How to match the air volume and static pressure of FFU in clean corridors?

Direct answer: First determine the target air volume based on the cleanliness requirements and air flow organization of the corridor, and then check whether the actual resistance can be overcome at this air volume after the FFU is equipped with the specified filter. Model selection should look at the air volume and static pressure data under the same working conditions, rather than comparing the 'maximum air volume' and 'maximum static pressure' separately.

Clean corridors are often long and narrow and connect multiple process rooms. Occupational traffic, door openings, and return air positioning all affect airflow. The air volume and static pressure of the FFU must be matched. It must not only ensure that the corridor receives sufficient air supply, but also combine the ceiling layout and the air supply and return scheme of adjacent rooms to confirm that the air can flow in the designed direction.

First determine how much air volume is needed in the corridor

The project should clarify the cleanliness level, length and width of the corridor, the location of doors, the traffic of people and materials, and the target air supply volume of each zone. Long corridors should be calculated in sections to check whether there are weak air supply areas near doorways, corners and return air.

Just because the total air volume reaches the design value does not mean that the air supply is uniform along the line. chooseWhen selecting the specifications and location of the FFU fan filter unit , the air outlet range and actual arrangement of a single unit should also be considered.

Check static pressure at target air volume

The focus of static pressure calibration is whether the FFU can overcome the resistance of the specified filter and related installation structures when reaching the target air volume. The filter, operating gear, test location and measurement conditions corresponding to the performance data should be confirmed with the supplier.

The resistance of the HEPA or ULPA filter will affect the fan operating point. Changing to a different filter, or the resistance rising after the filter is running, may cause the actual air volume to change. Therefore, the maximum air volume without a filter cannot be used as the corridor design air volume, nor can the maximum static pressure and maximum air volume under different test conditions be directly matched.

Corridor pressure difference and FFU static pressure are not the same parameter

The static pressure in the FFU performance data is used to judge the air supply capacity of the equipment to overcome resistance; the pressure difference between the corridor and adjacent rooms is determined by the air supply, return air, exhaust and door operating status of the entire area. The higher FFU static pressure does not mean that the pressure difference between the corridor and the room must be higher.

The project should put forward these two requirements separately: one for selecting the FFU working point, and the other for checking the overall air flow balance of the clean room.

How to verify the match?

For batch projects, it is recommended to first use a prototype to check the air volume, related pressure difference, power consumption and noise under the specified filter and design gear. After on-site installation, the actual air volume, wind speed distribution, cleanliness and pressure difference relationship with adjacent rooms in each partition of the corridor are measured according to the technical agreement.

If the air volume in a certain corridor is insufficient, you should first check the filter resistance, control settings, air inlet and outlet conditions and measurement methods, and then decide whether to adjust the gear position, FFU arrangement or quantity. Projects that require zoned speed regulation and condition monitoring can be planned simultaneously during the design phase.FFU group control system。

Aili Industrial can combine the corridor plan and ceiling plan, cleanliness goals, filtration requirements and target air volume to match fans, motors, filters, boxes and control solutions. The specific air volume, static pressure and configuration are subject to the project technical agreement and the test results under the agreed working conditions.

Q: The higher the maximum static pressure of the FFU, the more suitable it is for clean corridors?
Answer: Not necessarily. Performance at target air volumes should be compared, while power consumption, noise and installation conditions should be checked.

Q: If the total air volume in the corridor reaches the standard, what else needs to be checked?
Answer: You should also check the wind speed distribution along the line, return air path, cleanliness and pressure difference relationship with adjacent rooms.

Q: What parameters should be provided when enquiring?
Answer: It is recommended to provide corridor floor and ceiling plans, cleanliness requirements, target air volume, filter requirements, door and return air locations, as well as power supply and control requirements.