Flanking transmission caused by fire stops in wood frame constructions

In multi-family dwellings, the nominal party wall or floor between units is both fire and sound rated. At the joint between two fire rated assemblies, there must exist a fire stop to control smoke and flame spread in the event of a fire. Typically, the fire stop provides a physical connection between building elements thereby causing a flanking path. The degradation of the net sound isolation of a double leaf construction is examined for two types of fire stop materials listed in the National Building Code of Canada (NBCC). Fire stops formed from continued room surfaces are examined. A section through the specimen without any fire stopping is shown