Clean room suppliers design and install cold chambers, conduct certification processes or manufacture clean room equipment. Clean rooms are used in many sectors - among others in the pharmaceutical industry, chemical industry, microelectronics, healthcare, food industry etc. - as their processes are built upon clean room technology. Controlled environments are known for controlled indoor air quality, temperatures and humidity according to the ISO classification system. The system classifies clean rooms according to the number of particles present in the air above a given size.