Historical
ASTM D6158-99
Standard Specification for Mineral Hydraulic Oils
This specification covers mineral oils used in hydraulic systems, where the performance requirements demand fluids with one of the following characteristics: 1.1.1 A refined base oil (Class HH). 1.1.2 A refined mineral base oil with rust and oxidation inhibitors (Class HL), and 1.1.3 A refined mineral base oil with rust and oxidation inhibitors plus antiwear characteristics (Class HM).
ASTM International [astm]