ISO standards come into view

04/01/2000

Mark A. DeSorbo

WOBURN, MA— ONE DOWN, 10 TO go.

That's one way to sum up the draft process for new cleanroom standards that are being hammered out by Technical Committee 209 of the International Organization for Standardization's (ISO; Geneva).

Eight documents make up the 14644 standard, "Cleanrooms and Associated Controlled Environments," and one of them, 14644-1, "Classification of Air Cleanliness," has already been issued. The industry is now moving toward passage of the other seven documents as well as three sections of the 14698 standard on biocontamination control.

Both standards are the basis of a presentation by Richard Matthews, a CleanRooms Editorial Advisory Board member and chairman of Technical Committee 209. Matthews, founder of Filtration Technology Inc. (Greensboro, NC) and president of Micron Video International, gave his presentation "The New ISO Cleanroom Standards: Mandatory Criteria vs. Voluntary Criteria," at a New England Chapter meeting of the Institute of Environmental Sciences and Technology (IEST; Mount Prospect, IL) in mid-March.

"[Matthews] gives a very open presentation," says Roger Diener, a 209E committee and IEST member, who works as a contamination control engineer for Analog Devices (Wilmington, MA). "Questions will differ, depending on the needs of users who attend. This standard provides a cleanroom baseline because everybody's needs are different."

And accommodating the diversity of the contamination control industry is just what the standards aim to do, says Matthews, an advocate for the sunset of the Fed-Std 209E (See "What is Fed-Std-209E's fate?" Feb 2000, p. 46). "It is generic. There is flexibility, and you had it with Fed-Std 209E, but no one used it," he adds. "Nothing we do is industry specific."

While the air cleanliness portion of the standard has already been issued, there are several other portions that are in various stages of the approval process. The document 14644-2, "Specifications for testing and monitoring to prove continued compliance with 14644-1," is presently out for final vote. The "Design and Construction" segment of the standard, "14644-4, is also out for final vote. If accepted, both will be published as international standards within two months of the vote.

When comparing 14644-1 to Fed-Std 209E, Matthews says the ISO standard has tighter specifications when it comes to 0.1-micron particles, while provisions have been relaxed for 5.0 micron particles. Generally, he says, there are a reduced number of sample locations that are required for cleanroom classification.

Testing for compliance, the 14644-2 document stipulates that particle counts in cleanrooms less than ISO Class 5 (Class 100) must be conducted every six months, while in cleanrooms greater than ISO Class 5, tests should be conducted annually. Air pressure difference and airflow tests, according to the document, are to be conducted yearly regardless of the cleanroom class.

The design and construction provision of the standard, 14644-4, provides comprehensive parameters for clean and support utility spaces. There is also a section that outlines recommendations on materials selection and provides specifications on entry, storage and waste areas. "Millions of dollars," Matthews says, "ride on what is in this document."

The drafts of the third, fifth and seventh sections of the standard are scheduled to be sent out for comment by the third quarter of this year. The documents address metrology and test methods, cleanroom operations and enhanced clean devices (ECDs).

The third document of the standard focuses on metrology and test methods. Recommended primary tests include airborne particle count, and under that umbrella classification, ultrafine particle, and macroparticle tests are included. There are also a number of tests that are recommended, yet optional, including filter leakage, flow visualization and direction, temperature and humidity, electrostatic and ion generation, particle deposition, recovery and containment leak. "These tests are your call," Matthews adds.

Cleanroom operations, 14644-5, specifies the basic requirements for operating and maintaining cleanrooms and associated controlled environments, Matthews explains. The section includes requirements, operational systems, garments, personnel, equipment, materials and cleanroom integrity. "These are things you must concern yourself with," he says.

Enhanced clean devices, ECDs, are addressed in the 14644-7 document. Its scope, Matthews says, centers on the minimum requirements for the design, construction, installation, testing and approval of ECDs where they differ from cleanrooms.

Documents six and eight will go out for review during the third quarter of 2001. Terms and definitions, a so-called glossary of terms for the standard, will be outlined in 14644-6, while molecular contamination is addressed under 14644-8. "[Molecular contamination] cuts across all industries. It's a big issue, especially for the pharmaceutical people," he adds.

The three documents of the ISO 14698 standard on bicontamination will be finalized and approved by the fourth quarter of 2000. The standard features a general principle section for analysis, an evaluation and interpretation of data as well as a methodology for cleaning and disinfecting.