BS ISO 20852:2020 pdf free.Textiles-Determination of the total heat transfer through textiles in simulated environments.
BS ISO 20852 Textiles一Determination of the total heat transfer through textiles in simulated environments 1 Scope This document specifies the test method for determining the amount of heat transferred through clothing fabrics by the combined dry and evaporative heat emission under simulated and specified conditions. This test method can be used for fabrics, films, coatings, foams and leathers including multilayer assemblies used in hot environment or in activities. The application of this measurement technique is restricted to a maximum amount of total heat transfer which depend on the dimensions and construction of the apparatus used (e.g about 1200 W/m2 for the maximum specifications of the equipment according to ISO 11092). 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IS0 3696, Water for analytical laboratory use一Specification and test methods ISO 11092:2014, Textiles一Physiological efects一Measurement of thermal and water-vapour resistance under steady-state conditions (sweating guarded-hotplate test) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: 一IS0 Online browsing platform: available at https://www.so.org/obp 一IEC Electropedia: available at http://www.electropedia.org/dry heat emission heat transferred by the temperature difference between the two faces of a material divided by the resultant heat flux per unit area in the direction of the gradient in dry state.Note 1 to entry: It is a quantity which determines the dry heat flux across a given area in response to a steady
applied temperature gradient.3.2 evaporative heat emission heat transferred by the water-vapour pressure difference between the two faces of a material divided by the resultant evaporative heat flux per unit area in the direction of the gradient, when evaluated
non-isothermally Note 1 to entry: It is a quantity which determines the “latent” evaporative heat flux across a given area in response
to a steady applied water-vapour pressure gradient. The evaporative heat flux may consist of condensation as well as diffusive and convective components.BS ISO 20852 pdf download.