Owners and operators often assume that because their cleanrooms are equipped with HEPA filters and other state-of- the-art control systems for humidification, temperature, and pressurization, normal cleaning procedures were optional or even unnecessary.
The accululation of dust that one sees in many cleanrooms is the accumulation of both workers and manufacturing processes, which contribute to contamination. Particles too small to see add to the contamination of the cleanroom. Small charged particles combine with other charged particles, forming particles that are eventually large enough for the human eye to recognize as a contaminate. Where there are particles, there are bacteria. Each of these contaminates has the potential to destroy the product.
Micro cleaning's detailed techniques can result in an environment of highly maintainable integrity. The term micro cleaning directs us to a level of maintenance that is far beyond general housekeeping.
Our goal is to remove as much contamination that exists on surfaces that is not visible to the naked eye. Typically, particulate contamination in the range of 50 microns or larger in size can be seen with a visual inspection. When our goal is to clean at that level, we are dealing with what is termed "gross contamination" . This type of cleaning is performed prior to micro cleaning, usually after moving equipment, installing new equipment, or performing maintenance in the controlled environment.
After removing the visible particles, we need to remove particulate contamination at the level of .3 to .5 microns, as well as identify the bioburden (if any), adhering to industry stringent cleaning techniques.
Removing contamination that we can not see is more difficult to achieve because of electrostatic charges, ionic attraction, adhesion, and entrapment. Following strict protocols ensures that particles are removed and the room's maximum potential is realized.
Controlling bioburden in controlled environments is complex and labor intensive. But, it can be achieved with teamwork, periodic maintenance, cleaning techniques, and training of personnel in order to limit the amount of contamination being generated or brought into the cleanroom.