Airflow change rate utilized in cleanroom facilities is much higher than in typical general-purpose buildings, fan energy saving potential from cleanroom facilities is significant. Many independent reports have indicated that airflow quantities for cleanrooms are often over designed, mainly to meet the rule of thumb values published in FS-209 and IEST RP-12 for decades. This rule approach solely uses the “room cleanliness class” to determine air change rate, and ignores many other “critical variables” such as room particle generation rate, filter efficiency, particle surface deposition, particle entry through supply air, particle exit through return and exhaust air. Using existing over-simplified rule could often cause significant energy waste; however, due to lack of quantitative methodology, most of design and operating engineers still choose to obey the existing rule to avoid being challenged.

This research team has established a new theoretical model which is more comprehensive and inclusive than previous models during last few decades. The mew model has been further validated through testing in several labs. The comparison between the measured and model-predicted results has shown a good correlation. With this new approach, cleanroom air change rate can be “estimated and provided as needed” instead of “picking an arbitrary rate by rule of thumb”. Detailed analysis including charts, tables and key recommendations are provided.

Units: Dual