Frequently Asked Question - Cleanroom Section

      What are the advantages of the DOP in-place test over attempting a leak test  with a
       particle counter ?

To begin with, it is not possible to use DOP with a particle counter-the concentration of aerosol is so high that the counter becomes saturated and jams, requiring a trip to the factory for repairs (except where expensive high volume samples with a diluting air source, are employed). The DOP test tells the story right away-where the leaks are and how great. There are no time delays for readouts or probe recovery. The readouts relate to filter performance and not to an abstraction. The last applies to linear photometers only, log scale instruments give only relative results