Categorization of clean premises
There are three stages of categorization, which include taking into account the particles in clean premises:
- As-Built: A finished room with all services connected and functional, but without manufacturing equipment and personnel inside.
- At Rest: All services are connected, all the equipment is installed and functions as agreed, but there is no personnel.
- In Operation: all the equipment is installed and functions as agreed, there are also some members of personnel who work in accordance with agreed procedure.
The test for air particles quantity is performed by way of counting the particles in certain parts of the net in a clean room. Test points should be evenly distributed throughout the whole room and the working height to reflect the quality of air purity around the working area. Equipment location could lead to changes in standard network. The quantity of measurements accepted from every testing point depends on the clean room class and statistical requirements, provided in standards. The standards also state that the data should allow to define categorization level with credibility level of 95%. It is recommended to use particle counter.