ASTM F3426-20

4.1 This test method can be used to quantify and compare the insulation provided by different clothing items as long as each test is conducted using the same experimental procedures and test conditions. For example, variations in the design and fabric used in gloves can be evaluated. The effects of layering, closures, and fit can be measured for clothing items.

4.2 The measurement of the insulation provided by clothing is complex and dependent upon 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, humidity 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.

1.1 This test method covers the determination of the insulation value of clothing items that cover only the head (Option 1), a hand (Option 2), or a foot (Option 3). It describes the measurement of the resistance to dry heat transfer from a heated manikin form to a relatively calm, cool environment.

1.2 The insulation values obtained apply only to the particular clothing item 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 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.