Clean room filter leak detection method

Cleanroom filter leak detection actually uses scanning method, scanning spectrophotometer method and particle counter method. Two leak detection methods can be implemented, using American ATI photometer and aerosol generator.

Based on the specifications

• GB50591-2010 "Cleanroom Construction and Acceptance Specifications"

• GB50243-2002 "Ventilation and Air Conditioning Engineering Construction Quality Acceptance Specifications"

• GB/T25915-2010 "Cleanrooms and Related Controlled Environments"

• S014644 2006 Cleanrooms and associated controlled environments

Our point of view: PAO leak detection is generally for high-efficiency filters in pharmaceutical factories and laboratories. FDA recommends leak detection for sterile preparation production workshops every six months in the Sterile Drug Production Guide. China recommends that it is usually once a year in the GMP Inspection Guide. iso14644 recommends a maximum time interval of 24 months for leak detection of installed hepa. PAO leak detection should be performed after HEPA is installed or replaced. When environmental monitoring shows deterioration in air quality, or when a product fails a sterility test or a simulated culture medium filling test, leak detection can be performed as part of a deviation investigation. Filters that need to be leak tested also include hepa filters used in drying tunnels and dry ovens.

Solutions and features

1.Leak detector method

• The filter to be tested must have its Air volume measured and operate between 80% and 120%6 of the design air speed.

• When multiple filters are installed on the same air supply surface, if the structure allows, it is advisable to expose only one filter at a time for measurement.

• When several or all filters must be exposed to the aerosol at the same time, in order to achieve uniform mixing of all filters, it is advisable to introduce the leak detection aerosol into the fan suction end or the branch pipe in front of these filters, and measure the upwind concentration immediately in front of the filter to be tested.

• For high efficiency filters, when the leak detector is a logarithmic scale, the aerosol concentration on the upwind side should exceed 104 times the minimum scale of the instrument; when the leak detector is a linear scale, the aerosol concentration on the upwind side must reach 80~100ug. The leak detector should have a measurement range of 0.001~100ug.

2.Leak detection by particle counter method

• The air volume of the filter to be tested must have been measured and it must operate between 80% and 120% of the design wind speed.

• The number of particles of atmospheric dust on the upwind side of the high efficiency filter to be tested shall be based on particles greater than or equal to 0.5um, and its concentration must be greater than or equal to. If ultra-high efficiency filters are tested, the number of particles greater than or equal to 0.1um shall be based on particles greater than or equal to, and its concentration must be greater than or equal to.

• If the concentration on the upwind side does not meet the above requirements, unfiltered air should be introduced. If it still does not meet the requirements, it is not appropriate to use the particle counter method and condensation nucleus counter method for leak detection.

• When checking for leaks, place the sampling port 2 to 3 cm away from the surface of the filter being tested, move at a speed of 5 to 20 mm/s, and scan the entire cross section, end seal and mounting frame of the filter being tested.