How compressed does a HEPA gasket need to be?

'How much pressure is appropriate?' This question is difficult to answer with a number. Because the degree of compression of the gasket depends on the combination of material, thickness and mounting structure.

For the same 10 mm thick gasket, the recommended compression amounts of sponge rubber and silicone are different; for the same material, the requirements for installation on the end of the ceiling and the equipment end box are also different. What really needs to be confirmed is the compression state given by the supplier for this specific product, rather than applying a general ratio.

First check whether the contact surface is flat or not.

Whether the compression effect is good or not depends on the condition of the sealing surface itself.

Uneven installation frames, warped filter frames, and uneven distribution of compression parts will all cause insufficient local compression. In this case, even if the overall compression is achieved, there may still be gaps in some locations.

It is recommended to do a few things before installation: check that the sealing surfaces on all four sides are clean and flat, confirm that the sealing gasket is not broken or displaced, and check the location and number of the pressing parts. When retrofitting an old system, it is also necessary to check whether there is deformation of the frame and whether there is any change in the position of the liquid tank structure. The state of the contact surface is more fundamental than the number of compression.

Control the compression according to the structure, do not rely on feeling

For the tightening process, it is recommended to refer to the drawings or the supplier's installation requirements.

Press gradually, operate in a reasonable order, and observe the contact status of the four corners and straight edges. Do not rely on additional stacking of gaskets to make up for size mismatch - the compression state of each layer after stacking of gaskets is inconsistent, but local failure is prone to occur.

The operation of fasteners is also particular. Tightening one corner first may cause the frame to deform and create new gaps in other locations. Uniform force is the basic principle of compression operation. For structures using liquid tank seals, the way the blade is inserted into the tank is different from the way the gasket is pressed. For verification methods, please refer to the relevant interface instructions.

Confirm results with on-site leak detection

After compaction, the results must be verified by testing.

Check the frame for air leakage under the specified operating air volume. If repeated leaks occur, review the frame, gasket material and fastening structure, do not just increase the tightening force. Excessive compression may cause the frame to deform and make the sealing condition worse . This is especially important to note on lightweight frames.

Supporting At the end of the FFU fan filter unit , the accessibility of the leak detection path must also be confirmed. If the diffuser or structural part blocks the frame, it may need to be disassembled and assembled during leak detection. Device-side applications such as The EFU equipment-end fan filter unit has a compact internal space, and the feasibility of the compaction operation must also be considered in the planning stage.

Treatment of uneven compaction

If the scanning leak detection is only abnormal in one corner, first check the frame flatness and fasteners in that corner, and then compare the compression state of the gasket in other triangles.

Blindly increasing the pressing force at a single corner may distort the frame, but may cause new bypasses to appear in other locations. The processing sequence is: first locate the leakage point, then determine whether it is a material problem, a frame problem or an operation problem, and then deal with it in a targeted manner.

After the processing is completed, re-inspect according to project requirements, and record the processing location and results. For bulk replacement projects, if compression problems occur repeatedly in the same location, you need to consider whether the frame itself needs to be repaired or replaced.

Precautions when replacing gaskets

When replacing the filter element, the condition of the gasket should also be evaluated.

Gaskets that have been used for a long time may have lost their resilience and cannot return to their design state after compression. In this case, even if the pressing operation is in place, the sealing effect may not be ideal.

It is recommended to check the condition of the gasket when replacing the filter element: whether it has become hardened, cracked, or permanently deformed. If any abnormality is found, replace it according to the supplier's recommendations and do not continue to use it. for For different grades of HEPA/ULPA air filter products, the specifications of the gasket may be different. When replacing, follow the corresponding product information.

About Aili Industrial’s sealing packages

Aili Industrial provides supporting support for HEPA with different sealing structures and corresponding air supply equipment. The compression state of the gasket, arrangement of compression parts and on-site leak detection conditions can be confirmed at the planning stage.

It is recommended to provide the size of the installation frame, position of the clamping parts and operating conditions to facilitate verification of the sealing plan. Specific compression requirements are subject to product installation instructions and project technical documents.