First, the air cleanliness of the clean room should be tested as follows

(1) Empty state and static test

Empty test: The clean room has been completed, the purified air conditioning system has been in normal operation, and the test is carried out without process equipment and production personnel in the room.

Static test: The clean room air conditioning system is in normal operation, the process equipment is installed, and the test is carried out without production personnel in the room.

(2) Dynamic test

The clean room has been tested under normal production conditions.

The detection of air volume, wind speed, positive pressure, temperature, humidity and noise in the clean room can be implemented in accordance with the relevant provisions of general and air conditioning.

Two, empty state, static test

(1) Preparation before the test

1. The clean room and its purified air conditioning system should be thoroughly cleaned.

2. Use light scattering particle counter for leak detection test of high efficiency air filter. First of all, the number of dust particles with a particle size greater than or equal to 0.5μm in the hydrostatic chamber (or duct) of the upwind side of the high efficiency air filter should be greater than or equal to 30,000 particles/liter. If it is not enough, smoke can be introduced and the leak detection can begin. The sampling port of the particle counter (or leak detection device) is 2-3 cm away from the high efficiency air filter, and the speed of 2-4 cm/SEC can be moved to scan the entire section of the high efficiency air filter head glue and the installation frame.

When the particle counter reading is greater than or equal to 0.5μm of dust particles at the air port more than 3 particles/min · liter (or its penetration rate is greater than 0.01‰), it is considered that there is significant leakage and must be blocked.

(2) Test content

1. Total supply air, total return air, fresh air, exhaust air, etc.;

2. Clean room pressure value;

3. Laminar flow clean room section wind speed and air flow direction;

4. Clean working area cleanliness;

5. Adjustment test of indoor temperature, humidity and its control ability;

6. Clean room noise.

(3) Test method of air cleanliness in clean working area

For dust particles with a particle size greater than or equal to 0.5μm, light scattering particle counting method or filter membrane microscope counting method should be used.

Light scattering particle counting method:

1. Light scattered particle counter sampling volume 100 level: each sampling volume is greater than or equal to 1 liter. Class 1,000 - Class 10,000: Each sample volume is greater than or equal to 0.3 liters. Class 100,000: Each sample volume is greater than or equal to 0.1 liters. For class 100 clean rooms, large flow particle counters should be used for testing; If conditions are not available, a particle counter with a sample size of not less than 1 liter per sample can be used.

2. Sampling precautions:

① The sampling tube must be clean, and the connection is strictly prohibited from leaking.

The length of the sampling tube should be based on the allowable length of the instrument. When there is no provision, it should not be greater than 1.5 meters.

(3) The flow rate of the sampling pipe should be close to the average wind speed of the clean room section. The tester should be on the downwind side of the sampling port.

④ The sampling sequence should be conducted according to the dust concentration from low to high.

3. Measuring point arrangement:

① The test is carried out in a clean work area. When the production process has no special requirements, the sampling height should be 1 meter from the ground.

(2) The total number of test points in the laminar flow clean room is not less than 20 points, the distance between the test points is 0.5-2.0 meters, and the number of dust particles with a particle size greater than or equal to 0.5μm is allowed to have one point over. The measurement point of horizontal laminar flow clean room is only arranged in the first clean work area.

(3) The turbulence clean room can be arranged with 5 measuring points according to the clean area of less than or equal to 50 square meters (Figure 2). For every increase of 20-50 square meters, add 3-5 measuring points.

4. Data sorting:

① The data collection of each measurement point should be sampled three times in succession under the condition of stable operation of the test instrument, and the average value i the measured value of the point.

② For the number of dust particles greater than or equal to 0.5μm, the maximum value of each measuring point is taken in the laminar flow clean room, and the average value of each measuring point is taken in the turbulence clean room.

(4) The positive pressure value should be determined by using a micro-pressure meter with an accuracy of up to 0.01 mm water column.

Third, dynamic testing

At the operating position of the clean work area, the air flow of a representative measuring point is selected upwind. The test method is the same as empty state and static test.