NYC-WTC_000219925

NYC 9/11 Public Portal Document I Search -1 Result - APPENDIX A TO SUBPART E - INTERIM TRANSMISSION EL... Page 14 of 38

15. NSD -- No structure detected.

16. Operator — A person responsible for the TEM instrumental analysis of the sample.

17. PCM — Phase contrast microscopy.

18. SAED - Selected area electron diffraction.

19. SEM — Scanning transmission electron microscope.

20. STEM -- Scanning transmission electron microscope.

21. Structure -- a microscopic bundle, cluster, fiber, or matrix which may contain asbestos.

22. S <3> — Structures per cubic centimeter.

23. S/mm<2> - Structures per square millimeter.

24. TEM — Transmission electron microscope.

B. Sampling

1. Sampling operations must be performed by qualified individuals completely independent of the abatement contractor to avoid possible conflict of interest (See References 1, 2, and 5 of Unit III.L.) Special precautions should be taken to avoid contamination of the sample. For example, materials that have not been prescreened for their asbestos background content should not be used; also, sample handling procedures which do not take cross contamination possibilities into account should not be used.

2. Material and supply checks for asbestos contamination should be made on all critical supplies, reagents, and procedures before their use in a monitoring study.

3. Quality control and quality assurance steps are needed to identify problem areas and isolate the cause of the contamination (see Reference 5 of Unit III.L.). Control checks shall be permanently recorded to document the quality of the information produced. The sampling firm must have written quality control procedures and documents which verify compliance. Independent audits by a qualified consultant or firm should be performed once a year. All documentation of compliance should be retained indefinitely to provide a guarantee of quality. A summary of Sample Data Quality Objectives is shown in Table 11 of Unit II.B.

4. Sampling materials.

a. Sample for airborne asbestos following an abatement action using commercially available cassettes.

b. Use either a cowling or a filter-retaining middle piece. Conductive material may reduce the potential for particulates to adhere to the walls of the cowl.

c. Cassettes must be verified as "clean" prior to use in the field. If packaged filters are used for loading or preloaded cassettes are purchased from the manufacturer or a distributor, the manufacturer's name and lot number should be entered on all field data sheets provided to the laboratory, and are required to be listed on all reports from the laboratory.

d. Assemble the cassettes in a clean facility (See definition of clean area under Unit III.A.).

e. Reloading of use cassettes is not permitted.

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