Changes to ISO 14644-1: 2015 for Clean Room Testing

Changes to ISO 14644-1: 2015 for Clean Room Testing

If you are stakeholder in regards to a clean room facility it is worth noting that ISO 14644-1: 1999 has recently been updated to the 2015 version. It requires changes to sampling procedures and monitoring plans for cleanrooms and clean zones, all of which is outlined in the revised ISO 14644-1:2015 standard. Organisations will be required to redefine their validation sampling plans and data evaluation and will obviously affect the clean room testing reportage.


The updated ISO 14644-1:2015, specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean zones and is the first significant revision since its original release in 1999.

The major change from ISO 14644-1:1999 publication is the adoption of a more consistent statistical approach to the selection and number of sampling locations; and thereafter the evaluation of the data collected.

This new approach allows each location to be treated independently with at least a 95 % level of confidence that at least 90 % of the cleanroom or clean zone areas will comply with the maximum particle concentration limit for the target class of air cleanliness.


Cleanroom users will have to make changes to the cleanroom validation procedures to meet the requirements laid out in the latest version of ISO 14644-1:2015 and ISO 14644-2:2015.  It is possible that the revised standard will require cleanroom owners to make changes to their cleanroom to ensure they continue to achieve the required classification and remain compliant.

The main Changes the changes to ISO 14644-01:

  • Each sampling point is to be evaluated separately and all sampling locations must pass for a cleanroom to comply.
  • The 95% UCL (upper confidence limit) evaluation for 2-9 sampling locations has been removed.
  • The calculation used in ISO 14644-1:1999 to determine the minimum number of sampling locations has been replace with a look-up table. The table provides at least 95% confidence that at least 90% of the cleanroom or clean zone will comply with the ISO Class limit.
  • The removal of 5 size micron in class 5 areas. This can still be considered as a reference for continuity but will not form part of a pass/fail validation outcome.

APT Cleanroom Testing Services

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