Q: Do JM duct insulations comply with SBCCI requirements?
A: The Standard Building Code and the Standard Mechanical Code, written by SBCCI (Southern Building Code Congress International), is generally used in the southeastern US.
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 Standard Mechanical Code. The following are the major requirements from the 1997 Standard 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.
Must not flame, flow, smolder or smoke when tested by ASTM C 411 at 250 °F.
Must be labeled every 36" with R-value, nominal thickness, flame and smoke ratings, density and manufacturer.
When used on cooling air duct the insulation shall be covered with a vapor retarder with a maximum permeance of 0.05 perms.
Duct liner:
Flame spread rating of 25 or less, and smoke developed rating of 50 or less as composite.
Must not flame, flow, smolder or smoke when tested by ASTM C 411 at 250 °F.
Must be labeled every 36" with manufacturer, nominal thickness, flame and smoke ratings, and density or R-value.
R-value:
Supply and return air ducts located in unconditioned spaces shall be insulated with insulation having a minimum R-value of 4.2.
Ducts operating above 120 °F shall have insulation with R-value sufficient to keep exposed surfaces at or below 120 °F.
