Denray Posted January 24, 2013 Report Share Posted January 24, 2013 When furnace duct comes up an enclosed shaft from the first floor does it need to be sealed off at the second floor and attic planes? Click to Enlarge 58.24 KB Click to Enlarge 49.49 KB Quote Link to comment Share on other sites More sharing options...
ericwlewis Posted January 24, 2013 Report Share Posted January 24, 2013 I'd say "if fire can shoot up it, it needs fire blocking". But considering it's flex duct, it doesn't seem like it would make a bit of difference. Quote Link to comment Share on other sites More sharing options...
Marc Posted January 24, 2013 Report Share Posted January 24, 2013 I've never seen it in residential. Marc Quote Link to comment Share on other sites More sharing options...
Tom Raymond Posted January 24, 2013 Report Share Posted January 24, 2013 When was it built? Pretty much anything built after 1980 here has fire stops. Quote Link to comment Share on other sites More sharing options...
Darren Posted January 24, 2013 Report Share Posted January 24, 2013 Yes; it needs fire stops at every level. including the attic. Quote Link to comment Share on other sites More sharing options...
Stephen Lagueux Posted January 24, 2013 Report Share Posted January 24, 2013 if it needs fire stop then, most likely the duct work will need dampers. But that is mostly in commercial. Check local codes, most require fire stops every 8 foot. Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted January 25, 2013 Report Share Posted January 25, 2013 It's "fireblocking" and yes it's needed at those locations, regardless of what type of duct material. Quote Link to comment Share on other sites More sharing options...
inspector57 Posted January 25, 2013 Report Share Posted January 25, 2013 Agreed. Fire-stop if only for the energy value. (not to say that there is no value in fire-stopping around duct work) Quote Link to comment Share on other sites More sharing options...
Rob Amaral Posted January 25, 2013 Report Share Posted January 25, 2013 As acts as an insulation-baffle... (the fire-stop)... definitely bring this up.. Quote Link to comment Share on other sites More sharing options...
Denray Posted January 25, 2013 Author Report Share Posted January 25, 2013 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 65.06 KB Quote Link to comment Share on other sites More sharing options...
ericwlewis Posted January 25, 2013 Report Share Posted January 25, 2013 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 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 Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted January 25, 2013 Report Share Posted January 25, 2013 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. Quote Link to comment Share on other sites More sharing options...
Denray Posted January 26, 2013 Author Report Share Posted January 26, 2013 OK, got it, "Fireblocking". Makes sense. Thanks Bill. Quote Link to comment Share on other sites More sharing options...
ericwlewis Posted January 26, 2013 Report Share Posted January 26, 2013 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. Quote Link to comment Share on other sites More sharing options...
hausdok Posted January 26, 2013 Report Share Posted January 26, 2013 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 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 Quote Link to comment Share on other sites More sharing options...
Neal Lewis Posted January 27, 2013 Report Share Posted January 27, 2013 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. Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted January 27, 2013 Report Share Posted January 27, 2013 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. Quote Link to comment Share on other sites More sharing options...
Bill Kibbel Posted January 27, 2013 Report Share Posted January 27, 2013 I don't make stuff up. Click to Enlarge 31.76?KB Quote Link to comment Share on other sites More sharing options...
Erby Posted January 27, 2013 Report Share Posted January 27, 2013 Probably no longer called "firestopping" because they got sued when it didn't "STOP" a fire. Quote Link to comment Share on other sites More sharing options...
Jim Katen Posted January 27, 2013 Report Share Posted January 27, 2013 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. Quote Link to comment Share on other sites More sharing options...
Darren Posted January 28, 2013 Report Share Posted January 28, 2013 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. Quote Link to comment Share on other sites More sharing options...
John Dirks Jr Posted January 28, 2013 Report Share Posted January 28, 2013 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 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..... Quote Link to comment Share on other sites More sharing options...
LeePlace Posted January 29, 2013 Report Share Posted January 29, 2013 The most glaring issue is that of heat loss through the uninsulated chase into the attic. The holes for wiring need to be sealed so I think the space around the duct needs to be sealed to prevent air passage and insulated to match the attic insulation. Lee Quote Link to comment Share on other sites More sharing options...
hausdok Posted January 29, 2013 Report Share Posted January 29, 2013 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 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 Quote Link to comment Share on other sites More sharing options...
ericwlewis Posted January 29, 2013 Report Share Posted January 29, 2013 how did this topic get to fireblocking INSIDE the ductwork??? Quote Link to comment Share on other sites More sharing options...
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