There are many factors to consider for the proper maintenance of your cleanroom and its equipment and supplies. Before any cleaning is done, make sure you are using the correct cleaning equipment, supplies, procedures, and knowledgeable staff. Each class of cleanroom has its own specific cleaning equipment and solvents. Use lint-free, disposable mop heads, non-shedding wipes, plastic or stainless steel buckets, and HEPA filter vacuums. Improper cleaning tools easily introduce microorganisms into the environment, resulting in the contamination of your cleanroom.
Once you have the proper cleaning equipment, you need a well-trained and educated cleaning staff to implement the proper protocols and procedures for a successful, robust cleaning program. Establish standard operational procedures (SOPs). Train your personnel in proper cleanroom protocol and disciplines, restricting items due to their contamination generating properties. Establish and maintain a good housekeeping and preventative maintenance program to incorporate the work areas, as well as the cleanroom ceiling, walls, floors, and equipment. Establish and maintain an ongoing monitoring program for both viable/non-viable and ESD. These will be indicators of how well your area is doing and alert you to any negatives that occur. Make sure to create a checklist so that nothing is overlooked.
Your cleaning staff has to have a basic understanding of how the cleaning should be done and in what order and fashion. Always empty the trash container first. Clean all general purpose equipment outside of the cleanroom and then cover with clean bagging material. All small metallic and nonmetallic items must be cleaned with ultrasonic cleaners and inspected for any obvious signs of contamination. Use all sanitizers in the proper amounts, methods, and for the specific allotted time. Use extra caution when cleaning the delicate ceiling HEPA filters. Failure to adhere to these basic principles will increase the amount of contaminants. Cleanrooms are classified according to the number and size of particles permitted per volume of air, and 0.5 micron particles are the most commonly measured size. These counts are directly linked to the bacterial contamination levels.
There are four main aspects to a cleanroom, which require very specific, routine cleaning processes: the ceilings, walls, surfaces, and floors. Each is cleaned in a very particular manner to maintain its classification.
The ceiling should be cleaned from the top down using extended handle tacky rollers. In some cases it may be necessary to wet mop the ceiling with a self-wringing sponge or a flat mop, each having extendable handles. Occasionally, vacuum systems equipped with HEPA filters are used. Always use the proper blends of compatible solvents, such as DI water and Isopropyl alcohol, cleanroom compatible cleaners, and disinfectants.
When cleaning the cleanroom walls, using the hand wiping method is often the most effective. It’s recommended to use a dry, lint-free nonwoven or polyester knit cleanroom wipe, which if needed can be combined with solvents. These are best for being extremely low in particle generation and chemical extractables.
Typically, most of your cleanroom surfaces are cleaned using hand wipes. Consider implementing wipe dispensers to make the storage and distribution of wipes easy while eliminating waste and cross contamination. The use of pre-saturated wipes with a blend of 70% Isopropyl alcohol and 30% deionized water is very effective when wet cleaning is necessary. If static charge is a concern, ESD wipes employ carbon fibers within the knit fabric which undergoes a multitude of special processes that include cleaning, scouring, cutting, and a special cleaning process.
The same rules apply for cleaning floors as they do for the ceilings, except an edgeless string mop can be used. For these mopping systems, an autoclavable bucket and wringer is highly recommended.
In conclusion, the proper cleaning procedures and products used to disinfect your cleanroom are the key to maintaining compliance. The staff and all who are associated with your cleanroom can greatly impact the contamination levels and therefore need to exercise all cleaning practices and, most importantly, maintain proper cleanroom programs to ensure the overall operation.
While we have provided you with advice, tips, and suggestions, these are just considered common practices. Always remember each organization has its own protocols, procedures, and regulations based on their individual controlled environment specifications.
Kristyn Henke is Advertising Coordinator for Hutchins & Hutchins Inc., a provider of cleanroom equipment, supplies, and consulting. www.yourcleanroomsupplier.com
This article appeared in the May 2014 issue of Controlled Environments.