fischer UFS 310 is a one part water based intumescent sealant which is used for sealing construction joints and service penetration in both vertical and horizontal applications. Tested in accordance with ASTM E 814 (UL1479) ASTM E 1966 (UL2079) ASTM E 84 (UL723) the fischer UFS 310 can provide upto 4 hours fire rating. Vast testing with a variety of service penetrations and joint configurations makes it a universal firestop for most applications. properties and is formulated to be halogen and solvent free.