How much air volume will be lost if the FFU air inlet is blocked by the bridge? How to judge by actual measurement
There is no fixed ratio for occlusion loss
Cables, pipelines, lamps and air ducts are often arranged in the suspended ceiling mezzanine of clean rooms. If these facilities are located near the FFU air inlet, they may block the incoming air. Some projects will ask: How much air volume will be lost if the bridge blocks the FFU air inlet?
There is no unified answer to this question. The air volume loss depends on the size and position of the shield, the distance from the air inlet, the proportion of the shielding area, and the fan characteristics of the FFU itself. The closer the blockage is to the air inlet and the larger the blockage area, the more obvious the impact may be. Different FFU fans have different static pressure margins and different sensitivity to occlusion.
Therefore, a fixed ratio cannot be used to estimate air volume losses for all projects. A more reliable way is to judge by actual measurement under actual installation conditions. Aili Industrial has complete production capabilities in FFU complete machine and airflow design, and can cooperate with the project to analyze the impact of air inlet blocking. For the basic structure of the FFU machine, you can refer toAili Industrial FFU fan filter unit。
How shading affects air intake
Bridges or pipelines block the air inlet of FFU, which mainly affects the air volume in several ways. The obstruction reduces the effective air inlet area and narrows the path for air to enter the FFU. The obstruction changes the direction of the air inlet, causing the airflow to deflect or vortex. The obstruction increases the air inlet resistance, causing the fan to require a larger pressure difference to inhale the same air volume.
If the static pressure margin of the FFU fan is sufficient, the impact of blocking may be small. If the fan is already operating at a higher resistance, additional shading may significantly reduce air flow.
Blocking may also cause uneven air intake. Local air inlet obstruction may lead to uneven airflow distribution inside the FFU, affecting the uniformity of wind speed on the outlet surface.
How to describe occlusion conditions
The occlusion conditions should be described in detail before actual measurement. Include types of obstructions such as trays, conduits, light fixtures, or ducts. The size and location of the obstruction, including width, height, and distance from the FFU air inlet. The proportion of the air inlet covered by the obstruction. The relative direction of the occluder and the FFU. FFU operating status, including rotation speed, control settings and filter status.
The clearer the description, the more valuable the actual measurement results will be. If multiple locations have varying degrees of occlusion, they can be recorded and measured separately.
How to do controlled testing
To determine the impact of occlusion, control testing can be used. Under the same FFU, the same rotation speed, and the same filter status, measure the air volume or wind speed without obstruction and with obstruction respectively.
The unobstructed condition can be measured when the FFU is not equipped with an obstruction, or in a similar unobstructed position. Measured under actual installation conditions with occlusion. Measurement methods and measurement points should be consistent to ensure comparable results.
The measurement content can include the average wind speed, air volume, pressure difference and power near the air inlet on the FFU outlet surface. If conditions permit, you can measure the wind speed at different locations of the air inlet at the same time to observe whether the air intake is uniform.
Comparing the test results can help determine the actual impact of shading on air volume.
How to observe local wind speed distribution
In addition to overall air volume, occlusion may also affect the distribution of incoming and outgoing air. You can measure the local wind speed near the FFU air inlet and outlet surface to see if there is any obvious unevenness.
If the local wind speed at the air inlet is low, it may correspond to the blocked position. If the local wind speed on the air outlet surface is low, it may be related to uneven air inlet. Local wind speed distribution can help locate the specific location of occlusion effects.
Prioritize changes
If the actual measurement confirms that the impact of occlusion is large, rectification can be considered. Prioritizing improvements can start with the locations that have the greatest impact. Remove or adjust obstructions to increase air intake space. If the bridge cannot be moved, the FFU position or installation direction can be adjusted. If space permits, the FFU air inlet clearance can be increased or a diversion structure can be used. If occlusion cannot be avoided, you can evaluate replacing the FFU with a larger fan static pressure margin, or adjust the operating parameters.
After rectification, the measurement should be re-measured to confirm the recovery of air volume. For projects that have already been installed, rectification may need to be carried out in stages to avoid affecting production.
How to prevent it during the design and installation stages
During the design and installation stages, steps can be taken to reduce incoming air shielding. Allow sufficient air intake clearance when deploying FFU. Cables and pipelines should be kept away from the top of the FFU air inlet as much as possible. If you must cross, keep a certain distance or adjust the direction. Before installation, check the relative position of the facilities in the mezzanine and the FFU.
For renovation projects with limited space, you can refer toUltra-thin FFU andThe 70mm ultra-thin EFU understands the compact installation solution, but it also needs to confirm the air inlet clearance.
Issues that should be confirmed in advance during project communication
During the FFU air inlet shielding investigation stage, it is recommended to confirm the following with the FFU manufacturer and designer: the type, size and location of the shield; the distance between the shield and the air inlet; the proportion of the shielding area; FFU operating status and filter status; measurement methods and measuring points; comparison test conditions; rectification plans and retest methods; whether the FFU configuration needs to be adjusted.
If you are dealing with the FFU air inlet blocking problem, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also contact Aili Industrial for support on air flow and air inlet conditions.
in conclusion
There is no fixed ratio of air volume loss when the FFU inlet air is blocked by the bridge, and it depends on the blocking conditions, FFU fan characteristics and operating status. Impacts should be judged by control tests and local wind speed measurements rather than estimates. Corrections can start at the locations with the greatest impact, and allowing air inlet clearance during the design and installation stages can reduce occlusion problems.
Aili Industrial has complete production capabilities in FFU complete machine and airflow design, and can cooperate with the project to analyze the impact of air inlet blocking. If you need to know more about FFU air inlet conditions, you can visitAili Industrial FFU fan filter unit , you are also welcome to contact Aili Industrial for project support.
