Forwarding WTC air monitoring scope for final review, Aug 2002

NYC 9/11 Public Portal Document

Pt. 763. Subpt. E. App. A 40 CFR Ch. I (7-1-00 Edition) (1) If fibers, bundles, clusters, and/or mat­ from the group. Groupings must have more rices are found, list them in consecutive nu­ than two Intersections. merical order, starting over with each fleld. iv. Matrix. Fiber or fibers with one end free (2) Length. Record length category of as­ and the other end embedded in or hidden by bestos fibers examined. Indicate if less than a particulate. The exposed fiber must meet 5 gm or greater than or equal to 5 gm. the fiber definition. (3) Structure Type. Positive identification V. NSD. Record NSD when no structures of asbestos fibers is required by the method. are detected in the field. At least one diffraction pattern of each fiber n. After all necessary analyses of a particle type from every five samples must be re­ structure have been completed, return the corded and compared with a standard diffrac­ goniometer stage to 0 degrees, and return tion pattern. For each asbestos fiber re­ the structure to its original location by re­ ported, both a morphological descriptor and call of the original location. an Identification descriptor shall be specified o. Continue scanning until all the struc­ on the count sheet. tures are Identified, classified and sized In (4) Fibers classified as chrysotile must be the field. identified by diffraction and/or X-ray anal­ p. Select additional fields (grid openings) ysis and recorded on the count sheet. X-ray at low magnification; scan at a chosen mag­ analysis alone can be used as sole identifica­ nification (15.000 to 20.000X screen magnifica­ tion only after TOs/mm’ have been exceeded tion): and analyze until the stopping rule be­ for a particular sample. comes applicable. (5) Fibers classified as amphiboles must be identified by X-ray analysis and electron dif­ q. Carefully record all data as they are fraction and recorded on the count sheet. (X- being collected, and check for accuracy. ray analysis alone can be used as sole identi­ r. After finishing with a grid, remove it fication only after TOs/mm^ have been exceed­ from the microscope, and replace it in the ed for a particular sample.) appropriate grid hold. Sample grids must be (6) If a diffraction pattern was recorded on stored for a minimum of 1 year from the date film, the micrograph number must be indi­ of the analysis: the sample cassette must be cated on the count sheet. retained for a minimum of 30 days by the (7) If an electron diffraction was attempted laboratory or returned at the client's re­ and an appropriate spectra is not observed. N quest. should be recorded on the count sheet. (8) If an X-ray analysis is attempted but H. Sample Analytical Sequence not observed, N should be recorded on the 1. Carry out visual inspection of work site count sheet. prior to air monitoring. (9) If an X-ray analysis spectrum is stored, 2. Collect a minimum of five air samples the file and disk number must be recorded on inside the work site and five samples outside the count sheet, the work site. The Indoor and outdoor sam­ m. Classification Rules. ples shall be taken during the same time pe­ 1. Fiber. A structure having a minimum riod. length greater than or equal to 0.5 gm and an 3. Analyze the abatement area samples ac­ aspect ratio (length to width) of 5:1 or great­ cording to this protocol. The analysis must er and substantially parallel sides. Note the meet the 0.005 s/cm’ analytical sensitivity. appearance of the end of the fiber, l.e., 4. Remaining steps in the analytical se­ whether it is fiat, rounded or dovetailed. quence are contain^ in Unit IV. of this Ap­ 11. Bundle. A structure composed of three or more fibers in a parallel arrangement pendix. with each fiber closer than one fiber diame­ I. Reporting ter. Hi. Cluster. A structure with fibers in a The following information must be re­ random arrangement such that all fibers are ported to the client. See the following Table Intermixed and no single fiber is Isolated II;

698

NYC-WTC_000139313