Revised ISO Cleanroom Standards set new sampling and classification methods

Published: 13-Dec-2010

IEST calls for comments


A new principle for selection of cleanroom sample locations is one of the major changes in the newly revised ISO 14644 standards now available from the Institute of Environmental Sciences and Technology (IEST), the Secretariat for ISO Technical Committee 209 (ISO/TC 209).

The IEST urges users of the current ISO 14644 standards to review the new sampling plan in ISO/DIS 14644-1 – Part 1: Classification of air cleanliness by particle concentration and ISO/DIS 14644-2 – Part 2: Specifications for monitoring and periodic testing to prove continued compliance with ISO 14644-1 in comparison with the previous approach.

These documents are available from IEST as Draft International Standards (DIS). They may be used as trade reference per agreement between customers and suppliers, necessitating an urgent need for an understanding of the revised provisions by those involved in contamination control.

The DIS documents are under review by ISO member bodies for voting and comment by 2 May 2011, for approval for submission as Final Draft International Standards (FDIS).

In the US, public comments may be submitted to IEST through a form available on its website.

According to the ISO/TC 209 Working Group who developed the revisions, new provisions include 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 statistics behind the revisions will be published in an upcoming special edition of the Journal of the IEST.

IEST also plans a series of educational courses to inform the controlled environments community about the revisions in California and on the east coast, and in Chicago during ESTECH, the IEST annual technical meeting, in May 2011.

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