Air Conditioning in Clean Rooms
Air Conditioning has a serious role to play in environments where air quality is critical to operations and procedures. One such example of this is clean rooms. Clean rooms are controlled environments where products mainly pharmaceuticals, electronics and medical devices are manufactured. The objective is to remove airborne particles and control them within defined limits.
These particles contaminate the atmosphere and are generated by people, processes, and equipment. The only way to control contamination is to control the total environment. Air flow rates and direction, pressurisation, humidity, temperature, and specialised filtration all need to be tightly controlled. The sources of these particles need to be eliminated when possible.
In the following comparison, it will be seen clearly how controlled a clean room environment is. A typical office building contains from 500,000 to 1,000,000 particles (0.5 microns or larger) per cubic foot of air. Depending on the classification of the clean room, no more than 100 particles (0.5 microns or larger) per cubic foot of air up to 10,000 (0.5 microns or larger) per cubic foot of air. Human hair is approximately 75-100 microns in diameter. A particle 200 times smaller (0.5 micron) than the human hair can cause a catastrophe in clean room. Contamination can lead to expensive downtime while a clean room is decontaminated.
When you consider that at rest a human sheds 100,000 particles of 0.3 microns and larger which increases as the body becomes more physical by walking and performing tasks it can be seen how difficult the job of controlling the environment is. Even air conditioning debris can be responsible for contamination.
Air filters and sluices filter the finest particles out of the air and reliably protect clean rooms from particle contamination. Precision air-conditioning systems control the air pressure and must operate powerfully and evenly, and distribute the cleaned air through the clean room without turbulence. The systems use laminar flow, which moves the entire body of air within the room with uniform velocity along parallel flow lines. Most clean rooms would have 10 to 20 complete changes of air per hour.
The complexity of these air conditioning systems and filtering systems are crucial for the things we take for granted in everyday life. Without the sophisticated air conditioning technologies used for clean room situations, semiconductors, microsystems and medical devices would not be able to be manufactured. Life sciences are also users of clean rooms.
Personnel working in these environments adhere to strict regulations and wear special clothing and masks, are not permitted to wear perfume or cosmetics of any kind and have to go through an “air shower” particle removal process before they enter the clean room.
Clean rooms are just one of the speciality projects undertaken by air conditioning companies and are a real feat of engineering.
Posted in: Latest News - On: 3rd of April, 2012