ASTM D2500-02e1
(Test Method)Standard Test Method for Cloud Point of Petroleum Products
Standard Test Method for Cloud Point of Petroleum Products
SCOPE
1.1 This test method covers only petroleum products and biodiesel fuels that are transparent in layers 40 mm in thickness, and with a cloud point below 49°C.
Note 1—The interlaboratory program consisted of petroleum products of Test Method D 1500 color of 3.5 and lower. The precisions stated in this test method may not apply to samples with ASTM color higher than 3.5.
1.2 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. For specific hazard statements, see Section 7.
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An American National Standard
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Designation:D2500–02 British Standard 4458
Designation: 219/82
Standard Test Method for
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Cloud Point of Petroleum Products
This standard is issued under the fixed designation D2500; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
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e NOTE—Table1 was editorially corrected in August 2004.
1. Scope* 3.1.1.1 Discussion—To many observers, the cluster of wax
crystals looks like a patch of whitish or milky cloud, hence the
1.1 This test method covers only petroleum products and
nameofthetestmethod.Thecloudappearswhenthetempera-
biodiesel fuels that are transparent in layers 40 mm in
ture of the specimen is low enough to cause wax crystals to
thickness, and with a cloud point below 49°C.
form. For many specimens, the crystals first form at the lower
NOTE 1—The interlaboratory program consisted of petroleum products
circumferential wall of the test jar where the temperature is
ofTestMethodD1500colorof3.5andlower.Theprecisionsstatedinthis
lowest.Thesizeandpositionofthecloudorclusteratthecloud
test method may not apply to samples withASTM color higher than 3.5.
point varies depending on the nature of the specimen. Some
1.2 This standard does not purport to address all of the
samples will form large, easily observable, clusters, while
safety concerns, if any, associated with its use. It is the
others are barely perceptible.
responsibility of the user of this standard to establish appro-
3.1.1.2 Discussion—Upon cooling to temperatures lower
priate safety and health practices and determine the applica-
than the cloud point, clusters of crystals will grow in multiple
bility of regulatory limitations prior to use. For specific hazard
directions; for example, around the lower circumference of the
statements, see Section 7.
testjar,towardsthecenterofthejar,orverticallyupwards.The
crystals can develop into a ring of cloud along the bottom
2. Referenced Documents
circumference,followedbyextensivecrystallizationacrossthe
2.1 ASTM Standards:
bottom of the test jar as temperature decreases. Nevertheless,
D1500 Test Method for ASTM Color of Petroleum Prod-
the cloud point is defined as the temperature at which the
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ucts (ASTM Color Scale)
crystalsfirstappear,notwhenanentireringorfulllayerofwax
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E1 Specification for ASTM Thermometers
has been formed at the bottom of the test jar.
2.2 IP Standard:
3.1.1.3 Discussion—In general, it is easier to detect the
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Specifications for IP Standard Thermometers
cloud point of samples with large clusters that form quickly,
suchasparaffinicsamples.Thecontrastbetweentheopacityof
3. Terminology
the cluster and the liquid is also sharper. In addition, small
3.1 Definitions of Terms Specific to This Standard:
brightly-reflective spots can sometimes be observed inside the
3.1.1 cloud point, n—in petroleum products and biodiesel
cluster when the specimen is well illuminated. For other more
fuels, the temperature of a liquid specimen when the smallest
difficult samples, such as naphthenic, hydrocracked, and those
observable cluster of wax crystals first appears upon cooling
samples whose cold flow behavior have been chemically
under prescribed conditions.
altered, the appearance of the first cloud can be less distinct.
Therateofcrystalgrowthisslow,theopacitycontrastisweak,
and the boundary of the cluster is more diffuse. As the
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This test method is under the jurisdiction of ASTM Committee D02 on
temperature of these specimens decrease below the cloud
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
D02.07 on Flow Properties.
point, the diffuse cluster will increase in size and can form a
Current edition approved April 10, 2002. Published July 2002. Originally
general haze throughout. A slight haze throughout the entire
published as D2500–66. Last previous edition D2500–99.
2 sample, which slowly becomes more apparent as the tempera-
Annual Book of ASTM Standards, Vol 05.01.
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ture of the specimen decreases, can also be caused by traces of
Annual Book of ASTM Standards, Vol 14.03.
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Available from Institute for Petroleum, 61 New Cavendish St., London,
waterinthespecimeninsteadofcrystalformation(seeNote4).
England WIM 8AR.
*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.
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D2500–02
With these difficult samples, drying the sample prior to testing
Thermometer
Number
can eliminate
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