Specification History
| SWS Version | Created | Specification ID | Title | Specification | Objective | Supporting Materials | Rationale | Status |
|---|---|---|---|---|---|---|---|---|
| Version 2025 | 09/24/2023 - 17:08 | 4.0102.1c | Material selection | Select insulation materials that do not exceed a perm rating of 2 and have a flame spread and smoke development index of 75/450 or less when tested in accordance with ASTM E84 or UL 723 |
Select fire safe insulation |
The research linked applies to exterior walls, not attics. In attics the thickness of the insulation is sufficient in nearly all cases to stop vapor diffusion, and additional ignition barriers will also accomplish the same thing without limiting the type of insulation to be used. If anything, require that the insulation have a certain vapor perm rating in cold climates. In the field, roof leaks are far more problematic than vapor diffusion and no contractors in our region would install closed cell on a roof deck for that reason. The R value installed should inhibit moisture diffusion and specifying closed cell foam could be problematic if a roof leak occurred. Foam 6-8 inches will meet class 2 vapor retarder requirements. | Red Line | |
| Version 2020 | 08/14/2020 - 14:23 | 4.0102.1c | Material selection | Select insulation materials that have a flame spread and smoke development index of 75/450 or less when tested in accordance with ASTM E84 or UL 723 |
Select fire safe insulation |
Black Line | ||
| Version 2020 | 08/14/2020 - 14:23 | 4.0102.1c | Material selection | Select insulation materials that have a flame spread and smoke development index of 75/450 or less when tested in accordance with ASTM E84 or UL 723 |
Select fire safe insulation |
Black Line |