The technical parameters of FFU (Fan Filter Unit) are the key references for selection, acceptance, and operation. Below are the most important technical parameters of FFU, which can be categorized into three major types: performance parameters, structural parameters, and electrical & control parameters.
I. Core Performance Parameters
These parameters directly determine the purification effect, airflow capacity, and energy consumption level of FFU.
1. Rated Airflow: The volume of air delivered in a unit of time under rated frequency and zero static pressure conditions, measured in m³/h. It is calculated based on the face velocity (typically 0.35-0.55 m/s) of the cleanroom design and the effective area of FFU, making it the primary parameter for selection.
2. External Static Pressure: After overcoming its own filter resistance and return air resistance, the ability to maintain rated airflow, measured in Pa. It is a vital parameter that must have sufficient allowance (≥100-120 Pa) to deal with increased resistance from filter dust accumulation and prevent airflow decay.
3. Filter Efficiency: The ability of filter material to capture particles, targeting specific particle sizes (such as 0.3μm or 0.12μm).
- HEPA: Efficiency of ≥99.99% (H13) or ≥99.995% (H14) for 0.3μm particles.
- ULPA: Efficiency of ≥99.9995% (U15) or higher for 0.12μm particles. The choice depends on the cleanliness level required.
4. Airflow Uniformity: The stability of airflow velocity at various points on the exhaust surface, which is crucial for ensuring laminar flow effect. Well-performing FFUs should have a value of ≤ ±10% to ±15%, guaranteed by the diffuser plate, as poor uniformity can lead to air vortices.
5. Noise:The sound pressure level measured at 1.5 meters directly below the FFU under rated airflow conditions, in dB(A). For areas with personnel, low-noise models (such as ≤52-55 dB(A)) should be selected. EC motors are usually quieter.
6. **Vibration Amplitude:** A measure of the mechanical vibration generated during FFU operation. This parameter is critical for industries sensitive to micro-vibration, such as semiconductors and precision optics. EC motors have significantly less vibration than AC motors.
II. Structural and Material Parameters
These parameters determine the physical characteristics, durability, and applicable environment of FFU.
7. Casing Material: The primary material used to manufacture the FFU housing.
- Galvanized Aluminum Zinc Sheet: The most common, cost-effective, and widely used material, suitable for electronics and optics.
- Stainless Steel (SUS304/SUS316): Corrosion-resistant and easy to clean, it is used in biopharmaceuticals, food, and medical industries.
8. Dimension: The length, width, and height of FFU, in mm. It must match the ceiling grid module of the cleanroom. The most common sizes are 1200x600mm (metric) and 1175x575mm (4′x2′ inch).
9. Filter Dimension: The length and width of the high-efficiency filter installed inside, which is usually slightly smaller than the overall dimension. It is important to confirm if it is a standard part for easy replacement later on.
10. Weight: The total weight of the unit, in kg, which affects the structural design and load-bearing requirements of the ceiling grid.
11. Filter Replacement Method: How to replace the expired filter, with the “bottom replacement” style strongly recommended. It allows replacement within the cleanroom through quick-detach mechanisms (such as clips or handles) without entering the technical plenum, making it safe and convenient.
12. Sealing Method: The sealing form between the filter and the housing.
- Liquid Gasket Sealing: Offers the best seal but is complex for replacement.
- Pressure Sealing: Relies on mechanically compressing gaskets, which is common and reliable.
III. Electrical and Control Parameters
These parameters determine the intelligence level, energy-saving effect, and integration capability of FFU.
13. Motor Type: The core component driving the fan.
- EC Motor (Brushless DC): Absolutely mainstream. It boasts high efficiency and energy savings (efficiency>80%), smooth speed control, long life, and support for intelligent control.
- AC Motor (AC): Becoming obsolete. It has low efficiency, high energy consumption, and poor speed control performance.
14. Rated Voltage/Frequency: The input power supply requirements, such as AC 220V, 50Hz. It should be consistent with the power grid specifications of the project location.
15. Rated Power: The total input power of the unit under rated airflow and static pressure conditions, measured in W. It is the key to calculating total energy consumption, with EC motors having much lower power than AC motors, achieving significant energy savings.
16. Control Method: The method of adjusting the operating status of FFU.
- Single-Machine Control: Each unit is equipped with its own speed controller.
- Group Control: One master controller manages a group of FFUs.
- Networked Intelligent Control (Recommended): FFUs are connected to a central system through RS-485 interfaces to enable remote monitoring, speed control, and alarms.
17. Communication Interface: The protocol type used for intelligent group control. RS-485 is the most common communication protocol. Ensure compatibility with the facility monitoring system (FMCS).
Summary and Selection Process Recommendations
1. Determine Airflow: Calculate the required rated airflow based on the face velocity requirements of the cleanroom design.
2. Ensure Static Pressure: Choose a model with sufficiently high external static pressure (≥120 Pa) with a margin.
3. Select Efficiency: Determine the filter efficiency (HEPA or ULPA) based on the cleanliness level (ISO Class).
4. Choose Motor: 
Prioritize EC motor models.
5. Pick Structure: Select the material (galvanized aluminum zinc sheet/stainless steel) based on environmental corrosivity.
6. Plan Control: Plan the control method according to the project scale, with large projects mandating networked intelligent control.
7. Verify Credentials: Obtain third-party test reports to verify key parameters such as filter efficiency, leakage detection, and noise levels.
By systematically considering the above parameters, you will be able to precisely select the FFU product that best fits your project needs.
Post time: Oct-20-2025