1.1 This test method covers the determination of the performance of commercial sizes of both block and pipe forms of thermal insulating materials when exposed to simulated hot-surface application conditions. The term “hot-surface performance” has reference to a simulated use-temperature test in which the heated testing surface is in a horizontal position. 1.2 This test method refers primarily to high-temperature insulations that are applicable to hot-side temperatures in excess of 150°F (66°C). It is used for materials such as preformed insulations, insulating cements, blankets, and the like, by proper laboratory preparation of the samples. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 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. 1.5 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.