ISO 6743 establishes the general classification system, which applies to lubricants, industrial oils and related products called class L. Within class L are 18 families of products defined to cover all applications for which lubricants are used. These 18 families and some of their subdivisions are shown below. Not all families have been issued. Families 16, 17 and 18 are still awaiting issue at this time.

The family is defined as an ISO standard by using a slash or a dash followed by a number. For example ISO 6743/1 or ISO 6743-1 defines Family A. The categories under family A will start with the letter A, but the letters following the initial letter, taken separately have no significance of their own. For example family AB is a total loss system for open gears or wire ropes. The second letter “B” in AB has no significance on its own. However if lubricant starts with “B”, then it is a mold release application.

Furthermore under this system a particular lubricant for an application may be designated in a complete form as “class L” followed by the family designation. Hence a reference to L-EGD would refer to a lubricant (class L) that falls into the application “EGD” symbol with the understanding that this coding refers to ISO 6743.

A viscosity grade can be used following the symbols to designate the particular grade. Hence L-HL-32 would be an R&O lubricating oil, ISO 32.

Reciprocating, rotary drip-feed, rotary oil flooded (vane/screw)

 Two-stroke engines

                Soluble oils with rust prevention

        Synthetic base fluid lubricants

        Mineral oil with AW, CP, emulsifying and foam inhibition

             Undiluted fluid

             RD products having water-displacing properties

             Solvent-based fluid leaving oily or greasy film

  (**Note differences from DIN 51512 are base fluid code, EP code and code order**)