Modeling — Fire Resistance
Fire resistance is the ability of a structural assembly (walls, floors, roofs, beams, and columns) to successfully withstand a severe fire for a given time without collapse and without exceeding certain temperature limits. The intent of such fire resistive construction is to serve as a fire safety barrier in buildings in order to control fire propagation and heat transmission to adjacent compartments without structural failure. The fire testing procedures and acceptance criteria for fire resistance have traditionally been specified within a standard test method, such as that in ASTM E 119. The resulting time duration during which the test assembly exhibits adequate structural integrity, stability and temperature control on the unexposed surface and for any steel elements that may be contained within the assembly is expressed as a fire resistance rating, usually from one to four hours. This rating time quantifies the relative ability of the assembly to withstand the standard fire in comparison with other assemblies or elements. Published listings of generic and proprietary fire resistive assemblies are available. These prescriptive ratings inherently contain the assumptions and limitations of the standard test, which includes a single fire exposure under maximum design loads for a prototype assembly. Effects of different fires, partial loads, and larger assemblies with structural continuity cannot be evaluated in this manner.
Since prescriptive-type fire resistance ratings based on fire test standards are not predictive and can be inappropriate for some design conditions, broader interpretations of fire resistance for performance based engineering are being developed. These are based on more realistic structural performance under a design basis fire, as determined by more advanced analytical models, rather than just fire testing qualifications or their derived empirical correlations.
For more information contact:
Nestor Iwankiw
niwankiw@haifire.com
773-467-2013
