The clean-room classification standard ISO 14644-1 was first published in May of 1999. This standard covers the classification of air cleanliness by particle concentration. After more than 10 years of review, ISO published the first revision to the standard on December 15, 2015. Companies who currently use ISO 14644- 1 for classifying their clean-rooms can immediately begin using the new current version.
The main differences in the new ISO 14644-1:2015 vs 1999 are as follows:
1. The limit for 5 μm particles is removed for ISO Class 5.
ISO Class 5 no longer has a limit for 5 μm particles. The GMP 2008 reports, continue to include the same.
limits for 5 μm particles as before and the formulas are not changing for GMP 2008 reports at this time.
2. The minimum number of sampling locations is different.
In the 1999 standard, the minimum number of locations was equal to the square root of the area in square.
meters. This has been replaced with a table and more locations will be required in most cases. A new
formula can be used for areas greater than 1000 square meters.
3. The 95% UCL calculation has been eliminated.
The 95% UCL (upper confidence limit) is no longer calculated for sampling areas with 2 to 9 locations. Every
location must pass individually. The new higher minimum number of locations provides at least 95%
confidence that at least 90% of the clean room or clean zone does not exceed the class limits.