Sharing of items and standards for clean room testing 2/2

3. Pressure difference

The purpose of this test is to verify the ability to maintain a certain pressure difference between the finished facility and the surrounding environment, and between Spaces within the facility. This detection applies to all three occupied states. Such testing is indispensable. The detection of pressure difference should be carried out under the condition that the whole department is closed, starting from high pressure to low pressure, starting from the plane layout and the inner room far from the outside, and then testing outward in turn. Different grades of clean rooms with holes connected have only reasonable air flow at the entrance.

Pressure difference detection requirements:

(1) When all doors in the cleaning area are required to be closed, the static pressure difference is measured.

(2) On the clean plane, it should be carried out in the order of cleanliness from high to low until the room with direct access to the outside is detected.

(3) When there is no air flow in the room, the measuring pipe mouth should be set in any position, and the measuring pipe mouth surface is parallel to the air flow line.

(4) The data recorded by the measurement should be accurate to 1.0Pa.

Pressure difference detection steps:

(1) Close all doors.

(2) Use a differential pressure gauge to measure the pressure difference between each clean room, between the clean room corridor, and between the corridor and the outside world.

(3) Record all data well.

Pressure difference standard requirements:

(1) The static pressure difference between different levels of clean rooms or clean areas and non-clean rooms (areas) is required to be greater than 5Pa.

(2) The static pressure difference between the clean room (area) and the outdoor is greater than 10Pa.

(3) For unidirectional flow clean rooms whose air cleanliness level is stricter than level 5 (level 100), when opening the door, the indoor working surface dust concentration at 0.6m inside the door should be less than the dust concentration limit of the corresponding level.

(4) If it fails to meet the above standard requirements, the fresh air volume and exhaust air volume should be re-adjusted until qualified.

Clean room testing

4. Suspended particles

(1) Indoor test personnel must wear clean clothes, less than two people, should be located on the downwind side of the test point and away from the test point, and the action should be light when doing the change point operation, do not increase the interference of personnel on the indoor cleanliness.

(2) The equipment should be used during the calibration period.

(3) The equipment should be cleared before and after the test.

(4) In the unidirectional flow area, the selected sampling probe should be close to the isodynamic sampling, and the wind speed deviation between the wind speed entering the sampling probe and the air being taken should be less than 20%. If this is not done, the sampling port should be pointed in the main direction of the air flow. For the sampling point of a non-unidirectional flow, the sampling port should be straight up.

(5) The connection pipe between the sampling port and the dust particle counter sensor should be as short as possible.

5. Planktonic bacteria

The number of sampling points in the low position corresponds to the number of sampling points of suspended particles. The measuring point in the working area is about 0.8-1.2m above the ground, and the measuring point in the air supply outlet is about 30cm away from the air supply surface. The measuring point can be added to the key equipment or the key working activity range, and each sampling point is usually sampled once.

6. Settling bacteria

Work at 0.8-1.2m from the ground, place the prepared petri dish at the sampling point, open the lid of the petri dish, after the specified time, then cover the petri dish, and culture the petri dish in the constant temperature incubator, the time needs to be more than 48 hours, each batch should have a controlled test to check the contamination of the medium.

7. Noise

If the measuring height is about 1.2 meters from the ground and the clean room area is within 15 square meters, only 1 point in the center of the room can be measured; If the area is more than 15 square meters, it should also measure 4 diagonal points, 1 meter away from the side wall, and the measurement point is toward each corner.

8. Illumination

The measuring point surface is about 0.8 meters from the ground, the distribution point is 2 meters, the measuring point of the room within 30 square meters is 0.5 meters from the side wall, and the measuring point of the room larger than 30 square meters is 1 meter from the wall.