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1.1 This test method describes the use of offline particle quantification (often referred to as PQ) magnetometers to trend wear rates in machinery by monitoring the amount of ferromagnetic material suspended in a fluid sample that has been in contact with the moving parts of the machinery. It is particularly relevant to monitoring wear debris in lubricating oils and greases.

1.2 The values stated in SI units are to be regarded as standard. Values of the burden (mass) of ferrous wear debris in the sample are reported as a PQ Index. The PQ Index is a numerical value that scales with the ferrous debris burden.

1.3 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.

1.4 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.

5.1 This test method is intended for the application of PQ magnetometry in assessing the progression of wear in machinery, for example, engines and gearboxes, by trending the mass of ferrous debris in samples of lubricating oils or greases.

5.2 In-service oil analysis is carried out routinely by commercial laboratories on a wide range of samples from many sources and is accepted as a reliable means of monitoring machinery health by trend analysis. In particular, the extent of wear can be readily assessed from any changes in the ferrous debris burden within periodically extracted samples as reflected in the PQ Index.

5.3 PQ measurements can be used as a means of rapidly screening samples for the presence or absence of ferrous wear debris, allowing quick decisions to be made on whether or not to proceed to a more detailed spectroscopic analysis for probable wear metals in the sample.

5.4 The use of standardized sample containers and a consistent protocol enables reliable trending information to be recorded. Although it is not possible to assign general limits or thresholds for abnormal conditions, it is recommended that interpretation of PQ values should be carried out in consultation with historical data, equipment logs, and/or service history in order to formulate guidelines on individual items of machinery. Guide D7720 is particularly useful in this context.