The fire barrier must be installed in the structural gap before the Architectural Joint system. Install A/D FIREBARRIER Mineral Wool to the minimum 25% or 35% compression. Compression must always be perpendicular to the grain. Butt adjacent sections of A/D FIREBARRIER Mineral Wool tightly against each other. Leave no voids. A/D FIREBARRIER Mineral Wool is the recommended backup material for A/D FIREBARRIER Silicone. Determine the depth of fire stop sealant required, and recess the A/D FIREBARRIER Mineral Wool the appropriate depth