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.
These methods apply, in particular, to 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. They 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.
ISO 176:2005 also applies to 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.