CONTROL & DESIGN STANDARDS: AIRBORNE CONTAMINANTS

The level of cleanliness required inside the cleanroom is determined by the demands of the job at hand. What’s more than sufficient for one cleanroom may be woefully inadequate for another. Federal Standard 209D specifies six air cleanliness classes: from Class 100,000 down to Class 1.

The Class number refers to the maximum number of particles bigger than one-half a micron allowed in one cubic foot of air. As you might imagine, the precautions you’ll take for a room allowing only 1 particle per cubic foot (Class 1) will be much stricter than one allowing thousands of particles.

Examples depicting the number of particles in a cubic foot of air, from 100,000 down to 1.
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