DOH/DEP asbestos fact sheet draft, 105 Duane Street

NYC 9/11 Public Portal Document 12/11/2001 17:07 FAX 212 353 8306 ATC IR 012

4D D 5755 regular basis, and retain these records in the laboratory, in number for the Cu peak and be certain that readings arc accordance with the laboratory's quality assurance program. within ±10 ev. 20.2 Record calibrations in a log book along with dates of 20.4.2 Collect a standard EDXA of crocidoliie asbestos calibration and the attached backup documentation. (NIST SRM 1866). 20.3 A calibration list for the instrument is as follows: 20.4.2.1 The elemental analysis of the crocidolite must 20.3.1 TEM: resolve the Na peak. 20.3.1.1 Check the alignment and the systems operation. 20.4.3 Collect a standard EDXA of chrysotile asbestos. Refer to the TEM manufacturer's operational manual for 20.4.3.1 The elemental analysis oFchrysotile must resolve detailed instructions. both Si and Mg on a single chrysotile fiber, 20.3.1.2 Calibrate the camera length of the TEM in elec- 20.5 Ultrasonic bath calibration shall be performed as tron diffraction (ED) operating mode before ED patterns of follows: unknown samples are observed. Camera length can be mea- 20.5.1 Fill the bath water to a level equal to the height of '%red by using a carbon coated grid which a thin film of on

•suspension in the glass sample container that be used for gold has been sputtered or evaporated. A thin film of gold is will

the dust analysis Operate the bath until the water reaches the evaporated on the specimen

TEM grid to obtain zone-axis equilibrium temperature. ED patterns superimposed with a ring pattern from the poly- 20.5.2 Place 100 mL of water (at approximately 20'C) in crystalline gold film. In practice, it is desirable to optimize another 200 glass sample container, and record its -mi n

the thickness of the gold film so that only one or two sharp temperature. rings are obtained on the superimposed ED pattern. Thick 20.5.3 Place the simple container in the water in the gold films will tend to mask weak dif action spots from the ultrasonic bath (with the power turned oft). After 60 s, fibrous particles. Since the unknown d-spacings of most remove the glass container and record its temperature. interest in asbestos analysis are those which lieclosest to the 20.5.4 Place 100 nML of water (at approximately 20'C) in transmitted beam, multiple gold rings from thick films are another 200-mL glass sample container, and record its unnecessary. Alternatively, a gold standard specimen can be temperature. used to obtain an average camera constant calculated for that 20.5.5 Place the second sample container into the water in particular (nmument and can then be used for ED patterns the ultrasonic bath (with the power turned on). After 60 s, of unknowns taken during the corresponding period. remove the glaso container and record Its temperature. - 20.3.13 Perform magnification calibration at the fluores- 20.5.6 Calculate the rate of energy deposition into the cent screen. This calibration must be performed at the sample container using the following formula: magnification used for structure counting. Calibration is perforated with a grating replica (7.47) (for example, one R— 4.195 x r x p x !LZE (2) containing at least 2160 lines/mm). t (a) Define a field of view on the fluorescent screen. The where: field of view must be measurable or previously inscribed with 4.185 -Joules/cal, a scale or concentric circles (all scales should be metric). R - energy deposition, watts/mL, (b) Frequency of calibration will depend on the service 8, = temperature rise with the ultrasonic bath not open history of the particular microscope. atln (e) Check the calibration after any maintenance of the 82 = temperature rise with the ultrasonic bath operating, microscope that involves adjustment of the power supply to C. the leas or the high voltage system or the mechanical r = time in seconds, 60s (20.5.3 and 20.5.5), disassembly of the plectron optical column (apart from c - specific beat of . the liquid the glass sample in

filament exchange). contains, 1.0 cal/g, and (d) The analyst must ensure that the grating replica is p — density of the liquid in the glass sample .container, placed at the same distance from the objective lens as the 1.0

20.5.7 Adjust the operating conditions of the bath so that g/cm&.

specimen. the rate of energy deposition is in the range of 0.08 to 0.12 (e) For instruments that incorporate a eucentrie tilting specimen stage, all specimens and the grating replica must be MW/m 3 , as

defined by

this procedure.

placed at the eucentrie position. 20.3.1.4 The smallest spot size of the TEM must be 21.

Precision sad No

checked. 21.1 Precision—The precision of the procedure in this test (a) Al the crossover point, photograph the spot size at a method is being determined using round robin data from screen magnification of 15 000 to 20 000X. An exposure participating laboratorie& time of 1 s is usually adequate. 21-2 Bias—Since these is no accepted reirenc a material (b) The measured spot must be less than or equal to suitable for determining the bias of the procedure in this test method, bias has not been determined (see Specification size

250 am. 20.4 EDXA: D3670).

20.4.1 The resolution and calibration of the EDXA must Nom 3—Round robin dew is under development and win be be verified. presented as a

,regards report.

20.4.1.1 Collect a standard EDXA Cu peak from the Cu grid. 22.

Keywords

20.4.1.2 Compare the X-ray energy versus channel 22.1 asbestos; microvacuuming; settled dust; TEM

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