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by Brad Whitsel
The goal of business is to make a profit. In my many years of involvement in particle and microbial management, I have observed countless missed opportunities to increase product yield at very little to no cost. In virtually every case, the missing ingredient was not some costly machine or sophisticated technology; it was common sense.
Many examples come to mind. Perhaps the foremost is cleanroom operatives who are poorly trained and simply have not been made to understand the consequences of their actions and behaviors in the cleanroom. In this case, management has failed to explain the impact of humans on the product or process in ways that can be visualized and understood. Other examples include apparel storage facilities that are so primitive as to virtually assure continued contamination of cleanroom garments while not in use, or cleanrooms that are simply misused in such a way as to harm the process or product, or garments that are inappropriate to the application.
All of these cases involve a failure on the part of management to address what are really common-sense matters, and, in virtually every case, a little common sense could significantly increase product yield.
Another issue that is vexing at best regards the matter of how many fresh changes of garments companies provide their cleanroom employees with on a weekly basis. Cleanroom apparel service companies are called upon to produce excruciating levels of garment cleanliness for their customers. They are often directed to use highly polished water, non-ionic chemistry, multiple 18+ megohm deionized rinses, dryers fitted with ULPA filters and special packaging. They must operate sophisticated high classification cleanrooms. They are required to provide elaborate apparel cleanliness test data, execute SPCs, operate to a quality management system and maintain mountains of documentation to support product cleanliness and reliability. More often than not, the customer then receives this sparkling garment and directs the cleanroom operative to wear it for up to five days.
I have never been able to understand this endemic failing of common sense.
While the latest generation of technical fabrics has indeed addressed this curious issue of extended wear cycles, there is simply no substitute for responsible change frequency when it comes to in-use performance. A liquid repellant finish addresses the matter of severe soiling and makes cleaning easier, which helps prevent premature aging due to excessive soiling.
It does not reduce the particles shed by the wearer. An antimicrobial finish can help control garment odor and minimize bioburden and biopermeation. Unfortunately, it does not limit microbiological growth in the amplification zone—the area between the human and the barrier fabric. These sophisticated barrier fabrics, while providing unprecedented performance, do not eliminate the need to furnish cleanroom operatives fresh garments more than once or twice a week.
The human clothed in cleanroom apparel is shedding massive amounts of proteinaceous material into a moist and warm environment, the human micro-environment or zone within the protective envelope. These are the perfect conditions for microbiological growth. In fact, some individuals, because of shortcomings in their own personal hygiene or perhaps for biological reasons, will affect the work environment, perhaps even to their own embarrassment, when required to wear the same cleanroom garment for multiple days.
Now, factor into this bioplasma millions of particles and fibers and then try to imagine donning and doffing this same garment multiple times without grossly contaminating the exterior of the garment. It really can't be done.
Aseptic cleanroom operations and microelectronics manufacturing are examples where multiple weekly or daily changes are commonplace. In aseptic operations, for instance, workers change on each entry. Studies have shown that significant increases in product yield result when fresh garments are furnished to cleanroom personnel with greater frequency. In these cases, cleanroom apparel service providers are justifiably held to the highest standards. The overwhelming majority of cleanroom operations, however, suffer from the one-change-a-week syndrome, and while many of these also hold the cleanroom apparel service provider to the highest standards, it's usually more a matter of arrogance than need.
Keeping apparel costs down by changing only once or twice per week is a tactic without strategy; it is shortsighted and counterproductive. Beyond performance issues, much of what a company sets out to achieve in terms of worker morale and motivation is lost when an employee is made to wear apparel that, after several days use, is soiled, odorous and limp. This simply does not articulate the notions of cleanliness in the workplace and attention to detail, the key element of a successful cleanroom operation.
Even the best cleanroom garments lose effectiveness with frequent donning and doffing. In fact, initial garment cleanliness is a purely academic matter after a garment has been worn for several hours. Rather than making unreasonable cleanliness demands on the cleanroom apparel service provider, it would be far more productive to work with them to find that incremental increase in product yield. Perhaps one solution is increased frequency of change. It could be a great investment, improving profitability and worker morale.
It's a matter of common sense.
Brad Whitsel is President of Whitsel Associates Inc., a project management and consulting firm formed in 1986. A graduate of Penn State University, he has been involved in many aspects of microcontamination control since 1975. His experience includes engineering and cleanroom design, contamination control and sales training, marketing and management. Whitsel is an active member of several industry trade associations and is on the Editorial Advisory Board of the Journal of the Institute of Environmental Sciences and Technology.