This standard specifies the method for determining the length distribution of chrysotile asbestos fibres through a wet classification process. It details the procedure using a specialized apparatus known as the Turner and Newall classifier. This test is critical for grading asbestos fibres, which directly impacts the properties of asbestos-cement products.
Method of test for length distribution (wet classification of fibre length) of chrysotile asbestos fibre using Turner and Newall classifier
Quick Reference Values
Water flow rate through classifier9.0 ± 0.1 litres/min
Agitator speed600 ± 25 rev/min
Test specimen mass10.0 ± 0.05 g
Drying temperature for fibres105 to 110 °C
Key Formulas
Percentage of fibre retained on a screen = (Mass of residue on screen / Total mass of specimen) * 100
Practical Notes
Extreme caution is required due to the carcinogenic nature of asbestos fibres. All testing must be conducted in a controlled environment with appropriate ventilation and Personal Protective Equipment (PPE).
The accuracy of the results is highly dependent on the correct calibration of the classifier (especially water flow rate) and consistent operator technique.
Given the ban and restrictions on asbestos use in India and globally, this test is now rarely performed and is primarily of historical or forensic relevance.