This specification discloses a means for providing a barrier against the passage of fire through that portion of a wall aperture surrounding an electrical conduit, pipe, or the like. This is accomplished by placing a sleeve around that portion of the conduit passing through the wall, which sleeve is the central portion of an envelope which is anchored peripherally to the wall or to a more or less rigid material blocking the aperture through the wall and which sleeve connects to end portions of the envelope, each of which end portions extends to connect with the conduit on an opposite side of the wall. The annular region between the conduit and the surrounding envelope is filled with an intumescent gel. The boot is flexible and capable of some movement to compensate for thermal expansion, vibration or other forces during the life of the installation. In the event of heat and fire, the gel within the envelope intumesces, providing protection against passage of flames and gas through the annular region surrounding the conduit, which annular region is now occupied by a fire resistant mass formed by the solidification of the gel. The intumescible gel comprises sodium silicate solution, a filler, and a hardener.
William A. Mallow