PLM EPA/600/R-93/116 (400 Point Count)


PLM EPA/600/R-93/116 (400 Point Count)


The PLM EPA/600/R-93/116 (400 Point Count) is a comprehensive method for determining the asbestos concentration in bulk building materials. This method is widely used due to its increased accuracy and precision, especially when low asbestos concentration in a building material is suspected or detected.

Overview of the Method

The analysis includes testing of bulk building materials for asbestos by performing 400 point counts. This technique is more labor-intensive and less subjective than a visual estimate. The methodology, which has a detection limit of 0.25%, is widely used to comply with NESHAP regulations requirement of performing point counting on samples with low concentrations of asbestos.

Quantification Techniques

The PLM method outlines two quantification techniques. The first, and most widely employed is the visual estimate. This works well for most sample types. The second type of quantification technique is the point count. While more labor-intensive, it is somewhat less subjective than a visual estimate. This can be important especially at low asbestos concentrations. Both the accuracy and precision are improved with point counting. And the more points analyzed the better the accuracy and precision of the method.

Application of the 400 Point Count

The 400 point count is used mostly to comply with NESHAP regulations which require that point counting be performed for better precision and accuracy on samples with low concentrations of asbestos. The sample retention time for this method is 60 days, and the reporting limit is less than 0.25%.

Sample Types

The method can be applied to various types of samples including Bulk sample, Dust sample, and Soil sample.


Depending on the urgency, the turnaround for the results can be Standard, Next-day rush, Same-day rush, or Holiday-weekend rush.


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