When FFU and high-efficiency air supply vents are mixed, how to determine the specifications and quantity of FFU?

Direct answer: First define the areas responsible for the FFU and high-efficiency air supply vents, and then calculate the air supply requirements separately. The number of FFU should be determined based on the target air volume and layout requirements of the area it is responsible for. The total air volume of the entire room cannot be allocated to FFU, nor can the nominal air volume of the two types of ends be simply added. The final configuration needs to be confirmed by system air volume balancing and field testing.

In a new clean room, FFU and high-efficiency air supply vents may appear in different rooms, or they may serve different locations in the same room. The sources of air supply power of the two are different:FFU comes with its own fan, and the high-efficiency air supply vents are usually supplied by the upstream air conditioning system. Before determining the number of FFUs, one question must be answered: Which locations are supplied with air by FFUs and which locations are supplied with air by centralized systems?

First draw the air supply responsibility area to avoid double counting.

Mark the process equipment, personnel activity areas, doors, return air outlets and two types of air supply terminals on the floor plan and ceiling plan. Combined with the cleanliness target and air flow direction, determine the design air supply volume of each area.

If an FFU is responsible for the air supply in a certain local process area, when calculating the number of FFU in the area, the air volume allocated to the FFU in the area should be used instead of the air supply volume in the entire room. The air volume assumed by the high-efficiency air supply vents should be separately included in the centralized system and checked together with the return air, exhaust air and room pressure difference requirements.

Specifications are first filtered by installation conditions and then determined by performance

The overall dimensions of the FFU should match the ceiling module, equipment location and maintenance space. After the size is appropriate, you must also check the assembly specifications.When using HEPA or ULPA filters , the effective air volume, wind speed uniformity and power consumption are determined under the design operating gear and resistance conditions.

Do not use the maximum air volume to directly calculate the number of units. The air volume used for calculation should be the air volume that a single FFU can provide under the agreed working conditions of the project. If the filter or installation structure changes, the fan operating point should be rechecked.

The quantity must pass two checks

The first step is to check the air volume : divide the target air volume in the area responsible for the FFU by the effective air volume of a single FFU under the design working conditions, and round the result up.

The second step is to check the layout : put the initial calculated quantities into the ceiling diagram, check whether the key process positions are getting appropriate air supply, whether there is an obvious weak airflow area between the FFU and the high-efficiency air supply outlet, and confirm that the beam position, lighting fixtures, electrical and maintenance conditions allow for installation. If the layout does not meet the requirements, the specifications, location or air volume distribution of the two terminals should be adjusted instead of just increasing the number of FFU units.

What should be verified at the end of the hybrid solution?

The two types of terminals have reached the nominal air volume respectively, which does not mean that the entire room has reached the standard. The actual air supply volume of FFU, the actual air supply volume of high-efficiency air supply outlets, airflow distribution, cleanliness, and the pressure difference relationship in related areas should be checked on site. Particular attention should be paid to whether the originally designed air volume balance has been changed after FFU speed adjustment.

Aili Industrial can match the FFU complete machine specifications based on the clean area floor plan, ceiling conditions, target air volume, filtration requirements and control methods of the FFU responsible area. For batch projects, it is recommended to confirm the prototype first, and then write the performance, number of units, layout and test conditions of the single unit into the technical agreement. The specific configuration is subject to project design and on-site verification results.

FAQ: The high-efficiency air supply outlet already has air volume, can the number of FFU be directly reduced?
It is necessary to first confirm whether the air volume is sent to the area that the FFU is originally responsible for, and whether the air flow direction and cleanliness requirements still meet the design.

FAQ: Can two types of terminals use the same level of filters?
Filtration levels can be selected separately according to process requirements, but the respective filter resistance, sealing and air supply system capabilities must also be checked.

FAQ: What are the most critical drawings when making an inquiry?
It is recommended to provide floor plan and ceiling diagrams indicating the locations of FFU, high-efficiency air supply vents, return air vents and process equipment, and indicate the target air volume in each area.