High Temperature Insulation Density 2 lb/cu ft Facing Material FSK Facing Flexibility Not Applicable Foam Cell Type Closed Form Board Insulation Color Yellow Insulation Material PIR Foam Maximum Operating Temperature 297 Degrees F Minimum Operating Temperature -297 Degrees F Overall Length 4 ft Overall Width 24 in R Value 21.1 Thickness 4 in Standards ASTM D1622 C518 D2126 Dimensional Stability E84 at 1 in E96 Water Vapor Permeability 0.02 perm