Friday, December 16, 2011

Superfluous or Essential: Part 2

In the first installment, we discussed how to avoid superfluous materials and activities in cleanrooms. To accompany our inspiration of a man dressed for success in cholera prevention, we present his fashion-plate companion (Figure1).1* We now know much more not only about how to protect people from contaminants; we are also cognizant of steps needed to protect critical product from contamination by employees. People are a major source of contamination in the cleanroom. Those of us who are involved in manufacturing high value product can recount horrific and/or amusing stories about cleanroom “discipline” or the lack thereof. That is a topic for another column (or perhaps even a book).
“My background is in manufacturing, so I am very conscious that we utilize people to their best advantage. Making them spend their day doing unnecessary tasks may not be the best use of their time,” says Kelly Barton, Senior Sales Engineer at Clean Rooms West, Inc. in Tustin, California.
Image 1
Gowning procedures are exacting, complex, and are often required for product protection.
As Barton explains, even where air showers are considered prudent, workflow and personnel practices should be considered. “I have observed operators gowning with full coverage bunny suits that were processed in a Class 10 cleanroom laundry. They then step into an air shower to blow them off. Blow off what? After the air shower, they go into a Class 10,000 or higher class environment. This is a waste of money and of valuable production time.”
As an example, says Barton, “Consider a facility assembling product in a Class 100,000 cleanroom to minimize visible contamination. They require employees to use full bunny suits as well as to go through a 15 minute gowning procedure and a 15 minute exit procedure. Once you enter the cleanroom, you see broken drywall and bare concrete. The environment is causing the problem, not the people.”
Scott Mackler, Founder and Principal at Cleanroom Consulting LLC in Pittsford, New York, suggests that setting the gowning protocol according to the cleanroom classification rather than the workflow is na├»ve. Mackler advises that manufacturers establish the rationale for cleanroom activities. “Why clean but not verify? Why wear a bunny suit when a smock will do?”
We have observed that most cleanroom employees are fairly intelligent. We strongly suspect that, in at least some instances, the lack of cleanroom discipline may be symptomatic not of laziness, not a desire to destroy product, and not a desire to vex the supervisor. At least part of the lack of cleanroom discipline may be due to suboptimal cleanroom design and/or to incorrect process flow. If employees are asked to jump through arbitrary, unnecessary hoops in the name of “discipline” while the facilities or process contribute to contamination, they may be more likely to take shortcuts.
On the other hand, in the previous column, Kraft commented on the psychological effect of air showers. Keith Weber, Vice President of Engineering at Clean Rooms International Inc. in Grand Rapids, Michigan, recounts the rationale used by a manufacturing plant to justify the protocol at a rather large unclassified cleanroom. While it was not built to a specific classification, it was much cleaner than a typical office or manufacturing environment. Lab coats, hairnets, and the use of shoe scrubbers and tacky mats were required. “After a walk through,” recalls Weber, “I talked to the facility manager to question what appeared to be a waste of company assets. Her response was valid and insightful. She understood the room did not require this level of cleanroom protocol. Her goal was to make it visibly clear that the room was designated for special activities, that the room was off-limits to the general workforce. She felt that it was much easier to enforce well-defined rules than to have a system where the employees ‘should not’ enter the cleanroom with food or drink or ‘avoid’ tracking in mud.”
An initial capital investment that minimizes operator error may be prudent. Barton views a central vacuum system as one such example. “I’ve seen it many times, where a person assigned to clean the cleanroom only accomplishes moving the dirt from one point to another. Detailed cleaning takes concentration, dedication, and consistency. A central vacuum improves the operator’s chance of removing contamination every time he cleans. It also helps to provide a more consistent cleaning system for inconsistent cleaning people.”
“Who wants to hear from an expert that you need to spend more money? Maybe you need an expert to help you see how little to spend and where to spend it to get the most bang for your buck!” suggests Mackler. As might be suspected, the search for the non-superfluous cleanroom is ongoing; and the correct approach is process-specific and site specific.
Are cleanrooms a “do it yourself project?” Not completely. We suggest you work with appropriate experts in the design, operation, and ongoing monitoring2 of controlled environments and that you find experts who are also dispassionate advisers. We also suggest that you have to be involved, and that you take all recommendations with a grain of salt. Controlled environments are best thought of as part of a process, not as safeguards or window dressing. As the manufacturer, you are the one best suited to make the final decision.
  1. From “Dirt,” an exhibit at the Wellcome Collection, London, UK (2011); we thank Anselm Kuhn, from Finishing Publications, for suggesting this exhibit to us.
  2. R. Kraft, “Point of View–The Importance of Ongoing Facility Monitoring,” Controlled Environments Magazine, June 2011.

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