The first major change in ISO14644-1:2015 is the requirement to follow ISO 21501-4, which defines calibration and performance requirements of air particle counters. Many older air particle counters currently in use do not comply with this new requirement. Secondly, the number of required sample locations for the cleanroom validation/qualification process has increased significantly. The larger number of required samples vastly increases the number of associated paper records and manual data transcriptions and the subsequent risk of data loss/transcription errors.

As a result of these changes, all GMP cleanroom users will have to make changes to their cleanroom classification/re-qualification procedures to meet the requirements laid out in the new version of ISO 14644-1. Furthermore, it is possible that the required new classification sampling plan may affect the reported cleanroom class and some cleanroom owners may have to make changes to their cleanroom and the HVAC system to return to the required Class/Grade.