ISO 23993:2008 gives methods to calculate design thermal conductivities from declared thermal conductivities for the calculation of the thermal performance of building equipment and industrial installations. These methods are valid for operating temperatures from -200 °C to +800 °C. The conversion factors, established for the different influences, are valid for the temperature ranges indicated in the relevant clauses or annexes.
GSO ISO 23993:2010 history
2010GSO ISO 23993:2010 Thermal insulation products for building equipment and industrial installations -- Determination of design thermal conductivity