First, the concept of cleanroom

Clean area is the air suspended particles concentration of controlled limited space, construction and use should reduce the space induced, generated and retained particles, the space of other relevant parameters such as temperature, humidity, pressure, etc. Other relevant parameters in the space such as temperature, humidity, pressure, etc. are required to be controlled.

Air cleanliness refers to the extent of the amount of dust particles in the air in a clean environment, and a high concentration of dust is low cleanliness, while a low concentration of dust is high cleanliness.

The specific level of air cleanliness is differentiated by the air cleanliness level, which is expressed by the counted dust concentration of the air during the operation time.

Suspended particles are solid and liquid particles in the air with a size range of 0.15μm that are used for air cleanliness classification.

Second, the classification of Cleanroom


1, according to the cleanliness level is divided into 1, 2, 3, 4, 5, 6, 7, 8, 9. 9 is the lowest level.

2. According to the classification of airflow organization, Cleanroom can be divided into three categories:unidirectional flow, laminar flow, Cleanroom.

The airflow is parallel along a single direction and has the same wind speed on the cross-section. Among them, the one-way flow perpendicular to the horizontal plane is vertical one-way flow and the one-way flow parallel to the horizontal plane is horizontal one-way flow.

Non-unidirectional flow Cleanroom where the airflow does not meet the definition of unidirectional flow Cleanroom. Mixed flow cleanroom:a cleanroom where unidirectional flow and non-unidirectional flow combination of airflow.

3. According to the classification of suspended particles in the air to be controlled, the Cleanroom can be divided into industrial Cleanroom and biological Cleanroom.

Industrial Cleanroom, it is the main control parameters are temperature, humidity, air velocity, airflow organization, cleanliness.

Biological Cleanroom it is the same as the industrial Cleanroom is different from the control parameters increased control of indoor bacterial concentration.

4. The detection status of the Cleanroom can be divided into three categories.

(1) the empty state of the Cleanroom facilities are complete all pipelines connected and running but no production equipment, materials and production personnel.

(2) static state has been fully built in the facilities of the complete Cleanroom installed production equipment and according to the owner-supplier agreed to test the way far turn, but no production personnel in the field.

(3) Dynamic facilities are in a state of operation in the prescribed manner and have the required personnel present to work in the prescribed manner.

Three, clean air conditioning and general air conditioning difference

The difference between Cleanroom and general ventilation and air conditioning system Cleanroom air conditioning is a kind of air conditioning project, it is not only on the indoor air temperature, humidity, wind speed has certain requirements, but also on the number of dust particles in the air, the concentration of bacteria, etc. have higher requirements.

Therefore, it not only has special requirements for the design and construction of the ventilation project, but also has special requirements for the design and construction of the building layout, material selection, construction process, building practices, plumbing, heating, electrical ventilation and technology itself, and the corresponding technical measures to increase the cost accordingly.

1, the main parameters of control

General air conditioning focuses on the temperature, humidity, fresh air supply, while the Cleanroom air conditioning focuses on controlling the dust content of indoor air, wind speed, the number of air changes. In the temperature and humidity requirements of the room, they are also the main control parameters. Bio-Cleanroom on the bacterial content is also one of the main control parameters.

2, air filtration means

General air-conditioning have only coarse-effect primary filtration, the higher requirements are coarse-effect secondary filtration processing.

And clean air conditioning requires three filtration, namely, coarse, medium and high efficiency three filtration or coarse, medium and sub-high efficiency three filtration. In addition to the three-level filtration in the air supply system of biological Cleanroom, in order to eliminate the special odor of animals and avoid the pollution of the environment in the exhaust system, according to the different circumstances, there are still two high-efficiency filtration or filtration adsorption filtration.

3. Indoor Pressure Requirements

General air-conditioning on the indoor pressure without special requirements, and clean air-conditioning in order to avoid the penetration of outside contaminated air or different production workshops of different substances affect each other on the different clean areas of the value of the positive pressure have different requirements. In the negative pressure Cleanroom there is still a negative pressure degree of control requirements.

4, clean air conditioning system materials and equipment selection, processing technology, processing and installation environment, equipment parts storage environment in order to avoid external pollution have special requirements. This is also the general air conditioning system does not have.

5. Requirements for airtightness

General air-conditioning system on the system's airtightness of the seepage of air, although there are requirements.

But the clean air conditioning system requirements than the general air conditioning system much higher than the means of detection, the standard of each process have strict measures and testing requirements.

6. Requirements for civil engineering and other types of work.

General air-conditioning room on the building layout, thermal engineering and other requirements, but the selection of materials and airtightness requirements are not very much attention.

The evaluation of building quality for clean air conditioning is focused on dust prevention, anti-dusting and anti-leakage, in addition to the general appearance of the building and other requirements.

The requirements for construction process arrangement and overlap are very strict to avoid reworking to produce cracks causing leakage.

It is also very strict on the cooperation and requirements of other types of work, mainly focusing on the prevention of leakage to avoid external contaminated air infiltration into the Cleanroom and to prevent the accumulation of dust on the pollution of the Cleanroom.


Four, Cleanroom completion acceptance

After the completion of the Cleanroom and put into operation, need to carry out performance measurement and acceptance;in the system overhaul or update, but also to carry out a comprehensive determination in the determination of the former. Before the determination of the Cleanroom must be a comprehensive understanding of the profile.

The main content includes purification of air-conditioning system and process layout of the flat, sectional and system diagrams of the air environment conditions cleanliness level temperature, humidity, wind speed and other requirements of the air handling program to send back the wind, exhaust volume and airflow organization, people and things purification program Cleanroom use of the factory and its surrounding pollution.

(a) the appearance of the Cleanroom acceptance inspection should meet the following requirements

1, a variety of piping, automatic fire extinguishing devices and purification of air-conditioning equipment air conditioners, fans, purification of air-conditioning units, high-efficiency air filters and air blowing room should be installed correctly, firmly, tightly and its deviation should be The installation should be correct, firm and tight, and the deviation should be in accordance with the relevant regulations.

2. The connection between high and medium efficiency air filters and supporting frame and the connection between air duct and equipment should be reliably sealed.

3. All kinds of adjustment devices should be tight, flexible and easy to operate.

4. The purified air-conditioning box, static pressure box, air duct system and air supply and return ports are free of dust.

5, the Cleanroom wall, ceiling surface and ground should be smooth, flat, uniform color without dust floor without static electricity.

6, air supply and return vents and all kinds of end devices, all kinds of piping, lighting and power line piping and process equipment, etc. through the Cleanroom through the sealing treatment should be tight and reliable.

7, Cleanroom all kinds of switchboards, cabinets and into the Cleanroom of the electrical pipeline, pipe mouth should be sealed reliably. 8 all kinds of painting, insulation work should be in line with the relevant provisions.

(B) Cleanroom manufacturing acceptance of the debugging work

1, where there is a test run requirements of the equipment stand-alone test run should be in line with the relevant provisions of the technical documents of the equipment.

Belonging to the common requirements of mechanical equipment should also be consistent with the relevant provisions of the state and mechanical equipment construction and installation of the relevant industry standards. Usually, the Cleanroom is required to carry out stand-alone test run of the equipment are air conditioning units, air supply pressurized fan box, exhaust equipment, purification workbench, electrostatic self-cleaning device, clean drying box, clean storage cabinets, such as local purification equipment, as well as the air blowing shower room, residual pressure valves, vacuum vacuum cleaning equipment, and so on.

2, in the stand-alone test run after passing the air supply system, air return system, exhaust system air volume, air pressure regulator to set and adjust the air volume distribution of each system to meet the design requirements.

The purpose of this phase of testing is mainly to serve the air conditioning and purification system adjustment and balance often need to be repeated many times.

This test is mainly carried out by the contractor, and it is advisable for the maintenance manager of the construction side to follow up in order to familiarize with the system.

On this basis, the joint test run of the system including cold and heat sources is generally not less than 8 h. The equipment components of the system including purified air-conditioning systems, automatic control devices, etc. should be operated correctly without any abnormality in the process of linkage operation and coordination.


Five, Cleanroom testing process

Where the determination of all the instruments used in the instrumentation must be identified in accordance with the provisions of the calibration or calibration. Before the determination, the system, Cleanroom, machine room and other places to carry out a comprehensive cleaning;in the cleaning and system adjustment, must be run continuously for a period of time and then for leakage detection and other items of determination.

(a) The procedure of Cleanroom measurement is roughly as follows:

1, fan air blowing

2, indoor cleaning

3, adjusting the airflow

4, An intermediate filter

5, An efficient filter

6, System operation

7, Leakage testing of high-efficiency filters

8, adjust the air volume

9, adjust the indoor static pressure difference

10, adjust the temperature and humidity

11, single-phase flow of the Cleanroom cross-section of the average velocity, velocity non-uniformity of the determination
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12, the determination of indoor cleanliness

13, the determination of indoor planktonic bacteria and settled bacteria

14, and the production equipment related to the work and adjustments

(B) the test basis

(ii) the basis for the test

Including specifications, drawings, design documents and technical data of equipment, etc., divided into the following two categories.

1. Design documents, supporting documents for design changes and related agreements, as-built drawings.

2. Technical data of equipment.

3, "Clean Plant Design Code" GB50073-20012, construction and installation category "Ventilation and Air Conditioning Engineering Construction Quality Acceptance Code" GB50243-2002

Six, testing methods and results of the judgment

(a) air volume or wind speed test

1. Sampling of the district with design requirements for testing.

2, the air volume and wind speed must first be tested on the purification and air conditioning of the various effects, and must be in the design of the air volume and wind speed conditions obtained.

(1) Turbulent flow Cleanroom system should be greater than the measured air volume value of the respective design air volume value but should not be more than 20%;measured fresh air volume and the design of the new air volume should not be more than the design of the new air volume of ± 10%;indoor air volume of each air outlet and the respective design of the difference between the wind volume should not be more than the design of the air volume of ± 15%.

(2) Unidirectional flow laminar flow Cleanroom measured average indoor air velocity should be greater than the design air velocity but should not exceed 20%;the total measured new air volume and the design of the difference between the new air volume should not exceed the design of the new air volume of ± 10%.

3. Operation Process and Determination

(1) Turbulent flow Cleanroom

a. For the air outlet without filter can be in accordance with the comprehensive effectiveness of the general ventilation and air conditioning air outlet air volume test method.

b. For the air outlet with filter, the auxiliary duct can be selected according to the form of air outlet, i.e., made of rigid plate with the same cross-section inside the air outlet and the length is equal to 2 times the length of the straight section of the air outlet connected to the outside of the filter air outlet in the plane of the outlet of the auxiliary duct, the number of measurement points is at least 6 evenly arranged measurement points, and the points are measured by the hot bulb anemometer. The wind speed is determined by a hot bulb anemometer at each point, and the wind volume is determined by multiplying the average wind speed of the air outlet cross-section by the net cross-sectional area of the air outlet.

c. For the air outlet with similar diffusion plate, the air volume resistance curve and measured diffusion plate resistance can be based on the diffusion plate to find out the air volume measurement with micropressure meter and Bitou or fine oak tube instead of Bitou, but all must make the measurement of the plane of the holes perpendicular to the direction of the airflow so that the measured value correctly reflects the static pressure value.

d. Measurement of wind volume by wind cover method

① When the wind volume cover is used to determine the wind speed of each air outlet, the corresponding air velocity is Vs=As.

Vs------the average air velocity of each terminal filter or air diffuser. Air velocity m/s;

Qs------each terminal filter or air supply diffuser air volume m3/s;

As------air supply outlet air area m2.

② unidirectional flow -laminar flow Cleanroom'

① unidirectional flow -laminar flow Cleanroom
Unidirectional flow Cleanroom using room cross-section of the average wind speed and cross-sectional area of the product of the method to determine the amount of air supply, in which the vertical unidirectional flow laminar flow Cleanroom to determine the cross-section taken from the ground 0.8m of the horizontal cross section, horizontal unidirectional flow laminar flow Cleanroom to take the vertical cross-section from the surface of the air supply surface of 0.5m, the cross-section on the measurement points should not be greater than the distance between the 2m, the number of measurement points should be not less than 10 The number of measurement points should be not less than 10, and the hot bulb anemometer should be used for uniform arrangement of instruments.

③ Determination of air volume in the duct

For the wind side of the air outlet has a longer branch pipe section, and has been or can be punched, you can use the duct method to determine the air volume, the determination of the cross-section from the local resistance components in the local resistance components after the distance of not less than 5 times the diameter of the pipe or 5 times the length of the big side.

For rectangular duct, the determination of the cross-section is divided into a number of equal small sections, each small section as close as possible to the length of the square edge, preferably not more than 200mm measurement point, set in the center of the small section, but the number of measurement points on the entire section should not be less than 3.

For round duct, it should be divided into measurement sections and determine the number of measurement points according to the equal-area circle method. Specifically, it can be carried out according to the method of measuring the air volume of the general ventilation and air conditioning duct method with comprehensive efficiency.

(B) indoor static pressure difference test

1, instrumentation and environmental measurement instruments inclined micromanometer, digital micromanometer and so on. Ambient temperature at room temperature or design temperature.

2. Sampling of each adjacent area with design requirements to implement the test.

3. The results of the static pressure difference test shall comply with the following provisions.

(1) The static pressure difference between adjacent Cleanrooms of different levels and between Cleanrooms and non-Cleanrooms should not be less than 5Pa.

(2) The static pressure difference between the Cleanroom and the outdoor area should be more than 10Pa.

(3) Cleanliness Higher than 100 levels of unidirectional flow laminar flow Cleanroom in the open state at the entrance and exit of the indoor side of the 0.6m should not be measured more than the upper limit of the concentration of indoor level.

4, the operation process and judgment

(1) will be all the doors closed, will be measured with the hose caliber preferably below 5mm from the wall hole into the room not far from the wall, perpendicular to the direction of the air flow is set up around the direction of the unobstructed air flow disturbance is minimal.

(2) The determination of static pressure difference should be from the plane of the most inside the room, usually is the highest cleanliness level of the room, and its immediate neighboring rooms between the measurement of the pressure difference between the measured in turn outward measurement, until the measurement of the most out of the Cleanroom and the surrounding subsidiary environment, and the pressure difference between the outdoor environment.

(3) For cleanliness higher than Class 5 unidirectional flow laminar flow Cleanroom, should also determine the number of particles in the door open state from the door 0.6m at the height of the indoor side of the working surface.

5, the detection of attention

In the Cleanroom static pressure difference test before, must first verify the Cleanroom or clean facilities in the normal operation of the door should be closed under all the conditions of air supply and return air volume, exhaust air volume and the provisions of the air volume in line with the requirements of the air volume. If it is not up to the standard requirements should be re-adjusted new air volume, exhaust air volume until qualified.

(C) air filter leakage

1, instrumentation and environmental measurement instruments dust particle counter, aerosol generator. Ambient temperature at room temperature or design temperature.

2, sampling of high-efficiency filter body before entering the scene, the manufacturer should be in accordance with the provisions of the performance test, and provide a certificate of compliance. In the unidirectional flow Cleanroom on the installation of high-efficiency air filters should be one by one to carry out leakage detection, turbulent flow Cleanroom for 7 or lower level Cleanroom, as long as the Cleanroom to achieve the required air cleanliness level, you can not carry out leakage detection.

3, the technical requirements of the results of the leakage test to meet the conditions:the leakage concentration measured by the downwind side of the inspected filter is converted into a transmission rate for high-efficiency filters should be no greater than 2 times the factory qualified rate of the filter for ultra-high-efficiency filters should be no greater than 3 times the factory qualified rate of the transmission rate.

4. The operation process and the judgment of the filter leakage test refers to the installation of the completed air filter leakage test applies to the empty state or static Cleanroom.

For the high-efficiency filter installed at the end of the supply and exhaust air, the scanning method should be applied to filter the installation border and full section leakage detection, and there are two kinds of scanning methods, namely, the leak detector method, the photometer method, and the particle counter method with a minimum sampling volume of 1 L/min.

(D) air cleanliness level

1, instrumentation and environmental measurement instruments dust particle counter. Ambient temperature Cleanroom area temperature and relative humidity should be compatible with its production and process requirements.

2. Location and number of sampling points

a. Determination of the cleanliness of each minimum sampling volume;

b. The minimum number of sampling times for each clean area is 3 times, and when there is only one sampling point in the clean area, then the point will be at least Sampling 3 times;

d. For the expected air cleanliness level of 4 or cleaner environment sampling volume is very large can be used ISO14644-1 Appendix F provisions of the sequential sampling method.

3, technical requirements

① each sampling point of the average particle concentration Ci should be less than or equal to the cleanliness level limit;

② all sampling points of the average particle concentration N 95% confidence limit should be less than or equal to the cleanliness level limit. or equal to the cleanliness level limit.

4, the operating process and judgment

① instrument power on after warming up to a stable, before the instrument can be calibrated in accordance with the provisions of the instruction manual, self-checking, self-calibration, zero-counting;

② sampling tube mouthpiece placed in the sampling point sampling Confirmation of the counting stability before the start of continuous readings;

③ counter sampling port and the instrument's working position should be in the same air pressure and temperature, so as to avoid measurement errors;

④ for the unidirectional flow of Cleanroom sampling port should be directed towards the direction of the airflow for the turbulent flow of the Cleanroom sampling port upward. Sampling speed should be as close as possible to the indoor air velocity;

⑤ Record data evaluation.

5, the Cleanroom air suspended particles detection sampling should be noted

① static test indoor testers shall not be more than two people test report should be labeled with the state of the test;

② for Unidirectional flow test should be in the purified air conditioning system after the start of the normal operating time of not less than 10min non-unidirectional flow to be not less than 30min after the start;

③ must be in accordance with the instrument calibration cycle of the instrument for regular calibration. Depending on the characteristics of the instrument itself, the frequency of use, the use of the environment and other decisions;

④ each sampling point can be calculated according to the minimum sampling volume determined by the sampling air. However, according to the sampling volume and time setting of the particle counter used, the actual sampling may be higher than the minimum sampling volume.

⑤During the measurement, personnel entering the Cleanroom should wear clean clothes, go through the air shower room, and try to be in the downwind place in the room and be still and less moving.

6, indoor planktonic bacteria and sedimentation bacteria airborne microorganisms in the determination of a variety of, but its determination of the basic process of the process of capture, cultivation, counting, the current use of planktonic bacteria and sedimentation bacteria test methods.

(1) Instrumentation and environmental measurement instruments Petri dishes, centrifugal microbial sampler, constant temperature incubator, planktonic bacteria, settled bacteria before the test, the temperature and humidity of the Cleanroom area to be tested to meet the requirements of the provisions of the static pressure difference must be controlled in the specified value, the Cleanroom area to be tested has been disinfected.

Sampling device:The preparation before sampling and the processing after sampling should be operated in the negative pressure laboratory with high efficiency filter exhaust, and the test status has two kinds of static and dynamic and the test status is indicated in the report.

Test PersonnelTest personnel must wear work clothes that meet the cleanliness level of the environment. No more than two persons shall be allowed in the room during the static test.

(2) the location and number of sampling points

Indoor planktonic bacteria measurement points and cleanliness measurement points can be the same, sampling must be used in accordance with the instructions of the instrument described in the steps, pay special attention to the instrument disinfection and sterilization before testing. Sedimentation bacteria determination, petri dishes should be arranged in a representative location and the air flow disturbance is very small number of petri dishes in the location.

(3) Technical requirements of indoor planktonic bacteria and settled bacteria should meet the design requirements.

(4) Operation Process and Judgment

①Testing of planktonic bacteria

a. First of all, the surface of the testing instruments and petri dishes should be strictly sterilized, and the sampler should be sterilized with disinfectant of the disinfected room first when entering the room to be tested. Samplers used in class 5 Cleanrooms should be placed in the Cleanroom all the time.

b. Sampler should wear clean clothes and hands should be sterilized.

c. Start the vacuum pump to pump the residual disinfectant evaporation time in the instrument is not less than 5min, and adjust the flow rate turntable speed. Turn off the vacuum pump into the petri dish to cover the lid and adjust the sampler.

d. Place the sampling port in the sampling point and then turn on the sampler, vacuum pump, rotate the timer, and select the sampling time according to the sampling volume. After all the sampling, put the petri dish upside down in the constant temperature incubator at 30-35℃, and incubate it for not less than 48h.

e. Count the colonies directly with the naked eye, and then check whether there is any omission with 5-10 times magnification, and if there are two or more colonies on the plate overlapping and discriminating, it will still be counted by two or more colonies.

② sedimentation bacteria test

For unidirectional flow such as 5 purification room and laminar flow bench test should be in the purification of air-conditioning system normal operation of not less than 10 minutes after the start;non-unidirectional flow such as 7, 8 or more purification room test should be in the purification of air-conditioning system normal operation of not less than 30 minutes after the start. 30 minutes.

a. Sampling method:Place the prepared petri dish at the pre-determined sampling point, open the lid of the petri dish so that the surface of the medium is exposed for 0.5 hours and then invert the petri dish with the lid on.