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Frequency of Fit Testing - FY12

NOTE: This page is archived for historical purposes and is no longer being maintained or updated.


  • The specific aims of this project are to:

    • Determine – for time intervals of 6, 12, 18, 24, 30, and 36 months – the changes in respirator fit
    • Determine – for the same time periods – the number of instances when a subject’s fit becomes unacceptable
    • Determine the corresponding percentages of test subjects whose respirator penetration changes for different degrees of changes and whose fit becomes unacceptable during the these time intervals
    • Assess the extent to which changes in fit are associated with recognizable changes in facial anthropometrics
    • Investigate the correlation between respirator fit and subject characteristics at every six month interval

Applicable Standards

  • 29 CFR 1910.134
  • ISO TC94 SC 15

Key Partners

  • Tongji Medical College in China
  • Frazer Health, BC Canada


  • OSHA
  • MSHA
  • ANSI
  • AIHA
  • ISO
  • Respirator Users
  • Cal-OSHA
Man testing respirator with Portacount

Project Scope

  • A laboratory study will be conducted to assess causative factors affecting temporal changes in respirator fit. Initially, 229 subjects were enrolled and 175 subjects remain. Subjects perform fit testing every 6 months over a three year period. Among the possible causative factors are: weight gain or loss, face size change, 3-D scans and nose shape change.


  • Q1 Complete data reduction for the fourth visit
  • Q2 Complete data collection for the fifth visit
  • Q3 Complete data reduction for the fifth visit
  • Q4 Complete data collection for the sixth visit


  • Manuscripts published or submitted to peer review journals (1)
  • Presentations to stakeholders or conferences (2)
  • Standards committee meetings & public meetings (0)


  • Project data is used by NIOSH, CDC, OSHA, ISO, and ANSI in guidance documents, standards, or regulations
  • Employers and safety professionals will be more likely to follow OSHA regulations and conduct fit testing at the appropriate frequency
  • Other researchers utilize the project outputs to initiate new research related to fit testing
Page last updated: April 17, 2012
Page last reviewed: April 17, 2012
Content Source: National Institute for Occupational Safety and Health (NIOSH)
National Personal Protective Technology Laboratory