Clean Rooms

Characteristics and Related Performance Measurements

A cleanroom controls the level of micro-contamination in it by mechanical ventilation and filtration through high efficiency filters. The filters create an environment low in sub-micron particles. By removing such small particles, bacteria are also removed.

The level of particle control required is defined by the classification of the cleanroom as set out in ISO 14644-1:1999

The most basic performance measurement is therefore the airborne particle count. However, in order to assess the true condition of a cleanroom, more parameters need to be assessed as they have a critical bearing on how the cleanroom performs in every day use. The various performance tests and acceptance criteria are set out in ISO 14644-3:2005, IEST-RP-CC006.3 and IEST-RP-CC034.3. It is helpful to list the various major components which are key to maintaining control and the tests that are used to measure their performance.


HEPA/ULPA filters HVAC system Cleanrooms
Integrity Test Airflow Flow patterns
Airflow Pressure balance Pressure differentials
Air velocity and uniformity Temperature
Flow pattern Humidity
Filter pressure drop Noise