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发表于 2017-1-15 23:14:12
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本帖最后由 beiwei5du 于 2017-1-15 23:25 编辑
ISO不是没有要求（包括WHO HVAC指南），而是not recommended，不知道是出于什么原因？？？？@江苏新征鸿净化 @石头968 @意林枫
下文选自ISO 14644 PART 3,莫非考虑到D级区其本身的target cleanless lever,如果进行aerosol发烟的话，必须达到≥100倍的发烟量（particle size＜1μm）,那么其做相应的自净测试就显得风险较大吗，一般情况下不能接受？？？
This test is not recommended for ISO Classes 8 and 9.
When an artificial aerosol is used, residue contamination of the installation should be avoided.
B.12.3.1 Evaluation by 100:1 recovery time
Direct measurement of the 100:1 recovery time can be performed when it is possible to set up the initial particle concentration at 100 or more times the target cleanliness level.
Care should be taken to avoid coincidence error and potential contamination of the DPC optics. Before testing, calculate the concentration required to carry out the 100:1 recovery time test. If the concentration exceeds the maximum capability of the DPC such that coincidence occurs either use the dilution system, reduce the
concentration to avoid coincidence or replace the 100:1 recovery time test with the recovery rate test (B.12.3.2).
a) Set up the particle counter in accordance with the manufacturer's instructions and the apparatus calibration certificate.
b) Place the DPC probe at the testing point, the measuring points and the number of measurements should be determined by agreement between the customer and supplier. The DPC probe should not be placed directly under the air outlet.
c) Adjust the single sample volume to the same value used for determining the cleanliness class. The delaytime
of the counter from starting each count to the output recording should be adjusted to no more than 10 s.
d) The particle size used in this test should be less than 1 μm. It is recommended that the size channel used
by the DPC corresponds to that of the maximum number concentration of the aerosol.
e) The cleanroom area to be examined should be contaminated with an aerosol while the air-handling units are in operation.
f) Raise the initial particle concentration to 100 or more times the target cleanliness level.
g) Commence measurements at 1 min intervals. Note the time when the particle concentration reaches the 100 × target concentration threshold (t100n).
h) Note the time when the particle concentration reaches the target cleanliness level, (tn).
i) The 100:1 recovery time is represented by t0,01 = (tn − t100n).
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发表于 2017-1-17 09:02:11
not recommended直译是不推荐，不建议，隐藏的含义不就是不需要么？难道一定要用not required?