Temporal changes in filtering-facepiece respirator fit

Area of Science:

• Occupational Health and Safety
• Respiratory Protection
• Industrial Hygiene

Background:

• N95 filtering-facepiece respirators (FFRs) are critical personal protective equipment.
• Maintaining a proper seal is essential for effective respiratory protection.
• Changes in facial characteristics, such as weight fluctuations, can impact respirator fit.

Purpose of the Study:

• To evaluate changes in N95 FFR fit over time.
• To determine the relationship between weight changes and respirator fit.
• To assess the adequacy of current respirator fit-testing schedules.

Main Methods:

• A three-year longitudinal study involving 229 subjects.
• Six-month intervals for fit testing of N95 FFRs.
• Measurement of inward leakage and filter penetration to assess face seal leakage (FSL).

Main Results:

• Unacceptable N95 FFR fit increased from 10% at Year 1 to 25% by Year 3.
• Subjects experiencing a weight loss of 20 lb or more had a 24% rate of unacceptable fit.
• Respirator fit degradation was linked to time intervals between tests and significant weight loss.

Conclusions:

• Current annual fit testing requirements are supported by the study findings.
• Significant weight loss (≥ 20 lb) is a key indicator for mandatory respirator re-testing.
• Regular fit assessment is vital for ensuring the continued effectiveness of N95 FFRs in occupational settings.