We talk a lot about contamination control strategies in a cleanroom, but there is another type of strategy you need to consider: air distribution. This strategy is typically put into place during the planning and building of a cleanroom because it has a lot to do with infrastructure. But understanding your cleanroom’s air distribution strategy will give you a better understanding of your cleanroom’s overall environment.
Air distribution does a few things in your cleanroom.
First and foremost, it directs the flow of the air in your cleanroom. A proper cleanroom air distribution strategy makes ample use of laminar air flow (or unidirectional air flow). This forces particles to move with the flow of the air, quickly being directed through the appropriate HEPA and ULPA filters, limiting your cleanroom’s exposure to contamination. Your strategy should also account for a worse cast scenario: turbulent air flow, when air mixes with the room without any laminar flow. Ideally, though, all entry points for air would be accounted for and laminar air flow achieved.
Second, proper air distribution helps control the temperature of your cleanroom. A cleanroom should be kept at a crisp 21°C for most applications. An occasional variance of 2°C is acceptable in some industries. Many cleanrooms use a low-level air return system to help achieve laminar air flow and even temperatures. This means that air is returned from the top of the room to the bottom. Since hot air rises and cold air sinks, this combination of the air helps to maintain an even temperature.
Third, proper air distribution helps protect personnel from prolonged exposure to potentially hazardous chemicals. We all know that cleanrooms are highly controlled spaces for a reason. Most of the time, it is to protect the product from outside contamination. Many times, though, especially in the pharmaceutical and research spaces, the cleanroom serves the purpose of also protecting the personnel. Ideal cleanroom air distribution quickly removes and filters air to protect both the product and the personnel.