Test Method For Comprehensive Performance Of Clean Room

2022-07-15

Filter leak detection

For the high-efficiency filter installed at the air supply and exhaust ends, the scanning method shall be applied to the filter installation frame and full section leak detection. There are two scanning methods: leak detector method (photometer method) and particle counter method with a minimum sampling amount of 1l/min. For ultra-high efficiency filters, there are two scanning methods: condensation nodule counter method and laser particle counter method.

1. Leak detector method

(1) The leak detection filter must have measured the air volume and operate between 80% and 120% of the design air speed.

(2) When multiple filters are installed on the same air supply surface, the method of exposing only one filter at a time should be used for measurement if the structure allows.

(3) When several or all filters must be exposed to aerosols at the same time, in order to cause uniform mixing of all filters, aerosol for leak detection should be introduced into the suction end of the fan or the branch pipe in front of these filters, and the concentration on the windward side should be measured immediately in front of the tested filter.

(4) For high efficiency filters, when the leak detection instrument is logarithmic scale, the aerosol concentration on the windward side should exceed 104 times the minimum scale of the instrument; When the leak detector has a linear scale, the aerosol concentration on the windward side needs to reach 80 ~ 100 μ ｇ/L。 The leak detection instrument should have 0.001 ~ 100 μ G/l measurement range.

2. Particle counter leak detection

(1) The tested filter must have measured the air volume and operate between 80% and 120% of the design air speed.

(2) Measure the particle number of atmospheric dust on the windward side of the tested high-efficiency filter to be greater than or equal to 0.5 μ M particles,

(3) If the concentration on the windward side does not meet the above provisions, unfiltered air should be introduced. If it does not meet the provisions, it is not suitable to use particle counter method and condensate counter method to detect leakage.