The 4 important air-conditioning design considerations for clean room system design are:
- Supplying airflow in sufficient volume and cleanliness to support the cleanliness rating of the room.
- Introducing air in a manner to prevent stagnant areas where particles could accumulate.
- Conditioning air to meet clean-room temperature, humidity and filtration requirements.
- Ensuring enough conditioned makeup air to maintain the specified positive pressurization.
Besides the room preparation in terms of materials and finishes play an equally important role in meeting these requirements. The idea is to minimize the internal generation of contaminants from the surfaces.
Cleanroom is an environment which is mainly used in manufacturing or for scientific research, that has a low level of environmental pollutants like airborne microbes, dust, aerosol particles and chemical vapours.
Any cleanroom has a very specific controlled level of contamination which is measured by the number of particles/m3 and the maximum size of the particle . To provide a perspective, external environment has to be considered about a 5,000,000 class cleanroom.
Cleanrooms can be either small or large. Complete manufacturing facilities can come within a cleanroom with factory floors which covers thousands of square meters. They are mainly used in semiconductor manufacturing, Life sciences,biotechnology and other fields which are sensitive to environmental contamination.
The air which is entering a cleanroom from the outside is completely filtered to exclude the dust and the air inside is recirculated through the High Efficiency Particulate Air (HEPA) and Ultra Low Penetration Air (ULPA) filters so that internally generated contaminants are removed.
Cleanroom HVAC systems controls the humidity to such lower level that extra precautions has to be taken to prevent electrostatic discharges. For entering a cleanroom one is required to wear a cleanroom suit.