Everbuild fire mate intumescent sealant everbuild fire fire mate sealant is an intumescent acrylic sealant that swells when exposed to temperatures in excess of 125c to prevent the passage of fire and smoke and has a fire rating of up to 5 hours in certain joint configurations fire rated to bs 476 part 20en1366 4 2006 acoustic rates to bs en iso 1403 tested for air permeability to en13141 1 everbuild fire mate intumescent sealant white c3