Do you know what the number one source of cleanroom contamination is? According to the National Environmental Balancing Bureau (NEBB) report, 70-80% cleanroom contamination is operator based. Therefore, the number one source of contamination in your controlled environment is your operators. Let’s examine the why and how.
The four main issues causing the operators to be the primary source of your cleanroom contamination are: hygiene, street clothing (undergarments), residual smoke, & attitude.
goes without saying that if you do not have a clean face and hands, you are going to have loose skin, dandruff, hair follicles, and the like that will migrate out. Moreover, despite the fact that cosmetics are not permitted in a clean room, the number one source of trace extractables is titanium oxide. This is the most common material blended into make-up.
It is very important your operators have consistent hygiene practices. Hand and faces must be thoroughly washed, and no excess lotion or makeup on them. In order to prevent cross contamination from the natural particle shedding that occurs from the body, make sure your operators are fully gowned in appropriate apparel (garment, bouffant cap, hood, beard cover & facemask) and cleanroom glove. Ensure that the glove length, and garment cuff design stays in place during arm extensions. If the glove cuff is too short, a “naked cuff” will be exposed permitting operator particle shedding.
The next issue is, "What are your operators’ undergarments?" You may not pay much attention about it, but it matters what your operators are actually wearing under their controlled environment garments. Make sure the undergarments are made of low lint materials.
Any type of flannel, suede, sweat shirt, or velour material should be avoided. These materials have many loose fibers. If your operator is wearing undergarments made of these materials, the loose fibers will migrate out through the neck, open sleeves, and ankles, which will end up increasing particles in your controlled environment. To minimize contaminants from your undergarment, make sure to cover your neck, open sleeves and ankles with proper cleanroom apparel, using hood to cover the neck, wearing gloves over the cuff, and use proper shoe covers to cover the ankles.
3. Residual Smoke
Another overlooked issue is residual smoke. If operators smoke during breaks or lunch, when they come back into the controlled environment, the residual smoke in their lungs will emit into the critical environment. It is important to have them gargle or rinse their mouth out. Facemasks should always be used to prevent other microbe-carrying particles from being emitted into the controlled environment.
Finally, the most difficult aspect of cleanroom contamination control is the operator’s attitude. You want assurance your operators understand the "why" behind the best practices and protocols within the controlled environment. Making sure that your operators have a good foundation for understanding what their best practices should look like is mission critical. Involve them in the process of controlling contamination. Your production leads need to become internal advocates to monitor and maintain best practices. Benchmark and publically post your cleanliness levels, and encourage operators to suggest process change improvements.
Working in a controlled environment is challenging. With limited access, restrictive garments, no windows, an often repetitious work, there is a natural tendency for operator to deviate from the norm. In order to minimize the contamination caused by your operators, it is important to have them aware and understand the above mentioned issues, in addition to provide them with suitable cleanroom consumables and proper instructions before entering into the cleanroom area.
Valutek provides a free controlled environment garment guideline that will assist you with preparing the suitable cleanroom apparel for your specific controlled environment.