This is a liability that we find on most large projects. Would we find it on yours? (Part 2)

Last time we talked about the requirement of angle on non-insulated non-dampened ducts.  This time we will talk about WHY it is required. For the sake of easy calculations this time we are talking about a non-insulated duct that is 24″x48″ and running through a 1 hour rated assembly.  It doesn’t matter if it is a block or gypsum wall or even if it is a floor, the requirement will be basically the same.  The one exception is, that a floor is firestopped from the top side, so angle is required on the top side.  A wall will require both firestop AND angle on BOTH sides of the wall.

This is a big liability for your company, if the angle is not installed and today we will talk about WHY this is so important.  If there is a fire, you are pretty much guaranteed that your firestop application around the duct will fail if your 24″x48″ duct does not have retaining angle properly installed.  There are a few things we have to explain. First, is how assemblies are tested.  Second is about buttons on shirts. Third is a painless physics lesson dealing with the Coefficient of Linear Thermal Expansion. Fourth we will tie it all together for you.

Testing Assemblies:

ASTM E119 allows everyone to burn something and compare it something else using very specific criterion.  This way you can ensure that materials will perform as expected in a fire scenario.  This is one of the standards that is used for any of this firestop stuff we are talking about,and much more.  One section of the test is a “time  temperature curve” that details what temperatures must be reached inside the test furnace at specific time intervals. The temperature at the 1 hour mark its required to be 1700F.  Why am I telling you this?  It will make sense in a moment.

Physics of Buttons:

If you are wearing a button up shirt that only has two buttons and you pull on each side of your shirt; there will be a considerable gap between the two buttons.  How much of a gap will depend on how hard you pull and how far apart the buttons are.  If you have more buttons on your shirt, say six buttons; then rather than have one big gap you will have a series of smaller gaps between each button.  Stay with me now, on to a physics lesson and then we will relate your shirt buttons to physics and back to firestop, I promise!

Coefficient of Linear Thermal Expansion:

What happens when you heat something up? Many things respond the same way (at least prior to ignition).  They expands, right?  But how much something expands depends on three things, the initial temperature, the end temperature, and the coefficient of that item, in our case steel ductwork.  So, if we have a room that is 70F degrees  and we look only at the duct length of 48″ and we go back to the ASTM E119 time temperature curve that is used to test firestop, then at 1 hour the temperature in the furnace will be 1700F.  If you ran the calculations then a 48″ duct will expand to become 48.9389″. The formula is below if you want to play with it.

Pulling it all together:

So, the same way that your two-button shirt has a big gap, the duct with no retaining angle will have a gap because the extra length, created by the expansion, will have to go somewhere.  This movement will cause the duct to bow inward, because it can not bow outward because it is contained by the concrete or the metal framing of a gypsum wall assembly.   The bowing that occurs will (at the apex) create a gap of almost 1”.  Add that to whatever the annular space was before the increase in temperature (which I’m most cases is maximum 2″).   The firestop material required on these UL listed details is intumescent, meaning that it will expand when exposed to significant temperature. However, the expansion will not be enough to fill the void of the combination of the pre-existing annular space as well as the gap created by the bowing duct.  So, the angle is required to prevent this large gap from occurring. The same way the extra buttons reduced the gap on your shirt, but may vary based on the spacing-the requirements for the retaining angle will call for specific spacing and for the screws to go into the duct through the angle.  This creates a series of small gaps with smaller gap apices (yes, I had to google plural for apex).  This creates a scenario where the fire, smoke and toxic gas can not get to the non-fire side of the assembly prematurely.

So, at this point you should be asking about how to install (or inspect) the angle, the screws and the rest of it.

Our next blog will talk about where to find the requirement for the angle and what exactly is required and what you should be looking for so you can confirm that the installation is correct. You can find that here and the following one here. If you missed our first blog posts on this topic, please review here Part 1.

Remember the more you know the better you can be at your job!  Together we all can be part of a movement- “Saving Lives for the Life of the Building.”tm  If you have questions or comments please email us at info@halpertlifesafety.com.  We would love to hear from you.

 

Here is the formula or you can go on line for it.

dl = L0 α (t1 – t0)         (1)

where 

dl = change in object length (m, inches)

L0 = initial length of object (m, inches)

α =  linear expansion coefficient (m/moC, in/inoF) 

t0 = initial temperature (oC, oF)

t1 = final temperature (oC, oF)

Compliments of www.engineeringtoolbox.com

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Halpert Life Safety Consulting LLC’s

“Saving Lives for the Life of your Building” TM

Our mission is to make a colossal impact on the level of life safety of your building and on the talent of your people. We provide consultation, training, quality control and third party special inspection related to firestop and passive fire protection. We consult for the building industry in the New York/New Jersey (NY/NJ) metropolitan area, as well as across the United States and internationally.

This is a liability that we find on most large projects. Would we find it on yours? (Part 1)

The next few blog posts will cover an issue that is often a liability on large projects.  This non-compliant firestop installation impacts the liability for the owner, the architect, the mechanical contractor, the firestop installer and the inspector.

If you have a non-insulated duct that is 28×36 and it is going through a 2 hour rated wall, it will likely require a damper.  The damper manufacturer will require retaining angle be installed on one side of the damper. We could go into the purpose it serves, but that just makes for a long blog and here we are focusing on PASSIVE fire protection. (If you want to know why dampers require angles, please contact any damper manufacturer and they can fill you in.  The more you know the better you are at your job!)

Did you know that when this same duct runs through a 1 hour rated wall and may not need a damper, that it will still need retaining angle?  The angle in this case serves a very different purpose. Walk any job you’ve been on and if you see angle on BOTH sides of a duct through 1 hour rated wall WRITE TO ME.  Take a picture and send it to me!  I hope to eventually be wrong when I say this is an issue that is missed more commonly than not.  I say this because as long as I am right; then buildings are not as safe as they should be.  Our primary goal at Halpert Life Safety is to improve the level of passive fire protection in buildings.  We can only do that with YOUR help.  If we can help you to be better at your job, together we make buildings safer.  Check back for the next post and I will tell you all about WHY this is a requirement and WHERE you can find the documentation, so you can make sure this problem doesn’t happen on YOUR project.

Please write to me and tell me your thoughts on our blog or firestop in your community.  Did you know about this requirement?

If you want to read the next posts on this topic, please review them here. Part 2, Part 3, Part 4.

I’ve been on projects all over the world and it just makes me want to make a bigger difference…to improve the life safety in more jurisdictions.  After all at Halpert Life Safety we are “Saving Lives for the Life of the Building.”  If you have questions or comments please email us at info@halpertlifesafety.com.  We would love to hear from you.

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__________________________________________________

Halpert Life Safety Consulting LLC’s

“Saving Lives for the Life of your Building” TM

Our mission is to make a colossal impact on the level of life safety of your building and on the talent of your people. We provide consultation, training, quality control and third party special inspection related to firestop and passive fire protection. We consult for the building industry in the New York/New Jersey (NY/NJ) metropolitan area, as well as across the United States and internationally.

Do this and your insurance company might not have to pay if your building burns

The article below is basically about a building that was insured against fire, but because the owner did not properly maintain the buildings sprinkler system, as is required by code; the insurance company did not have to pay after a fire. In fact the owner had to repay the advance that they were given.

You can read the article below, but I wanted to start a conversation about passive fire protection.  The building codes require rated walls be maintained so when your IT crews run new lines or new tenants renovate an office space or whatever may happen to any building, with any occupancy type, that could interfere with the integrity of a rated wall.  Would the insurance company be able to identify this as a risk that would allow them to not have to pay out during a fire?   The building codes are changing and now many projects are required to have third party special inspection of firestop installations. All it will take is one major loss and insurance companies will look more closely at passive fire protection.  Also you will find that premiums will change and the way premiums are evaluated will change.

If you don’t want to run this risk, contact Halpert Life Safety and we will help you assess the risk in your building, we can help with due diligence before you purchase a building or during construction we can help ensure that your contractors are not missing anything.  Check out next weeks blog post to learn about a major problem with ductwork that is very rarely done correctly. (at least from my experience…if I am wrong I’d love to know…write to me)  It doesn’t matter if you are on a project in China, the Caribbean, Las Vegas or New York there are certain problems that are common. I can say that because Ive been there.  Stay tuned to learn more about them!  Together we all can be part of a movement- “Saving Lives for the Life of the Building.”tm

http://www.insurancejournal.com/news/east/2011/07/20/206553.htm#.T8O55FcdLD0.email

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__________________________________________________

Halpert Life Safety Consulting LLC’s

“Saving Lives for the Life of your Building” TM

Our mission is to make a colossal impact on the level of life safety of your building and on the talent of your people. We provide consultation, training, quality control and third party special inspection related to firestop and passive fire protection. We consult for the building industry in the New York/New Jersey (NY/NJ) metropolitan area, as well as across the United States and internationally.

Key questions for your firestop installer/inspector

If you are a building owner hiring a third party special inspector or a contractor hiring a firestop installer you want to know that you are bringing someone onto your team who knows what they are doing.  This and subsequent blog posts will cover some questions you can ask to be sure these individuals are competent.  The problem is you need to know the answer and the logic behind the answer; so you can gauge the response you are given…so here goes.  Let’s start with a discussion of insulated pipes.  The first question is pretty simple.

Question 1:  What UL listed assembly would you use to firestop an insulated pipe?

Answer: You would use a WL5000 series detail for a gypsum wall and likely a CAJ5000 series detail for a concrete floor or wall, though WJ5000 or FA5000 would work for walls and floors respectively.

Why does this question matter:  If an inspector/installer knows the UL nomenclature (the naming system used by Underwriters Laboratories- the primary source for third party testing of firestop) they can more readily flip through the firestop submittals and find the proper details to inspect/install to. If they don’t know how to find the UL detail they are probably not referencing it during inspection/installation which means the best they can do is guess on how the installation should be completed.  This is a liability for everyone involved from the installation firm to the building owner and designer because you won’t know if the installation is truly compliant with the project plans, specifications, submittals or building code.

Other BLOG articles go into this in greater detail and additionally explains the UL nomenclature in a general way that is very useful to inspectors and installers alike.

Please let me know if this information is useful and other topics you would like us to over here.  The more you learn the better you can build and together we can build better buildings “Saving Lives for the Life of your Building”tm

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__________________________________________________

Halpert Life Safety Consulting LLC’s

“Saving Lives for the Life of your Building” TM

Our mission is to make a colossal impact on the level of life safety of your building and on the talent of your people. We provide consultation, training, quality control and third party special inspection related to firestop and passive fire protection. We consult for the building industry in the New York/New Jersey (NY/NJ) metropolitan area, as well as across the United States and internationally.

Firestop on Insulated Pipes

Firestop on Insulated Pipes

Learn about some common firestop problems involving insulated pipes.  Don’t let these scenarios happen on your projects.

https://slate.adobe.com/cp/IPSZY/

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__________________________________________________

Halpert Life Safety Consulting LLC’s

“Saving Lives for the Life of your Building” TM

Our mission is to make a colossal impact on the level of life safety of your building and on the talent of your people. We provide consultation, training, quality control and third party special inspection related to firestop and passive fire protection. We consult for the building industry in the New York/New Jersey (NY/NJ) metropolitan area, as well as across the United States and internationally.