The number of times a cleanroom can completely replace its air volume within an hour.Cleanrooms employ air filtration to limit the particles in the environment air. Typically, this is through the use of either a highly efficient particulate air (HEPA) or ultra-low particulate air (ULPA) filter. These filters can remove roughly 99.9 percent of all microparticles in room air by applying either laminar air flow or turbulent air flow techniques to the environment air.
