ISO/TR 15657:2013概述了在理解结构如何响应火灾方面取得的进展。本文从主要标称（炉膛）火灾对结构元件的传热、高温变化、结构材料的物理和机械特性，以及如何将信息用于火灾极限状态下结构元件的分析等方面进行了综述。在审查火灾场景时，报告主要集中在标准化加热曲线上，但包括特征曲线的基础，这些特征曲线可能在未来某个时候以标准化的方式采用。在ISO 834熔炉试验中，将自然或特征火灾与等效加热时间联系起来时，参考时间等效作为公认的方法。

ISO/TR 15657:2013 provides an overview of the advances that have been made in understanding how structures respond to fire. This is reviewed in terms of heat transfer to the structural elements from primarily nominal (furnace) fires changes in the elevated temperature, physical and mechanical characteristics of structural materials, and how the information is used in the analysis of structural elements for the fire limit state. In reviewing the fire scenarios the report concentrates primarily on standardized heating curves but includes the basis of characteristic curves, which may at some time in the future be adopted in a standardized way. Reference is made to time equivalent as a recognized methodology in relating a natural or characteristic fire to an equivalent period of heating in the ISO 834 furnace test.