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.

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).”

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.

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.

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.

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.

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