Fit testing is a test that checks whether a specific make, model, style and size of tight-fitting respirator forms an adequate seal on a worker's face. OSHA's respiratory protection standard requires employees who use tight-fitting respirators to pass a fit test before first use, whenever a different facepiece is used, and at least annually after that.
Fit testing matters because a respirator, like any personal protective equipment, only protects when contaminated air cannot leak around the edges. Faces differ in shape and size, and a mask that fits one worker can leak badly on another. Without a passing fit test, a worker may be breathing respirable crystalline silica, solvent vapor or infectious aerosols while believing they are protected.
What Is Respirator Fit Testing?
Under 29 CFR 1910.134(f), a fit test uses an approved protocol to evaluate the fit of a respirator on an individual. It applies to tight-fitting facepieces, including filtering facepiece respirators (such as N95s), elastomeric half masks and full facepiece respirators. Loose-fitting hoods and helmets are not fit tested.
Fit testing is different from a user seal check. A seal check is a quick positive or negative pressure check the wearer does every time they put on the respirator. A fit test is a formal, documented test of a specific respirator model and size on that person.
When Fit Testing Is Required
- Before initial use of a tight-fitting respirator in the workplace.
- Whenever a different facepiece (size, style, model or make) is used.
- At least annually after the previous fit test.
- When physical changes may affect fit, such as facial scarring, dental changes, cosmetic surgery or an obvious change in body weight, as reported by the employee or observed by the employer or a physician or other licensed health care professional (PLHCP).
- When the employee says the fit is unacceptable, in which case they must be allowed to select a different respirator and be retested.
Before a fit test, the employee must be medically evaluated and cleared to wear a respirator. Tight-fitting respirators may not be worn by employees with facial hair that comes between the sealing surface and the face, or that interferes with valve function.
Qualitative vs. Quantitative Fit Testing
Qualitative fit testing (QLFT)
QLFT is a pass or fail test that relies on the wearer's response to a test agent. OSHA-accepted protocols in Appendix A use isoamyl acetate (banana oil), saccharin, Bitrex or irritant smoke. QLFT may only be used to fit test negative-pressure air-purifying respirators that must achieve a fit factor of 100 or less, which in practice means half masks and filtering facepieces.
Quantitative fit testing (QNFT)
QNFT uses an instrument to measure leakage and produces a numerical fit factor. Accepted methods include the generated aerosol method, the ambient aerosol condensation nuclei counter (CNC) method, including modified CNC protocols added in 2019, and controlled negative pressure (CNP) methods. QNFT can be used for any tight-fitting respirator and is required for full facepieces used where a fit factor above 100 is needed.
Passing fit factors
- Tight-fitting half facepieces: a fit factor of at least 100.
- Tight-fitting full facepieces: a fit factor of at least 500.
Tight-fitting powered air-purifying respirators and atmosphere-supplying respirators are fit tested in the negative pressure mode, using a facepiece of the same make, model, style and size.
The Fit Test Exercises
Standard OSHA protocols have the wearer perform exercises that mimic work movements, such as normal and deep breathing, turning the head side to side, moving the head up and down, talking, bending over and, for QNFT, grimacing. The respirator must stay sealed through each exercise. The 2019 modified CNC protocols use a shorter set of exercises. The employee should wear the respirator for at least five minutes before the test to check comfort.
How to Run a Fit Testing Program Step by Step
- Confirm medical clearance. Make sure each employee has a current medical evaluation for respirator use.
- Offer a choice of models and sizes. Let the employee pick the most comfortable respirator before testing.
- Check facial hair and PPE. Confirm the employee is clean-shaven where the seal meets the face and test with any PPE that may affect fit, such as safety glasses.
- Choose the method. Use QLFT for half masks where allowed, or QNFT for full facepieces and higher fit factors.
- Run the protocol. Follow the Appendix A procedure exactly, including all exercises.
- Record the results. Document the employee name, test type, make, model, style and size of respirator, date and result.
- Schedule the retest. Set a reminder within 12 months, or sooner if the facepiece or the employee's face changes.
Records to Keep
OSHA requires a fit test record that includes the employee's name or identification, the type of fit test performed, the specific make, model, style and size of respirator, the date of the test, and the result. For QLFT, record pass or fail. For QNFT, record the fit factor and the strip chart recording or other recording of the test. Fit test records must be kept until the next fit test is administered.
Common Mistakes to Avoid
- Letting workers use a different respirator model than the one they were tested on.
- Missing the annual retest date.
- Allowing beard growth or stubble on employees who wear tight-fitting respirators.
- Confusing a user seal check with a fit test.
- Testing before the employee has medical clearance.
How SMS360 Helps
SMS360's Training Management module tracks fit test dates, respirator models and sizes, with reminders before annual retests are due. Document Library stores the written respiratory protection program, and Risk Assessment links respirator use to the tasks and exposures that require it.
The fit testing protocols are in Appendix A of 29 CFR 1910.134 on eCFR.
Frequently Asked Questions
How often is respirator fit testing required?
Before first use, whenever a different respirator facepiece is used, and at least annually. Retesting is also required when physical changes could affect fit.
Do N95 respirators need fit testing?
Yes, when they are required by the employer. Filtering facepiece respirators are tight-fitting and must be fit tested. Voluntary use of filtering facepieces is not subject to fit testing, but the employer must provide the information in Appendix D of the standard.
What is a passing fit factor?
For quantitative fit testing, a fit factor of at least 100 for tight-fitting half facepieces and at least 500 for tight-fitting full facepieces.
How long must fit test records be kept?
Until the next fit test is administered. Many employers keep them longer as part of their respiratory protection program records.
