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In the cleanliness test of the biopharmaceutical purifi […]
In the cleanliness test of the biopharmaceutical purification workshop, although the minimum sampling amount of air is specified, in actual work, we should use the large flow rate according to the existing testing equipment under the premise of ensuring the minimum sampling amount. Dust particle counter.
1, the selection of testing equipment
Although the cleanliness of the purification plant can be measured, a cleaned engineering light scattering particle counter, a condensed tube particle counter, an electron microscope, and an optical microscope can be used, but the light scattering particle counter is currently the most used. Since the particle counter can automatically and continuously measure the dust content of the indoor air in use, and can directly display the instantaneous dust concentration, it can also measure the dust concentration of different particle sizes, and use Simple, convenient, timely and flexible. The counter can be roughly divided into two types: a side scattering type in which the optical axis of the illumination system is arranged to intersect the optical axis of the detection system; and another is a forward scattering type in which the two optical axes are arranged on the same straight line.
2. When the clean room is cleaned, the sample amount of the light scattering particle counter is used.
Regarding the air sampling amount when the dust particle counter is detected, it is specified in the national standard GBJ73-84: for the 100-level purification workshop, the sampling amount should be greater than or equal to 1L each time. For the purification workshop of 1000~10000 level, the sampling amount should be Greater than or equal to 0.3L, for the 10,000-level purification workshop, the sampling amount should be greater than or equal to 0.1L.
For Class 100 purification plants, high flow particle counters should be used for testing. If not, a particle counter with a sampling amount of not less than 1L should be used.
In the clean room inspection of the clean room, although the minimum sampling amount of air is specified, in actual work, we should use large-flow dust particles according to the existing testing equipment under the premise of ensuring the minimum sampling amount. counter.
3. Arrangement of detection points
According to the National Standard of the People's Republic of China GBJ73-84 "Code for Design of Clean Plants": When testing the cleanliness of the purification workshop, the inspection point should be within 1.00m from the indoor floor; for the one-way flow purification workshop The total number of points should be no less than 20 points, and the distance between the measuring points is 0.5-2.0m. The horizontal one-way flow measurement points are only arranged in the first purification workshop working area; the non-unidirectional flow purification workshops are arranged with five measurement points according to the purification workshop area being less than or equal to 50 m2.
4, on the issue of equal power sampling
The so-called equal-power sampling is that when the detection, the inlet direction of the sampling tube of the particle counter coincides with the direction of the sampled unidirectional airflow, and the average velocity of the air entering the inlet of the sampling tube is the same as the average velocity of the unidirectional airflow at the position.
Because of the inspection of the purification project, we mainly care about two particle sizes, namely 0.5um and 5um. Non-equal power sampling has little effect on particles ≤0.5um. If the sampled air is used to calculate a particle size concentration greater than or equal to 0.5 um, if the particles are not affected by non-equal dynamic conditions, the calculation results are not affected. Therefore, non-equal power sampling in the purification plant area is only meaningful for particles larger than or equal to 0.5 um.