ASTM D7721 - 11

    Standard Practice for Determining the Effect of Fluid Selection on Hydraulic System or Component Efficiency

    Active Standard ASTM D7721 | Developed by Subcommittee: D02.N0

    Book of Standards Volume: 05.04


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    Significance and Use

    The purpose of a hydraulic fluid is to cool and lubricate fluid power components, as well as transmit power. Several standard test methods are available to measure the lubrication performance of hydraulic fluids. This practice provides uniform guidelines for comparing fluids in terms of their power-transmitting abilities as reflected in their effect on hydraulic system or component efficiency.

    GeneralEnergy efficiency benefits of hydraulic fluids are the differences between two large numbers. Consequently, it is essential to ensure that the differences observed are statistically valid (within defined confidence limits, typically 95%) and that proper precautions to ensure the necessary experimental controls have been put in place to compare the energy efficiency performance of two or more different hydraulic fluids under identical operating conditions.

    Practical advantages of enhanced hydraulic system efficiency may include increased productivity (faster machine cycle time), reduced power consumption (electricity or fuel), and reduced environmental impact (lowered emissions).

    This practice implies no evaluation of hydraulic fluid quality other than its effect on hydraulic system efficiency.

    1. Scope

    1.1 This practice covers all hydraulic fluids.

    1.2 This practice is applicable to both laboratory and field evaluations.

    1.3 This practice gives overall guidelines for conducting science-based evaluations. It does not prescribe a specific efficiency test methodology.

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


    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

    D4174 Practice for Cleaning, Flushing, and Purification of Petroleum Fluid Hydraulic Systems

    D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants

    ISO Standards

    ISO8426 Hydraulic fluid power--Positive displacement pumps and motors--Determination of derived capacity


    ICS Code

    ICS Number Code 75.120 (Hydraulic fluids)

    UNSPSC Code

    UNSPSC Code 25172800(Hydraulic systems and components)


    Referencing This Standard

    DOI: 10.1520/D7721-11

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM D7721-11, Standard Practice for Determining the Effect of Fluid Selection on Hydraulic System or Component Efficiency, ASTM International, West Conshohocken, PA, 2011, www.astm.org

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