Effects of different air change rates on cleanroom 'in operation' status

The objective of this experimental study is to analyze non-viable and viable particle loads in a pharmaceutical cleanroom under 'in operation' conditions using different air change rates (ACRs). Regulatory guidelines give limit values for particles/m³ and colony forming units (CFUs)/m³. A widely used ACR is 20 h^-1 as this value is recommended by the Food and Drug Administration (FDA) in its guidance for industry on sterile drug products. However, this value may be too high, resulting in increased costs for energy. A typical pharmaceutical cleanroom was used for this study, and operations were simulated with a process unit and two operators in the room. The experiments were conducted twice with four different ACRs and four different types of operator garments, resulting in 32 trials in total. Particle load and CFUs were measured by calibrated particle counters and microbial air samplers. The results give evidence that an ACR of 20 h^-1 is not required. ACR 10 h^-1 is sufficient without compromising the demanded air quality. Furthermore, it was found that regulatory agencies should reevaluate the expected limits as these currently give a high buffer between the required and actual values, which potentially cover up problems in aseptic manufacturing.