ASTM C870-24 PDF

SIGNIFICANCE AND USE 5.1 The conditioning prescribed in this recommended practice is designed to obtain reproducible test results on thermal insulating materials. Results of tests obtained on these materials under uncontrolled atmospheric conditions are not comparable with each other. Some of the physical properties of thermal insulating materials are influenced by relative humidity and temperature in a manner that affects the results of tests. In this regard, such information is provided in pertinent material specifications and test methods by stating the physical properties relative to the specific ambient or test conditions. Note 1: In some cases (for example, dimensionally unstable materials), the dry mass cannot easily be established and original mass has to be used. SCOPE 1.1 This practice covers the conditioning of thermal insulating materials for tests. Since prior exposure of insulating materials to high or low humidity will affect the equilibrium moisture content, a procedure is also given for preconditioning the materials. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.3 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. 1.4 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.