How to determine the air supply area and coverage rate of ULPA? Cleanliness goals and airflow layout

The air supply area and coverage of the ULPA filter need to be determined based on the target air volume, average surface wind speed and process layout. The ceiling coverage ratio cannot alone prove the cleanliness level. The key is how the air passes through the protected area. Coverage is a calculation result, not a starting point for design: first there are cleanliness goals and air volume requirements, then there are face wind speed and area, and then there is the value of coverage. On the contrary, by first determining the coverage and then adding in the air volume, it is easy to get a solution that 'looks full but partially fails to meet the standards'. Aili Industry isFFU fan filter unit andIn the matching of the fan filter unit at the EFU equipment end , the air supply area, surface wind speed and fan working point are calculated in the same plan. The results of the area calculation directly correspond to the specific model and layout quantity.

1. Calculation relationships and units: first write down the formulas and definitions clearly

If Q is the volume air volume (m³/h) and v is the average wind speed on the agreed plane (m/s), then the initial calculated effective air supply area A = Q÷ (3600×v), unit m². The coverage rate needs to be defined uniformly first. For example, when calculating the total projected area of ​​the filter ÷ the net area of ​​the ceiling × 100%, this caliber should be noted and cannot be mixed with the effective air outlet area.

The formula itself is not complicated, what is prone to error is the caliber. The effective air supply area, the filter projected area, and the net area of ​​the suspended ceiling are three different quantities. Which one is used as the numerator and denominator will have completely different results. Aili Industry isThe HEPA/ULPA filter supporting solution provides corresponding data according to the caliber adopted by the project, and the filter projected area and effective air outlet area are given separately.The FFU computer group control system can count the air supply area and actual air volume by partition, providing a clear data source for coverage calculations. The relationship between grade and air supply requirements can be referred toISO cleanliness level comparison。

2. Distinguish different areas: the outer frame projection, effective air outlet surface and room area have different meanings

The outer frame projection, effective air outlet surface and room area have different meanings and should be unified in the calculation. The conversion of air volume and speed also needs to keep the time and length units consistent.

The projected area of ​​the outer frame includes the frame, and the effective air outlet area only counts the area of ​​the filter material that actually passes through the airflow. The difference between the two may not be small. Using the projected area of ​​the outer frame to calculate the coverage rate will result in a higher value; using the effective air outlet area to calculate the coverage rate will be closer to the actual air supply capacity. Aili Industry isTank seal ULPA filter andThe technical data of the non-partitioned ULPA ultra-high-efficiency filter indicates the outer frame size and effective filtration area respectively. The project party selects the corresponding caliber as needed and will not mix the two areas when calculating. The relationship between face wind speed and resistance can be referred toHEPA FAQs and Selection Guide。

3. Check the layout from the protected area: Doesn’t the area mean that the airflow passes through the workstation?

Confirm the location of equipment, personnel and return air to avoid sufficient area but partial obstruction, or clean airflow not passing through sensitive workstations.

The area calculation solves the problem of 'whether the total amount is enough', and the layout solves the problem of 'the airflow cannot reach the key positions'. Similarly, the total air supply area is concentrated at one end of the room, and the workstations at the other end may not be protected; the equipment is densely arranged above the equipment, but the return air is blocked, and the airflow still forms a vortex. Aili Industry isNon-standard ULPA filters andIn the layout plan of the FFU fan filter unit , check the air supply surface coverage according to the workstation location and equipment layout. Local protection inside the equipment can be combinedThe fan filter unit at the EFU equipment end is configured separately. The relationship between air supply layout and airflow organization can be referred toULPA ultra-high efficiency filter FAQ and selection guide。

4. Use the system to verify the design: coverage is a layout indicator, not a conclusion

Combined with air volume, uniformity, flow pattern and related environmental test confirmation, coverage can be used as a layout indicator and cannot replace test conclusions.

The calculated coverage rate only shows the proportion of the air supply surface on the plane. Whether the actual air flow is uniform, whether the direction is stable, and whether the particle concentration in the protected area reaches the standard must be confirmed through testing. Aili Industry isWhen ULPA ultra-high efficiency filters are delivered, they can cooperate with the project party to clearly verify the project.The FFU computer group control system records partition air volume and operating status, making it easy to compare design coverage with actual air volume. For verification of internal scenes of the device, please refer toEFU FAQ and technical support。

5. Related questions and answers

Can I directly check the fixed coverage rate according to the cleanliness level?
The empirical value can only be used as a preliminary reference, and the actual solution needs to be verified based on the process and air flow organization.

If the total air supply area is concentrated at one end of the room, can the workstations at the other end be protected?
Usually not. The layout and return air should be re-evaluated to ensure that the area is not sufficient for airflow to pass through the protected area.

Does meeting the coverage rate equal to meeting the cleanliness standard?
Not equal to. Coverage is a layout indicator, and cleanliness needs to be confirmed through air volume, uniformity, flow pattern and particle testing.

6. Related articles

ULPA ultra-high efficiency filter FAQ and selection guide

No partition ULPA ultra high efficiency filter

Non-standard customized ULPA ultra-high efficiency filter

HEPA FAQs and Selection Guide

7. Key points for selection and acceptance inspection

8. Product matching and technical support from Aili Industrial

Aili Industry isFFU fan filter unit andIn the EFU equipment end fan filter unit package, the air supply area, surface wind speed and fan working point are calculated in the same plan, and the area calculation results directly correspond to the specific model and layout quantity;HEPA/ULPA filter supporting solutions provide corresponding data according to project caliber.Tank seal ULPA filter andThe technical data of the non-partitioned ULPA ultra-high-efficiency filter respectively indicates the outer frame size and effective filtration area.Non-standard ULPA filters andThe FFU fan filter unit layout plan checks the coverage according to the workstation location and equipment layout.The FFU computer group control system counts the air supply area and actual air volume by partition, which facilitates comparison between design and actual measurement. Provide process objectives, installation drawings, operating conditions and acceptance requirements for further communicationULPA ultra-high efficiency filters . Standard specifications, non-standard interfaces, samples and batch matching of The specific parameters and test range are based on the confirmed model and technical documents.