ASTM D3321-19(2023)
(Test Method)Standard Test Method for Use of the Refractometer for Field Test Determination of the Freezing Point of Aqueous Engine Coolants
Standard Test Method for Use of the Refractometer for Field Test Determination of the Freezing Point of Aqueous Engine Coolants
SIGNIFICANCE AND USE
4.1 This practice is commonly used by vehicle service personnel to determine the freezing point, in degrees Celsius or Fahrenheit, of aqueous solutions of commercial ethylene and propylene glycol-based coolant. A durable hand-held refractometer is available that reads the freezing point, directly, in degrees Celsius or Fahrenheit, when a few drops of engine coolant are properly placed on the temperature-compensated prism surface of the refractometer. This refractometer is for glycol and water solutions, and is not suitable for other coolant solutions.
4.2 The hand-held refractometer should be calibrated before use (see Section 7).
4.3 Care must be taken to use the correct glycol freezing point scale for the glycol type being measured. Use of the wrong glycol scale can result in freezing point errors of 18 and more degrees Fahrenheit.
4.4 Ethylene glycol/propylene glycol mixtures will result in inaccurate freezing point measurements using either freezing point scale.
SCOPE
1.1 This test method covers the use of a portable refractometer for determining the approximate freezing protection provided by ethylene and propylene glycol-based coolant solutions as used in engine cooling systems and special applications.
Note 1: Some instruments have a supplementary freezing protection scale for methoxypropanol coolants. Others carry a supplemental scale calibrated in density or specific gravity readings of sulfuric acid solutions so that the refractometer can be used to determine the charged condition of lead acid storage batteries.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.
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.
General Information
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: D3321 − 19 (Reapproved 2023)
Standard Test Method for
Use of the Refractometer for Field Test Determination of the
1
Freezing Point of Aqueous Engine Coolants
This standard is issued under the fixed designation D3321; 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 E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method covers the use of a portable refracto-
meter for determining the approximate freezing protection
3. Summary of Test Method
provided by ethylene and propylene glycol-based coolant
solutions as used in engine cooling systems and special
3.1 These coolant testers are critical-angle refractometers
applications.
designed for rapid, approximate measurement of ethylene and
propylene glycol coolant freezing point protection. Only a few
NOTE 1—Some instruments have a supplementary freezing protection
drops of test solution are required. Some testers automatically
scale for methoxypropanol coolants. Others carry a supplemental scale
calibrated in density or specific gravity readings of sulfuric acid solutions
correct for ambient air temperature and the temperature of the
so that the refractometer can be used to determine the charged condition
solution being tested. The instrument is rugged, simple to read,
of lead acid storage batteries.
and easy to clean and maintain.
1.2 The values stated in SI units are to be regarded as
3.2 The coolant freezing point readings are taken at points
standard. The values given in parentheses after SI units are
where the dividing line between light and dark crosses the
provided for information only and are not considered standard.
scales. Some refractometers have a coolant scale for indicating
1.3 This standard does not purport to address all of the
the freezing point of aqueous ethylene glycol coolants only,
safety concerns, if any, associated with its use. It is the
while other refractometers also have a scale for indicating the
responsibility of the user of this standard to establish appro-
freezing point of aqueous propylene glycol coolants. The range
priate safety, health, and environmental practices and deter-
of the scales varies from one device to another.
mine the applicability of regulatory limitations prior to use.
3.3 Freezing point measurements are concentration-related
1.4 This international standard was developed in accor-
values and are in turn directly related to refractive index. It has
dance with internationally recognized principles on standard-
been empirically determined that freezing point measurements
ization established in the Decision on Principles for the
are accurate within 1 °C (2 °F).
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4. Significance and Use
Barriers to Trade (TBT) Committee.
4.1 This practice is commonly used by vehicle service
2. Referenced Documents
personnel to determine the freezing point, in degrees Celsius or
2
2.1 ASTM Standards:
Fahrenheit, of aqueous solutions of commercial ethylene and
D1177 Test Method for Freezing Point of Aqueous Engine
propylene glycol-based coolant. A durable hand-held refracto-
Coolants
meter is available that reads the freezing point, directly, in
E177 Practice for Use of the Terms Precision and Bias in
degrees Celsius or Fahrenheit, when a few drops of engine
ASTM Test Methods
coolant are properly placed on the temperature-compensated
prism surface of the refractometer. This refractometer is for
glycol and water solutions, and is not suitable for other coolant
1
This test method is under the jurisdiction of ASTM Committee D15 on Engine
solutions.
Coolants and Related Fluids and is the direct responsibility of Subcommittee
D15.03 on Physical Properties. 4.2 The hand-held refractometer should be calibrated before
Current edition approved Sept. 1, 2023. Published September 2023. Originally
use (see Section 7).
approved in 1974. Last previous edition approved in 2019 as D3321 – 19. DOI:
10.1520/D3321-19R23.
4.3 Care must be taken to use the correct glycol freezing
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
point scale for the glycol type being measured. Use of the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
wrong glycol scale can result in freezing point errors of 18 and
Standards volume information, refer to the standard
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