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OSHA offers guidance on respirator protection
APFs have limited application to HC workplace
How protective is the respirator that you provide your employees? The N95 designation refers to the filter only - filtering out 95% of a potential airborne contaminant. The "assigned protection factor" actually designates the overall ability of a respirator to reduce exposure. It takes into account, for example, the potential contaminant that leaks through the face seal of an N95 filtering facepiece respirator.
The U.S. Occupational Safety and Health Administration has released a new guidance document to clarify the protection levels of different types of respirators and to help employers select the appropriate ones. It shows, for example, that a powered air-purifying respirator (PAPR) with a hood or loose-fitting facepiece would allow only 4% of contaminated air to penetrate, while an N95 would allow 10% penetration (www.osha.gov/Publications/3352-APF-respirators.pdf).
The OSHA guidance also details the OSHA-accepted fit-test protocols.
While the document contains useful information for health care employers, including information on respirator cleaning and maintenance, it reveals some limitations in the current science of respirators, notes Lewis J. Radonovich, MD, director of Biosecurity Programs in the Office of Program Development at the North Florida/South Georgia Veterans Health System in Gainesville, FL.
Assigned protection factors are determined by measuring the level of an air contaminant inside and outside the respirator. But the risk of infection is dependent on the type of pathogen and other factors, not just the concentration. "In many cases, we don't know what dose of a pathogen it takes to make someone ill," says Radonovich, who is engaged in research on respiratory protection in health care. "We often aren't able to measure accurately the concentration of that pathogen in the air."
While health care employers should be knowledgeable about the factor of respirators and the OSHA requirements, they also need to use administrative and engineering controls, such as isolation of patients and proper ventilation, experts say.