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Firestop needed?


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Yep, seems like it would have to be metal ducting at the firestops to be effective. And then there was this exterior drain pipe for the upstairs. Sheessh. Thanks for the help all.

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I originally had the thought that the ductwork would have to be metal at the fireblocking to work. But it would need to be metal for the entire run, right? If it caught on fire two feet below the fireblocking it would shoot up through the metal duct and out the next section of flex[:-bigeyes

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The correct term is fireblocking. It's certainly not expected to stop a serious fire. The intent is to resist the movement of flames, gases, and smoke through concealed spaces.

Being concerned about flex ducts would be if penetrating through a required fire-rated assembly.

Like a furnace located in the garage and flex going into the house. I have a picture of that somewhere.

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Yep, seems like it would have to be metal ducting at the firestops to be effective. And then there was this exterior drain pipe for the upstairs. Sheessh. Thanks for the help all.

Click to Enlarge
tn_2013125115731_Yaple12413%20035.jpg

65.06?KB

I originally had the thought that the ductwork would have to be metal at the fireblocking to work. But it would need to be metal for the entire run, right? If it caught on fire two feet below the fireblocking it would shoot up through the metal duct and out the next section of flex[:-bigeyes

Yeah,

I dunno. Fire has to have something to burn. How does it go up through a metal duct if there's nothing inside the duct for it to burn? Come to think of it, I've never seen it climb up the inside of a metal stove unless there was fuel up higher for it to burn - like creosote in a stack, etc..

I can understand the concern to prevent smoke and fumes from entering the next level, but isn't fire going to set at the bottom of that duct and shake its fist in frustration at the other end of that duct?

ONE TEAM - ONE FIGHT!!!

Mike

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The correct term is fireblocking.

This is what hart & Cooley calls it in their installation instructions.

In multi-story buildings, a firestop must be provided

at every point where the vent passes through a floor

or ceiling. These firestops may be provided as

indicated in the paragraph above.

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The correct term is fireblocking.

This is what hart & Cooley calls it in their installation instructions.

In multi-story buildings, a firestop must be provided

at every point where the vent passes through a floor

or ceiling. These firestops may be provided as

indicated in the paragraph above.

The current, correct term for what is needed for what's pictured in the OP is fireblocking.
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The correct term is fireblocking.

This is what hart & Cooley calls it in their installation instructions.

In multi-story buildings, a firestop must be provided

at every point where the vent passes through a floor

or ceiling. These firestops may be provided as

indicated in the paragraph above.

Hart & Cooley just haven't updated their instructions for a while. Firestopping was the old term that was last used, in CABO anyway, in the 1995 edition. It's an obsolete term now.

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As whats needed in the OP photo, the correct term is fireblocking.

However, in the field, the term firestop or firestopping is still used when referring to filling the annular space around any penetration through a fire rated or smoke barrier assembly.

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Yep, seems like it would have to be metal ducting at the firestops to be effective. And then there was this exterior drain pipe for the upstairs. Sheessh. Thanks for the help all.

Click to Enlarge
tn_2013125115731_Yaple12413%20035.jpg

65.06?KB

I originally had the thought that the ductwork would have to be metal at the fireblocking to work. But it would need to be metal for the entire run, right? If it caught on fire two feet below the fireblocking it would shoot up through the metal duct and out the next section of flex[:-bigeyes

Yeah,

I dunno. Fire has to have something to burn. How does it go up through a metal duct if there's nothing inside the duct for it to burn? Come to think of it, I've never seen it climb up the inside of a metal stove unless there was fuel up higher for it to burn - like creosote in a stack, etc..

I can understand the concern to prevent smoke and fumes from entering the next level, but isn't fire going to set at the bottom of that duct and shake its fist in frustration at the other end of that duct?

ONE TEAM - ONE FIGHT!!!

Mike

I'm no expert on fire by any measure but I've heard that the fumes given of by fire are themselves flammable. Also, if a fire is starving for air, could the duct be the supply and coax the flames up through it? I don't know, maybe physics wont allow this. Just pondering.....

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Yep, seems like it would have to be metal ducting at the firestops to be effective. And then there was this exterior drain pipe for the upstairs. Sheessh. Thanks for the help all.

Click to Enlarge
tn_2013125115731_Yaple12413%20035.jpg

65.06?KB

I originally had the thought that the ductwork would have to be metal at the fireblocking to work. But it would need to be metal for the entire run, right? If it caught on fire two feet below the fireblocking it would shoot up through the metal duct and out the next section of flex[:-bigeyes

Yeah,

I dunno. Fire has to have something to burn. How does it go up through a metal duct if there's nothing inside the duct for it to burn? Come to think of it, I've never seen it climb up the inside of a metal stove unless there was fuel up higher for it to burn - like creosote in a stack, etc..

I can understand the concern to prevent smoke and fumes from entering the next level, but isn't fire going to set at the bottom of that duct and shake its fist in frustration at the other end of that duct?

ONE TEAM - ONE FIGHT!!!

Mike

I'm no expert on fire by any measure but I've heard that the fumes given of by fire are themselves flammable. Also, if a fire is starving for air, could the duct be the supply and coax the flames up through it? I don't know, maybe physics wont allow this. Just pondering.....

Well,

That was my point. If flames could climb a metal pipe just with the presence of oxygen above why doesn't every metal stack on the planet look like a Roman candle?

Fireblocking outside the duct I understand and I understand backdraft damping to prevent movement of smoke and vapors through ducts but the idea that fireblocking is needed inside metal ducting just seems weird to me and not very efficient - seems like it would cause gross inefficiencies in air movement.

ONE TEAM - ONE FIGHT!!!

Mike

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