New ISO standard defines design criteria for separative devices
02/01/2005
ROLLING MEADOWS, Ill.-In hopes of defining how separative devices differ from a cleanroom, ISO 14644-7, Cleanrooms and associated controlled environments-Part 7: Separative devices (clean air hoods, gloveboxes, isolators, and minienvironments), specifies the minimum requirements for the design, construction, installation, testing, and approval of separative devices for use across a variety of industries.
The Institute of Environmental Sciences and Technology (IEST; www.iest.org), which serves as secretariat for the ISO technical committee that developed ISO 14644-7 as part of a series of documents to serve the needs of the global contamination control community, announced the release of the standard in December.
Roberta Burrows, IEST director of communication, explains, “The new standard deals with a small portion of a work station-an area of a cleanroom rather than the whole facility. As used in the standard, [separative] device doesn’t necessarily mean a handheld device, but an application-specific requirement for a smaller area.”
The standard focuses on myriad equipment present in a variety of industries where the fundamental equipment feature is separation between interior and external environments. Although the exterior environment in which the device is located is often a cleanroom, the standard considers the separative device itself-including such issues as monitoring, design, testing, molecular contamination, and material compatibility.
Common contamination control terms, such as clean air hoods, gloveboxes, isolators and mini- environments, have different meanings depending on the industry in which they are used, and the standard seeks to define how these “separative devices” differ from a cleanroom and its issues.
Working group 7, under the leadership of Dr. David Ensor of Research Triangle Institute, was established in 1994, and is comprised of ten member countries, including Belgium, Finland, Germany, Italy, Japan, Korea, Russia, Switzerland, the United Kingdom, and the United States. The initial scope of the group was to “define performance requirements in areas of minienvironments and isolators.”
Rapid changes in such fields as healthcare products, electronics, and mechanical fabrications, however, rendered the writing of the standard difficult, as the group encountered other standards bodies that were independently developing aseptic processing standards.
Upon request from the working group, “minienvironments and isolators” was changed to “enhanced clean devices,” allowing for a focus on the generic aspects of the core technical requirements that could apply to all industrial applications, and eliminating the need to write industry-specific annexes. But based on international community comments in 2001, the term was changed to “separative devices,” with industry-specific terms-such as clean air hoods, gloveboxes, isolators, and minienvironments-in parentheses.
The standard’s terminology change has prompted some concern within the industry. Michael Buckwald, publications director at Terra Universal (Anaheim, Calif.; www.terrauniversal.com), provider of gloveboxes, hoods, and minienvironments, says: “Without specificity, you lose the relevance of a spec. It may be useful to put it out there as a point of international concern that there be some consensus on what these terms mean, and it may be useful as a first step in that direction, but I think they’ll have to elaborate along industry-specific guidelines for it to be useful.”
But according to JST Manufacturing (Boise, Idaho; www.jstmfg.com) general manager Terry McDevitt, “What the standard really does is help define common terminology, creating a consolidated document to establish an industry norm. We see it as a positive thing. JST concentrates on connecting cleanroom and transport equipment to help reduce stress and address ergonomic issues. I believe the next logical step in the standards process will be how devices interconnect.”
 The new standard covers separative devices such as this Laminar Flow Glovebox/Isolator (LFG) from Purified microenviornments (Ormand Beach, Fla.) |
While often located in cleanrooms, separative devices exist primarily to create conditions not found within the cleanroom itself. Examples include very clean conditions, special atmospheres, and physical barriers to protect workers from hazardous materials. Also included are devices that address the difficulties experienced in the manufacture and handling of certain products or materials, such as product sensitivity to particles, chemicals, gases or microorganisms; operator sensitivity to the process materials or byproducts; and both product and operator sensitivity. These are just some of the design issues addressed by the standard.
While air cleanliness definitions and test methods are defined in ISO 14644-1, 14644-2 and 14644-3, some applications have special monitoring requirements based on extreme conditions-and these, too, are covered in ISO 14644-7.
A variety of separative device issues are not addressed by the standard, including: application-specific requirements; requirements agreed upon by customer and supplier; specific processes accommodated in the separative device installation not specified; fire and safety regulations; and full-suits.
When asked if the industry would need to make significant investment to adhere to the new standard, Louise Bertagnolli, president of JST Manufacturing, Inc., explains, “We design all of our equipment to semiconductor standards, which are usually more stringent than ISO standards. For companies that do not adhere to these more stringent standards, ISO 14644-7 levels the playing field.”
Copies of the standard are available from IEST at www.iest.org or by calling 847-255-1561.