prEN 12667

Thermal performance of building materials and products - Determination of thermal resistance by means of guarded hot plate and heat flow meter methods - Products of high and medium thermal resistance

Publication date:   Oct 16, 2025

Scope

This document specifies principles and testing procedures for determining, by means of the guarded hot plate or heat flow meter methods, the thermal resistance of dry test specimens having a thermal resistance of not less than 0,5 m2·K/W.
NOTE 1 The above limit is due to the effect of contact thermal resistances. An upper limit for measurable thermal resistance depends upon a number of factors described in this document, but a unique figure cannot be assigned.
It applies in principle to any mean test temperature, but the equipment design in Annex D is essentially intended to operate between a minimum cooling unit temperature of -100 °C and maximum heating unit temperature of +100 °C.
NOTE 2 Limits to the mean test temperature are only imposed by the materials used in the apparatus construction and by ancillary equipment.
This document does not supply general guidance and background information (e.g. the heat transfer property to be reported, product-dependent specimen preparations, procedures requiring multiple measurements, such as those to assess the effect of specimen non-homogeneities, those to test specimens whose thickness exceeds the apparatus capabilities, and those to assess the relevance of the thickness effect).
This document does not apply to cover measurements on moist products of any thermal resistance or measurements on thick products of high and medium thermal resistance.