Cleanrooms: Contaminant-Free Environments

by Andy on August 21, 2009

Cleanroom is a term that is thrown around a lot but what does it really mean? Cleanrooms are more than just a clean counter and a swept floor.

First off, according to Global Spec a cleanroom is an environment that is contaminant-free and often used for high-tech assembly and manufacturing.

There are several different classes of cleanrooms, each with their own standards, and these standards limit the number of particles in the air per cubic meter. Cleanrooms are classed from FED STD 209E Class 1 to Class 100,000 or from ISO 1 to ISO 9. FED STD 209E used to be the standard but was replaced with ISO 14644 in 2001 by the U.S. General Services Administration (GSA); but FED STD 209E is still widely used.

To put things into perspective, outside air in a typical city may have as many as 35,000,000 particles (size 0.5 μm and larger) per cubic meter but an ISO 5 cleanroom will have a maximum of 3,520 particles (size 0.5 μm and larger) per cubic meter. To give you an idea of how involved these rooms are, here’s an article in which Intel explains the process of entering a cleanroom; according to Intel there are over 40 steps that must be repeated every time someone leaves and re-enters a cleanroom.

So what is a contaminant? Most cleanroom contaminants seem innocuous in every day situations but they do cause problems in contamination-free environments. According to Coast Wide Labs, most contaminants come from five sources; people, tools, facilities, fluids and the product being manufactured. Cosmetics, perfume, floor finishes, aluminum particles and yes, even vibration, are just a few common contaminants.

Controlling contaminants is all dependant of the class of the cleanroom but some key components include:

  • HEPA air filters – this is probably one of the biggest elements to a cleanroom – these filters can remove particles that are as small as 0.3 microns and highly efficient (remove at least 99.97% of airborne particles)
  • Design of the cleanroom – this has to do with airflow; little airflow causes turbulence which can cause particle movement
  • Special garments – these garments range from cleanroom coveralls to masks to booties and gloves – cleanroom garments reduce the lint and particles in the air
  • Cleanroom furniture such as workstations and chairs –this equipment has the same result as the garments mentioned above
  • Cleaning – the specialized rooms must be cleaned with special materials, substances, etc…

This is just a brief overview; cleanrooms are very complex and can vary from company to company.

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