5.1 The tendency of oils to foam at high temperature can be a serious problem in systems such as high-speed gearing, high volume pumping, and splash lubrication. Foaming can cause inadequate lubrication, cavitation, and loss of lubricant due to overflow, and these events can lead to mechanical failure.

5.2 Correlation between the amount of foam created or the time for foam to collapse, or both, and actual lubrication failure has not been established. Such relations should be empirically determined for foam sensitive applications.

1.1 This test method covers the procedure for determining the foaming characteristics of lubricating oils (specifically transmission fluid and motor oil) at 150 °C.

1.2 Foaming characteristics of lubricating oils at temperatures up to 93.5 °C are determined by Test Method D892 or IP 146.

1.3 The values stated in SI units are to be regarded as standard.

1.3.1 Exception—The values given in parentheses are provided for information only.

1.4 WARNING—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.

1.5 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.

1.6 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.