| Popis: |
In the European standardization organization CEN, a working group has developed a standard describing the procedures to be used when determin ing the thermal conductivity of masonry materials such as brick, aerated concrete, etc. It applies to measurements using a guarded hot plate or a heat flow meter appara tus. This paper deals with those clauses of the standard related to measurements on moist materials and describes the background and considerations needed for the drafting of these clauses. Preparation and conditioning of the test specimens are described. The paper analyses the effect of moisture redistribution during the measurements and reviews different options for dealing with these effects. It is possible, for the materials considered, to restrict the errors caused by effects of moisture in the materials to less than about 5%-that is to the same order of magni tude as the errors of the guarded hot plate or heat flow meter apparatus itself when testing dry masonry materials. |
