This test method provides a simple procedure for obtaining information on the fiber length distribution of suitable asbestos fiber. The use of relatively low cost apparatus, small test specimens, and a short test period, enhance the usefulness of this test method.
Normally, results obtained by this test method are reproducible under comparable laboratory conditions. However, close agreement cannot be expected unless all deviations from the procedure, however minor, are avoided. Moreover, results for longer fiber grades are influenced to a greater extent by differences in fiber length distribution, and characteristics, than are those for shorter grades.
This test is suitable for specification acceptance and manufacturing control.
It is assumed that all undersized fibers, and only those, will pass through any given sieve aperture. However, this idealized condition is not normally achieved. Thus, results should not be misconstrued as true length distribution data.
1.1 This test method covers the operation of the Turner and Newall (T and N) wet sieving classifier for asbestos, and a procedure for the determination of fiber length distribution and fines (defined in Terminology D 2946) content of milled asbestos fiber (74 m (200 mesh)) sieve described in Specification E 11.
1.2 For purposes of estimating length distribution, the test is limited to samples free from excessive quantities of non-fibrous particles or contaminants. Quantities exceeding 0.05 g retained in any given length fractions are considered excessive.
1.3 For comparisons between different fiber grades, only those specimens which have approximately the same degree of fiberization as determined by Test Methods D 2752 will give completely meaningful results.
1.4 This test method is not applicable to ultrafine grades of asbestos powders which contain little or no fibers retained on a 74-m (200 mesh) sieve. This method is restricted to Quebec Standard grades 4A to 7D inclusive as determined by Test Method D 3639. Note 1This is an alternative procedure to Test Method D 2589.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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