Cleanrooms are classified by how clean the air is. In Federal Standard 209 (A to D) of the USA, the number of particles equal to and greater than 0.5mm is measured in one cubic foot of air, and this count is used to classify the cleanroom. This metric nomenclature is also accepted in the most recent 209E version of the Standard. Federal Standard 209E is used domestically. The cleanroom classification standards FS 209E and ISO 14644 require specific particle count measurements and calculations to classify the cleanliness level of a cleanroom or clean area. In the UK, British Standard 5295 is used to classify cleanrooms. This standard is about to be superseded by BS EN ISO 14644 .
Clean Rooms used in manufacturing or scientific research, a cleanroom is a controlled environment that has a low level of pollutants such as dust, airborne microbes, aerosol particles, and chemical vapors. To be exact, a cleanroom has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size. The ambient air outside in a typical city environment contains 35,000,000 particles per cubic meter, 0.5 micron and larger in diameter-and Follows as per ISO 14644 standards.
Cleanrooms are used in practically every industry where small particles can adversely affect the manufacturing process. They vary in size and complexity, and are used extensively in industries such as semiconductor manufacturing, pharmaceuticals, biotech, medical device and life sciences, as well as critical process manufacturing common in aerospace, optics, military and Department of Energy.
A cleanroom is any given contained space where provisions are made to reduce particulate contamination and control other environmental parameters such as temperature, humidity and pressure. The key component is the High Efficiency Particulate Air (HEPA) filter that is used to trap particles that are 0.3 micron and larger in size. All of the air delivered to a cleanroom passes through HEPA filters, and in some cases where stringent cleanliness performance is necessary, Ultra Low Particulate Air (ULPA) filters are used.
Personnel selected to work in cleanrooms undergo extensive training in contamination control theory. They enter and exit the cleanroom through airlocks, air showers and/or gowning rooms, and they must wear special clothing designed to trap contaminants that are naturally generated by skin and the body.