History
The original HEPA filter was designed in the 1940s and used in Manhattan projects to prevent the spread of airborne radioactive pollutants. It was commercialized in the 1950s and became a registered trademark, with the general term being a very efficient filter. In a decade the filter evolved to meet the higher and high demand for air quality in a variety of high-tech industries, such as aerospace, pharmaceutical processing, hospitals, healthcare, nuclear fuel, nuclear power and electronic microcircuitry (computer chips).
The specified value of the HEPA filter in the respirator: the filter efficiency performance standard and the minimum value are the equivalent NIOSHN100 values. The United States Department of Energy (DOE) has specific requirements for HEPA filters in DOE regulated applications. Products marked as “HEPA type”, “HEPA” or “99% HEPA” may not meet these requirements in an independent laboratory and may not be tested.