ASTM D6046 Standard Classification of Hydraulic Fluids for Environmental Impact
4. Significance and Use
4.1 This classification establishes categories of hydraulic fluids which are distinguished by their response to certain standardized laboratory procedures. These procedures indicate the possible response of some environmental compartments to the introduction of the hydraulic fluid. One set of procedures measures the aerobic aquatic biodegradability (environmental persistence) of the fluids and another set of procedures estimates the acute ecotoxicity effects of the fluids.
4.1.1 Although this classification includes categories for both persistence and ecotoxicity, there is no relationship between the two categories. They may be used independently of each other, that is, a hydraulic fluid can be categorized with respect to both sets of laboratory procedures, or to persistence but not ecotoxicity, or to ecotoxicity but not persistence.
4.1.2 There is no relationship between the categories achieved by a hydraulic fluid for persistence and for ecotoxicity. The placing of a hydraulic fluid with regard to one set of categories has no predictive value as to its placement with regard to the other set of categories.
4.2 The test procedures used to establish the categories of hydraulic fluids are laboratory standard tests and are not intended to simulate the natural environment. Definitive field studies capable of correlating test results with the actual environmental impact of hydraulic fluids are usually site specific and so are not directly applicable to this classification. Therefore, the categories established by this classification can serve only as guidance to estimate the actual impact that the hydraulic fluids might have on any particular environment.
4.3 This classification can be used by producers and users of hydraulic fluids to establish a common set of references that describe some aspects of the anticipated environmental impact of hydraulic fluids which are incidental to their use.
4.4 Inclusion of a hydraulic fluid in any category of this classification does not imply that the hydraulic fluid is suitable for use in any particular hydraulic system application.
4.5 The composition of hydraulic fluids may change with use and any change could influence the environmental impact of a used hydraulic fluid. Therefore, the classification of a hydraulic fluid may change upon use depending on the type and extent of the use.
