Page:NIOSH Manual of Analytical Methods - 5000.pdf/3

 CARBON BLACK: METHOD 5000, Issue 2, dated 15 August 1994 - Page 3 of 4 CALIBRATION AND QUALITY CONTROL: 10.

11.

Zero the microbalance before all weighings. Use the same microbalance for weighing filters before and after sample collection. Calibrate the balance with National Institute of Standards and Technology Class S-1.1 or ASTM Class 1 weights. The set of replicate samples should be exposed to the same dust environment, either in a laboratory dust chamber [6] or in the field [7]. The quality control samples must be taken with the same equipment, procedures and personnel used in the routine field samples. Calculate precision from these replicates and record Sr on control charts. Take corrective action when the precision is out of control [6].

MEASUREMENT: 12.

Weigh each filter, including field blanks. Record the post-sampling weight, W anything remarkable about a filter (e.g., overload, leakage, wet, torn, etc.).

2

(mg). Record

CALCULATIONS: 13.

Calculate the concentration, C (mg/m 3), of carbon black in the air volume sampled, V (L):

where: W 1 = tare weight of filter before sampling (mg) W 2 = post-sampling weight of sample-containing filter (mg) B1 = tare weight of blank filter (mg) B2 = post-sampling weight of blank filter (mg)

EVALUATION OF METHOD: Method S262 [5] was issued on January 30, 1976, and validated over the range 1.9 to 7.7 mg/m 3 for a 200-L sample and over the range 7.8 to 28 mg/m 3 for a 100-L sample using Vulcan XC72 (0.03-µm particle size; Cabot Corp.) in a Wright Dust Feeder [1]. Overall precision, SˆrT, was 0.056. Collection efficiency was between 99 and 100%.

REFERENCES: [1] [2] [3] [4]

Documentation of the NIOSH Validation Tests, S262 and S349, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-185 (1977). Unpublished data from Non-textile Cotton Study, NIOSH/DRDS/EIB. NIOSH Criteria for a Recommended Standard ... Occupational Exposure to Carbon Black, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-204, 80-88 (1978). NIOSH Manual of Analytical Methods, 2nd ed., V. 3, S349, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-157-C (1977).

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94