Q: Do JM duct insulations comply with the International Building Code and the International Mechanical Code?
A: It is planned that the International Code will replace the other regional codes. When used for their intended purpose and when selected so that the R-value requirements are met, Johns Manville duct insulation products comply with the requirements of the International Mechanical Code.
The following are the major requirements from the 1998 International Mechanical Code:
Duct board:
UL 181 class 0 or 1.
Duct wrap:
Flame spread rating of 25 or less, and smoke developed rating of 50 or less as composite.
Shall not flame, glow, smolder or smoke when tested by ASTM C 411 at 250 °F.
Must be labeled every 36" with manufacturer, R-value at specified installed thickness, and flame smoke ratings.
When used on cooling ducts, the insulation must be covered with a vapor retarder with a maximum permeance of 0.05 perms, or an aluminum foil a minimum of 2 mils thick.
Duct lining:
Flame spread rating of 25 or less, and smoke developed rating of 50 or less as composite.
Shall not flame, glow, smolder or smoke when tested by ASTM C 411 at 250 °F.
Must meet air stream surface durability requirements of UL 181.
R-value must be sufficient to:
Comply with energy code.
Prevent condensation on cooling ducts (or other means to prevent condensation must be used).
Maintain exposed surfaces below 120F on heating ducts.
