Filtering out Confusion: 

Frequently Asked Questions about Respiratory Protection

Fit Testing 

Over 3 million United States employees, in approximately 1.3 million workplaces, are required to wear respiratory protection. The 

Occupational Safety and Health Administration (OSHA) (29 CFR 

1910.134) requires an annual respirator fit test to confirm the fit of 

any respirator that forms a tight seal on the wearer’s face before it 

is used in the workplace. This ensures that users are receiving the 

expected level of protection by minimizing any contaminant leakage 

into the facepiece. The following are some frequently asked questions 

about respiratory protection and fit testing.

What is a Respirator Fit Test?

A fit test is conducted to verify that a respirator is both comfortable and 

correctly fits the user. Fit test methods are classified as either qualitative 

or quantitative. A qualitative fit test is a pass/fail test that relies on the 

individual’s sensory detection of a test agent, such as taste, smell, or 

involuntary cough (a reaction to irritant smoke*). A quantitative fit 

test uses an instrument to numerically measure the effectiveness of the 

respirator.

The benefits of a fit test include better protection for the employee and 

verification that the employee is wearing a correctly-fitting model and 

size of respirator.1 Higher than expected levels of exposure to a contaminant may occur if the respirator has a poor face seal against the 

user’s skin, which can result in leakage.

How Often Must Fit Testing Be Conducted?

In addition to fit testing upon initially selecting a model of respirator, OSHA requires that fit testing be conducted annually, and repeated “whenever an employee reports, or the employer or the physician or other licensed health care professional makes visual observations of changes in the employee’s physical condition that 

could affect respirator fit (e.g., facial scarring, dental changes, cosmetic surgery, or an obvious change in body 

weight).” 2

The appropriate length of time between respirator fit tests has been a point of debate and discussion for many 

years due to its use of workplace time and resources, especially in reference to the commonly-used filtering 

facepiece respirator (FFR).3 In response to these concerns, NIOSH completed a study that confirmed the necessity of the current OSHA respirator fit testing requirement, both annually and when physical changes have 

occurred.2
Once I am Fit Tested, Can I use any Brand/Make/Model Respirator 

as Long as it is the Same Size?

A successful fit test only qualifies an employee to use the specific brand/make/model and size of respirator that 

he or she wore during that test. Respirator sizing is not standardized across models or brands. For example, a 

medium in one model may not offer the same fit as a different manufacturer’s medium model. 

Can I Have Facial Hair and still be Fit Tested to Wear a Tight-Fitting 

Respirator?

The OSHA respirator standard prohibits tight-fitting respirators to be worn by workers who have facial hair that 

comes between the sealing surface of the facepiece and the face of the wearer. Facial hair that lies along the sealing area of a respirator, such as beards, sideburns, or some mustaches, will interfere with respirators that rely on a 

tight facepiece seal to achieve maximum protection. 

Research tells us that the presence of facial hair under the sealing surface causes 

20 to 1000 times more leakage compared to clean-shaven individuals.4 Gases, 

vapors, and particles in the air will take the path of least resistance and bypass the 

part of the respirator that captures or filters hazards out. A common misconception is that human hair can act as a crude filter to capture any particles that are in 

the airstream between the sealing surface and the user’s skin. However, while human hair appears to be very thin to the naked eye, hair is much larger in size than 

the particles inhaled. Facial hair is not dense enough and the individual hairs are 

too large to capture particles like an air filter does; nor will a beard trap gases and 

vapors like the carbon bed in a respirator cartridge. Therefore, the vast majority of 

particles, gases, and vapors follow the air stream right through the facial hair and 

into respiratory tract of the wearer. In fact, some studies have shown that even a 

day or two of stubble can begin to reduce protection.

This document is in the public domain

and may be freely copied or reprinted.

DOI: https://doi.org/10.26616/NIOSHPUB2018129

DHHS (NIOSH) Publication No. 2018-129

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References

1. Duling MG, Lawrence RB, Slaven JE, Coffey CC [2007]. Simulated workpalce protection factors for half-facepiece respiratory protective devices. J Occup Environ Hyg. 4(6):420-431.

2. OSHA [1998]. Respiratory Protection. 29 CFR 1910.134. Final rule. Fed Regist 63:1152-1300. 

3. Zhuang Z, Bergman MS, Brochu E, Palmiero AJ, Niezgoda G, He X, Roberge RJ, Shaffer RE [2016]. Temporal changes in filtering-facepiece respirator fit. J Occup Environ Hyg. 13(4), pp.265-274.

4. Stobbe TJ, daRoza RA, Watkins MA [1988]. Facial hair and respirator fit: a review of the literature. Am. Ind Hyg Assoc J. 49(4):199-204.

Photos courtesy of NIOSH and Shutterstock

Incorrect respirator use due to beard and 

strap placement

Do Powered Air-Purifying Respirators (PAPRs) Require Fit Testing?

The answer to this question depends on the type of facepiece that the respirator has. Any facepieces that form a 

tight seal to the wearer’s face, e.g., half-masks and full facepieces, must be fit tested. 

Loose-fitting PAPRs, in which the hood or helmet is designed to form only a partial seal with the wearer’s face or 

hoods which seal loosely around the wearer’s neck or shoulders, do not require fit testing.

Where can I Find More Information? 

This information and more is available on the NIOSH Respirator Trusted-Source webpage. 

*NIOSH does not endorse or recommend the use of the irritant smoke fit test. NIOSH, in its formal comments to OSHA on the proposed revision of 29 CFR 1910, 1915, and 1926, strongly 

recommended against the use of this fit test method because of the health risk associated with exposure to the irritant smoke. That recommendation was primarily based on studies conducted as 

part of a NIOSH HHE (HETA 93-040-2315) and described in Appendix A of the NIOSH comments to OSHA dated May 15, 1995 (docket H-049)