What it means to report to N
We break down what the 'N' means on your cleanliness code!
When reporting to N or “number of particles per part” the Contamination Level Code is dispensed with entirely – which makes this mode of reporting uniquely different. After listing the Size Class code letter (or range of size code letters) it calls out the actual number of particles per part as in this example CCC = N(C-E23536/F-G997/H-I92/J-K0). When testing very small parts it remains wise to test a batch of parts and we still recommend testing at least 250-500cm2 worth of combined surface area in the test batch as a rule of thumb to aid accuracy even though your Standardized particle counts will be reported “per part” via mathematical extrapolation. When gravimetric results are cited on a “reported to N” report they should also be reported “per part” via mathematical extrapolation and clearly labelled as such.