of the older blog posts we have shared.
In order to make this information practical, so you can use it in the field, please remember that knowing how assemblies are tested helps you understand how they fail when not properly installed. Think about the hose stream test when you are looking at applications with large annular space, with insufficient annular space or installations with just a smear of sealant. These are both critical to the performance of a firestop installation. The various hyperlinks will bring you to different segments for further discussion if you are interested in learning more.
Please share this with anyone you think might benefit from this information.
As always, if you have any questions or even topics for future blog posts, don’t hesitate to reach out to us. We are happy to help when we can.
UPDATE: Jan 6
I want to give a HUGE shout out to RICK BARONE for making a correction for me. This video clip was edited from one of the first classes I did when I started teaching again, and as with most things we are new at, there were errors. I noticed it during editing a few months ago but forgot to comment on it when I posted it. Rick says it better than I could so I will just include his comments here and say THANK YOU RICK. I love when people support others to do better.
“You have some inaccuracies in the video…The time temperature curve is controlled by the test facility….If your test specimens furnace isn’t at 1000f at 5 minutes it will be because the lab tech didn’t maintain the time temp curve within the prescribe tolerance. The customer doesn’t fail, the lab must abort the test and rerun..usually at their own cost if they are a credible lab…but a nice start with a new communication vehicle..” Rick Barone 1/5/2017
Last week we heard yet another story of a construction worker death on a jobsite in NYC. I know, I typically go on and on about firestop and passive fire protection. If you have been following me for a while, you also know I love to tell a story, so today I have two for you and I hope they make you think about safety on your project, regardless of your job title.
I was working on a massive project and in one of the regular meetings someone from the safety department gave a talk about safety. No big surprise there. He asked everyone who worked in safety to raise their hand. I didn’t raise my hand because I was an engineer, not a safety person. He asked everyone to look around the room…THEN HE LET US HAVE IT. He explained every single one of us needed to have raised their hand. EVERY one of us was responsible for safety. We were all responsible to check that holes are covered, that railings are secure and that other people are tied off and a list of other things. Then, in our own smaller team meeting, my boss reiterated the importance of this and required that everyone of us write up a safety report at least once a week. Even if the report said that we checked a bunch of things and found no issues. I still do that, even when it is not a formal requirement, it is no less important.
Later on a different project, we had just gotten out of a safety lunch. This was supposed to be a celebration of X number of days on the job with no recordable accidents. It was a grand BBQ and everyone got T-shirts. Before I take this story any further, if you have not met me you should know I am a short, skinny, chick with long brown hair and I remind most people of their kid sister or something similar. I used to teach kindergarten, so I have a sugary sweet side and a firm, Momma bear tone that I reserve for special needed occasions.
So, after I left the Safety Lunch, I noticed a guy in a lift, sporting his new safety shirt but NOT HIS HARNESS. I hollered up and him with a flirty voice but quite enough that he could not hear me well over all the noise. So he lowered the lift with a big ole smile on his face and said, “What, sorry I couldn’t hear you.” I asked him if he went to the BBQ and we talked about what a great spread it was and oh look the new shirt. I asked him why they had the BBQ in the first place and he went on to explain that they do that on projects to celebrate a good safety record. We talked about how it really made him feel appreciated and on and on. (Guy’s be careful when someone asks you an obvious question, they may be setting you up.) Then, I asked him for his Mother’s phone number. He smiled quickly when he heard the request for the phone number, then when it sank in that I didn’t ask for HIS number, a look of confusion spread over his face. Out came the Momma bear voice as I told him, I didn’t know how to get it through to him. He has clearly sat in innumerable safety meetings. He JUST LEFT a safety lunch and climbs into a rig, leaves his harness on the floor and starts to get to work. I wanted his mothers phone number, so I could call her and ask for her help. Maybe she could get through to him and remind him to be safe on the project . Maybe she could succeed where the rest of us have failed. He hung his head, grabbed his harness and started to put it on. Before he climbed into the rig again I told him, I don’t care about the safety numbers. I care about the actual safety of the actual people of the project. About a month later I saw the guy again. Again, he was in his rig. This time however he was tied off. I was happy to be able to shout up at him nice and loud (so he could hear me this time), “Good to see you tied off Joe. “
If you work in construction, please do not sit idly by if you see a safety violation.
This is a 1-hour wall that separates an exit corridor from a condo unit. We are looking at it from the unfinished condo side and the firestop has been installed from the corridor side. From the corridor side of the wall, the installation looks good at a glance. The firestop is installed the full circumference around the cables. The cables are rigidly supported as required by the UL listing. The installer used an intumescent material that matches the submitted UL listed detail. When the wall is complete these MC cables will not penetrate the room side of the wall so technically this is a membrane penetration rather than a through penetration, but UL requires the same installation regardless of this fact. Bare in mind, this is changing and UL is requiring that membrane penetrations be tested separately, because they may perform differently than a through penetration. Stay tuned for more on these changes in the coming posts. Can you tell what is wrong with this installation? Better yet, can you explain why it is wrong and more importantly, two other issues. 1) What might the impact be in a fire scenario? 2) How might this improper installation impact the project over time?
Most UL listed firestop details will require 5/8” depth of sealant. I can tell you that the installer did not achieve even half of that. If you look closely, you too can see this just from looking at the picture. You can see that there are 2 layers of drywall. You can see an ever so faint line at the top of the opening where the papers from both layers of drywall are in contact. That means that the line between the two layers of drywall would mark 5/8” depth of sealant. As you can see, the installer did not even come close to achieving the required depth on this installation. Then, if you want to go on further to critique this installation, there is very little drywall between the hole on the left and the center hole. Furthermore, there is NO drywall between the center hole and the one on the right, so technically this is one opening. As such, most UL listed details will require that the cables be tightly bundled, which they are not. When cables are loosely laid together, there are a few problems. First, the installer can’t easily get sealant between the gaps around the cables; so this means the sealant depth is not achieved. Further, the gaps increase the risk of cables moving and the chance of the sealant pulling away from the opening or adjacent cables is increased which can lead to a failure of this installation in a fire scenario. These gaps are a weak point for both reasons.
Impact in a fire scenario: One of the steps in testing a firestop system is a hose stream test. This portion of the test is designed to judge the integrity or durability of the installation because during a fire there is a lot of pressure in the room of origin and a lot of movement of the various elements in the building. We want to know that the firestop system will have the integrity to withstand the impact of these things. Every fire will be different, so no one can say for certain what dynamics any firestop application must endure, but if a PROPERLY installed firestop system is subject to a real world fire scenario we have a good idea of how it will perform. This installation is not a properly installed firestop system and while I can say it will definitely fail, I can say that this installation presents a liability for the firestop installer, the electrical contractor, the GC or CM, the owner, the buildings insurance company and the occupants of the building. Don’t worry, the firestop contractor was required to remediate this particular problem on this project. Please make sure they do the same on your project. For more information about the hose stream test check out these other blog posts as well. Here is one example.
Impact over life cycle of the building: There are a myriad reasons why the cables in this picture might be bumped, jostled or otherwise moved in a way that could dislodge the thin layer of firestop. However if the sealant is installed at the required depth of 5/8” and there is movement, the firestop material will likely still remain in the annular space of the opening. This means, it will be in the proper location so it can perform as expected, even if it pulls out of the wall slightly over time.
Here is a great article by a fellow blogger and fire code junkie. I hope you enjoy. This is appropriate considering a conversation I just had about the Avalon fire here in New Jersey. Cables run unprotected through rated walls and draftstopping after the building was inspected and signed off, was considered a considerable contributing factor in how the fire was allowed to spread rapidly through the entire building.
I will be back with you again soon with more of my own stuff just for you.
For now, I will leave you with Mr. Johnson!
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!