The ignorance factor

It's easy to take a cleanroom for granted. The contractor has just completed your cleanroom. He has done a thorough clean-up and tested and certified it “as built.” Now you are ready to occupy this space and begin manufacturing, so you can get a return on this investment.

Some people maintain that this is the cleanest day in your cleanroom's life. From this day forward, your pristine clean space will be constantly contaminated by people, processes, materials maintenance and ignorance.

In today's sophisticated cleanroom environment, if you have purchased good quality air handling equipment, quality HEPA or ULPA filters, and insisted on good cleanroom design, your air supply should not be a source of contamination. Maintenance will ensure the life of your air handling system for 20 or more years. But maintenance is not cheap. Good maintenance is just smart business insurance. Practice poor maintenance at your own peril. We see this everyday in the cleanroom community. It is part of the “ignorance factor.”

Many people assume that because a cleanroom has been tested and certified, it will be clean until the next test and certification a year later. Unfortunately, the room is only as good as its test at the exact time the test was taken. Five minutes later, all hell can break loose. Production people occupy the space. Materials are moved in. Process machinery is started. Management walks in for a quick check. A cleaning crew comes in. The maintenance staff comes by. There is a power failure.

Others assume that because they constantly monitor their cleanroom conditions for particle count, pressure difference, temperature and relative humidity, the cleanroom must be clean. Constant monitoring is an excellent tool for providing real-time data, assessing problems, anticipating potential contamination and helping to autopsy a failure after the fact.

But constant monitoring is only a tool. It is not a contamination control panacea. You must pay attention to all potential contamination sources, including areas of the clean space not close to the constant monitoring pick-up points. People can fool a particle counter; so too can a particle counter fool people. Another “ignorance factor” potential.

Then there are those who say, “of course, [the product] is clean. It just came through the air shower.” Air shower effectiveness is one of the most controversial subjects in the cleanroom community. There are those who swear by them. There are just as many who say they are a waste of money. As in all aspects of the cleanroom business the old adage “let the buyer beware” is true. Do not succumb to the “ignorance factor.”

Another expensive choice is the value of a perforated raised floor. Does it guarantee cleanliness? Does it guarantee laminarity of airflow? Does anyone ever clean this space? It is amazing how many cleanroom owners figure the area under their raised floor is just a giant vacuum cleaner bag. We have witnessed countless abuses of this critical area. Perforated raised floors are extremely valuable, particularly for ISO Class 5 and cleaner rooms. The laminarity, speed, direction and pattern of clean air flow can be enhanced or adversely affected by process equipment location and work flow arrangements. Again, do not get caught by the “ignorance factor.”

“Anybody can clean a cleanroom. It is just a glorified janitorial job with clean buckets, special mops and non-shedding wipes.” Couple those comments with a lack of proper contamination control training, and you are on a slippery slope. It takes special skills to clean a cleanroom properly.

People have to be trained for this job. It does not just happen. Because cleaning staffs are subject to high turnover rates, training must be continuous. Video-based training is ideal for this, along with ever vigilant on-the-job training and supervision.

Some people continue to use portable non-HEPA vacuum cleaners in cleanrooms. Their theory is because they are vacuuming clean air, they are just putting this clean air back into the room. Whoa! Why vacuum clean? To pick up contaminants, right? Why re-entrain these same contaminants back into the cleanroom air? All vacuuming should be done with either a portable HEPA-equipped vacuum cleaner or with a central system where the discharge air is located outside the clean space.

Constant vigilance is required for achieving and maintaining cleanroom cleanliness. Cleanroom cleanliness is common sense applied every day. Relax this attitude and you lose out to the “ignorance factor.” Here are some examples.

  • I recently visited a Class 10,000 cleanroom that was experiencing higher than normal counts. Housekeeping in the immediate area of their critical fill process was acceptable. However, the product containers prior to filling came from outside the cleanroom, and were not wiped down before filling. The pre-fill holding area had the same quality air as the parking lot.

    Inside this same cleanroom care and attention was paid to critical production equipment. Yet the return air grilles located about 30 feet away from this equipment had not been cleaned for years. The owner said they did not need to be cleaned because they were away from the critical area and beside that was return air. These grilles were coated with a 1/16- to 1/8-inch film of dirt. Explaining the flaws in this customer's thinking was a delicate part of the job.

  • In a Class 100 room a client used the area under his raised floor as a catch basin. When asked how often this area was cleaned, his response was, “Not since I've been here.” By the way, his room was no longer maintaining Class 100 conditions. Two of his ceiling HEPA filters were punctured.

  • On a visit to a Class 100 laminar flow hospital operating room, the customer complained of particle count problems. This particular room had just been thoroughly cleaned and then sterilized by ultraviolet light for four hours. Mounted about nine feet up on one wall was a round clock. On top of this clock was a layer of fine green lint from the surgical garment and surgical drape materials.

    When quality care is lacking, an owner only shortchanges himself, his customers and his employees.

    Ignorance is not bliss, it is expensive.

    Richard A. Matthews is founder of Filtration Technology Inc. (Greensboro, NC) and president of Micron Video International. He is chairman of the International Organization for Standardization Technical Committee ISO/TC 209 “Cleanrooms and associated clean environments,” and past president of the Institute of Environmental Sciences and Technology. He is on the CleanRooms Editorial Advisory Board.


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