Restrained vs. Unrestrained

September 12, 2018
Publication: Structure Magazine
Author(s): Kevin LaMalva Therese McAllister Luke Bisby

Most structural fire protection designs in the U.S. are conducted using prescriptive code requirements. This approach allows designers to select fire resistant assemblies from available listings that are qualified through standard furnace testing. Standard furnace testing exposes structural elements to a standard fire to determine a fire-resistance rating, typically expressed in hours. For certain listings, the designer must decide if the assembly is “restrained” or “unrestrained.” Indeed, architects routinely ask structural engineers to provide guidance on what classification should be assigned. This article reviews the history of this paradigm and provides considerations for designers tasked to classify restraint.

Services: Structural Design
Keywords: Fire Engineering