This International Standard specifies the minimum requirements for new mineral oil hydraulic fluids and is intended for hydraulic systems, particularly for hydrostatic hydraulic fluid power application. The purpose of this International Standard is for the guidance of suppliers and end users of mineral oil hydraulic fluids and for the direction of equipment manufacturers of hydraulic systems. This International Standard is written in a general form so that its application can accommodate various climatic conditions throughout the world. This International Standard also stipulates the requirements for mineral-oil hydraulic fluids at the time of delivery. Classification of fluids used in hydraulic applications is defined in ISO 6743-4. Of the categories covered by ISO 6743-4, only five types of mineral oil based fluids are covered in this International Standard. These categories are HH, HL, HM, HV and HG.