So what exactly makes a cleanroom… A cleanroom? First and foremost, a cleanroom needs to be clean. You are able to communicate just how clean it is through its cleanroom classification.
But you cannot attain the classification without first making sure your cleanroom is really that clean. You do this through a proper cleanroom contamination control strategy and design.
Whether your cleanroom is one room or a network of rooms connected by hallways, you need to pay attention to airflow. The only air that enters the space must come through the proper filters. Additionally, the temperature and humidity must be closely controlled. This is why Air Handling Units (AHUs) in cleanrooms normally consume at least 60% of its power usage.
Proper airflow ensures that clean, fresh air, as well as filtered, recirculated air, is used to constantly flush cleanrooms. This is often done through the strategic use of positive and negative pressure.
Essentially, a room with negative pressure has a lower air pressure than surrounding rooms and hallways. When a door is opened, air rushes in. This keeps particles and contaminants in the room, but can also introduce particles from the exterior corridor.
The reverse is true in a positive pressure room. When the door is opened, air rushes out. This pushes contaminants out of the room.
This physics phenomenon creates what we call "clean corridors" and "dirty corridors". If air is rushed out into the corridor from a positive pressure room, the corridor is considered dirty. But the sensitive contents of the room are saved from contamination. As part of your cleanroom contamination control strategy, you should coordinate the clean and dirty corridors and the pressure in each area. When planning your doors, ensure they open towards the higher pressure area.
Beyond the structure around the air flow, you need to ensure that everything in your cleanroom is free of particle traps. This means everything should be built from non-porous, easily sanitized materials.
While this is all pivotal in keeping a cleanroom clean, why does it even matter? What are cleanrooms used for?