HH-I-1972/3, FEDERAL SPECIFICATION, INSULATION BOARD, THERMAL, POLYURETHANE OR POLYISOCYANURATE FACED WITH PERLITE INSULATION BOARD ON ONE SIDE AND AS

HH-I-1972/3, FEDERAL SPECIFICATION, INSULATION BOARD, THERMAL, POLYURETHANE OR POLYISOCYANURATE FACED WITH PERLITE INSULATION BOARD ON ONE SIDE AND ASPHALT/ORGANIC FELT OR ASPHALT/GLASS FIBER FELT ON THE OTHER SIDE OF THE FOAM (12 AUG 1981), This specification covers the requirements for faced thermal insulation boards composed of rigid cellular polyurethane or polyisocyanurate faced with perlite insulation board on one side of the foam and asphalt/organic felt or asphalt/glass fiber felt faced on the other side of the foam. This specification does not cover cryogenic applications. For intended use see 6.1 of HH-I-1972/GEN.