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NIOSH to mandate better-fitting respirators, ease fit-test requirements
With new rule, more HCWs will pass fit-tests
Better-fitting respirators are on the horizon. Newly proposed criteria will require manufacturers to prove that their N95 filtering facepiece respirators meet a minimal level of fit — right out of the box.
This doesn't mean the end of fit-testing. But along with implementing these criteria, the National Institute for Occupational Safety and Health (NIOSH) is researching whether annual fit-testing could be replaced by intervals of two or three years.
The bottom line for consumers, such as hospitals: Your employees will be more likely to fit the respirators that meet tougher minimum standards, and the respirators on the market will be of more consistent quality. The draft standard would limit the total inward leakage of respirators — the amount of air that leaks around the face seal or exhalation valve or through the filter material — to 5%. To meet the criteria, an N95 model must pass 26 of 35 fit-tests.
"It does not guarantee fit on an individual, [but] it should increase the probability that a respirator they buy is likely to fit," explains Roland Berry Ann, deputy director of the NIOSH National Personal Protective Technology Laboratory in Pittsburgh.
A revision of the criteria for N95 respirators was long overdue, says Bill Borwegen, MPH, health and safety director for the Service Employees International Union (SEIU) in Washington, DC. "This will hopefully spur manufacturers to design products that fit a wider array of facial features and sizes," he says.
Currently, the quality and fit of the respirators vary greatly. A NIOSH study of 18 N95 models found that three fit well out of the box, even without fit-testing. Yet the performance of the other respirators dropped off sharply. The highest pass rate for any respirator using a qualitative fit-test method (Bitrex or saccharin) was 55%. With one respirator model, only three of 24 people tested with Bitrex passed and no one passed the saccharin test. Five respirator models failed all fit-tests using the Portacount.1
That means that hospitals that purchase respirators with poorer fit characteristics will spend more time and effort trying to match employees with a correct size and fit, says Chris Coffey, PhD, chief of the laboratory research branch of the NIOSH Division of Respiratory Disease Studies in Morgantown, WV.
"No matter what the final level is [with the new fit criteria], the quality of respirators will be improved," he says.
NIOSH has always counted on fit-testing to ensure a good fit for N95s. For the past 12 years, NIOSH focused its certification requirements on the filter material. An N95 respirator must be able to filter out at least 95% of an airborne contaminant.
Designs will match modern face of America
The new criteria put a greater emphasis on the quality of the face seal, which may differ based on respirator style. NIOSH also has updated the test panel that reflects the facial structure of the "average" respirator wearer.
Although the U.S. population has aged, become more ethnically diverse and heavier, NIOSH had not updated its test panel since the 1970s. "Our intent is to use the new test panel and then have performance criteria based upon their ability to fit the people on that test panel," says Berry Ann.
Changing the test panel represents an important advance, says Coffey. "That [outdated test panel] may be one of the reasons that even the larger manufacturers didn't do too well [on total inward leakage tests]. They were designing these respirators using outdated, obsolete panels that didn't represent the average person in the United States today."
NIOSH is accepting comments on its "total inward leakage" requirements and held a public meeting on the proposed criteria in late June. While the changes are widely lauded, there may be some debate about where to set the criteria and how to phase in the changes.
"There are respirators out there that are going to pass this test easily," says Steve Lenhart, a retired NIOSH industrial hygienist, who studied respirator performance. He suggests that consumers should look for specific data from manufacturers on how they performed on total inward leakage tests. "If the respirator I'm about to buy just barely passed, I want to know that," he says.
Meanwhile, it will take time before respirators will be required to meet the higher standards. Finalizing the rule will take about 18 months, estimates Berry Ann. NIOSH also will likely provide a phase-in period during which currently certified respirators will be allowed to remain on the market, perhaps with a different certification symbol.
Fit-testing will continue to be an important part of respirator programs, says Berry Ann. In fact, if your current model performs well in fit-tests of your current employees, you may choose to continue using it, since that fit-test is the ultimate determinant of individual fit, he says.
Will better-fitting respirators require less frequent fit-testing? NIOSH isn't prepared to say that. But further information should come from a study of respirator fit over time. Individuals will be tested every six months over a three-year period to see how their fit changes due to aging, weight gain, or other factors.
"We're going to be remeasuring their facial characteristics to try to [compare] the changes in their facial characteristics with the changes in their fitting," says Berry Ann.
The end result, hopefully, will be better-fitting respirators and a lesser fit-testing burden on employers.
(Editor's note: More information on the Total Inward Leakage requirement is available from www.cdc.gov/niosh/npptl/resources/certpgmspt/meetings/062607/lttr-062607.html.)