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How to test the high efficiency air filter on the FFU?

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High efficiency filter

1. How to test on FFUHigh efficiency filter?

The main purpose of testing the high efficiency filter on the FFU is to find the high efficiency filter itself and its installation process by measuring the allowable leakage;

2. How to test the high efficiency filter on the FFU fan filter unit?

The main purpose of testing the high-efficiency filter on the FFU is to measure the allowable leakage and find the defects of the high-efficiency filter itself and its installation process, such as small pinholes and other damages in the filter medium, frame seals, gaskets Seals and leaks on the filter frame for remedial measures and replacement.

3. Conditions required to test the high efficiency filter on the FFU:

1. InstallationHigh efficiency filterPreviously, each FFUU unit was air blown for at least 48 hours, and the test state has been confirmed as static.

2. The room related to the test has been cleaned and disinfected.

3. Relevant technical personnel and construction personnel must be present during the test and be able to adjust and correct the facilities according to the test results.

4. Prepare the nitrogen cylinder, aerosol (Emery 3004), smoke generator (TDA-5B), and aerosol photometer (2H) required for the test, and the measuring instrument must be qualified.

5. Remove the diffusion orifice plate and the protection net outside the high efficiency filter.

6. Turn off the alarm system of the room and air conditioning system.

4. Confirmation method:

1. Before the test, remove the secondary medium-efficiency filter of the air-conditioning box, place the aerosol generator in the negative pressure section of the fan, and heat it to 400°C.

2. Connect the air inlet of the aerosol generator to the nitrogen bottle, slowly open the pressure reducing valve at the outlet of the nitrogen bottle to keep the nitrogen pressure at about 0.2-0.5Mpa, and aerosol particles will be generated immediately.

3. After stabilizing for a period of time, measure the aerosol concentration with an aerosol photometer at the wind speed of the main air supply pipe, which is the upstream concentration value. The measured aerosol concentration should be in the range of 10-20ug/L.

4. Before testing the downstream aerosol particles, set the aerosol concentration reference value to the upstream measured concentration value. Use the aerosol photometer sampling probe to scan the high efficiency filter and its surrounding frame for leak detection. Detect the time meter probe 2~4cm away from the filter surface, scan back and forth along the inner frame of the filter for leak detection, the scanning speed is 3~5cm/s, the scanning sequence is the whole section of the filter, between the filter paper and the frame, The frame itself and other installation nodes.

5. Two people should operate the leak detection. One person scans the filter back and forth with the photometer sampling probe on the top, and the other person observes the value displayed on the photometer below and makes a record.


5. Acceptable standards:

1. When the reading (penetration rate) on the photometer exceeds 0.01% (that is, the maximum leakage concentration downstream of the filter exceeds 0.01% of the upstream concentration), the filter is deemed to be unqualified and needs to be repaired or replaced.

2. FFU fan filter unitHigh efficiency filterThe leakage rate of the frame seal should be 0; otherwise, it should be reinstalled.

3. FFU fan filter unit high-efficiency filter filter material leakage is allowed to be repaired with special glue, but the area of a single leakage cannot be greater than 1% of the total area; the area of all leaks cannot be greater than 5% of the total area; the leakage point is not More than 3. Otherwise, it must be replaced. , The filter must be replaced.

4. The integrity test must be performed again after the high efficiency filter is repaired or reinstalled. Under normal circumstances, leak detection once a year, and replace the unqualified ones.


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