BS EN 12939:2001

Foreword
Introduction
1 Scope
2 Normative references
3 Definitions, symbols and units
4 Instrumentation
5 Procedures
6 Calculations and test report
Annex A (normative) Instrumentation
Annex B (normative) Conversion utilities
        for thick specimens
Annex C (informative) Advanced procedures
        to test thick specimens exceeding thickness
        capabilities of the apparatus
Annex D (informative) Items which are
        expected to be specified in product standards

This standard particularly addresses towards specific problems related with testing according to European product standards, thick high and medium thermal resistance specimens with heat flow meter or guarded hot plate. The guarded hot plate and heat flow meter apparatus can be operated up to thickness of 100 mm to 150 mm and the accuracy has to be kept within 2%.

This standard gives the procedures to determine the thermal resistance of products the thicknesses of which exceed the maximum thickness for guarded hot plate or heat flow meter apparatus. In any case most of the procedures described in this standard require apparatus that allows tests on specimens up to 100 mm thick. This standard gives guidelines to assess the relevance of the thickness effect, i.e. to establish whether the thermal resistance of a thick product can or cannot be calculated as the sum of the thermal resistances of slices cut from the product, these guidelines complement the indications given in ISO 8302:1991 on the guarded hot plate apparatus.This standard describes testing conditions which prevent the onset of convection. which could take place in some products under the considered temperature differences and thicknesses.