Question: I am trying to better understand the product requirements specific to cleanroom apparel in the sterile and non-sterile pharmaceutical segments, globally. I have listed some specific questions that I have.

Answer: I always recommend turning to Institute of Environmental Sciences and Technology (IEST) documentation on a cleanroom subject. The IEST recently published the latest revision of IEST-RP-CC003.3, "Garment Considerations for Cleanrooms and Other Controlled Environments" in 2003. It outlines all aspects of cleanroom garment systems including the recommended components and construction of cleanroom garments and testing of the apparel used in cleanrooms.

Q: What are the specifications (test threshold) that must be reported for apparel in order to be considered for cleanrooms in the United States? Asia? Europe? Rest of the World (ROW)? For example, is there a specific particle size that must be reported for Gelbo or Helmke tumble testing?

A: The most important, universal specification for cleanroom apparel is that it is appropriate to protect the cleanroom process or product manufactured in the cleanroom and that it is always worn correctly.

There are several recommended tests for cleanroom apparel listed in IEST-RP-CC003.3. In addition to the Helmke tumble test, the body box test specifically addresses the particle filtration containment of the full garment system in a 100% HEPA (or ULPA) filtered environment. The releasable large particles test, similar to the method outlined in ASTM F-51 Appendix X1, evaluates the fabric of the cleanroom garment microscopically (100X) for fibers and larger particles (5 microns and greater). The microbial penetration test assesses the garment fabric’s ability in preventing penetration of both viable and non-viable particles. The combination of the results of all these tests provides a comprehensive evaluation of the barrier and shedding properties of the cleanroom fabric or garments.

There are many associations worldwide recommending tests for non-woven and disposable products including INDA (United States), EDANA (Europe), and ISO (international). However, none of these groups set criteria for material consideration in cleanrooms. For example, the Gelbo test is a method described in INDA IST 160.1 1995, EDANA Method 220.0 1996 and ISO 9073-10-2003 (each method being slightly different but with the same basic approach), yet none of these tests contain specifications for cleanroom apparel for use in certified cleanroomclassifications.

Only IEST-RP-CC003.3 recommends that apparel used in cleanrooms meet Category I particle cleanliness derived from the Helmke tumble test. The classification table describes cleanliness categories in size ranges of 0.3 microns and 0.5 microns.

Both the ISO 9073-10-2003 and IEST-RP-CC003.3 documents stress ranking of all results to create more reproducible data. The IEST-RP-CC003.3 Working Group performed a statistical, round robin Helmke tumble test in 1999 and established the ranking of woven garments into categories I, II, and III at both 0.3 and 0.5 microns per cubic-foot-minute of air cumulative. (Refer to IEST Journal articles, “Improving the Repeatability and Reproducibility of the Helmke Drum Test Method” and “The Size Distribution of Particles Released by Garments During Helmke Drum Tests”, Journal of the IEST 44, no.44 (Fall 2001)).

For more detailed information and discussion comparing both tests, please attend the technical session describing the similarities and differences of these tests at ESTECH 2006 in Phoenix, AZ in May 2006.

Q: For disposable apparel, what are the general tests that are completed in the U.S.? Asia? Europe? Rest of the World (ROW)? e.g. grab tensile, tongue tear, seam strength, Gelbo, Helmke Drum, hydrohead, MVTR.

A: The tests performed on disposable cleanroom apparel manufactured in the U.S. are similar to the tests performed on all reusable fabrics manufactured worldwide. Some of the most common tests and the standards applicable to those tests are:

• Weight ASTM-D-3776
• Thickness ASTM-D-1777
• Grab Tensile ASTM-D-1682
• MVTR ASTM-E-96B
• Air Permeability ASTM-D-737
• Pore Size Coulter porometer
• Suter Hydrostatic AATCC-127
• Flammability 16CFRPart 1610 or NFPA 70E
• Surface Resistivity ASTM-D-257 or AATCC-76
• Static Decay FTM 4046
• Bacterial Filtration Modified Ford Peterson

Method Efficiency or IEST-RP-CC003.3 Section

Additionally, some cleanroom fabric manufacturers have created “in house” testmethods.

Q: What are the ESD tests required? e.g. static decay @ 90%, surface resistivity@ 25% RH? Others?

A: The most common ESD tests required for cleanroom fabric and apparel are:

• Static Decay FTM 4046
• Surface Resistivity ASTM-D-257
• Surface Resistance @ 50%RH ESD STD 2.1.

Additional ESD testing may be specified in the scope of work in a customer’s contract based on the protection of the product or process in the cleanroom.

Q: What SAL (Sterility Assurance Level) is typically required?

A: All cleanroom materials used in sterile cleanroom manufacturing must undergo a quarterly dose audit test and be validated for sterility assurance levels using ANSI/AAMI/ISO 11137 - 1994 “Sterilization of Health Care Products - Requirements for Validation and Routine Control – Radiation Sterilization” and ANSI/AAMI/ ISO 11737-1-1995 “Sterilization of Medical Devices - Microbiological Methods - Part 1: Estimation of Population of Microorganisms on Products” if the sterilization method is gamma or e-beam radiation.

Typically an FDA regulated manufacturer that is producing a product in an aseptic cleanroom with a final product sterility level of 10-6 SAL will specify that all materials required during the manufacturing process be validated and certified sterility to 10-6 SAL. However, an FDA regulated, terminally sterilized, non-implantable medical device manufacturer in a non- sterile cleanroom may specify that all cleanroom materials used in the process be validated and certified sterility to 10-3 SAL.

It is in the best interest of the cleanroom materials manufacturer to reduce the average device bioburden levels during the manufacturing process, to in turn reduce the level of gamma radiation required to terminally sterilize the product to the sterility assurance level required by the customer. It is also most cost effective to radiate the manufactured materials to the same sterility assurance level. Therefore most suppliers of sterile cleanroom materials validate their processes to deliver sterile cleanroom reusable or disposable materials at 10-6 SAL to serve a broader, universal market.

The ISO 14698-1&2, Cleanrooms and Associated Controlled Environments - Biocontamination Control, Part 1: General Principles and Methods and Part 2: Evaluation and Interpretation of Biocontamination Data and the recently published IEST recommended practice IEST-RP-CC023.2 “Microorganisms in Cleanrooms” addresses recommendations for garment sterility.

Q: What unmet needs are there for apparel?

A: There are as many unmet needs for cleanroom apparel as there are products and processes performed in cleanrooms. As nanotechnology expands worldwide and the geometries of cleanroom manufactured products reduce, the control of potential viable and non-viable contamination will increase. The safety and security of food and food products will increase the demand for cleanroom apparel world-wide. The use of sterile and non-sterile cleanroom apparel is one method of controlling contamination in a cost effective manner.

Q: What is preferred, reusable or disposable apparel? Why?

A: The decision to use reusable or disposable apparel is based on several factors such as:

• Product manufactured
• Process used during manufacturing
• Ability of the cleanroom garment laundry to service the customer with reusable garments
• The number of garments required during cleanroom manufacturing

Disposable apparel is used during cleanroom manufacturing of toxic or biohazardous products or if the process uses hazardous chemicals such as acids or alkali. Disposable apparel is used if a reusable garment system and service is not readily available or the limited number of garments required for the cleanroom manufacturing application does not make the use of reusable cleanroom garments cost effective. Reusable garments are preferred in all other cleanroom manufacturing applications.

(For more information, please refer to my “ASK JAN” column, “Changing from Disposable to Reusable,” A2C2 Magazine, Vol. 7, No.11, (November, 2004), p. 31.)