Document VGnXqRmZX7ojMEXxRp5mK6qM4

Fed^rdl'Register '/ ^Vol::61.' No. 119 / Friday, June 20, 1986 /'Rules and Regulations :.22763 comparisons between microscopists to monitor the variability of counting by each micro8Copl8t and.between microscopists. In acompany with more then one laboratory, the program shall include all laboratories, and shall also evaluate the laboratory-tolaboratory variability. 2. Interlaboratory program. Each laboratory analyzing asbestos,, tremolite. anthophyllite. and actinolite samples-for compliance determination shall implement an interlaboratory quality assurance program that as a minimum includes participation of at least two other independent laboratories. Each laboratory shall participate in round robin testing at least once every 6 months with at least all the other laboratories in ita interlaboratory quality assurance group. Each laboratory shall submit slides typical of its own workload for-use in this program; The round robin shall be designed and results analyzed using appropriate statistical methodology. 3. All individuals performing asbestos, tremolite. anthophyllite, and actinolite analysis-must have taken the NIOSH course for sampling and evaluating airborne asbestos, tremolite. anthophyllite. and actinolite dust or an equivalent course. 4. When the use of different microscopes contributes to differences between counters and laboratories, the effect of the different microscope shall.be evaluated and the microscope shall be replaced, as necessary. 5. Current results of these quality assurance programs shall be posted in each laboratory to keep the microscopists informed. Appendix B to 1926.58--Detailed Procedure for Asbestos Tremolite, Anthophyllite, and Actinolite Sampling and Analysis--^Non* Mandatory This appendix contains, a detailed . procedure for sampling and analysis arid includes those critical elements specified in Appendix A. Employers are not required to use this procedure, but they are required to use Appendix A. The purpose of Appendix B is to provide a detailed step-by-step sampling and analysis procedure that-conforms to the' elements specified in Appendix A. Since this procedure may .also standardize the anulysis and reduce Variability, OSHA encourages employers to us$ this appendix. Asbestos. Tremolite, Anthophyllite, and Actinolite Sampling and Analysis Method . Technique:'Microscopy, Phase Contrast. Analyte: Fibers (Manual count). Sample Preparation: ACetone/triacetin method; . Calibration: Phase-shift detection.limit about 3 degrees. Range: 100 to 1300 fibers/mm* filter area. Estimated Limit of Detection: 7 fibers/mm* filter area.. Sampler. Filter (0.8-1.2 um mixed cellulose ester membrane. 25-mm diameter). . Flow Rate: 0.5 l/min to 2.5 l/min.(25-mm cassette): 1.0 l/min to 2.5 1/min (37-mm cassette). - Sample Volume: Adjust to obtain 100 to 1300.fibers/mm*. s'i,~Shipni`enl:'Routine. Sample Stability: Indefinite. Blanks: -10% of samples (minimum 2). Standard.Analytical Error: 0.25. Applicability: The working range is 0.02 f/ cc (1920-L air sample) to 1.25 f/cc (400-L air sample). The method gives an index of airborne asbestos, tremolite. anthophyllite. and actinolite fibers but may be used for other materials such as fibrous glass by inserting suitable parameters into the counting rules. The method does not differentiate between asbestos, tremolite. anthophyllite. and actinolite and other fibers. Asbestos, tremolite, anthophyllite, and actinolite fibers less than ca. 0.25 um diameter will not be detected by this methodinterferences: Any other airborne fiber may interfere since all particles meeting the counting criteria are counted. Chain-likc particles may appear fibrous.Tligh levels of nonfibrous dust particles may obscure fibers in the field of view and raise the detection limit. Reagents 1. Acetone. '2. Triocotin (glycerol triacetate), reagent grade.. Special Precautions Acetone is an extremely flammable liquid and precautions must be taken not to ignite itHeating of acetone must be done in a ventilated laboratory fume hood using a flameiess, spark-free heal source. Equipment 1. Collection device: 25-mm cassette with 50-mm extension cowl with cellulose ester filter. 0.8 to 1.2 mm pore size and backup pad. Note.---Analyze representative filters for Tiber background before use and discard the . filter lot if more.than S Hbcrs/lOO fields are found! 2. Personal sampling pump, greater than or equal to 0.5 L/min, with flexible connecting tubing. 3. Microscope, phase contrast, with green or blue filter, 8 to 10X eyepiece, and 40 to 45X phase objective (total magnification ca 400X): numerical aperture=0.85-to 0.75. 4. Slides, glass, single-Trosted, pre-clcaned. 25 X 75'mm. . 5. Cover slips, 25 x 25 mm, no. 1`A unless otherwise specified by microscope manufacturer. 6. Knife; #1 surgical steel, curved blade. 7. Tweezers. 8. Flask. Guth-type, insulated neck, 250 to 500 mL (with single-holed rubber stopper and elbow-jointed glass tubing. 16 to 22 cm long). 9. Hotplate, spark-free, stirring type; heating mantle; or. infrared.lamp arid magnetic stirrer.' 10. Syringe, hypodermic, with 22-gauge needle. 11. Graticule, Walton-Beckctt type with 100 um diameter circular field at the specimen . plane (area=s6.00785mmJ)1 (Type G-22). Note.--The graticule is custom-made for each microscope. 12. HSE/NPL phase contrast test slide. Mark IL* 13. Telescope, ocular phase-ring centering. 14. Stage micrometer (0.01 mm divisions). Sampling 1. Calibrate each personal, sampling pump with a'representative sampler in line. 2. Fasten the sampler to the worker's lapel ns close as possible to the worker's mouth. . Remove the top cover from the end of the cowl extension (open face) and orient face down. Wrap the joint between the extender and the monitor's body with shrink tope to prevent air leaks. 3. Submit at least two blanks (or 10% of the total samples, whichever is greater) for each set of samples. Remove the caps from the field blank cassettes and store the caps and cassettes in a clean urea (bag or box) during the sampling period. Replace the caps in the cassettes when sampling is completed. ' 4. Sample at 0.5 L/min or greater. Do not exceed 1 mg total dust loading on the filter. Adjust sampling flow rate. Q (L/min). and time to produce a fiber density. E (fibers/ mm2), of 100 to 1300 fibers/m2 J3.85X10* to !>X108 fibers per 25-mm filter with effective collection area (Ac=305 mm2)) for optimum counting precision (see step 21 below). Calculate the minimum sampling time, tninimum (min) at the action level (one-half of the current standard), L (f/cc) of the fibrous aerosol being sampled: (Ac m (Q)(!.)10A 5. Remove the field monitor at the end of sampling, replace the plastic top cover and small end cap9, and store the monitor. 8. Ship the samples in a rigid container with sufficient packing material to prevent jostling or damage. NOTE: Do not use polystyrene foam in the shipping container because of electrostatic forces which may . cause fiber loss from the sampler filter. Sample Preparation Note.--The object is to produce samples with a smooth (non-grolny) background in a medium with a refractive index equal to or less than 1.46. The method below collapses, the filter for easier focusing and produces permanent mounts which are useful for quality control'and interlaboratory comparison. Other mounting techniques meeting the above criteria muy.also be used, e.g., the nonpermanent field mounting . technique used in P &-CAM 239. . 7. Ensure that the glass slides and cover slips are free of dust and fibers. . 8. Place 40 to 60 m) of acetone into a'.Guth- type flask. Stopper the-flask with a singlehole rubber stopper through which a glass tube extends 5 to 8 cm into the flask. The portion of the glass tube that exits the top of the stopper (8 to 10 cm) is bent downward in an elbow that makes an angle of 20 to'30, degrees with the horizontal. 9. Place the flask in a stirring hotplate or wrap in a heating mantle. Heat the acetone gradually to its boiling temperature (ca. 58*C) Caution.---The acetone vapor must be generated in a ventilated fume hood away . from all open flames and spark sources.. Alternate heating methods can be used. - providing no open flume or spArks are- ' present. GLEASON-001011