Probability of overexposure and adequacy of the assigned protection factor for half-facepiece respirators

Details

• Personal Author:
  Myers W ; Zhuang Z
• Description:
  A number of field studies have been conducted over the last 10-13 years to evaluate the worker protection provided by negative pressure, half-facepiece respirators. Protection was assessed by workplace protection factors (WPF). The appropriateness of the assigned protection factor (APF) (or negative pressure half-mask respirators has generally been evaluated based on the fifth percentile estimate of a WPF distribution. No evaluation has been based on the comparison of in-facepiece concentration and an exposure standard. A new approach based on probability of overexposure was developed to use the combined WPF data published in peer-reviewed journals to evaluate the appropriateness of the APF for half-facepiece respirators. The new approach first utilized a graphical representation of WPF data and hazard ratios (ambient concentration divided by permissible exposure limit). The adequacy of the APF was then evaluated from binomial statistics based on the number of successes (no overexposure) and failures (overexposure). In the studies reviewed, the probability of overexposure occurring during a wearing period for workers wearing half-facepiece respirators represented, was 0.5%, with a 95% confidence interval of 0.01 to 2.7%. If we consider 50% in-facepiece sampling errors, the probability of overexposure was 29% with a 95% confidence interval of 1.1 to 6.3%. Based on this analysis, our professional judgment is that the current APF of 10 for half-face-piece respirators is appropriate. [Description provided by NIOSH]
• Subjects:
  Environmental Monitoring Occupational Health Personal Protective Equipment Respiratory Protective Devices Respiratory System Safety
• Keywords:
  Air-purifying-respirators Anthropometry Exposure-assessment Exposure-levels Exposure-limits Face-masks Hazards Health-protection Performance-capability Permissible-concentration-limits Personal-protective-equipment Respirators Respiratory-equipment Statistical-analysis Testing-equipment

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• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Georgia ; OSHA Region 3 ; OSHA Region 4 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  60-61
• NIOSHTIC Number:
  nn:20043988
• Citation:
  American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :60-61
• Federal Fiscal Year:
  1998
• Peer Reviewed:
  False
• Source Full Name:
  American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ca8f92b22d657b016d505e62c6c9f3ad275ba36b40d4348beaada79fcd55c7f5c00e0ea10b41ddab4067f206af87f323338ab0ba31f100b5bf5d6cdd6b0bc0a9
• Download URL:
  https://stacks.cdc.gov/view/cdc/199845/cdc_199845_DS1.pdf
• File Type:
  [PDF - 785.08 KB ]