I work for a medical device company and we set up an ISO 7/8 cleanroom. I set up an environmental monitoring procedure that includes quarterly monitoring of our particulate, as well as viable microorganisms for air and surfaces. We now have several sessions-worth of data, and I now need to establish alert and action levels. I’m not familiar with how to decide these levels, however.

Are there any industry norms or statistical techniques for setting up initial levels? If we claim, ISO 7 at rest and ISO 8 in operation, do we need to establish levels for each state?