How is cleanroom cleanliness measured?
Cleanroom cleanliness is measured by how many micron sized particles pass through one cubic foot of air per minute (cfm). This is how a cleanroom's classification is determined.
What do the classifications mean?
A Class 10 cleanroom has no more than ten micron sized particles passing through each cubic foot of air per minute. That's really clean. A Class 100,000 may have up to one hundred thousand particles per cubic foot. For comparison, your home has around 300,000 and a hospital operating room has about 1,000.
Where do all these tiny particles come from?
Most particulate contamination comes from people. We are shedding particulate matter every minute, even by breathing.
What is laminar flow?
It's when all of the air in a cleanroom is forced to move in the same direction and speed to a filter. One common example of laminar flow is when the air moves from the ceiling through the floor, is forced up through the walls to be filtered above the ceiling and then reenters the room and continues the cycle.
What does HEPA stand for?
High Efficiency Particulate Air. These replaceable filters will catch almost 100% of particles as small as .3 microns. You might find them in your own home or office as part of an air conditioner filtering system or a vacuum filter.
What exactly is an airshower?
It's a hallway or room leading to the entrance of the cleanroom. Often there is an airshower between the dressing room or gowning area and the main entrance to the cleanroom. In the airshower, high velocity air blows off debris that could contaminate the cleanroom environment. Sometimes de-ionizers are used to remove static thereby increasing the effectiveness of removing hair and lint.