Asbestos Identification by
PLM (Polarized Light Microscopy)
For Bulk fibre Identification

Methodology for PLM Analysis: NIOSH 9002
This method is useful for the qualitative identification of asbestos and the semi-quantitative determination of asbestos in bulk samples. This method measures the percentage of asbestos as perceived by the analyst in comparison to standard projections, photographs and experience. The quality of the results are dependant upon the skill and judgment of the operator.

Required Microscope Equipment

• Polarized Light Microscope 100X thru 400X with 10X Dispersion Staining Objective (see below)
• Stereo microscope 10X thru 45X.

Dispersion Staining Objectives
Dispersion staining is a process by which color is imparted to colorless objects with the refractive index measured and used to identify the object being tested. The Meiji Dispersion Staining Objective is a 10X pre-centered central stop objective for 160mm tube length microscopes with RMS mounting threads. The technique differentiates between the refractive indices of the particulate solid and the liquid medium in which the solids are immersed. This method is most commonly used in asbestos fibre testing. The central stop positioned inside the Dispersion Staining Objective achieves certain colors at the perimeter of the fibres depending on the refractive indices between the fibre and the suspension medium.