To limit the spread of fire and smoke through a structure special substances must be installed in openings in which wires, pipes, conduits, and ducts pass. These materials form what’s known as a “fire stopping system.”

The openings of pipes are sealed by graphite or caulk sealants. This is generally around a quarter-inch in thickness.

In ducts, another type of material, known as”wrap strap” is used “wrap strap” is put on any duct opening. Each strap measures 1 and a quarter inches wide, has plastic films on each side, and connected to the wall or the duct by two layers foil tape.

All other holes that are not for conduits, are filled with “fire barrier” pillows. The pillows prevent fire from entering ceilings and walls. rk5tpvgby1.