The design air volume has been determined, how to determine the FFU specifications and quantity?

Direct answer: First allocate the total design air volume to each clean area, and then select the FFU that can provide effective air volume under the specified filter, operating gear and actual resistance. Calculate the preliminary number of units in each area based on the air volume, and then modify it based on the ceiling layout, airflow at key locations and maintenance space. Finally confirmed by prototype and on-site testing.

There is also a key parameter between 'how much air volume the room needs' and 'how many FFUs are needed': how much air volume a single FFU can actually provide under project conditions . The maximum air volume in the product information cannot be directly substituted into the calculation of the number of units.

From total air volume to single FFU: three numbers to distinguish

Assume that the design air supply volume of a certain area is Q area , and the selectedFFU unit under project conditions is The effective air volume of a single Q units , then the initial number of units in the area based on air volume is:

N air volume = Q area ÷ Q station, the result is rounded up.

The Q area should be determined by the project cleanliness target, air supply range and air flow organization; the Q station should be designated by the assemblyPerformance data of HEPA or ULPA filters , using the designed operating gear and considering the relevant resistance. Both numbers must correspond to the same design.

If there are areas with different cleanliness requirements in the room, it is not advisable to add all the designed air volumes first and then distribute them evenly with one FFU specification. Calculations should be made by zoning and consideration should be given to whether local process equipment requires independent air supply.

Specifications are not only determined by air volume

After the air volume of a single FFU meets the requirements, the ceiling module, installation height, target wind speed, air outlet uniformity, power consumption and noise must be checked. The same air volume can be provided by FFUs of different sizes and gears, but the actual air supply coverage and maintenance conditions may not be the same.

You should especially check the static pressure data corresponding to the target air volume to make sure whether the filter resistance and related system resistance are included in the complete machine test conditions. Just writing 'maximum air volume' and 'maximum static pressure' into the equipment list cannot prove that FFU can achieve both indicators at the same time in actual projects.

Correct the initial calculation of the number of units using the layout diagram

Put the FFU calculated based on the air volume into the ceiling or equipment installation diagram, and check whether the key process locations receive appropriate air supply, and whether beams, lamps, sprinklers, return air outlets and maintenance channels affect the layout.

If the total air volume is sufficient, but weak air supply areas are formed locally, the location, size, or number of FFUs should be adjusted; if the ceiling cannot accommodate the initial number of units, the single unit specifications, regional air volume distribution, and airflow organization need to be re-evaluated. The final selection cannot be made solely on the result of one division.

Turn calculation results into acceptable solutions

For batch projects, it is recommended to first use a prototype to confirm the actual air volume, static pressure, wind speed uniformity and installation conditions of a single FFU under the specified filter and design gear. After on-site installation, check the total air volume, airflow and cleanliness of key locations in each area according to the technical agreement. When multiple units need unified speed adjustment, you can plan in advanceThe partition and address of the FFU group control system can avoid inconsistent operating conditions of each unit during debugging.

Aili Industrial can match FFU specifications and form a batch configuration plan based on the zone design air volume, floor plan and ceiling plan, filtration requirements and control requirements. During technical communication, it is recommended to clarify the Q area, designated filter, operating gear and test method , so that the same set of working conditions is used for the calculation of the number of units and the final acceptance. Specific specifications and quantities are subject to the project technical agreement and on-site verification results.