Abstract: A backer rod adapted for forming a fire-resistant seal within a construction joint. The backer rod may include an elongated tube defining a total assembly volume and a hollow interior, and a core disposed within the hollow interior. The tube is formed of a combustible foam plastic which disintegrates when exposed to fire. The core material is expandable when exposed to fire, such that the core has an intumescent expansion factor sufficient to expand to a volume beyond the total assembly volume. The backer rod may be press fit into a void between two surfaces to a depth. A sealant layer may be formed within the void. When exposed to fire on a side opposite the sealant layer, the external shell disintegrates, the core expands within the void in a direction away from the sealant layer, and a fire-resistant barrier is formed within the void between the surfaces.

Abstract: A backer rod adapted for forming a fire-resistant seal within a construction joint. The backer rod may include an elongated tube defining a total assembly volume and a hollow interior, and a core disposed within the hollow interior. The tube is formed of a combustible foam plastic which disintegrates when exposed to fire. The core material is expandable when exposed to fire, such that the core has an intumescent expansion factor sufficient to expand to a volume beyond the total assembly volume. The backer rod may be press fit into a void between two surfaces to a depth. A sealant layer may be formed within the void. When exposed to fire on a side opposite the sealant layer, the external shell disintegrates, the core expands within the void in a direction away from the sealant layer, and a fire-resistant barrier is formed within the void between the surfaces.

Abstract: A backer rod adapted for forming a fire-resistant seal within a construction joint. The backer rod may include an elongated tube defining a total assembly volume and a hollow interior, and a core disposed within the hollow interior. The tube is formed of a combustible foam plastic which disintegrates when exposed to fire. The core material is expandable when exposed to fire, such that the core has an intumescent expansion factor sufficient to expand to a volume beyond the total assembly volume. The backer rod may be press fit into a void between two surfaces to a depth. A sealant layer may be formed within the void. When exposed to fire on a side opposite the sealant layer, the external shell disintegrates, the core expands within the void in a direction away from the sealant layer, and a fire-resistant barrier is formed within the void between the surfaces.