Page:NIOSH Manual of Analytical Methods - 7400.pdf/11

 ASBESTOS and OTHER FIBERS by PCM: METHOD 7400, Issue 2, dated 15 August 1994 - Page 11 of 15

The curves in Figure 1 are defined by the following equations: and , where

=	 subjective interlaboratory relative standard deviation, which is close to the total interlaboratory when approximately 100 fibers are counted, =	total fibers counted on sample, =	lower 95% confidence limit, and =	upper 95% confidence limit. Note that the range between these two limits represents 90% of the total range. REFERENCES: [1]	 Leidel, N. A., S. G. Bayer, R. D. Zumwalde, and K. A. Busch. USPHS/NIOSH Membrane Filter Method for Evaluating Airborne Asbestos Fibers, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 79-127 (1979). [2]	 Baron, P. A. and G. C. Pickford. “An Asbestos Sample Filter Clearing Procedure,” Appl. Ind. Hyg., 1, 169–171, 199 (1986). [3]	 Occupational Safety and Health Administration, U.S. Department of Labor, Occupational Exposure to Asbestos, Tremolite, Anthophyllite, and Actinolite Asbestos; Final Rules, 29 CFR Part 1910.1001 Amended June 20, 1986. [4]	 Rooker, S. J., N. P. Vaughn, and J. M. LeGuen. “On the Visibility of Fibers by Phase Contrast Microscopy,” Amer. Ind. Hyg. Assoc. J., 43, 505–515 (1982). [5]	 Baron, P. and G. Deye, “Electrostatic Effects in Asbestos Sampling,” Parts I and II, Amer. Ind. Hyg. Assoc. J., 51, 51–69 (1990). [6]	 Johnston, A. M., A. D. Jones, and J. H. Vincent. “The Influence of External Aerodynamic Factors on the Measurement of the Airborne Concentration of Asbestos Fibers by the Membrane Filter Method,” Ann. Occup. Hyg., 25, 309–316 (1982). [7]	 Beckett, S.T., “The Effects of Sampling Practice on the Measured Concentration of Airborne Asbestos,” Ann. Occup. Hyg., 21, 259–272 (1980). [8]	 Jankovic, J. T., W. Jones, and J. Clere. “Field Techniques for Clearing Cellulose Ester Filters Used in Asbestos Sampling,” Appl. Ind. Hyg., 1, 145–147 (1986). [9]	 Crawford, N. P., H. L. Thorpe, and W. Alexander. “A Comparison of the Effects of Different Counting Rules and Aspect Ratios on the Level and Reproducibility of Asbestos Fiber Counts,” Part I: Effects on Level (Report No. TM/82/23), Part II: Effects on Reproducibility (Report No. TM/82/24), Institute of Occupational Medicine, Edinburgh, Scotland (December, 1982). [10]	 NIOSH Manual of Analytical Methods, 2nd ed., Vol. 1., P&CAM 239, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-A (1977). [11]	 Revised Recommended Asbestos Standard, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-169 (1976); as amended in NIOSH statement at OSHA Public Hearing, June 21, 1984. [12]	 Asbestos International Association, AIA Health and Safety Recommended Technical Method #1 (RTMI). “Airborne Asbestos Fiber Concentrations at Workplaces by Light Microscopy” (Membrane Filter Method), London (1979). [13]	 Abell, M., S. Shulman and P. Baron. “The Quality of Fiber Count Data,” Appl. Ind. Hyg., 4, 273–285 (1989). [14]	 “A Study of the Empirical Precision of Airborne Asbestos Concentration Measurements in the Workplace by the Membrane Filter Method,” Asbestos Information Association, Air Monitoring Committee Report, Arlington, VA (June, 1983). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition