:| Do you allow friction fiberglass batts as fireblocking per this section? Do they fulfill the requirement to be "installed in suach a manner as to be securely retained in place"? Or do you require solid blocking, or kraft-faced batts?
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R602.8.1 Materials for fireblocking
- Thread starter ewenme
- Start date
J
JayHawkInspector
Guest
I think you should remove the paper before I would allow it to be used as a fireblock.
Yankee
Registered User
Yes to fiberglass insulation (minus the paper backing)
RJJ
Co-Founder
No Kraft faced batts. I want them secured or real tight.
Darren Emery
Registered User
Just curious - why (and per what section of the code) do you require the paper to be removed?
Builder Bob
Sawhorse
paper is combustible;hence kinda opposite of "fire" blocking........ Plus paper doesn't compress as easily as unkrafted rolls of fiberglass insulation. Fiberglass batting has to be compacted in order to be effective as fire stopping.
Yankee
Registered User
If it is packed tight into a space and the kraft side is right against another material, then I guess it wouldn't matter. But the kraft facing may not be left exposed (as per instructions on the paper backing). That means exposed even within a cavity IMHO.Darren Emery said:
Mac
Gold Member
If it is in a cavity then why is it exposed?
Yankee
Registered User
Its surface is exposed to the air. Installed so that another material is against (touching) the paper backing is not exposed (to an airspace).Mac said:
See R302.10.1 Exception 1 (2009 IRC)
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In the UBC the requirement that the batts be unfaced was worded more clearly, but I think it is still there in R602.8.1. The fact that R602.8.1.1 speaks of unfaced fiberglass implies that that is what is meant in R602.8.1. Beyond that, R602.8.1 list the materials that are allowed. Batts or blankets of mineral or glass fiber are listed. Paper is not listed, therefore it is not allowed.Darren Emery said:
Mac
Gold Member
Does the full depth & width cavity insulation in an exterior wall cavity count as fireblocking?
My point is that the paper doesn't matter - the code allows combustible material to be used as fireblocking. Friction-fitted insulation can come loose and sag or settle, and if concealed in an enclosed stud bay or cavity it willnot be seen, and won't perform its intended funciton. Stapled in place paper face FG has a better probability of staying put.
My point is that the paper doesn't matter - the code allows combustible material to be used as fireblocking. Friction-fitted insulation can come loose and sag or settle, and if concealed in an enclosed stud bay or cavity it willnot be seen, and won't perform its intended funciton. Stapled in place paper face FG has a better probability of staying put.
High Desert
Gold Member
The paper faced insulations does not meet flame spread requirements if left exposed. If it's exposed, then it has to be removed. If not exposed, leave it on.
Yankee
Registered User
The paper used to stable it up with will be the first to go, then the batt better be stable on its ownhMac said:
Mac: That was my original question: does the batt fulfill the requirement to 'be securely retained in place?' Two of my inspector disagree. When I read the code section, I say it does fulfill the requirement. Not that I like it. Always in the past I'd required solid blocking for fire blocking. If the requirement is to prevent a chimney effect in the stud bay, then I think the FG batts would do it.
Thanks everyone for the comments and discussion. I found the faced/un-faced batt discussion particularly interesting. I still think that if FG batts suffice, then Kraft-face would also suffice. The backing of the gypsum board is paper too!
Thanks everyone for the comments and discussion. I found the faced/un-faced batt discussion particularly interesting. I still think that if FG batts suffice, then Kraft-face would also suffice. The backing of the gypsum board is paper too!
Darren Emery
Registered User
Thanks for the replies, all. I have allowed paper faced batts as fireblock, but I sure didn't like it. I just don't think the code is clear enough, either way.
Okay, I'm thinking here.....scary but true!
Okay...there's a flame inside a wall or whatever...If the paper on the insulation is facing the flame, the paper burns off and you still have the insulation left as a fireblock.
Okay...there's a flame inside a wall or whatever...If the paper on the insulation is where the flame cannot get to the paper, it doesn't burn because there is fireblocking.
The code allows wood, plywood, gypsum, particleboard and these are all combustionable materials.
R602.8.1 Materials. includes mineral or glass fiber as allowable material for fireblocking.
Then a little farther along in the code there is a specific section for unfaced fiberglass batt insulation.
R602.8.1.1 Unfaced fiberglass. Unfaced fiberglass batt
insulation used as fireblocking shall fill the entire cross
section of the wall cavity to a minimum height of 16
inches (406 mm) measured vertically. When piping, conduit
or similar obstructions are encountered, the insulation
shall be packed tightly around the obstruction.
In my opinion paper on insulation is okay for fireblocking.
Okay...there's a flame inside a wall or whatever...If the paper on the insulation is facing the flame, the paper burns off and you still have the insulation left as a fireblock.
Okay...there's a flame inside a wall or whatever...If the paper on the insulation is where the flame cannot get to the paper, it doesn't burn because there is fireblocking.
The code allows wood, plywood, gypsum, particleboard and these are all combustionable materials.
R602.8.1 Materials. includes mineral or glass fiber as allowable material for fireblocking.
Then a little farther along in the code there is a specific section for unfaced fiberglass batt insulation.
R602.8.1.1 Unfaced fiberglass. Unfaced fiberglass batt
insulation used as fireblocking shall fill the entire cross
section of the wall cavity to a minimum height of 16
inches (406 mm) measured vertically. When piping, conduit
or similar obstructions are encountered, the insulation
shall be packed tightly around the obstruction.
In my opinion paper on insulation is okay for fireblocking.
Glennman CBO
Silver Member
- Joined
- Oct 20, 2009
- Messages
- 441
If you read the words printed on the paper that is backing the insulation, it will state that it is not just flamable, but it's highly flamable, and that it must be covered with an approved building material. If the paper will be in full contact with the inside of the drywall, then it is fine. However, if the paper will be left exposed in the cavity, it must be removed.
I have yet to see a kraft faced paper that doesn't have these words on it. I even ran across some a while back at a remodel that was of the foil covered paper type that said the same thing on it. Check with the manufacturer.
I have yet to see a kraft faced paper that doesn't have these words on it. I even ran across some a while back at a remodel that was of the foil covered paper type that said the same thing on it. Check with the manufacturer.