Are you aware that incorrect materials transfer could pose one of the biggest potential sources of contamination within a cleanroom? How many of you can say that while performing the transfer of materials into the cleanroom environment you are fully aware of your actions, practices, and methods?
KEEP THE PRODUCT CLEAN
Paperwork, raw materials for manufacturing the product, tools, and equipment must be successfully transferred to the cleanroom. The goal of a materials transfer program is to keep contamination from the outside world from entering the cleanroom. Benefits of investing effort in a materials transfer program include higher quality product, lower costs, and an enhanced competitive position.
Some materials are double bagged, some single bagged, and may be stored for long periods of time in cardboard boxes in warehouse environments. Other materials such as tools may not be bagged at all and are likely to have come from an uncontrolled environment.
Contamination control protocols for material transfer are vital. Materials brought into the cleanroom that have not been cleaned effectively during the transfer process are an immense source of particulate and thin film contamination. Inadequately cleaned materials can be a huge source of spore forming bacteria, extremely resistant bugs that are very difficult to eradicate from a cleanroom environment. Manufacturers of all critical product should be concerned about the impact of biological contamination, not just those producing medical devices and pharmaceuticals. Many people are not aware that biological contamination will dramatically affect particulate counts which are required in every cleanroom industry. At the same time, sterility is not enough; “dead dirt” can wreck havoc with critical devices. Water soluble lubricants and near-neutral pH processes can provide water, warmth, and nutrients, a favourable environment for biological contamination.
ROOM DESIGN
Materials transfer may be through a hatch leading directly from an unmonitored manufacturing area to a cleanroom or a transfer hatch between two cleanrooms. Is this an optimal arrangement for your process? With a hatch, employees are tempted to stand on either side, engaging in lively conversation, even enjoying their morning coffee. Such behaviour increases the likelihood of contamination. For new construction, consider a material transfer room.
Material transfer rooms should function like gowning rooms with a ‘clean’ side and a ‘dirty’ side. Very often a line of tape separates these areas. In practice, a “line in the sand,” does not keep personnel from crossing over to the ‘clean’ side inadequately gowned or in street clothes. Too often we see issues with high levels of contamination on the ‘clean’ side of the material transfer room where the root cause is the ‘dirty’ side.
Rather than a strip of tape, consider an “étagère,” a physical barrier such as racking or cabinets that allows expedited transfer of materials while discouraging personnel movement to the clean side. If racking or cabinets are on wheels, it is simple to move them to allow access of large equipment or bulky materials. Of course, because such barriers are not physically distinct rooms, the dirty side of the transfer room should also be fairly clean.
CONVENIENCE
Cleaning materials within the transfer area must be convenient. A wipe down station should always be visible in the material transfer room with a low-residue cleaning agent such as isopropyl alcohol (IPA) and low-lint wipes readily accessible. If there is a hatch rather than a room, consider wipe down stations immediately before and immediately after transfer. If no wipe down station is present, there is the temptation for personnel to pass material in without cleaning it.
TRANSFER VERSUS GOWNING
The changing/gowning areas should not be used for wiping down and transferring materials to avoid potential contamination of personnel and cleanroom clothing. Good practice within a cleanroom should generally allow clean materials to come in one way and used materials to exit by another area.
STAY TUNED
In Part 2, we will discuss techniques for cleaning during transfer, managing bulky materials, and automation.
Dr. Kevina O’Donoghue, is a Microbiologist at Specialized Sterile Environments, Galway, Ireland. She can be reached at kevina@cleanrooms.ie.
Barbara Kanegsberg and Ed Kanegsberg, “the Cleaning Lady and the Rocket Scientist,” are independent consultants in critical and precision cleaning, surface preparation, and contamination control. They are the editors of The Handbook for Critical Cleaning, CRC Press. Contact them at BFK Solutions LLC., 310-459-3614; info@bfksolutions.com; www.bfksolutions.com.
