1.1 Significance and Determination of Viscosity—The purpose of this guide is to provide sufficient knowledge for a person with some technical background in lubrication or condition monitoring from which they can determine the best choice for measuring viscosity of an in-service oil. Such information from this guide should enable the user to engage in productive discussions with colleagues, service providers, managers, and service personnel about obtaining and using information on and from viscosity. There are a number of different approaches to viscometric measurement, and this guide is intended to be a helpful resource in selecting the most appropriate viscometric approach to gain information for the in-service fluid.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

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.