3M™ Fire Barrier Packing Material PM4 is an easy-to-dispense, non-asbestos, inorganic material designed to be used as an alternative packing material to mineral wool, fibreglass and backer rod in through-penetration firestop systems. 3M™ Fire Barrier Packing Material PM4 is an installation-friendly material that is easy-to-dispense and features compact packaging that is optimized for portability. The smooth-textured woven material can be torn by hand, eliminating the need for a knife. 3M™ Fire Barrier Packing Material PM4 material is less irritating to the skin when compared to conventional mineral wool. Meets International Building Code (IBC) and other key life safety building codes. With excellent strength and flexibility characteristics it is an ideal through-penetration packing material. 3M™ Fire Barrier Packing Material PM4 meets International Residential Code (IRD) as a stand-alone fireblocking material.