1.1 ,This test method covers the determination of the relative friability of a particular size of sized coal. It affords a means of measuring the liability of coal to break into smaller pieces when subjected to repeated handling at the mine or subsequently, by the distributor or by the consumer. This test method is serviceable for ascertaining the similarity of coals in respect to friability rather than for determining values within narrow limits to emphasize their dissimilarity. This test method also may serve to indicate the relative extent to which sized coals will suffer size degradation in certain mechanical feed devices. This test method may be used for differentiating between certain ranks and grades of coal, and therefore the test method is of service for coal classification purposes.