CONTROL & DESIGN STANDARDS: MONITORING

When analyzing witness plates, the results are defined as being one of two types: either as particulate matter or as non-volatile residue (NVR).

Surface particulate matter, except for its location, is essentially the exact same material as the room’s airborne particulates, and it’s defined in similar terms: size in microns and maximum number per square foot.

Comparison of a witness plate to a cubic foot of air.
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Florida Space Research Institute ©2002