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.

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.