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exposed fiberglass batt insulation

Coder

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Joined
Nov 15, 2011
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306
Location
Colorado
I have a building permit holder that is building a 38,000 sq. ft. sprinklered distribution facility. it is type VB construction with a combination of steel framing, beams, cmu walls and open web wood truss roof. They are insulating the entire underside of the roof deck with R-38 fiberglass batt insulation and hoping to just leave it and the trusses exposed. besides it looking like crap unfinished, I told them they at least need a vapor retarder over the insulation. But what? Do they need a 15 minute thermal barrier as well? I have been at this code enforcement thing for 14 years and I am stumped. Thanks in advance for any input.
 
Start with this I think:

711.3 Nonfire-Resistance-Rated Floor and Roof Assemblies

Nonfire-resistance-rated floor, floor/ceiling, roof and roof/ceiling assemblies shall comply with Sections 711.3.1 and 711.3.2.

711.3.1 Materials

Assemblies shall be of materials permitted by the building type of construction.

711.3.2 Continuity

Assemblies shall be continuous without vertical openings, except as permitted by Section 712.


Which then points me to:

602.5 Type V

Type V construction is that type of construction in which the structural elements, exterior walls and interior walls are of any materials permitted by this code.

802.1 Interior Wall and Ceiling Finish

The provisions of Section 803 shall limit the allowable fire performance and smoke development of interior wall and ceiling finish materials based on occupancy classification.

803.1 General

Interior wall and ceiling finish materials shall be classified for fire performance and smoke development in accordance with Section 803.1.1 or 803.1.2, except as shown in Sections 803.1.3 through 803.15. Materials tested in accordance with Section 803.1.1 shall not be required to be tested in accordance with Section 803.1.2.


And down the rabbit hole you will go...
 
Without skrim the insulation sags and falls out…. Then there’s the dust that collects.
 
I'm not sure what the material is but I've seen warehouses like what you're describing that use some kind of membrane (plastic/PCV/similar?) to cover the insulation and prevent the issues ICE is describing. I would assume it have some kind of rating for vapor retarding and/or smoke spread...
 
I believe there is batt insulation available with a foil-skrim-kraft vapor barrier that has a flame spread of 25 and can be left exposed.
 
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