Formerly under the jurisdiction of Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, this test method was withdrawn in March 2023 and replaced by Test Method D2265 for Dropping Point of Lubricating Grease Over Wide Temperature Range. This test method was withdrawn because the method created considerable occupational, environmental, and regulatory challenges, and D2265 was identified as a suitable replacement. One challenge with the method was that it utilized an oil bath over open flame and created considerable risk of fire and/or burns to the operator. Another challenge was that the method utilized thermometers from ASTM E1, mercury in glass thermometers, which are illegal to use in some countries/states, create occupational hazards for the operator, and create disposal challenges when the thermometers are no longer usable. Key stakeholders have noted that they have been slowly transitioning grease specifications from D566 to D2265 over the last couple of years, so this test method is minimally utilized at this point. Any users of D566 should utilize D2265 instead, if possible. Alternately, ISO 2176 (the ISO equivalent to D566) is still active and users can utilize that test method instead.

5.1 Historically, the dropping point was the temperature at which the grease passed from a semisolid to a liquid state under the conditions of test. This change in state is typical of greases containing thickeners of conventional soap types. Greases containing thickeners other than conventional soaps can, without a change in state, separate oil. This test method is useful to assist in identifying the grease as to type and for establishing and maintaining bench marks for quality control. The results are considered to have only limited significance with respect to service performance of conventional soap thickeners as dropping point is a static test. Above 200 °C, the dropping point has no correlation with the maximum upper operating temperature of the grease.

Note 1: Historical cooperative testing on conventional soap-thickened greases indicated ( RR:D02-1164) that in general, dropping points by Test Method D566 and Test Method D2265 were in agreement. In cases where results differ, there is no known significance. However, agreement between producer and consumer as to the test method used is advisable.

1.1 This test method covers the determination of the dropping point of lubricating grease.

1.2 This test method is not recommended for use at bath temperatures above 288 °C. For higher temperatures Test Method D2265 should be used.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 WARNING—The dropping point does not have any bearing on the performance of the grease.

1.5 WARNING—This test method uses mercury-filled thermometers. Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use Caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location. The responsible subcommittee, D02.G.3, continues to explore alternatives to eventually replace the mercury thermometers.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 6.4 and 8.1.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.