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.

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 describes 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 D 892 or IP 146.

1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

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 and health practices and determine the applicability of regulatory limitations prior to use.