ASTM F1291-22

SIGNIFICANCE AND USE 4.1 This test method can be used to quantify and compare the insulation provided by different clothing systems. For example, variations in the design and fabric used in component garments can be evaluated. The effects of garment layering, closure, and fit can be measured for clothing ensembles. The insulation values for ensembles can be used in models that predict the physiological responses of people in different environmental conditions. Garment insulation values can be compared as well (see Annex A1). 4.2 The measurement of the insulation provided by clothing is complex and dependent on the apparatus and techniques used. It is not practical in a test method of this scope to establish details sufficient to cover all contingencies. Departures from the instructions in this test method have the potential to lead to significantly different test results. Technical knowledge concerning the theory of heat transfer, temperature and air motion measurement, and testing practices is needed to evaluate which departures from the instructions given in this test method are significant. Standardization of the method reduces, but does not eliminate, the need for such technical knowledge. Report any departures with the results. 4.3 Report the insulation values in SI units or clo units as standard procedure. Conversion factors to other units are given in Test Method D1518. SCOPE 1.1 This test method covers the determination of the insulation value of clothing ensembles. It describes the measurement of the resistance to dry heat transfer from a heated manikin to a relatively calm, cool environment. Information on measuring the local thermal resistance values for individual garments and ensembles is provided in Annex A1. 1.1.1 This is a static test that provides a baseline clothing measurement on a standing manikin. 1.1.2 The effects of body position and movement are not addressed in this test method. 1.2 The insulation values obtained apply only to the particular ensembles evaluated and for the specified environmental conditions of each test, particularly with respect to air movement. 1.3 The values stated in either clo or SI units are to be regarded separately as standard. Each system shall be used independently of the other. The thermal resistance units, clo or SI, shall be identified clearly and consistency of units shall be maintained throughout reporting process. 1.4 The evaporative resistance of a clothing ensemble can be measured in accordance with Test Method F2370. 1.5 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. 1.6 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.