Great Stuff 12 oz fireblock insulating foam sealant, helps impede the spread of fire and smoke through service penetrations, such as pipes, cables and ducts. tested according to astm e84, astm e814 ul1715/ recognized as an alternative fireblocking material. bright orange colored foam for visual inspection. fills, seals & insulates gaps up to 3/4 inch with an airtight, water-resistant bond.