DRP in cleanroom;provide back-up AHU to control temp at 22+/-3C and HUMIDIFIER or DEHUMIDIFIER to control %rh from 40% to 60% relative humidity.Predictive maintenance for Hepa Filters(class 100 ,class 1000,class 10k).Proper gowning and de gowning of people...and proper cleanroom smock gown or bunny suits and proper air shower room prior entering the cleanroom. These are some of the things we had done before.
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http://nebbaccreditedassociate.org/