Preventing Cross-Contamination

Prior to introducing any improvements, it is imperative that all parties involved understand the current process, its expectations and deficiencies, and establish realistic improvement goals and benchmarks. Total commitment from decision makers and key managers is required prior to implementation of any program improvements. A master plan should be created that establishes the parameters of the current manufacturing process, establishes the specific change criteria, benchmarks the monitoring of the change process, and identifies parameters expected with the completion of these improvements. Additionally, a comprehensive training and implementation plan will allow all parties to observe and analyze the progress.
There are several components that affect the level of control of contamination. However, there are basically two significant options for improvements to increase your level of contamination control – control the environment and/or control the people working in the environment.
Of all the components in cleanrooms and controlled environments, people contribute the greatest amount of contamination, yet the people in the cleanroom and controlled environment have the ability to exercise the greatest amount of control over the environment. The most significant improvement would be to train the people working in the controlled environment in contamination control practices and procedures and encapsulate the people in reuseable cleanroom garments.
Tech suits or building suits (100% polyester, long-sleeved shirts and pants) are recommended undergarments for ISO Class 3, 4, and 5 cleanrooms under the cleanroom compatible coveralls, hoods, and boots. Additionally, the advancement in weaving technology has produced undergarment fabrics with reduced pore size equal to that of cleanroom fabrics used for coveralls, hoods, and boots. Therefore the 100% polyester, long-sleeved shirts and pants are suitable for wearing in ISO Class 6, 7, and 8 cleanrooms with and/or without additional cleanroom garments. These shirts and pants are extremely comfortable. Some undergarment fabrics have a carbon thread stripe that imparts static dissipation to the fabric. Therefore, companies achieve better compliance in contamination control practices when personnel wear them rather than street clothes covered by 100% polyester frocks or lab coats.
The contamination control industry recommends removing street clothes in assigned locker rooms and donning cleanroom tech suits. Personnel can then don shoe covers and bouf-fants when entering either the ISO Class 7 or 8 cleanroom areas. To prevent cross contamination between the ISO Class 7 and 8 cleanrooms, a frock may also be donned over the tech suit to be worn only in the ISO Class 7 cleanroom area. The aseptic ISO Class 5 room requires sterile gloves, coveralls, hoods, and boots to be donned prior to entering the sterile cleanroom area.
After training manufacturing personnel in contamination control theory, the next step is the evaluation of the implementation of the training and auditing for compliance. A written test may serve as objective evidence of attendance and knowledge base. However, observation of daily execution of the contamination control principles and routine test data of viable and non-viable particle counts of the personnel, air, and surfaces of the controlled space versus the certified clean-room is the recommended objective evidence when auditing for compliance