What are the key changes to sampling, classification and reclassification?
Annex 1 refers to ISO 14644-1:2015 for room classification including the number of required sample points and sample sizes. The 2015 update has been simplified in terms of sampling and classification. The annex changes require organizations to redefine their classification sampling plans and data evaluation as the new method will likely result in an increase in sample points compared to the prior square root calculation.
- 95% UCL (upper confidence limit) evaluation for 2-9 sampling locations has been eliminated
- Each sampling location must be evaluated separately and all sampling locations must pass for a cleanroom/clean zone to comply
- The square root calculation (ISO 14644-1:1999) to determine the minimum number of sampling locations has been replace with a look-up table. The table now provides at least 95% confidence that at least 90% of the cleanroom or clean zone will comply with the ISO Class limit