N95 Fit Testing.
Fit tests are essential to insuring that a respirator forms a good seal against the user’s face and prevents contaminants from leaking into the mask. Manufactures provide fitting instructions and use limitations on the product package. Respirator face pieces are made in various sizes to fit a wide variety of face shapes and sizes.
A fit test is a test protocol conducted to verify that a respirator is both comfortable and correctly fits the user. Fit testing uses a test agent, either qualitatively detected by the wearer’s sense of taste, smell or involuntary cough (irritant smoke) or quantitatively measured by an instrument, to verify the respirator’s fit. See questions related to qualitative and quantitative fit testing for more specific information.
Why is fit testing necessary? Fit testing each model of respirator the employee is to use in workplace tasks before their use is important to assure the expected level of protection is provided by minimizing the total amount of contaminant leakage into the facepiece. The benefits of this testing include better protection for the employee and verification that the employee is wearing a correctly-fitting model and size of respirator. Higher than expected exposures to a contaminate may occur if users have poor face seals with the respirator, which can result in excessive leakage.
Are there different methods for respirator fit testing? Yes. Fit test methods are classified as either qualitative or quantitative, and there are multiple protocols of each classification that are OSHA-accepted, ANSI-accepted, or NIOSH-recommended. A qualitative fit test is a pass/fail test to assess the adequacy of respirator fit that relies on the individual’s sensory detection of a test agent. A quantitative fit test numerically measures the effectiveness of the respirator to seal with the wearer’s face, without relying on the wearer’s voluntary or involuntary response to a test agent.
Are respirator fit tests required? Yes. The Occupational Safety and Health Administration (OSHA) (29 CFR 1910.134) requires a respirator fit test to confirm the fit of any respirator that forms a tight seal on the wear’s face before it is to be used in the workplace. That same OSHA respirator standard also 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.
How often must fit testing be done? Because each brand, model, and size of particulate facepiece respirators will fit slightly differently, a user should engage in a fit test every time a new model, manufacture type/brand, or size is worn. Also, if weight fluctuates or facial/dental alterations occur, a fit test should be done again to ensure the respirator remains effective. Otherwise, fit testing should be completed at least annually to ensure continued adequate fit.
Once I am fit tested can I use any brand / make / model respirator as long as it is the same size? No. A fit test only qualifies the user to put on (don) the specific brand/make/model of respirator with which an acceptable fit testing result was achieved. Users should only wear the specific brand, model, and size respirators that he or she wore during successful fit tests. [Note: respirator sizing is variable and 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.
What is a respirator user seal check? It is a procedure conducted by the respirator wearer to determine if the respirator is properly seated to the face. The user seal check can be either a positive pressure or negative pressure check, which are generally performed as follows: The positive pressure user seal check is where the person wearing the respirator exhales gently while blocking the paths for exhaled breath to exit the facepiece. A successful check is when the facepiece is slightly pressurized before increased pressure causes outward leakage. The negative pressure user seal check is where the person wearing the respirator inhales sharply while blocking the paths for inhaled breath to enter the facepiece. A successful check is when the facepiece collapses slightly under the negative pressure that is created with this procedure. A user seal check is sometimes referred to as a fit check. A user seal check should be completed each time the respirator is put on (donned). It is only applicable when a respirator has already been successfully fit tested on the individual.
When should a user seal check be done? Once a fit test has been done to determine the best model and size of respirator for a particular user, a user seal check should be done by the user every time the respirator is to be worn to ensure an adequate seal is achieved.
How do I do a user seal check on a particulate respirator? A user seal check may be accomplished by using the procedures recommended by the manufacturer of the respirator. This information can be found on the box or individual respirator packaging. There are positive and negative pressure seal checks and not every respirator can be checked using both. You should refer to the manufacturer’s instructions for conducting user seal checks on any specific respirator .