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One hour fire rating roof 1

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stripez

stripez

Structural
Feb 26, 2021
65

Can you give example of a one hour fire rating roof?

For bare I-beam w8x21 and C-purlin 2x6" 1.8mm without any fire retardant or fire cover carrying lightweight metal roof. How long before the I-beam would bend and the C-purlin and thin metal roof melt if they were exposed directly to fire?

Any photos of bent I-beam, melted C-purlins and thin metal roof?

 
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Not very long. The roof you describe would not be given a fire rating.

BA
 
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So what example of a one hour fire rated roof?

But if the structure can only support a metal roof. And no way to fire rated it even with plaster coating, then the floor has to be condemned and made unoccupied?
 
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I've seen fire damage in a similar metal building situation. Purlins were pretty torqued out. Roof was absolutely gonzo. Beam did not show much damage (observed as: bent flanges, buckled webs, etc). Connections did show some signs of damage through material testing. It was more of an explosive type fire, as opposed to a slow burn from the base.
 
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They can design the coating for whatever rating you need. Many of us have used this method often. Take a note of your M/D ratio of your member, which is the mass over exposed surface area, as different ratings/products may have different M/D ratios.
 
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I've seen them 'draped' over the columns like spagetti...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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If you don’t mind me asking, why do you need to protect the roof? In the UK you would only do so in four circumstances. 1. The roof behaves as a floor. 2. That part of the roof is a means of escape, say for maintenance staff. 3. A local boundary condition exists i.e. fire may spread to an adjacent building. 4. Local to a compartment wall, in effect a bit like 3.

C-purlins imply your roof is probably not a floor; I’m not sure whether the other factors apply.

 
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Depending on the use and occupancy, some buildings require a FRR roof. In addition, some buildings require that if the construction is combustible, that it requires a FRR. There are also some spatial separation issues that require non-combustible or a FRR.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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If you don’t mind me asking, why do you need to protect the roof? In the UK you would only do so in four circumstances. 1. The roof behaves as a floor. 2. That part of the roof is a means of escape, say for maintenance staff. 3. A local boundary condition exists i.e. fire may spread to an adjacent building. 4. Local to a compartment wall, in effect a bit like 3.

C-purlins imply your roof is probably not a floor; I’m not sure whether the other factors apply.
Click to expand...

The roof is just a thin metal roof. And the only reason we want to coat all the metal part and make it fire rated to at least 2 hours is because there is adjacent building thrice higher less than a foot away. In case of fire, we won't want the flame to go up through the roof and scorching the neighbor's concrete walls, because they could sue my client big, like saying it has weaker their structural beams and columns and the entire building costing millions of dollars need to be replaced, etc.

Has anyone heard of cases like this or encounter one?

So what is the best steel coating with 1 and 2 hours fire rating?
 
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In that case you are in category 3 and have a boundary condition. You may not need to protect the whole roof, but just the section adjacent to the boundary. I am not sure what your local standards are, but I would have thought they ought to stipulate a minimum stand-off.

With a thin deck you may struggle to achieve 2hrs with an intumescent coating. I suspect boarding the soffit with fire lining may be more realistic.

Hope this helps.
 
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[image][/image]

I can't find any youtube video of burning test of such 0.5mm metal roof. What temperature do you think it would melt and how many hours or minutes before it happened?

Can you successfully coat the bottom with fire coating material to create maybe 1 to 2 hour fire rating?

Or is it hopeless?
 
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A metal roof will not achieve anywhere near a 1 hour fire rating.

You can get roof panels that are insulated and may achieve the fire rating you need.

roof_ficq7p.jpg
 
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A metal roof will not achieve anywhere near a 1 hour fire rating.
Click to expand...

One like the metal roof above was already installed in place years ago. If you would spray it with fire coating, what is the maximum rating it can get?

And how long and what temperature before a 0.5mm thin metal sheet melt?



You can get roof panels that are insulated and may achieve the fire rating you need.
Click to expand...

Cant do this because the 0.5mm thin metal roof already installed years ago.
 
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Let's say you already put up a 4 hour rated firewall with parapet and you make the roof and ceiling 1 or 2 hour fire rated. How do you deal with a 4" plastic or pvc rain gutter drain pipe like the following? Are there also fire rated drain pipe? How thick should it be? Let's say the drain is half inch thick, how long before it melts and the flame gets out of the hole? Or let's say it's still pvc or plastic drain pipe, how would exiting flame through a 4" hole looks like or behave?

[image][/image]
 
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Yes you should be able to achieve this - but you would be best off talking to local suppliers.
 
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If you built solid concrete or thick concrete masonry firewall with concrete roofing. You are sure it will be rated at least 2 hours. Now imagine you use gypsum x wall cladding and gypsum x cladding. What if the tenant one day without you knowledge removed a panel to insert a lighting fixture or airconditioner pipe. Then wouldn't that one removed panel caused any flame to shoot up and melt the thin cladding metal fixture?

And even you use intumescent coating, it has only limited effectivity, is it not?

Therefore the most sure way to guarantee certain fire rating is to build concrete wall and concrete roofing. And if the building can't support these, then not use the floor at all, isn't it?

Anyway how far from the neighbor property line exterior wall must one setback the living units so any flame through the roof couldn't reach the neighbor? What distance when the flame can no longer damage any concrete walling of neighbor? Is it 10 feet? 20 feet?
 
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