40 CFR Part 763 (EPA AHERA) PDF

Pt. 763, Subpt. E, App. A 40 CFR Ch. I (7–1–07 Edition) rfrederick on PROD1PC67 with CFR i. Individual grid openings with greater than 5 percent openings (holes) or covered with greater than 25 percent particulate matter or obviously having nonuniform loading shall not be analyzed. ii. Examine th...

Pt. 763, Subpt. E, App. A 40 CFR Ch. I (7–1–07 Edition) rfrederick on PROD1PC67 with CFR i. Individual grid openings with greater than 5 percent openings (holes) or covered with greater than 25 percent particulate matter or obviously having nonuniform loading shall not be analyzed. ii. Examine the grid at low magnification (<1000X) to determine its suitability for detailed study at higher magnifications. iii. Reject the grid if: (1) Less than 50 percent of the grid openings covered by the replica are intact. (2) It is doubled or folded. (3) It is too dark because of incomplete dissolution of the filter. iv. If the grid is rejected, load the next sample grid. v. If the grid is acceptable, continue on to Step 6 if mapping is to be used; otherwise proceed to Step 7. f. Grid Map (Optional). i. Set the TEM to the low magnification mode. ii. Use flat edge or finder grids for mapping. iii. Index the grid openings (fields) to be counted by marking the acceptable fields for one-half (0.5) of the area needed for analysis on each of the two grids to be analyzed. These may be marked just before examining each grid opening (field), if desired. iv. Draw in any details which will allow the grid to be properly oriented if it is re- loaded into the microscope and a particular field is to be reliably identified. g. Scan the grid. i. Select a field to start the examination. ii. Choose the appropriate magnification (15,000 to 20,000X screen magnification). iii. Scan the grid as follows. (1) At the selected magnification, make a series of parallel traverses across the field. On reaching the end of one traverse, move the image one window and reverse the traverse. NOTE: A slight overlap should be used so as not to miss any part of the grid opening (field). (2) Make parallel traverses until the entire grid opening (field) has been scanned. h. Identify each structure for appearance and size. i. Appearance and size: Any continuous grouping of particles in which an asbestos fiber within aspect ratio greater than or equal to 5:1 and a length greater than or equal to 0.5 µm is detected shall be recorded on the count sheet. These will be designated asbestos structures and will be classified as fibers, bundles, clusters, or matrices. Record as individual fibers any contiguous grouping having 0, 1, or 2 definable intersections. Groupings having more than 2 intersections are to be described as cluster or matrix. See the following Figure 5: 806 VerDate Aug<31>2005 14:36 Aug 06, 2007 Jkt 211171 PO 00000 Frm 00816 Fmt 8010 Sfmt 8002 Y:\SGML\211171.XXX 211171 Pt. 763, Subpt. E, App. A 807 VerDate Aug<31>2005 14:36 Aug 06, 2007 Jkt 211171 PO 00000 Frm 00817 Fmt 8010 Sfmt 8006 Y:\SGML\211171.XXX 211171 EC01AP92.012</GPH> rfrederick on PROD1PC67 with CFR Environmental Protection Agency 40 CFR Ch. I (7–1–07 Edition) An intersection is a non-parallel touching or crossing of fibers, with the projection having an aspect ratio of 5:1 or greater. Combinations such as a matrix and cluster, matrix and bundle, or bundle and cluster are categorized by the dominant fiber quality—cluster, bundle, and matrix, respectively. Separate categories will be maintained for fibers less than 5 µm and for fibers greater than or equal to 5 µm in length. Not required, but useful, may be to record the fiber length in 1 µm intervals. (Identify each structure morphologically and analyze it as it enters the ‘‘window’’.) (1) Fiber. A structure having a minimum length greater than 0.5 µm and an aspect ratio (length to width) of 5:1 or greater and substantially parallel sides. Note the appearance of the end of the fiber, i.e., whether it is flat, rounded or dovetailed, no intersections. (2) Bundle. A structure composed of 3 or more fibers in a parallel arrangement with each fiber closer than one fiber diameter. (3) Cluster. A structure with fibers in a random arrangement such that all fibers are intermixed and no single fiber is isolated from the group; groupings must have more than 2 intersections. 808 VerDate Aug<31>2005 14:36 Aug 06, 2007 Jkt 211171 PO 00000 Frm 00818 Fmt 8010 Sfmt 8002 Y:\SGML\211171.XXX 211171 EC01AP92.013</GPH> rfrederick on PROD1PC67 with CFR Pt. 763, Subpt. E, App. A rfrederick on PROD1PC67 with CFR Environmental Protection Agency Pt. 763, Subpt. E, App. A (4) Matrix. Fiber or fibers with one end free and the other end embedded in or hidden by a particulate. The exposed fiber must meet the fiber definition. (5) NSD. Record NSD when no structures are detected in the field. (6) Intersection. Non-parallel touching or crossing of fibers, with the projection having an aspect ratio 5:1 or greater. ii. Structure Measurement. (1) Recognize the structure that is to be sized. (2) Memorize its location in the ‘‘window’’ relative to the sides, inscribed square and to other particulates in the field so this exact location can be found again when scanning is resumed. (3) Measure the structure using the scale on the screen. (4) Record the length category and structure type classification on the count sheet after the field number and fiber number. (5) Return the fiber to its original location in the window and scan the rest of the field for other fibers; if the direction of travel is not remembered, return to the right side of the field and begin the traverse again. i. Visual identification of Electron Diffraction (ED) patterns is required for each asbestos structure counted which would cause the analysis to exceed the 70 s/mm2 concentration. (Generally this means the first four fibers identified as asbestos must exhibit an identifiable diffraction pattern for chrysotile or amphibole.) i. Center the structure, focus, and obtain an ED pattern. (See Microscope Instruction Manual for more detailed instructions.) ii. From a visual examination of the ED pattern, obtained with a short camera length, classify the observed structure as belonging to one of the following classifications: chrysotile, amphibole, or nonasbestos. (1) Chrysotile: The chrysotile asbestos pattern has characteristic streaks on the layer lines other than the central line and some streaking also on the central line. There will be spots of normal sharpness on the central layer line and on alternate lines (2nd, 4th, etc.). The repeat distance between layer lines is 0.53 nm and the center doublet is at 0.73 nm. The pattern should display (002), (110), (130) diffraction maxima; distances and geometry should match a chrysotile pattern and be measured semiquantitatively. (2) Amphibole Group [includes grunerite (amosite), crocidolite, anthophyllite, tremolite, and actinolite]: Amphibole asbestos fiber patterns show layer lines formed by very closely spaced dots, and the repeat distance between layer lines is also about 0.53 nm. Streaking in layer lines is occasionally present due to crystal structure defects. (3) Nonasbestos: Incomplete or unobtainable ED patterns, a nonasbestos EDXA, or a nonasbestos morphology. iii. The micrograph number of the recorded diffraction patterns must be reported to the client and maintained in the laboratory’s quality assurance records. The records must also demonstrate that the identification of the pattern has been verified by a qualified individual and that the operator who made the identification is maintaining at least an 80 percent correct visual identification based on his measured patterns. In the event that examination of the pattern by the qualified individual indicates that the pattern had been misidentified visually, the client shall be contacted. If the pattern is a suspected chrysotile, take a photograph of the diffraction pattern at 0 degrees tilt. If the structure is suspected to be amphibole, the sample may have to be tilted to obtain a simple geometric array of spots. j. Energy Dispersive X-Ray Analysis (EDXA). i. Required of all amphiboles which would cause the analysis results to exceed the 70 s/ mm2 concentration. (Generally speaking, the first 4 amphiboles would require EDXA.) ii. Can be used alone to confirm chrysotile after the 70 s/mm2 concentration has been exceeded. iii. Can be used alone to confirm all nonasbestos. iv. Compare spectrum profiles with profiles obtained from asbestos standards. The closest match identifies and categorizes the structure. v. If the EDXA is used for confirmation, record the properly labeled spectrum on a computer disk, or if a hard copy, file with analysis data. vi. If the number of fibers in the nonasbestos class would cause the analysis to exceed the 70 s/mm2 concentration, their identities must be confirmed by EDXA or measurement of a zone axis diffraction pattern to establish that the particles are nonasbestos. k. Stopping Rules. i. If more than 50 asbestiform structures are counted in a particular grid opening, the analysis may be terminated. ii. After having counted 50 asbestiform structures in a minimum of 4 grid openings, the analysis may be terminated. The grid opening in which the 50th fiber was counted must be completed. iii. For blank samples, the analysis is always continued until 10 grid openings have been analyzed. iv. In all other samples the analysis shall be continued until an analytical sensitivity of 0.005 s/cm3 is reached. l. Recording Rules. The count sheet should contain the following information: i. Field (grid opening): List field number. ii. Record ‘‘NSD’’ if no structures are detected. iii. Structure information. 809 VerDate Aug<31>2005 14:36 Aug 06, 2007 Jkt 211171 PO 00000 Frm 00819 Fmt 8010 Sfmt 8002 Y:\SGML\211171.XXX 211171 Pt. 763, Subpt. E, App. A 40 CFR Ch. I (7–1–07 Edition) rfrederick on PROD1PC67 with CFR (1) If fibers, bundles, clusters, and/or matrices are found, list them in consecutive numerical order, starting over with each field. (2) Length. Record length category of asbestos fibers examined. Indicate if less than 5 µm or greater than or equal to 5 µm. (3) Structure Type. Positive identification of asbestos fibers is required by the method. At least one diffraction pattern of each fiber type from every five samples must be recorded and compared with a standard diffraction pattern. For each asbestos fiber reported, both a morphological descriptor and an identification descriptor shall be specified on the count sheet. (4) Fibers classified as chrysotile must be identified by diffraction and/or X-ray analysis and recorded on the count sheet. X-ray analysis alone can be used as sole identification only after 70s/mm2 have been exceeded for a particular sample. (5) Fibers classified as amphiboles must be identified by X-ray analysis and electron diffraction and recorded on the count sheet. (Xray analysis alone can be used as sole identification only after 70s/mm2 have been exceeded for a particular sample.) (6) If a diffraction pattern was recorded on film, the micrograph number must be indicated on the count sheet. (7) If an electron diffraction was attempted and an appropriate spectra is not observed, N should be recorded on the count sheet. (8) If an X-ray analysis is attempted but not observed, N should be recorded on the count sheet. (9) If an X-ray analysis spectrum is stored, the file and disk number must be recorded on the count sheet. m. Classification Rules. i. Fiber. A structure having a minimum length greater than or equal to 0.5 µm and an aspect ratio (length to width) of 5:1 or greater and substantially parallel sides. Note the appearance of the end of the fiber, i.e., whether it is flat, rounded or dovetailed. ii. Bundle. A structure composed of three or more fibers in a parallel arrangement with each fiber closer than one fiber diameter. iii. Cluster. A structure with fibers in a random arrangement such that all fibers are intermixed and no single fiber is isolated from the group. Groupings must have more than two intersections. iv. Matrix. Fiber or fibers with one end free and the other end embedded in or hidden by a particulate. The exposed fiber must meet the fiber definition. v. NSD. Record NSD when no structures are detected in the field. n. After all necessary analyses of a particle structure have been completed, return the goniometer stage to 0 degrees, and return the structure to its original location by recall of the original location. o. Continue scanning until all the structures are identified, classified and sized in the field. p. Select additional fields (grid openings) at low magnification; scan at a chosen magnification (15,000 to 20,000X screen magnification); and analyze until the stopping rule becomes applicable. q. Carefully record all data as they are being collected, and check for accuracy. r. After finishing with a grid, remove it from the microscope, and replace it in the appropriate grid hold. Sample grids must be stored for a minimum of 1 year from the date of the analysis; the sample cassette must be retained for a minimum of 30 days by the laboratory or returned at the client’s request. H. Sample Analytical Sequence 1. Carry out visual inspection of work site prior to air monitoring. 2. Collect a minimum of five air samples inside the work site and five samples outside the work site. The indoor and outdoor samples shall be taken during the same time period. 3. Analyze the abatement area samples according to this protocol. The analysis must meet the 0.005 s/cm3 analytical sensitivity. 4. Remaining steps in the analytical sequence are contained in Unit IV. of this Appendix. I. Reporting The following information must be reported to the client. See the following Table II: 810 VerDate Aug<31>2005 14:36 Aug 06, 2007 Jkt 211171 PO 00000 Frm 00820 Fmt 8010 Sfmt 8002 Y:\SGML\211171.XXX 211171