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Filter integrity

can any one suggest how to carried out filter integrity test

Hi,

Their is basically 2 way to make filter integrity, both are well described in the ISO14644 standard are uses the same metrology but not the same instruments: on one side of the filter you generate an aerosol with a concentration you measure and fix it as 100% of concentration, and on the other side you measure what goes thought the filter by screening its surface with a probe and should not find any points where the concentration rise over a defined limit.

2 different instruments can be used for the screening: a photometer, measuring the concentration in % and a standard particle counter.

Using a particle counter is bit more tricky and I do not know the details but maybe someone could answers the following questions for this case:

  • What should be the concentration before the filter? The ISO standard remain unclear for me, and how to measure it?
  • can we make the leak test without generating aerosol if the dust concentration is sufficient?
  • Does it take much more time to screen the filter (or is the screening speed slower than with a photometer?)
  • is their specific problems to use particle counter instead of photometers.

Best regards,
christophe