SpecSeal SSS Firestop Sealant is a premium grade water-based intumescent firestop sealant. SpecSeal SSS Sealant incorporates our proprietary two-stage intumescent technology making it the go to choice for any combustible or non-combustible penetrants. As little as a 1/2″ applied depth of SSS Sealant is required to provide up to a 4 Hr Fire resistance rating when tested to ASTM E814/UL 1479.