In Grade A areas monitoring is mandatory
“For grade A zones, particle monitoring should be undertaken for the full duration of critical processing.”
Getting a complete picture is mandatory too
“Grade A zones should be monitored at a frequency and with suitable sample size that all interventions, transient events, and any system deterioration can be captured”
Continue at: http://www.gmpua.com/CleanRoom/Monitoring/ContinuousParticleMonitoring/Continuous%20Particle%20Monitoring.pdf
The text above is owned by the site above referred.
Here is only a small part of the article, for more please follow the link