ASTM D2422 Standard Classification of Industrial Fluid Lubricants by Viscosity System
5. Adoption of System
5.1 Adoption of this viscosity system is to be voluntary on the part of all persons or organizations. The system will be effective only if used widely by designers, producers, and consumers. There is nothing to prohibit use of a viscosity grade not listed in the system if the producer and consumer mutually agree. It may be expected, however, that viscosity grades not in accordance with this classification will be less readily available to the purchaser than those grades which do conform.
5.2 For the sake of world-wide uniformity of nomenclature in identifying the viscosity characteristics of fluid lubricants the following wording shall be used to designate a particular viscosity grade:
ISO viscosity grade ...
which may be abbreviated to:
ISO VG ...
The wording would be followed by the nominal viscosity at 40°C expressed in centistokes (millimetres squared per second) units of measurement.
5.3 The establishment of standardized viscosity grades as has been done herein shall not imply nor require that every viscosity grade be made available by all lubricant suppliers for each and every type of fluid which he markets. The availability will be dictated by the demand that exists in any one locality at any given point in time.
6. Keywords
6.1 classification; lubricant; viscosity
