Introducing a Standard Testing Method for Fan-Filter Units

Cleanroom HVAC systems, especially those requiring fan filter units (FFU) for recirculating air, typically account for a large portion of energy use in cleanrooms. Performance of HVAC systems varies significantly from cleanroom to cleanroom largely because of various factors, such as contamination control requirements, air handling unit designs, air system resistance, and efficiency levels offered by system components. The studies not only uncovered energy-saving opportunities in many cleanroom applications, but also indicated that optimizing aerodynamic performance in air recirculation systems appears to be a useful approach to improve energy efficiency in cleanrooms.

Because of their ease of installation, adaptability, and specific contamination control schemes, fan-filter units are being used more and more in air recirculation systems in cleanrooms. The large number of small fans can consume considerable energy in providing air recirculation. Therefore, understanding the performance of FFUs is important and can help to promote best practices in cleanroom design and operation. To date, typical manufacturers data sheets usually contain claims that are seemingly similar; however, they usually do not reveal test methods, if at all exist. Furthermore, statements of performance data that include power, airflow, and sound are commonly vague and could be misleading. In recent years, industries have shown growing interest in having a uniform method for testing and reporting FFU performance. Lawrence Berkeley National Laboratory (LBNL) is performing research to improve energy efficiency in contamination control facilities such as cleanrooms. This project is to develop a standard testing method of evaluating the performance of a fan-filter unit (FFU).

This article describes the activities that LBNL has led in developing the standard for FFUs energy performance. It also summarizes results of laboratory-measured performance of 20 fan filter units (FFUs) tested by Industrial Technology Research Institute (ITRI).