Annex A of the standard discusses various types of packing used to re-establish the integrity of fire-rated structures when these barriers have been penetrated by cable. The section that briefly discusses passive mechanical systems and non-mechanical systems such as putty, caulk, cements, intumescent sheets and strips, silicone foams and pre-manufactured pillows. The most common method is stuffing the aperture with ceramic/mineral wool and caulking both sides with fire-resistant putty. The information refers the designer to check manufacturer specifications and UL ratings against NFPA, ASTM and NEC codes.

Cutaway of Typical Firestop