ASTM D7721-22

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

SIGNIFICANCE AND USE
5.1 The primary function of a hydraulic fluid is to transmit power. 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 and productivity.  
5.2 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 (lower emissions).  
5.3 Differences in fluid performance may be relatively small. Consequently, it is essential that the necessary experimental controls are implemented to ensure consistency in operating conditions and duty cycle when comparing the energy efficiency of different hydraulic fluid formulations.  
5.4 This practice implies no evaluation of hydraulic fluid quality other than its effect on hydraulic system efficiency.
SCOPE
1.1 This practice covers all types and grades of hydraulic fluids.  
1.2 This practice is applicable to both laboratory and field evaluations.  
1.3 This practice provides guidelines for conducting hydraulic fluid 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, 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.

General Information

• Status: Published
• Publication Date: 31-Aug-2022
• ICS: 75.120 - Hydraulic fluids
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.N0 - Hydraulic Fluids

Standards Content (Sample)

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.
Designation: D7721 − 22
Standard Practice for
Determining the Effect of Fluid Selection on Hydraulic
1
System or Component Efficiency
This standard is issued under the fixed designation D7721; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
3
1. Scope* 2.2 ISO Standards:
ISO 4391 Hydraulic fluid power—Pumps, motors and inte-
1.1 This practice covers all types and grades of hydraulic
gral transmissions—Parameter definitions and letter sym-
fluids.
bols
ISO 4392–1 Hydraulic fluid power—Determination of char-
1.2 This practice is applicable to both laboratory and field
acteristics of motors—Part 1: At constant low speed and
evaluations.
constant pressure
1.3 This practice provides guidelines for conducting hy-
ISO 4409 Hydraulic fluid power—Positive-displacement
draulic fluid evaluations. It does not prescribe a specific
pumps, motors and integral transmissions—Methods of
efficiency test methodology.
testing and presenting basic steady state performance
ISO 5598 Fluid power systems & components—Vocabulary
1.4 The values stated in SI units are to be regarded as
ISO 8426 Hydraulic fluid power—Positive displacement
standard. No other units of measurement are included in this
pumps and motors—Determination of derived capacity
standard.
1.5 This standard does not purport to address all of the 3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 For additional definitions related to petroleum products
responsibility of the user of this standard to establish appro-
and lubricants, see Terminology D4175. For additional defini-
priate safety, health, and environmental practices and deter-
tions related to fluid power systems and components, see ISO
mine the applicability of regulatory limitations prior to use.
5598.
1.6 This international standard was developed in accor-
3.2 Definitions:
dance with internationally recognized principles on standard-
3.2.1 baseline oil, n—oil of known performance character-
ization established in the Decision on Principles for the
istics used as a basis for comparison.
Development of International Standards, Guides and Recom-
3.2.1.1 Discussion—For purposes of this practice, the base-
mendations issued by the World Trade Organization Technical
line oil may be a hydraulic fluid of any suitable composition.
Barriers to Trade (TBT) Committee.
3.2.2 component, n—of a hydraulic system, an individual
unit, excluding piping, comprising one or more parts designed
2. Referenced Documents
to be a functional part of a fluid power system, for example,
2
2.1 ASTM Standards:
cylinder, motor, valve, or filter.
D4174 Practice for Cleaning, Flushing, and Purification of
3.2.3 critical parts, n—those components used in the test
Petroleum Fluid Hydraulic Systems
that are known to affect test severity.
D4175 Terminology Relating to Petroleum Products, Liquid
3.2.4 cycle time, n—the amount of time it takes for a
Fuels, and Lubricants
machine to perform a repetitive segment of an operation,
typically measured as the time it takes a machine to return to
the original position after completing a task.
1
This practice is under the jurisdiction ofASTM Committee D02 on Petroleum
3.2.5 energy consumption, n—the total energy content con-
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-
sumed during a test in kWh; determined from electric power
mittee D02.N0 on Hydraulic Fluids.
Current edition approved Sept. 1, 2022. Published October 2022. Originally
meter readings or calculated from the mass of fuel consumed
approved in 2011. Last previous edition approved in 2017 as D7721 – 17.
and the lower heating value of the fuel.
DOI:10.1520/D7721-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from International Organization for Standardization (ISO), ISO
Standards volume information, refer to the standard’s Document Summary page on Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
the ASTM website. Geneva, Switzerland, http://www.iso.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7721 − 22
3.2.6 energy effıciency, n—the work output divided by the 3.3.3.1 Discussion—The power factor
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7721 − 17 D7721 − 22
Standard Practice for
Determining the Effect of Fluid Selection on Hydraulic
1
System or Component Efficiency
This standard is issued under the fixed designation D7721; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice covers all types and grades of hydraulic fluids.
1.2 This practice is applicable to both laboratory and field evaluations.
1.3 This practice provides guidelines for conducting hydraulic fluid 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 safety, health, and healthenvironmental 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
2
2.1 ASTM Standards:
D4174 Practice for Cleaning, Flushing, and Purification of Petroleum Fluid Hydraulic Systems
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
3
2.2 ISO Standards:
ISO 4391 Hydraulic fluid power—Pumps, motors and integral transmissions—Parameter definitions and letter symbols
ISO 43924392–1 Hydraulic fluid power—Determination of characteristics of motorsmotors—Part 1: At constant low speed and
constant pressure
ISO 4409 Hydraulic fluid power—Positive displacement pumps—Methods power—Positive-displacement pumps, motors and
integral transmissions—Methods of testing and presenting basic steady state performance
ISO 5598 Fluid power systems & components—Vocabulary
1
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.N0 on Hydraulic Fluids.
Current edition approved May 1, 2017Sept. 1, 2022. Published June 2017October 2022. Originally approved in 2011. Last previous edition approved in 20112017 as
D7721 – 11.D7721 – 17. DOI:10.1520DOI:10.1520/D7721-22.⁄D7721-17.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D7721 − 22
ISO 8426 Hydraulic fluid power—Positive displacement pumps and motors—Determination of derived capacity
2.3 Other Standards:
4
VDI 2198 Type Sheets for Industrial Trucks
3. Terminology
3.1 For additional definitions related to petroleum products and lubricants, see Terminology D4175. For additional definitions
related to fluid power systems and components, see ISO 5598.
3.2 Definitions:
3.2.1 baseline oil, n—oil of known performance characteristics used as a basis for comparison.
3.2.1.1 Discussion—
For purposes of this practice, the baseline oil may be a hydraulic fluid of any suitable composition.
3.2.2 component, n—of a hydraulic system, an individual unit, excluding piping, comprising one or more parts designed to be a
functional part of a fluid power system, for example, cylinder, motor, valve, or filter.
3.2.3 critical parts, n—those components used in the test that are known to affect test severity.
3.2.4 cycle time, n—the amount of time it takes for a machine to perform a repetitive segment of an operation, typically measured
as the time it takes a machine to return to the original position after completing a task.
3.2.4 effıcienc
...