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This is an excerpt from the National Institute for Occupational Safety and Health (NIOSH) TB Respiratory Protection Program in Healthcare Facilities: Administrator’s Guide (September 1999).
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.
In the Dec. 11, 1998, Mortality and Morbidity Weekly Report, NIOSH found that fit-testing "N95 respirators is essential in programs employing these respirators and can eliminate poorly fitting respirators, ensuring at least the expected level of protection. Without surrogate fit-testing, average exposure for the 25-person panel was reduced to 33% of the ambient level, which is much less protection than expected of this class of respirators (i.e., exposure reduced to <10% of ambient levels). However, when fit-tested first, the panel received substantially greater protection than normally expected (the average exposure was reduced to 4% of the ambient level). Without fit- testing, persons unknowingly may have poor face seals, resulting in excessive leakage and exposure." Fit-testing is also required by OSHA [29 CFR 1910.139(e)(5)].
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 have inherently different fitting characteristics. Moreover, each of the several brands that are marketed has slightly different fitting characteristics. Although every manufacturer designs facepieces to fit the broadest possible section of the working population, no single respirator fits everyone. 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.
Having more than one facepiece from which to choose also gives the worker a better chance of finding a respirator that provides reasonable comfort and good protection.
The respirator program administrator must decide whether to use QLFT or QNFT procedures. After fit-testing, a wallet-sized card should be provided to the respirator user showing the worker’s name, date, type, brand, model, and size of respirator.
Conduct a risk assessment for the entire facility and for specific areas within the facility. The elements of the risk assessment are included [in the guide] for complete information on how to conduct the assessment. Perform a follow-up risk assessment at the intervals indicated by the most recent risk assessment (using the table from the Centers for Disease Control and Prevention guidelines included in the administrator’s guide). Determine who must wear a respirator and be included in the program.