Fireresistant Assemblies

determined through standardized testing procedures carried out by impartial laboratories. These ratings are tabulated both in the publications of those laboratories and in literature that is available from relevant trade associations and individual manufacturers. The detailer should assemble and keep current a collection of these publications for use in selecting appropriately fire-resistant building components. A good start on this collection would be to acquire the Underwriters Laboratory's Fire Resistance Directory and the Gypsum Association's Fire Resistance Design Manual; see the reference list in the back of this book for information on ordering these publications.

4. Penetrations of lire-rated assemblies such as floors, lire walls, and lire separation walls must be sealed or otherwise protected against the passage of fire by codc-approved means. Small holes through floors, such as pipe and conduit penetrations, are usually closed with lire-rated sealant systems marketed j by a number of manufacturers. Gaps between exterior cladding and the edges of floors are sealed with safing, which usually consists of high-temperature mineral fiber batts supported by simple metal hooks or clips. Doors and door frames in fire walls and fire separation walls must have fire resistance ratings, as specified by the relevant building code. Glass areas in fire doors and in lire-rated walls are restricted bv building codes, and must be wired glass, which holds together even after it has been broken by fire. At the point where a duct passes through a fire-rated wall, it must be fitted with a metal fire damper, a flap that closes automatically bv means of a fusible r »

link if the temperature in the duct rises above a set level. Vertical chases and shafts that pass through floors must be enclosed by walls of specified fire resistances. ■

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