Structural systems protected with qualified assemblies according to prescriptive methods may be resistant to heating during fire events, but they are not specifically designed to endure thermal load effects. The emerging field of structural fire engineering involves the explicit design of structural systems to adequately endure thermal load effects from uncontrolled fire exposure using rationally-allocated means of protection and potential modifications to preliminary structural system designs. 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. 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.
Currently in the U.S., designers and building authorities lack comprehensive 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. In recent years, the American Society of Civil Engineers: Structural Engineering Institute (ASCE/SEI), the Society of Fire Protection Engineers (SFPE), the National Fire Protection Association (NFPA) and other organizations each have endeavored to develop standardized guidance for determination of structural response to thermal load effects from fire exposure. It is envisioned that the aggregate of these standardized documents will provide designers a baseline level of guidance to practice structural fire engineering.