This report describes the work performed under ASHRAE Research Project 652-RP "Optimum Airflow Velocity in Cleanrooms." The research project was initiated by Technical Committee, TC 9.2, Industrial Air Cleaning; however, the project was monitored by Task Group, TG 9.CS (Clean Space).

The worked performed under this project included (1) development of a PCbased computer program to model airflow and particle transport in a cleanroom, (2) verification of the computer model using experimental data collected in a cleanroom of Class 100 (or better), (3) a parametric study to investigate the effects of room airflow rate on particle concentrations for various cleanroom configurations and activity, and (4) additional experimental investigations on the effects of room airflow rate and activity on cross contaminations for locations on a cleanroom workbench.

Findings from the research show that nominal airflow velocities as low as 60 fpm are possible without a loss of cleanliness for specific work sites in the cleanroom. Cross contamination between adjacent workspace on the cleanroom bench was found not to be a significant problem. However, the room airflow rate required depends on the room configuration as well as the location and strength of the source of contamination. Therefore, a nominal velocity of 60 fpm may not be appropriate for all cleanrooms.