In the U.S., the vast majority of structures are designed to resist fire exposure according to prescriptive methods in the building codes. Accordingly, the designer selects qualified assemblies from available listings that describe the process or details of construction for the purpose of achieving an intended level of safety or performance. The level of fire resistance assigned to a particular assembly is typically determined by its performance during standard fire testing.
Standard fire testing does not include member connections, structural system response, or natural fire exposure. Due to these limitations, standard fire testing may not provide an adequate basis to determine the actual performance of structural systems during uncontrolled fire exposure. Moreover, structural damage and collapses of engineered buildings due to fire (One Meridian Plaza building, WTC 1 and 2 buildings, WTC 5 building, WTC 7 building, Windsor Tower, and others) have highlighted the need for structural engineering participation in evaluating fire effects on structural systems.
In cases where prescriptive methods would not properly address stakeholder objectives, performance-based methods may be judicially employed to provide a rational basis for determination of structural performance during uncontrolled fire exposure (also known as structural fire engineering). For instance, performance-based methods may be required as part of building code variances in order to demonstrate the adequacy of innovative and/or nonconventional design. Performance-based methods specify the desired level of performance through specific design objectives (e.g., tolerable level of damage), but do not necessarily define specific requirements for design or construction.
Currently in the U.S., designers and building authorities lack standardized guidance for practicing and evaluating structural fire engineering. In spite of this and to a certain extent, structural engineers are presently engaged in performance-based design of structures subject to fire exposure and building authorities need guidance to help them with the approval of proposed designs. To address this issue, ASCE/SEI has endeavored to develop a guideline on the practice of structural fire engineering. It is envisioned that the guideline in conjunction with the prospective ASCE/SEI 7-16 Appendix E will provide designers a baseline level of guidance to practice structural fire engineering.