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The 7 Basic Items That Need To Be Tested In Clean Rooms

  • 2024-02-01
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Clean rooms are widely used in pharmaceutical and biological engineering, precision machinery, medical and health care, food, electronic materials, etc. Why Use A Cleanroom? Clean room is defined as a room with air filtration, distribution, optimization, construction materials and devices where specific rules of operating procedures to control the concentration of airborne particles to achieve the appropriate level of particle cleanliness.

The 7 Basic Items That Need To Be Tested In Clean Rooms

The degree of cleanliness of the clean room and the continuous stability of the control of contamination are the core criteria for testing the quality of the cleanroom. Then the scope of testing in the clean room generally includes: clean room environment level assessment, engineering acceptance testing, including food, health care products, cosmetics, barrels of water, milk production workshop, electronic products production workshop, GMP workshop, hospital operating room, biosafety laboratory, biological safety cabinet, ultra-clean bench, clean room, sterile workshop, etc.

Testing items: air speed and volume, air exchange, temperature and humidity, pressure difference, suspended particles, floating bacteria, settling bacteria, noise, illumination, etc. Specific reference can be made to the relevant standards for clean room testing and What is a cleanroom services?

01、Air speed and volume and number of air changes

Clean room, clean area cleanliness is mainly by sending in a sufficient amount of clean air, in order to discharge, dilute the particle pollutants produced indoor to achieve. For this reason, the determination of clean room or clean facilities air supply, average air speed, air supply uniformity, air flow and flow type and other items is very necessary.

The unidirectional flow mainly relies on clean airflow to push out and replace the polluted air in the room and area to maintain the cleanliness of the room and area. Therefore, its air supply section air speed and uniformity is an important parameter affecting the cleanliness. Higher, more uniform cross-sectional air speed can be faster and more effective to exclude indoor processes generated by pollutants, so they are the main concern of the test items.

Non-unidirectional flow mainly relies on the clean air sent in to dilute and dilute the pollutants in the room and area to maintain its cleanliness. Therefore, the greater the number of air changes, the more reasonable the airflow flow pattern, the more significant the dilution effect, cleanliness is also improved accordingly. So the non-single-phase flow clean room, clean area air supply and the corresponding number of air changes, is the main concern of airflow test items.

In order to obtain repeatable readings, record the time average of the air speed at each measurement point.

The number of air changes: according to the total air volume of the clean room divided by the volume of the French clean room to find

02、Temperature and humidity

Clean room or clean facility temperature and humidity measurement, usually divided into two grades: general test and comprehensive test. The first grade is suitable for in the empty state of the delivery acceptance test, the second grade is suitable for static or dynamic comprehensive performance test. This type of test is applicable to the temperature and humidity performance requirements are relatively strict occasions. This test is conducted after the airflow uniformity test and after the adjustment of the air conditioning system. When this test is carried out, the air conditioning system has been fully operational and the conditions have been stabilized. At least one humidity sensor is set up in each humidity control zone, and the sensor is given sufficient time to stabilize. The measurement should be suitable for the purpose of actual use, and the measurement should start only after the sensor has stabilized, and should take no less than 5 minutes.

The purpose of this test is to verify the ability to maintain the specified pressure differential between the completed facility and the surrounding environment and between the spaces within the facility. This test is applicable to all 3 occupancy states. This test needs to be performed periodically. The pressure difference test should be in all the doors are closed under the conditions, from high pressure to low pressure, from the farthest room in the plan layout and the outside world, in order to test outward; there are holes connected to the different levels of adjacent clean room (area), the hole at the mouth of the appropriate reasonable air flow direction, etc..

03, differential pressure testing requirements.

(1) the determination of the static pressure difference required in the clean area of all the doors are closed under the circumstances.

(2) in the clean plane should be in order from high to low cleanliness, has been detected to the room directly outside.

(3) the measurement of the mouth of the tube is located in any place in the room without the influence of airflow can be, the measurement of the mouth of the tube surface and airflow parallel to the flow line.

(4) the data measured and recorded should be accurate to 1.0Pa.

Differential pressure detection steps.

1) First close all the doors.

2)Measure the pressure difference between each clean room, between clean room corridor, between corridor and outside world with micro differential pressure meter.

3)Record all the data.

Differential pressure standard requirements

According to the clean room design or process requirements to decide to maintain the positive or negative pressure value of the clean room under test.

(1) different levels of clean room or clean area and non-clean room (area) between the static pressure difference, should not be less than 5Pa.

(2) clean room (area) and the outdoor static pressure difference, should not be less than 10Pa.

(3) for the air cleanliness level is more than 5 levels (100 levels) of the one-way flow clean room in the door, the indoor working surface dust concentration at 0.6m inside the door should not be greater than the corresponding level of dust concentration limit.

(4) If the above standard requirements are not met, the new air volume and exhaust air volume should be readjusted until qualified.

04、Suspended particles

A. Indoor test personnel must wear clean clothes, no more than 2 people, should be located on the downwind side of the test point and away from the test point, and should remain stationary. The action should be light when changing points and should reduce the interference of personnel to indoor cleanliness.

B. The equipment should be used within the calibration period.

C, before and after the test equipment "zero"

D. In the unidirectional flow area, the selected sampling probe should be close to the same power sampling, the wind speed into the sampling probe and the wind speed deviation of the air taken should not exceed 20%. If this is not possible, the sampling port will be facing the main direction of airflow. Non-unidirectional flow of the sampling point, the sampling port should be vertical up.

E. The connection tube from the sampling port to the particle counter sensor should be as short as possible.

Sampling points are generally about 0.8-1.2m from the ground, to be evenly distributed scientifically, and to avoid the return air outlet. For any small clean room or local air purification area, the number of sampling points shall not be less than 2, the total number of sampling can be obtained according to the area open 2 times root. The minimum number of sampling points corresponds to the number of suspended particle sampling points, work area measurement point location from the ground 0.8-1.2m or so, the location of the air outlet measurement point away from the air supply surface of about 30cm, key equipment or key work activities can be increased at the range of measurement points, each sampling point is generally sampled once.

After all the sampling, the petri dish will be placed in the constant temperature incubator incubation time of not less than 48 hours, each batch of culture medium should have control experiments to test whether the culture medium is contaminated.

05、Sedimentation bacteria

Work area measurement point location from the ground about 0.8-1.2m, the prepared Petri dish will be placed at the sampling point, open the Petri dish cover, so that it is exposed to the specified time, and then the Petri dish cover, the Petri dish will be placed in the constant temperature incubator incubation, the time is not less than 48 hours, each batch of medium should have control experiments to test whether the medium is contaminated.


Measurement height from the ground about 1.2 meters, clean room area of 15 square meters or less, can only measure the center of the room 1 point; area of 15 square meters or more, should also be measured again diagonal 4 points, 1 meter from each side wall, measurement points towards each corner.


Measuring point plane from the ground about 0.8 meters, according to 2 meters spacing points, within 30 square meters of the room measuring point from the side wall 0.5 meters, more than 30 square meters of the room measuring point from the wall 1 meter.

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