PLM NOB 198.1

This is New York state's method for Polarized Light Microscopy (PLM) analysis of bulk samples (building materials) for asbestos. 

It is a point counting method which is more time consuming and labor intensive than the typical visual estimate technique.  

New York believe's that a point counting strategy overcomes some of the subjectivity of the visual estimate typically employed in PLM analysis.

The method encompasses procedures for both friable and non friable organically bound (NOB) samples.