ISO 6743-4 standard is for Lubricants, industrial oils and related products (class L) Classification - Part 4: Family H (Hydraulic systems) (ISO 6743-4:1 999).
ISO 6743 consists of the following parts, under the general title Lubricants, industrial oils and related products (class L) — Classification:
Part 0: General
Part 1 : Family A (Total loss systems)
Part 2: Family F (Spindle bearings, bearings and associated clutches)
Part 3A: Family D (Compressors)
Part 3B: Family D (Gas and refrigeration compressors)
Part 4: Family H (Hydraulic systems)
Part 5: Family T (Turbines)
Part 6: Family C (Gears)
Part 7: Family M (Metalworking)
Part 8: Family R (Temporary protection against corrosion)
Part 9: Family X (Greases)
Part 1 0: Family Y (Miscellaneous)
Part 1 1 : Family P (Pneumatic tools)
Part 1 2: Family Q (Heat transfer fluids)
Part 1 3: Family G (Slideways)
Part 1 4: Family U (Heat treatment)
Part 1 5: Family E (Internal combustion engines)

This ISO 6743-4 establishes the detailed classification of fluids of family H (Hydraulic systems) which belong to class L (Lubricants, industrial oils and related products). It should be read in conjunction with ISO 6743-0. This classification excludes, for the time being, automotive brake fluids and airborne fluids. However, this edition includes environmentally acceptable fluid categories, i.e.: HETG, HEPG, HEES and HEPR.






