The rotating drum dustiness tester: Variability in dustiness in relation to sample mass, testing time, and surface adhesion

A rotating drum dustiness tester was used to characterize variability of du stiness in dependence of type and mass of test material, testing time, and surface adhesion, Powders of six common materials entered the study: benton ite, barium sulphate, talc, Aloxite, carbon black, and coal. Except for coa l, dustiness was in general positively correlated to the mass of powder und er testing. Surface adhesion tended to be affected from the type of test ma terial. For a fixed dust dispersion time (180 sec) the dependence of dustin ess on time was characterized in terms of the time required to arrive at th e median of the cumulative distribution of mass delivered at the outlet of the drum. In general the time required was positively correlated to the mas s of material under testing. A three-parameter multiplicative model for dustiness potential was develope d for two of the test materials (bentonite and barium sulphate). The model included surface adhesion, time, and mass of material under testing as pred ictors. The model was highly significant (p < 0.001) and accounted for more than 80% of the observed variation in dustiness, It is concluded that for dustiness testing to become useful a careful control of all the operating p arameters are required in order to have reproducible tests. Therefore stand ardization of the method is essential. (C) 1999 British Occupational Hygien e Society. Published by Elsevier Science Ltd. All rights reserved.