1.1 ,This specification covers rigid, closed cell, polyurethane and polyisocyanurate thermal insulation for sandwich panels used in shelter construction for exposure to ambient temperatures of ,−,25 to 160 ,°,F (−,32 to 71 ,°,C). Painted surfaces of shelters in actual field use reach temperatures of 200 ,°,F (93 ,°,C). The materials in this specification must be capable of withstanding processing, (laminating) temperatures of 230 ,°,F (110 ,°,C).