Safety Team- who’s on board?

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.

Inspecting firestop- Can you see the issue?

 

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.

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.

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!

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-

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?

 

NO WAY!

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.