scope:

The properties determined by these tests are inherent in the brush materials, themselves as distinct from performance characteristics in operation on electrical equipment. Values of physical properties published in catalogues, etc., shall be based upon test methods, given in these recommendations. The purpose of the different sections in these recommendations is to provide a uniform procedure for determining the following properties of brush materials: - Density and porosity; - Hardness; - Resistivity ; - Transverse strength; - Ash content.