Our company currently manufactures in a controlled environment but not a cleanroom environment. What improvements can we make to increase our level of contamination control?
PRIOR TO INTRODUCING any improvements, it is imperative that all parties involved understand the current process and its deficiencies and establish realistic improvement goals and benchmarks. Total commitment from decision makers and key managers is required prior to implementation of any improvements. A master plan should be created that establishes the parameters of the current manufacturing process, establishes the specific change criteria, benchmarks monitoring the change process, and identifies parameters expected with completion of the 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.
The first improvement would be to evaluate the critical points of the clean manufacturing process. The international standard, ISO 14644-4, “Cleanrooms and Associated Controlled Environments – Part 4: Design” will provide information in methods to encapsulate the controlled environment, increase the level of HEPA filtration and build and validate a certified cleanroom environment. This may require a significant capital investment.
Of all the components in cleanrooms and controlled environments, the people contribute the greatest amount of contamination, yet the people in the cleanroom and controlled environment have the ability to exercise greatest amount of control over the environment. The second improvement would be to train the people working in the controlled environment in contamination control practices and procedures and encapsulate the people in cleanroom garments.
There are several resources for information to train personnel in contamination control practices and procedures. The International Standard, ISO 14644-5 “Cleanrooms and Associated Controlled Environments – Part 5: Operations” establishes the international requirements for all manufacturing in cleanrooms and controlled environments. The Institute of Environmental Sciences and Technology recommended practices in contamination control are good resources of information to achieve the prescribed requirements of the international standard. Specifically, the recommended practice to train cleanroom personnel on behavior in the cleanroom is IEST-RP-CC027.1, “Personnel, Practices and Procedures in Cleanrooms and Controlled Environments.” Additionally, encapsulating the people working in the environment in cleanroom garments will increase the level of contamination control. The IEST recommended practice, IEST-RP-CC003.3, “Garment Considerations for Cleanrooms and Other Controlled Environments” table of recommended garment configurations is a good reference for the appropriate type of garments for different air classifications required to control contamination for your application. This table also recommends the frequency of the changeof the 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.
After training manufacturing personnel in contamination control theory, the next step is 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 cleanroom is the recommended objective evidence when auditing forcompliance.
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