Air flow and wind speed test standard of purific-Nanjing Enigmar Instrument Technologies Co., LTD

After the completion of the construction of the purification workshop, it is necessary to conduct a systematic wind speed test on the entire indoor ventilation system, including inlet and outlet air. Neither too high nor too low wind speed will directly affect the service life of the air filter of the purification equipment, or directly blow through the air filter; If the wind speed is too small, it will directly affect the circulation of indoor air and the cleanliness of indoor air, leading to the indoor air department reaching the standard. The specific test methods are as follows: hot bulb anemometer, ultrasonic anemometer, vane anemometer, etc. can be used for wind speed testing instruments; The air volume test can use the air hood with flowmeter, Venturi flowmeter, orifice flowmeter, etc.
1、 Test of sectional wind speed, surface wind speed and air volume of one-way flow facilities
For the wind speed test of one-way flow facilities, the test plane shall be perpendicular to the supply air flow, and the test plane shall be 150~300mm away from the air outlet surface of the HEPA filter, which should be 300mm. Divide the test plane into several grids of equal area. The number of grids shall not be less than the square of the test section area (m2). The measuring point shall be at the center of each grid. All measuring points shall not be less than 3.
When directly measuring the air speed on the filter surface, the distance between the measuring point and the air outlet surface of the filter is 150 mm. Divide the test surface into grids of equal area, each with a size of 600mm × 600mm or less, and the measuring point is at the center of each grid.
The duration of the test at each point shall be at least 10 seconds, and the maximum, minimum and average values shall be recorded.
The total air supply volume (Qt) of one-way flow clean room (area) shall be calculated according to the formula:
（m3/h）
Where: Vcp - average wind speed of each grid (m/s);
A -- area of each grid (m2).
The above formula is used to test the wind speed distribution of one-way flow facilities. Generally, the height of the working face is selected as the test plane. The number of grids divided on the plane is not less than the square of the test section area (m2). The measuring point is at the center of each grid.
Nonuniformity of wind speed distribution β 0 shall be calculated according to the following formula, and generally shall not be greater than 0.25
β ０= s/v
Where, v - average value of wind speed at each measuring point;
S -- standard deviation.
The wind speed distribution test is suitable for the air state test. When the process equipment and workbench are installed, the data measured near them may not reflect the characteristics of the clean room itself.

净化车间风量与风速测试标准

Test the wind speed and air volume of non unidirectional flow facilities;
1. Wind speed and air volume tested by tuyere method:
The duration of the test at each measuring point shall be at least 10 seconds to obtain a representative average value. For the test of wind speed and air volume of each air filter or air supply diffuser, refer to the test and calculation methods of mid surface wind speed and air volume in C.2.2.1.
2. Air volume test by air duct method:
If there is a long branch air duct section at the upper air side of the HEPA filter or diffuser outlet and there are reserved holes, the air volume can be measured by the air duct method. The measuring section should be located at a position that is greater than or equal to 3 times the pipe diameter in front of the local resistance component or 5 times the pipe diameter or long side length behind the local resistance component.
The test section of rectangular air duct shall be divided into several equal small sections. Each small section shall be square, and the side length shall not be greater than 200mm. The measuring point shall be located in the center of the small section, but the measuring points shall not be less than 3; The test section of circular air duct shall be divided into several concentric rings with the same area according to the pipe diameter. Each ring shall be tested at 4 points, and the number of rings shall not be less than 3.
3. Air volume tested by hood method:
The fan hood method is used to test the air volume. When the fan hood with a flowmeter is used to measure the air supply volume of the air filter, the opening of the fan hood shall completely cover the air filter or diffuser, and the fan hood surface shall be fixed on a flat plane to avoid inaccurate readings caused by air leakage.
If a venturi or orifice flow device has been installed on the windward side of the HEPA filter or diffuser, the flow meter can be used to directly measure the air volume.
Therefore, after the purification workshop is built, professional testing equipment will be used for linkage testing to achieve the design effect. Ensure the safe operation of the purification workshop.