1PHARMACEUTICAL ENGINEERING JANUARY/FEBRUARY 2014facilities and equipmentControlled Manufacturing Environments1JANUARY/FEBRUARY 2014 PHARMACEUTICAL ENGINEERINGEvaluation of Controlled Manufacturing Environments following an Air Handling Unit Shutdownby Catherine E. Anderson and Brian J. Lloyd, PhDThis article provides a methodology to evaluate the environmental impact of an air handling unit shutdown in a GMP manufacturing environment. E nvironmental control within the bio- pharmaceutical and medical device industries usually involves a continual cycle of steady state activities interrupted by maintenance and recovery measures. Systems and practices, such as air tem- perature and humidity control, number of air exchanges, and room cleaning prac- tices, are in place to maintain the overall environmental control. When the environment is challenged or breached, recovery measures are in place to ensure the controlled classified area returns to the qualified state with minimal impact to the environment and product. In many cases, the recovery measures may involve significant clean- ings, limited access, and additional environmental monitor- ing which can reduce manufacturing time and increase cost. This case study evaluated the impact of a short term breach to a biopharmaceutical controlled classified manufacturing cleanroom areas and determined how long it would take these areas to recover with minimal recovery measures and intervention.Introduction Air Handling Units (AHUs) are the primary engineering control for classified controlled environments. They provide humidity/temperature control as well as the filtration and air exchanges necessary to ensure an environment meets its classified requirements. These units must be shut down periodically to allow routine maintenance, calibration activi- ties, or planned construction. An example of the activities required to shut down a GMP AHU are listed in Table A.The average costs associated with AHU shutdowns include two to four planned events annually per unit with an estimated annual cost of $2000 to $4000 per unit for parts and labor. The disruptive impact to the environment can be even longer for unplanned outages caused from mechani- cal or power failures. An average AHU also has one to two unplanned outages annually. The frequent disruption to the environment, whether planned or unplanned, can have a significant impact to production. These disruptions cause ActivityTimeAHU Shutdown (Power down)10 15 minRoutine Maintenance Work Performed30 min 4 hoursAHU Operation Resumed (Restart)15 30 minClassified Area Cleaning2 4 hoursAdditional Environmental Monitoring2 4 hoursOverall Potential DelayUp to 12 hours per AHU ShutdownTable A. Typical planned AHU shutdown activities.Reprinted from PHARMACEUTICAL ENGINEERING THE OFFICIAL TECHNICAL MAGAZINE OF ISPEJANUARY/FEBRUARY 2014, VOL 34, NO 1Copyright ISPE 2014 www.PharmaceuticalEngineering.org2JANUARY/FEBRUARY 2014 PHARMACEUTICAL ENGINEERINGfacilities and equipmentControlled Manufacturing Environmentsdelays in the production schedule due to required area cleanings, additional environmental monitoring, and time and resources necessary to assess product impact if the envi- ronmental disruption occurred during manufacturing opera- tions. The degree of the appropriate response to an environ- mental disruption, especially a short duration of less than a few hours, is needed and data should be generated. This article presents a methodology that evaluated the impact of a temporary AHU shutdown on a classified environment and the potential for an AHU recovery period to minimize recovery efforts, specifically re-cleaning and monitoring of classified rooms. Case Study Design Along with climate control, AHUs utilize High Efficiency Particulate Air (HEPA) filters to control the level of particulates, both viable and non-viable, in the environment. An AHU shutdown increases the potential to reach or exceed allowable particulate levels in a controlled environment. To evalu- ate the potential impact and determine how long it takes for an area to recover with minimal intervention, a study was designed to shut down full scale AHUs for a prescribed amount of time, collect samples, then return to operation and al- low the classified environment to recover for a prescribed amount of time. Samples would be collected again following the recovery period. No additional area cleaning would be performed as part of the recovery. The intention was to utilize the study results to temporary AHU shut- downs, whether planned or unplanned.Industry Requirements Controlled environments are used to protect products from contamination by greatly reducing the probability that airborne contamination will come in contact with the product or product intermediates or components. Controlled environments are classified based upon their potential impact on product quality. The gene