This part of ISO 14644 specifies test methods for designated classification of airborne particulate cleanliness
and for characterizing the performance of cleanrooms and clean zones. Performance tests are specified for
two types of cleanrooms and clean zones: those with unidirectional flow and those with non-unidirectional flow,
in three possible occupancy states: as-built, at-rest and operational. The test methods recommend test
apparatus and test procedures for determining performance parameters. Where the test method is affected by
the type of cleanroom or clean zone, alternative procedures are suggested. For some of the tests, several
different methods and apparatus are recommended to accommodate different end-use considerations.
Alternative methods not included in this part of ISO 14644 may be used if based on agreement between
customer and supplier. Alternative methods do not necessarily provide equivalent measurements.
This part of ISO 14644 is not applicable to the measurement of products or of processes in cleanrooms or
separative devices.