Some cleanroom industries rely on a subjective, aesthetic evaluation of the cleanroom garment or number of launder cycles for replacement. Most cleanroom garment laundries have validated their processes for at least 100 launder cycles for the cleanroom garments they supply to the cleanroom industry. However, I recommend an objective testing of the cleanroom garment and fabric as well as establishing the efficacy of particle entrapment, the lack of particle shedding, and ESD efficacy as the criteria for replacement.
Since 2003, the IEST-recommended practice IEST-RP0CC003.3 has recommended specifications for clean-room fabrics, garment design, garment laundering, and testing of the cleanroom garments over time. The integrity and durability of cleanroom fabrics and design of clean-room garments have significantly improved in the last ten years. The laundering and testing of the cleanroom garments has been standardized.
The Helmke Tumble test evaluates the entire garment for shedding of particles from 0.3 µm to 10 µm. The specifications for Category I cleanliness is less than 1,200 particles at 0.5 µm and greater, cumulative, per feet per minute.
The same tests used to evaluate the cleanroom fabric can also be used to determine if and when the cleanroom garment should be replaced.
A percentage of change from the original test data can be an objective criterion to determine the replacement of the cleanroom garment.
In summary, most cleanroom garments will last longer than and are meeting the particle specifications of IEST-RP-CC003.3 and ASTM F-51 in real-time use after more than the validated 100 launder cycles when laundered per IEST-RP-CC003.3. There are typically 17 process cycles in one calendar year. Therefore, the cleanroom garments should be functional over six years of typical cleanroom use providing the employees wearing the clean-room garments are consistently adhering to accepted cleanroom protocol. The repair of clean-room garments must be performed as specified by the fabric and/or garment manufacturer to guarantee the efficacy and durability of the repair.
The cleanroom, the products, and the processes inside the cleanroom should not be compromised if the cleanroom garments are meeting the above specifications for both viable and non-viable particle containment/shedding, ionic contamination, and ESD and are physically in good repair per the above criteria. Therefore, I recommend replacing the cleanroom garments when one component of the above criteria fails.
From: “Ask Jan: When Should Cleanroom Garments be Replaced”
