We have customers that reference NASA KSC-C-123H Specification for Surface Cleanliness for Fluid Systems

I'm figuring it's whatever media is flowing through or around my device.

Does that sound right?

Scott, your question flowed right over my head!:lol:

Sorry I can't help, but did want to let you know I dedicated my four brain cells to it for a few minutes and came up with nothing.

Non-volatile residue testing methods are called out in ASTM D2109-71 and NASA KSC-C-123H. NVR is a simple test that can be performed with lab equipment available in most facilities. It is critical with this and all other tests that the cleanliness of the lab area is of a sufficient level to protect the samples from outside contamination. Purity of test solvents must be adhered to insure consistency and accuracy of the results.

This is found in this article (http://cr.pennnet.com/display_article/92328/15/ARTCL/none/none/Cleanroom-packaging-films:-Beyond-clean/).
If you are in packaging, this may be relevant (http://www.aeropackaging.com/info/quality_system.shtml).