This International Standard specifies two empirical methods for the quantitative determination of the loss of mass from a plastic material under defined conditions of time and temperature, in the presence of activated carbon. These methods are used, in particular, for the quantitative determination of the loss on heating of plasticizers from plasticized plastic materials, in which case it is generally assumed that no significant amounts of other volatile materials are present. These are empirical test methods, suitable only for a rather rapid comparison of the losses of plasticizers or, in general, of volatile compounds, from different plastics. They may also be employed for the comparison of different types of plasticizers; in this case, standard compounds should be prepared, on the basis of a well characterized resin, with known ratios of resin to plasticizer. NOTE These comparisons are possible only if the test specimens are of the same thickness. If it can be assumed that, after reconditioning, the moisture content of the exposed specimens is equal to that obtaining after the original conditioning, the effect of moisture may be ignored. Two methods are specified: — Method A: The test specimens are in direct contact with the carbon; this method is particularly useful for materials that have to be tested at relatively low temperatures because they flow at higher temperatures. — Method B: The test specimens are placed in wire cages that prevent direct contact between the test specimens and the carbon.