Methods for Testing Performance of Fan Filter Units (FFU) —— Interpretation of CRAA Standard Draft Testing Fan Filter Units
Abstract Introduces the background of the CRAA draft Testing Fan Filter Units. Presents the overview of the standard, including The scope of application, main content, and characteristics. It Focuses on performance test methods, covering such test items as aerodynamic performance & energy consumption, airflow velocity uniformity, noise, vibration, total harmonic distortion, and air leakage of the fan box.
Keywords Fan Filter Unit; Performance Test Method; CRAA Standard Draft
FK9926-D Electrical Cabinet Cooling Fan Filters cut-out size 292mm
Fan filter unit is a kind of air purification equipment composed of fan and air filter, which has the advantages of flexible overall design, convenient installation and construction, simple and effective sealing method, and easy to control, etc., and has been widely used in clean rooms, especially in electronic clean plants. In recent years, the rapid development of the domestic LCD panel industry, for example, a 5-generation panel production line needs about 12,000 units of 1200 × 1200 mm (4 × 4 ft) FFU, 6-generation line needs about 25,000 units, 8-generation line needs about 42,000 units, while 10-generation line needs about 80,000 units. In addition, the demand for equipment-side fan filter units (EFUs) is also high. With the increasing market demand, rising production capacity and advancing production technology, the performance requirements for FFUs are getting higher and higher. However, the performance of FFU products from different manufacturers on the market varies, and the performance test methods used are not the same, and the results lack comparability. Therefore, the preparation of scientific and reasonable, uniform and standardized FFU performance test method standards, to help users reasonably select FFU products, as well as to promote the benign development of the FFU manufacturing industry are very important.
The air volume of FFU is usually given by the face velocity, and the volumetric air volume is equal to the face velocity multiplied by the effective air flow area of the filter. The air volume is measured through the nozzle group. The number and size of the nozzles should be appropriate to ensure that the static pressure difference before and after the nozzle is not less than 100Pa. External static pressure, also known as residual pressure, refers to the static pressure loss caused by external equipment on the FFU air flow channel, that is, the static pressure value of air provided by the FFU for use by the external ventilation system after overcoming the resistance of the filter, box structure, etc. Since the FFU outlet wind speed is usually low and the dynamic pressure is very small, the dynamic pressure value is ignored and the static pressure is used instead of the total pressure. The residual pressure is measured in a static pressure box near the FFU air inlet. Since the FFU outlet is connected to the atmosphere, the absolute value of the static pressure in the static pressure box is the residual pressure. While testing the volumetric air volume and residual pressure, electrical parameters such as current, voltage, total input power and power factor should be tested and recorded.