Structural Fire Tests Research Articles

Scale Modeling of Compartment Fires for Structural Fire Testing

Current design for fire protection subjects an individual structural element to a standard temperature profile that is meant to ensure the element's load-carrying capacity for a predetermined period of time during a fire. While this approach satisfies the structural component's fire resistance requirement, it does not provide an understanding of the behavior of the structure in a fire. To fully understand a structure's behavior in a fire, a full-scale fire experiment is necessary. Scaled experiments offer an economical alternative to full-scale fire experiments. This paper discusses a method for scaling a compartment fire by using the laws of similitude. The profiles of hot gas temperature versus time in such a reduced-scale compartment will be similar to those in a full-scale compartment, which is a necessary condition for conducting reduced-scale structural fire testing. Experimental verification at two different scales are performed to show the validity of the proposed approach. It has been shown that ...

Building Fire Safety, Structural Fire Tests, and Performance Based Codes

Building fire safety is a general term covering life safety of occupants and fire resistance of buildings. The former deals with emergency exits, escape signs, detecting system, alarms, sprinklers, smoke control, and fire extinguishers. The later involves with construction materials, architectural design to prevent fire spread, and theoretical analysis as well as experimental study to maximize structural performance in fire. Among them the experimental study, particularly structural fire tests, has attracted serious attentions from international engineering societies. The first ISO TC-92 meeting held in London, 1961 entitled, “Fire Tests on Building Materials and Structures” set a landmark of fire resistance research. Since then, innovative technologies on building materials, engineering analyses, structural designs, and fire tests have been developed to generate fire ratings of steel and concrete elements. Of these developments, an element fire test is the most expensive attributed to a need a large furnace equipped with sophisticated hydraulic system, temperature control and data acquisition units. The obtained data have been widely used by engineers, insurers, and building officials in assessing fire safety of buildings. Fire tests of full sized concrete beams, slabs, and columns in North America were carried out in accordance with the ASTM E-119 standard procedure or ISO 834. One of the standard’s weaknesses involves with a provision allowing the supported regions of a specimen be protected from fire exposures. The fire endurance of a structural element tested without exposing its end points to fire conceivably differs from that of a correspondent member of an actual building in fire. An idea to include structural joints in a fire test surfaced 4 decades ago but did not receive public attention until PBC was introduced in early 1980’s. The uniqueness of PBC includes design flexibility and requiring verification tests of frame structures. The 911 WTC disaster investigation conducted by National Institute of Standards and Technology (NIST) supports PBC requirements on frame fire tests.

Restrained Fire Resistance Ratings in Structural Steel Buildings

Unique to North America is a dual classification for fire resistance of supporting members in floor and roof system in buildings, depending on whether these members are restrained or unrestrained at their ends. When this dual classification was first introduced in 1970, the ASTM E-5 Fire Test Committee clearly recognized that architects, engineers and building code administrators not familiar with the nuances of structural fire testing would have difficulty in properly applying restrained and unrestrained fire ratings in the design of real buildings. As a result, general guidance was added to ASTM E119 Standard Fire Test in the form of Appendix X3, reproduced in its entirety herein as Appendix A, with the permission of ASTM. The purpose of this paper is to eliminate the confusion that has persisted in some regions of the USA concerning the proper application of restrained and unrestrained fire resistance ratings for steel beam floor and roof assemblies. The ASTM E119 Standard Fire Test and fire test procedures are discussed. Current building code requirements are summarized and results of extensive fire research and analysis of steel beam and concrete floor constructions are reviewed. Recent studies that provide greater understanding of how steel beam and concrete floor systems endure the effects of uncontrolled fire events in real buildings are briefly referenced. The information in this paper will enable architects and engineers to satisfy code provisions requiring justification where fire resistance for steel beam floor and roof systems are based on restrained assembly ratings.