Thread: Cellulose Insulation Clearance Requirements

This is more a rant on the rubbish builders and installers are spreading to discredit inspectors or at least defend their actions.

CIMA (CIMA - Cellulose Insulation Manufacturers Association) advises a 3-inch clearance from their products to chimneys and flues in their technical bulletin #2. I have also personally spoken to two technical reps from two different manufacturers confirming such. So I commented on this finding in my report.



Turns out the builder absolutely refuses to sweep the insulation off and away from the flue.

Here is an exerpt from their subsequent correspondence:

"I spoke to [name removed] just a minute ago. He is adamant that this is not an issue and that the fire department reinforces his position on the safety of this material and its proximity to the flue. He is confident that this is proper and does not agree that this needs to be addressed. He has told me that they have built houses over the last four years with this same material. He also stated that any house fires that have happened in the past, any damage was minimized by the fact that they use this material. The bottomline is that the manufacturer advises a certain tolerance, but the city inspectors have latitude within the tolerance to approve, which has been done on all the houses within this subdivision and apparently with all the homes that [name removed] has built over the past four years. [emphasis mine] [name removed] is not going to make a change that he has confirmed with the city inspector that meets the city's building fire code."

Now, I don't doubt this is a great product and that it is fire-retardant due to being chemically treated. And I have also seen the studies regarding its excellent properties in house fires. But it is downright SCARY that builders, installers, and/or AHJ are adapting, diminishing, derating or otherwise changing manufacturers' instructions and recommendations.

I had to share my story and get it off my chest for what it's worth...

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Tim:

All of the vent manufacturers also have clearance requirements. Find out whos it is an look it up. Duravent is here:

http://www.duravent.com/docs/instruct/L204A_apr00.pdf

Aaron

You are correct about boxing out area around heat sources. Was the venting BVENT?

Originally Posted by JORY LANNES

You are correct about boxing out area around heat sources. Was the venting BVENT?

Yes, it was a type-B vent.

Tim, Thanks for posting this. I have client who is planning on using this in a NC project coming up soon. I'll check out the CIMA site for info. The cellulose/blown in isn't big around here (at least for what I run into).
On a related note, it amazes the lines of BS builders/developers/contractors come up with when they get busted for something by an HI. Sometimes I can't help myself, I start laughing, the excuses just floor me. Of course they are adamant the HI (I) am wrong even after I provide doc's/code section copies to my client.
Hang in there, I know it is very frustrating at times. Do you also get the "well, it's not really a big deal, we are just going to live with it because the GC says fixing it will really delay the project substantially" from your clients?
Just wondering if it's only mine.
Good luck

This from a American Metal:

One-inch (1") minimum air space clearance required to combustibles and insulation.

http://www.americanmetalproducts.com...20-%20ADFC.pdf

And from Hart & Cooley

One inch (1”) minimum air space clearance required to combustibles and insulation.

http://www.hartandcooley.com/vent/in...structions.pdf

The Combustible part is a no brainer, but insulation even if non-combustible is also a problem. It needs AIR space for proper cooling.

Jim,

The original post's photo was of a Type B Gas Vent, your links were to Double Wall Gas Vent Connectors - not the same thing.

5. When installed as a Type B Gas Vent, a
minimum of one (1) inch airspace clearance to
combustible material is required.

http://www.hartandcooley.com/vent/instructions/851339%20Round%20Type%20B%20Gas%20Vent.pdf

Firestopping

All Type B Gas Vent passing through floors, ceilings
or within vertical stud walls must be firestopped at
floors or ceilings. The Firestop must effectively close
the opening between the outer wall of the Vent Pipe
and the hole cut in the structure. In attics, the
Firestop should be placed on top of the framed
ceiling opening to prevent insulation and debris from
coming into contact with the Vent Pipe.

Can Type B Vent be wrapped with insulation to keep it warm?
No. The vent requires a minimum of one-inch clearance to all combustible material. For severe problems such as cold attics, contact the Technical Services Department of the manufacturer for alternative solutions.

AmeriVent® Products

http://www.americanmetalproducts.com...structions.pdf

Firestopping
All Type B Gas Vent passing through floors, ceilings or
within vertical stud walls must be firestopped at floors or
ceilings. The Firestop must effectively close the opening
between the outer wall of the Vent Pipe and the hole cut
in the structure. In attics, the Firestop should be placed
on top of the framed ceiling opening to prevent insulation
and debris from coming into contact with the Vent Pipe.

Lots of information out there that specifies no insulation in contact with the pipe.

Jim,

You da man.