1.1 本试验方法包括定量测量和主观观察，表征材料、防护服和设备暴露在热空气循环烘箱中时的耐热性评估性能。 1.2 本试验方法旨在评估材料、防护服和设备在规定热暴露下的物理变化。 1.2.1 热风循环炉中的规定热暴露是对流热和辐射热的组合。 1.3 评估材料、防护服和设备的可见变化，或在规定的热暴露后进行材料性能测量。 1.3.1 本试验方法不用于评估粘附性。NFPA 1975第7.2.1和8.3节描述了评估织物粘附的可接受方法。NFPA 1975试验方法通过评估在规定重量下放置在玻璃板之间的折叠试样在符合本试验方法中使用的烘箱相同特性的烘箱内的堵塞情况，评估试样的热稳定性。 1.4 本试验方法能够定量测量由于热空气循环烘箱中的特定热暴露而发生的尺寸变化。 1.5 以国际单位制表示的数值应视为标准值。括号中给出的值是到热测试常用的其他单位的数学转换。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 注1: 阻燃和耐热材料在一系列不同的标准中描述，并满足一系列不同的要求。对于根据本试验方法进行试验的材料，应使用适用标准确定预处理、调节和试验条件和要求。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法用于评估材料、衣物和设备在热空气循环烘箱中受热时的耐热性。本试验方法的主要结果是观察试样对热暴露的反应。 5.1.1 本试验方法中规定的大多数程序适用于扁平材料试样的评估。 5.1.2 在评估非平面材料时，需要使用替代程序来安装试样并解释热暴露的影响。 5.2 如有规定，本试验方法用于测量热空气循环烘箱中对流热暴露后的材料尺寸变化。 5.3 本试验方法不用于模拟材料、衣物或设备在高温条件下（如火灾环境）的实际暴露。

1.1 This test method covers quantitative measurements and subjective observations that characterize the performance for evaluating the heat resistance of materials, protective clothing, and equipment when exposed in a hot air circulating oven. 1.2 This test method is intended to evaluate physical changes in materials, protective clothing, and equipment at a specified heat exposure. 1.2.1 The specified heat exposure in the hot air circulating oven is a combination of convective heat and radiant heat. 1.3 Materials, protective clothing, and equipment are evaluated for visible changes or subjected to a material property measurement following a specified heat exposure. 1.3.1 This test method is not to be used for the evaluation of sticking. An acceptable method for evaluating sticking of fabrics is described in NFPA 1975, Sections 7.2.1 and 8.3. The NFPA 1975 test method evaluates the thermal stability of specimens by assessing the blocking of folded specimens placed between glass plates, under a specified weight, inside an oven meeting the same characteristics of the oven used in this test method. 1.4 This test method enables the quantitative measurement of dimensional change that occurs as a result of a specified heat exposure in a hot air circulating oven. 1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to other units that are commonly used for thermal testing. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Note 1: Flame-resistant and heat-resistant materials are described in a range of different standards and meet a range of different requirements. For materials tested in accordance with this test method, the applicable standard shall be used to establish preconditioning, conditioning, and testing conditions and requirements. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method is used to evaluate the heat resistance of materials, clothing, and equipment when exposed to heat in a hot air circulating oven. The principal findings of this test method are observations of the specimen response to the heat exposure. 5.1.1 The majority of procedures specified in this test method apply to the evaluation of flat material specimens. 5.1.2 When evaluating non-flat materials, alternative procedures are required for mounting specimens and interpreting the effects of the heat exposure. 5.2 If specified, this test method is used for the measurement of material dimensional change following a convective heat exposure in a hot air circulating oven. 5.3 This test method is not intended to simulate the actual exposure of material, clothing, or equipment in high-heat conditions such as a fire environment.