Metacaulk Fire Rated Mortar is a specially formulated rapid hardening gypsum/ cement compound, that provides the optimum combination of workability, strength and fire resistance. When mixed with clean water to the required consistency, the Metacaulk FRM sets without shrinking to form a rigid, gas tight, fire resistant seal. Tested in accordance with ASTM E814 (UL 1479) and ULC-S115-95 standards can provide up to 4 hr fire resistance on a wide range of firestop penetrations where they pass through fire rated walls or floor assemblies. Can easily be cut or drilled and resealed if future penetrants are needed. No special tools are required to mix or install the product. Metacaulk Fire Rated Mortar systems are rated for up to 4 hours