Fan filter unit noise standard
- 10, 06, 2021
How loud is the FFU? How many decibels of FFU noise is reasonable?
There are much data on the noise of FFU. For example, when a single FFU is tested in the laboratory at 0.9m/s, the noise is measured 1 meter below the filter. Due to different fan models, specifications, and manufacturers, the measured noise is different. The measured noise data of VCR fan filter unit (such as FFU 1175*575*230) is 55±3dB with the average air velocity around 0.9 m/s
Of course, the noise of the fan filter unit should be measured on the spot, as long as it does not affect the normal working noise, it can generally be acceptable (generally not greater than 65dB). In addition, FFU noise has a superimposed effect, which means the more the fan filter unit, the greater the noise.
The FFU speed control switch has three gears, and it is generally fine to adjust to the middle gear.
Sources of FFU noise in cleanroom
1. Noise generated when FFU motor is running, such as running frequency and mechanism collision.
2. The noise generated by the operation of the fan impeller driven by the motor.
3. The noise generated by the vibration of the FFU fan filter unit casing.
Sampling noise reduction method
The sample characteristics of the noise are extracted (sampling), and the noise signal is removed from the original sound signal, which does little damage to the original sound.
Filtering noise reduction method
The filter is used to block the frequency band where the noise occurs in the audio, but the usable audio frequency in the same frequency band as the noise will also be blocked and destroyed. Has a certain destructive effect on the original sound.
Provide a threshold to remove the noise in the audio below the threshold. This method will also damage the original audio file, but it is limited to the low-level part (the noise gate will not be very high).
The best noise reduction effect is the sampling noise reduction method. Here we introduce you to the method of sampling noise reduction with built-in noise reducer
Four methods to reduce FFU noise
1. Choose a low-noise FFU because the FFU is located in the technical mezzanine.
2. Add a soft joint to avoid resonance between the FFU and the air duct. The noise is mainly generated by the FFU. The connection between the air duct and the air-conditioning box should originally be a soft joint.
3. Install the muffler pipe, as long as the duct design is reasonable, the noise is unlikely to be large.
4. Lift the fan filter units as far as possible.
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