NYC-WTC_000232512

NYC 9/11 Public Portal Document

Taylor environmental group, inc. =iy\P #10928

Non-Friable Organically Bound Materials (NOBs)

NOTE: The following procedure is an outline of NYS DOH Method 198.1 / 198.4 (NOB Section) which is to be followed for the analysis of bulk material samples that are determined to be non-friable organically bound material (e.g. floor tile, roof felt, mastic, etc.).

1) Preliminary Preparation: Remove all extraneous materials (wax, polish, mastic) prior to sample preparation. Mastic is considered a separate sample and must removed for independent analysis.

2) Organic Reduction: Shave off approximately 100-500 mg of material into a tared crucible and weigh. Place tn muffle furnace at 480° Celsius until mass stabilizes (1 to 12 hours). Cool tn a dessicator, re-weigh and calculate percent organic loss.

3) Acid Digestion: Grmd residue tn crucible with 0.5 ml of 0.1 pm - filtered deionized water and add 2 to 5 ml of concentrated HCl. After 15 minutes, pour solution into filtration apparatus loaded with a tared 0.4 um polycarbonate filter, rinse crucible twice with deionized wate:;, and apply vacuum. Rinse sides of filtration apparatus with deionized water, transfer filter and residue to a tared petri dish, and allow filter/residue to dry to stable mass. Weigh filter/residue and calculate percent carbonate loss.

NOTE: At this stage, if the residue mass is less than 1 % of the subsample's original mass, analysis is terminated and the sample is reported as non-asbestos containing material.

4) Sample Analysis tldenrificaiion): A minim'am of four subsampies from each filter are mounted and analyzed using procedures outlined in the Appendix to this Report titled "Bulk Material Sample Collection & Analysis Methodology."

5) Sample Analysis fOuantification’l: Quanrification of posibvely identified asbestos fibers is achieved bv comparing each slide preparation to verified standards. The amount of asbestos is then calculated as follows:

% asbestos = PAM x AOS OM

P.AM = mass of residue after furnace and acid treatments (mg) OM = mass of original subsample (mg) AOS = mean percentage of asbestos in final slide preparations.

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NYC-WTC_000232518