NYC-WTC_000220345

NYC 9/11 Public Portal Document

Clean Air Testing Labs, Inc. 1 n 1 Steete Blvd. Baldwin. New York 11510 T©l./Fax; (516) 546-2640

Clean Air Testing LaBs conducts analysis of bulk samples (e.g. floor tile, plaster, pipe insulation, etc.) for asbestos content by numerous applications under Polarized Light Microscopy (PLM) and Transmission Electron Microscopy(TEM). Listed below is a highlight of those methods

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PLM is the most commonly used method for the analysis of bulk samples, using lOX to 400X power magnification. .PLM bulk sample analyses follow the EPA method of the Determination of Asbestos in Bulk Insulation Sample (EPA 600/144-82-020.) , Samples are first examined with a stereo-binocular microscope. . Representative portions of the sample are mounted on slides with refractive index oils and analyzed .with a Polarized Light Microscope (PLM)'. If no asbestos is found in a sample, "ND" (None Detected) is reported. If asbestos is found in a sample, two' kinds of information are reported in the "asbestos minerals" column of the PLM report; First, identify the types of asbestos found. Second, identify the area percentage of asbestos, as determined by visual estimation by PLM. Additional information about .non- asbestos fibers and non-fibrous materials is also recorded. Many samples consist of distinct materials or layers, which are analyzed separately. Asbestos results from.'each layer or material are reported individually.

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If Routine PLM analysis finds the sample to be non asbestos-containing material or containing asbestos in low concentration levels, the sample can be analyzed by an alternative method known as point counting (required by NYSDOH for all friable samples). Point counting can be used to more accurately determine the amount of asbestos present by removing some of the interferences (i.e. binder, carbonate mineral, etc.) that may hinder the analyst’s ability to determine the amount of asbestos present. Point counting uses larger quantities of sample and systematically analyzes individual particles, whereas visual estimation analyzes fields of view.

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NYC-WTC_000220348