Understanding
the UL Fire Resistance Directories
4
Air Duct:á Any UL Class 0 or Class 1 flexible air duct installed in accordance with the instructions provided by
the damper manufacturer.
3A
Loose Fill
Material: As an alternate to Item 3, any loose fill material bearing the UL Classification
Marking for Surface Burning Characteristics, having a min density of 0.5 pcf
and installed at a max thickness of 3-1/2 in.
Batts
and Blankets:á Glass fiber insulation fitted in the concealed space, draped
over the resilient channels and gypsum wallboard ceiling membrane. Any glass fiber insulation bearing the UL
Classification Marking as to Surface Burning Characteristics and/or Fire
Resistance, having a min density of 0.5 pcf.
3