Improvements in the Use of Water Washes in Testing for NVR

Some improvements have been made to enhance the role of water as a test solvent for determining the amount of hydrocarbon nonvolatile residue (NVR) present on an item of hardware that is required to be totally or nearly devoid of such residue. Water is now used as an NVR-testing solvent because (1) even highmolecular- weight hydrocarbon greases are at least slightly soluble in water, (2) water is safer and less expensive than are chlorofluorocarbon solvents [in particular, 1,1,2- trichloro-1,2,2-trifluoroethane (also known as CFC-113), which was used previously in testing for hydrocarbon NVR], and (3) CFC solvents are expensive and are now recognized as environmentally harmful.