Fit testing 101: The basics from NIOSH and OSHA
Selection, fit important before testing
Now that annual fit-testing in back on the compliance books, a little refresher may be in order. The following information on respirator fit-testing in health care settings is summarized from guidance by the National Institute for Occupational Safety and Health (NIOSH) and U.S. Occupational Safety and Health Administration (OSHA):
Conduct a risk assessment and determine who must wear a respirator and be included in the program. A fit-test must be conducted to determine which brand, model, and size of respirator fits the user adequately and to ensure that the user knows when the respirator fits properly. Such knowledge is important because TB aerosol can leak around the facepiece into the respirator and be inhaled if the respirator does not fit the user's face.
Determining facepiece fit involves qualitative fit-testing (QLFT) or quantitative fit-testing (QNFT). A QLFT test relies on the wearer's subjective response to taste, odor, or irritation. A QNFT uses another means of detecting facepiece leakage and does not require the wearer's subjective response. Respirator models and brands have inherently different fitting characteristics. Therefore, more than one brand or model, and various sizes of a given type of respirator should be purchased to take advantage of the different fitting characteristics of each and to increase the chances of properly fitting all workers.
Procedures for fit testing:
OSHA requires employers to conduct fit testing using the following procedures:
- Employees choose the most acceptable respirator from a selection of various sizes and models.
- Prior to selection, employees are shown how to put on a respirator and determine an acceptable fit. This is a review, not formal training.
- Employees are informed that they are being asked to select the respirator that provides the most acceptable fit for protection.
- Employees must hold each facepiece up to the face and eliminate those that do not provide an acceptable fit.
- The most acceptable mask is worn at least five minutes to assess acceptability.
- Assessment of acceptability includes reviewing the following points with each employee:
- position of the mask on the nose;
- room for eye protection;
- room to talk;
- position of mask on face and cheeks.
- Adequacy of fit includes the following criteria:
- chin properly placed;
- adequate strap tension;
- fit across nose bridge;
- proper size for distance between nose and chin;
- tendency of respirator to slip;
- self-observation in mirror to evaluate fit and position.
- Employees conduct negative- and positive-pressure fit checks, after being told to seat the mask on the face by moving the head from side to side and up and down slowly while taking slow, deep breaths.
- The test shall not be conducted if there is stubble beard growth, beard, mustache, or sideburns that cross the respirator sealing surface.
- Employees who have difficulty breathing during tests shall be referred to health care professionals for assessment of their ability to wear a respirator.
- Employees who find the respirator fit unacceptable are allowed to select a different respirator and be retested.
- Before the fit test, employees are given a description of the test procedure and their responsibilities during it.
- Employees shall perform exercises during the test while wearing applicable safety equipment that may be worn during respirator use that could interfere with fit, in the following order:
- breathing normally in a standing position;
- breathing slowly and deeply in a standing position;
- slowly turning the head from side to side, inhaling at each extreme position;
- slowly moving the head up and down, inhaling at the up position;
- talking slowly and loudly enough to be heard by the test conductor;
- grimacing by smiling or frowning;
- bending over at the waist;
- breathing normally again.
Each test exercise should be performed for one minute, except for the grimace, which is performed for 15 seconds. The employee should be asked about the acceptability of the respirator upon completion of the protocol. If unacceptable, the process should be repeated with another respirator before proceeding to the specific qualitative or quantitative test protocols.