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    ASTM D7945 - 21

    Standard Test Method for Determination of Dynamic Viscosity and Derived Kinematic Viscosity of Liquids by Constant Pressure Viscometer

    Active Standard ASTM D7945 | Developed by Subcommittee: D02.07

    Book of Standards Volume: 05.04

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    Significance and Use

    5.1 Many petroleum products are used as lubricants and the correct operation of the equipment depends upon the appropriate viscosity of the liquid being used. In addition, the viscosity of many petroleum fuels is important for the estimation of optimum storage, handling, and operational conditions. Thus, the accurate determination of viscosity is essential to many product specifications.

    5.2 Density is a fundamental physical property that can be used in conjunction with other properties to characterize both the light and heavy fractions of petroleum and petroleum products and in this test method is used for the calculation from dynamic to kinematic viscosity.

    1. Scope

    1.1 This test method covers the measurement of dynamic viscosity and density for the purpose of derivation of kinematic viscosity of petroleum liquids, both transparent and opaque. The kinematic viscosity, ν, in this test method is derived by dividing the dynamic viscosity, η, by the density, ρ, obtained at the same test temperature. This test method also calculates the temperature at which petroleum liquids attain a specified kinematic viscosity using Practice D341.

    1.2 The result obtained from this test method is dependent upon the behavior of the sample and is intended for application to liquids for which primarily the shear stress and shear rate are proportional (Newtonian flow behavior).

    1.3 The range of kinematic viscosity covered by this test method is from 0.5 mm2/s to 1000 mm2/s in the temperature range between –40 °C to 120 °C; however the precision has been determined only for fuels and oils in the range of 2.06 mm2/s to 476 mm2/s at 40 °C and 1.09 mm2/s  to 107 mm2/s at 100 °C (as stated in Section 12 on Precision and Bias). For jet fuels, the precision of kinematic viscosity has been determined in the range of 2.957 mm2/s to 5.805 mm2/s at –20 °C and 5.505 mm2/s to 13.03 mm2/s at –40 °C (as stated in Section 12 on Precision and Bias), and the precision of the temperature at 12 mm2/s (cSt) has been determined in the range of –38.3 °C to –58.1 °C (as stated in Section 13 on Precision and Bias). The precision has only been determined for those materials, viscosity ranges, and temperatures as indicated in Section 12 on Precision and Bias. The test method can be applied to a wider range of materials, viscosity, and temperature. For materials not listed in Section 12 on Precision and Bias, the precision and bias may not be applicable.

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

    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.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D341 Practice for Viscosity-Temperature Equations and Charts for Liquid Petroleum or Hydrocarbon Products

    D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)

    D1655 Specification for Aviation Turbine Fuels

    D2162 Practice for Basic Calibration of Master Viscometers and Viscosity Oil Standards

    D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants

    D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material

    D7566 Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons

    ISO Standards

    ISO 5725

    ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories

    ICS Code

    ICS Number Code 75.180.30 (Volumetric equipment and measurements)

    UNSPSC Code

    UNSPSC Code 15101500(Petroleum and distillates)

    Referencing This Standard
    Link Here
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    DOI: 10.1520/D7945-21

    Citation Format

    ASTM D7945-21, Standard Test Method for Determination of Dynamic Viscosity and Derived Kinematic Viscosity of Liquids by Constant Pressure Viscometer, ASTM International, West Conshohocken, PA, 2021, www.astm.org

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