A new Standard Practice for Determining a Detection Limit for Asbestos Measurements Based on Counts is being developed by scientists serving on ASTM Subcommittee D22.07 on Sampling and Analysis of Asbestos under Committee D22 on Sampling and Analysis of Atmospheres.

In the final stages of development at ASTM, the proposed detection limit practice applies to asbestos in air samples measured by phase contrast microscopy or transmission electron microscopy, and asbestos in dust measured by transmission electron microscopy. Nearly 20 scientists drafting the standard collaborated on the specific requirements of asbestos fiber-counting, instrumentation, and protocol, according to D22 member Naomi S. Montague, vice president, E. M. Analytical, Inc., Dania, Fla.

Montague said the detection-limit concept addresses potential measurement interpretation errors: “For our subcommittee, the detection limit is a parameter that is used to determine whether the fiber measurement in a sample is statistically different than the background level. To date, no formal method or practice for determining a detection limit for asbestos measurements is available from ASTM or any other organization.

“The methods for sampling and analysis of asbestos that our subcommittee has published (as well as all other published methods) have employed a definition of detection limit that has become accepted only because of convention and the passage of time. This practice now allows our subcommittee to provide a definition of detection of limit and a constructive procedure for determining its numerical value that is scientifically sound.”

For further technical information, contact Bertram Price, Price Associates, Inc. (phone: 202/457-9007). Committee D22 meets April 2-5 in Phoenix, Ariz. For meeting or membership details, contact Director George Luciw, ASTM (phone: 610/832-9710). //

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