ISO Cleanroom standards update

February 11, 2011 — The Institute of Environmental Sciences and Technology (IEST) published a technical paper to help professionals in industries that use cleanrooms understand the new air sampling plan described in the recently released Draft International Standard (DIS) versions of the landmark ISO cleanroom standards. The peer-reviewed paper, titled "Sampling Plan for Cleanroom Classification with Respect to Airborne Particles" and published as a Special ISO Edition of the Journal of the IEST, was written by members of ISO Technical Committee 209, Working Group 1 (ISO/TC 209, WG 1), the experts who developed ISO/DIS 14644-1, Cleanrooms and associated controlled environments – Part 1: Classification of air cleanliness by particle concentration and ISO/DIS 14644-2, Cleanrooms and associated controlled environments – Part 2: Specifications for monitoring and periodic testing to prove continued compliance with ISO 14644-1.

It is imperative for those involved in cleanroom operations to understand the procedural changes contained in ISO/DIS 14644-1 and ISO/DIS 14644-2, as well as the rationale for those changes, for several reasons. First, the Draft International Standards now may be used worldwide as trade references per agreement between customers and suppliers, as may the original Standards. When deciding which version of these standards to use, both customers and suppliers should be aware that the new DIS documents provide a simplified classification process based on a more accurate scientific sampling method. The new statistically based plan for selecting sample locations calls for a greater number of locations, but in turn eliminates the need to apply a statistical test to the data. This approach reportedly allows for different concentration levels in different parts of the cleanroom and is designed to ensure with a given statistical confidence that at least 90% of the cleanroom area complies with the maximum particle concentration.

The DIS documents are under review by ISO member bodies for voting and comment. US users of these documents are encouraged to submit comments through April 15 to their ISO Member Body, IEST, via

"Sampling Plan for Cleanroom Classification with Respect to Airborne Particles," is available for complimentary download from the IEST website, On that same website, contamination control professionals may order ISO/DIS 14644-1 and ISO/DIS 14644-2 (via the Bookstore) and find additional information on related ISO documents and Recommended Practices. IEST is an international technical society of engineers, scientists, and educators that serves its members and the industries they represent (simulating, testing, controlling, and teaching the environments of earth and space) through education and the development of recommended practices and standards. IEST is an ANSI-accredited standards-developing organization; Secretariat of ISO/TC 209 Cleanrooms and associated controlled environments; Administrator of the ANSI-accredited US TAG to ISO/TC 209; and a founding member of the ANSI-accredited US TAG to ISO/TC 229 Nanotechnologies.

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