1.Scope 1.1 This test method covers the quantitative measurement of thermal effusivity of woven, knitted, or non-woven fabrics using a guarded modified transient plane source (MTPS) instrument. This test method is applicable to a wide range of thicknesses; however, due to the maximum test penetration of 0.8 mm for highest thermal effusivity samples, the thickness of the fabric shall be greater than 0.8 mm. That thickness ensures that even if the fabric is on the higher end of the thermal effusivity range, the penetration depth of the heat flux during the measurement time is maintained within the fabric. For samples less than 0.8 mm in thickness, a blotter test should be performed as outlined in section 7.1. 1.2 This method is non-destructive, and takes rapid, short-term measurements on small specimens using a sensor that provides a small amount of heat into the specimens and measures the temperature change at the interface. 1.3 This test method is comparative since specimens of known thermal effusivity are used to calibrate the apparatus at the factory level. Thermal effusivity of the calibration specimens are confirmed through calculations that use established properties of thermal conductivity, density and specific heat. 1.4 This test method is intended for measuring fabrics in a dry state at standard atmospheric conditions. 1.5 UnitsThe values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 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 and health practices and determine the applicability of regulatory limitations prior to use.
This standard test method measures thermal effusivity, which is the transient heat exchange between a fabric specimen and a heated surface. It has been established that there is a strong correlation between thermal effusivity and thermal sensations (i.e., warm or cold feeling), where lower values indicate sensations of warmth and higher values indicate sensations of coolness. This fabric property is important to assist product developers with appropriate fabric selection. This draft method is being re-balloted as many revisions were made after the last subcommittee ballot.
Keywordsfabrics; heat transfer; modified transient plane source; textiles; thermal effusivity.
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top