When is point counting required according to NYSDOH-ELAP?

Point counting is a quantitative analytical method used in asbestos analysis, particularly important for determining the concentration of asbestos in a sample. According to the New York State Department of Health's Environmental Laboratory Approval Program (NYSDOH-ELAP), point counting is required specifically when the polarized light microscopy (PLM) analysis shows asbestos percentages in the range of 1-10%.

In this context, point counting is necessary to provide a more accurate estimation of the asbestos fibers in that specific percentage range, as it helps to quantify the material more reliably. This requirement helps ensure proper management and assessment of asbestos-containing materials, particularly when the levels are low enough that visual inspection alone may not yield an accurate representation of the presence of asbestos.

When analyzing samples with percentages over 20% or when visible asbestos is present, different methodologies might apply. If no fibers are detected, point counting is not applicable since there are no fibers to quantify. Therefore, the correct application of point counting is crucial for effective asbestos investigation and management, especially in the defined percentage range of 1-10%.