What is the protocol for fit testing of N95 (Non-Invasive Non-Powered Air-Purifying Respirators) respirators?

N95 Respirator Fit Testing Protocol

Fit testing is a mandatory OSHA requirement for all N95 respirators used in healthcare settings to ensure proper protection against airborne pathogens by determining whether a respiratory protective device adequately fits the user. 1

Types of Fit Testing

Qualitative Fit Testing

• Uses subjective response of the healthcare worker (HCW) to aerosolized substances
• Procedure:
  • HCW is exposed to aerosolized substances that can be tasted
  • HCW reports whether they can detect the substance
  • Limitations: Results depend on subjective response of the HCW being tested 1

Quantitative Fit Testing

• Uses detectors to objectively measure inward leakage
• Procedure:
  • Specialized equipment measures the concentration of particles inside and outside the respirator
  • Calculates a fit factor (ratio of particles outside vs. inside)
  • A fit factor of at least 100 is required to pass 2
  • For disposable N95 respirators, quantitative testing is best performed if manufacturer provides a test respirator with a probe 1

Fit Testing Protocol Steps

1. Selection of appropriate respirator models:

   • HCW may need to be tested with several devices to determine best fit
   • Consider availability of different sizes (some disposable respirators come in only one size) 1

2. Preparation:

   • Ensure HCW has no facial hair that interferes with seal
   • Remove eyewear, jewelry, or other items that may interfere with fit
   • Educate HCW on proper donning technique before testing 3

3. Simulated workplace exercise protocol:

   • Normal breathing
   • Deep breathing
   • Turning head side to side
   • Moving head up and down
   • Talking
   • Bending over or jogging in place
   • Normal breathing again 2

4. Evaluation of results:

   • For quantitative testing: Pass requires overall fit factor ≥100
   • Individual steps should also maintain fit factor ≥100 2
   • For qualitative testing: Pass requires no detection of test substance during exercises

Important Considerations

Face-Seal Leakage

• Primary source of inward leakage in N95 respirators with HEPA filters
• Factors affecting face-seal:
  • Incorrect facepiece size or shape
  • Facial hair
  • Perspiration or facial oils
  • Improper positioning or head strap tension 1

Fit Check vs. Fit Testing

• Fit testing is the formal evaluation process (annual requirement)
• Fit check (user seal check) is performed by the user before each use:
  • Performed according to manufacturer's instructions
  • Uses negative-pressure or positive-pressure test
  • Some cup-shaped disposables are difficult to fit check reliably 1

Special Considerations

• Facial characteristics impact fit success rates
• Race/ethnicity may correlate with facial shape and fit success 4
• Skin protectants (bandages, tapes, barrier creams) can significantly reduce fit factors and should be avoided unless specifically tested 5
• Prior training in respirator use does not necessarily correlate with better fit test results 4

Post-Fit Testing Requirements

1. Documentation:

   • Record the specific make, model, style, and size of respirator that passed
   • Document date of testing and results

2. Retraining:

   • Provide education on proper donning, doffing, and seal checking
   • Training through fit testing has been shown to improve knowledge, attitude and performance regarding respiratory protection 3

3. Retesting requirements:

   • At least annually
   • When physical changes occur (significant weight change, facial surgery, dental work)
   • When switching to a different respirator model 1

Common Pitfalls to Avoid

• Assuming one-size-fits-all respirators work for everyone (59% of N95 users failed at least one step of quantitative fit testing in one study) 2
• Neglecting to perform fit checks before each use
• Applying skin protectants without retesting fit 5
• Reusing respirators without proper inspection for damage or soiling 1
• Assuming prior experience with respirators guarantees proper fit 4

By following this comprehensive protocol for N95 respirator fit testing, healthcare facilities can ensure their workers have properly fitted respiratory protection, significantly reducing the risk of exposure to airborne infectious agents.