A HEPA respirator is a breathing aide that utilizes a high-efficiency particulate air (HEPA) filter. It is an air-purifying respirator, meaning that the filter helps keep harmful dust and other particles out of the air the wearer breathes. Although an isolation mask or dust mask is made of thin material that covers the nose and mouth, a HEPA respirator is often much larger and thicker. HEPA respirators are typically made in three styles: those that cover just the mouth and nose, those that cover the entire face and those that cover the entire head.
HEPA filters were first developed in the 1940s to help prevent the spread of airborne radioactive materials during the Manhattan Project. The United States Department of Energy and the European Union both have set standards for HEPA filters. Filters are typically made of fiberglass fibers that are randomly arranged to trap airborne particles. According to U.S. standards, for example, a HEPA filter must eliminate at least 99.97 percent of airborne particles .03 micrometers in diameter. In addition to their use in respirators, HEPA filters are also commonly used in air filtration and purification systems and vacuum cleaners.
Someone who could be exposed to dangerous airborne particles, including bacteria, fungi, fumes, mists and gases, should protect himself or herself with a HEPA respirator. Respirators are commonly used by those who work in welding, medicine, construction, demolition and various industrial trades. A HEPA respirator might also be used by a homeowner working to remove asbestos or lead paint as well as by landscapers and pest control managers who spray chemicals that might be harmful if inhaled.
HEPA respirators can be certified by certain organizations, such as the National Institute for Occupational Safety and Health (NIOSH) in the United States. The NIOSH filter ratings system classifies the best HEPA filter that can be used with any type of particulate as a P100 filter. R100 and N100 HEPA filters have usage restrictions. Before HEPA respirators are used in a workplace, it is recommended for employers to try reducing employees' exposure to harmful airborne particulates through other means. If a respirator is still needed, employees should first be trained in how to use the respirator, and the respirator should be tested for proper fit.
