KeLing Purification Technology Company Limited
Advanced. High-Qulity. Reasonable.
1. Small fans force air through filters. The units often have adjustable speed control and typically have full speed energy consumption of 190 – 250 watts. The newer installations use more efficient DC motors.
2. The main advantage of FFU system is simplicity and these systems are very popular in mini-environment cleanrooms. However, the FFU puts out a quantum amount of flow in a 2'x4' ceiling space. Flow rate and velocity are not independent variables and therefore these do not lend itself to efficient design for proper airflow distribution.
3. Fan-filter units are quite expensive. Even though the unit cost of a fan-filter unit is low, a typical cleanroom module will require many such units; and the total cost quickly exceeds that of centralized RAH system.
4. The fan-filter units require larger air passageways in order to reduce static pressure losses. This increases both the overall building width and height.
5. Fan-filter units can be set in a gasketed ceiling. Other options will generally have pressurized supply plenums, which require a gel-track ceiling.
6. The electrical distribution cost is highest for fan-filter units. Even though the motors are much smaller, there are many more of them. Also, the automation costs are higher for fan-filter units, again due to the large quantity of fans.
7. Ceiling distributed fan-filter units do not develop much static pressure and therefore either custom air-handlers or booster fans are often required in conjunction with the FFUs. The system does not lend it self to double HEPA filtration.
8. The noise level from a typical FFU is low at 53dba @ 90 FPM face velocity. However, the use of multiple fans (in some cases hundreds of them) can result in significant noise level being radiated into the cleanroom.
9. The use of multiple fans necessitates use of electronic monitoring system to check the status of each motor.
Contact Person: Mrs. Zhao
Tel: 86 20 13378693703