ASTM D2500-99

ASTM-D2500
ADOPTION NOTICE
ASTM-D2500, "PETROLEUM PRODUCTS, CLOUD POINT OF", was adopted on
15-OCT-91 for use by the Department of Defense (DoD). Proposed
changes by DoD activities must be submitted to the DoD Adopting
Activity: Commander, US Army Tank-Automotive and Armaments
Command, ATTN: AMSTA-TR-E/IE, Warren, MI 48397-5000. Copies of
this document may be purchased from the American Society for
Testing and Materials 100 Barr Harbor Drive West Conshohocken,
Pennsylvania, United States, 19428-2959. http://www.astm.org/____________________
Custodians: Adopting Activity:
Army - AT Army - AT
Navy - SH
Air Force - 11
Reviewer Activities:
Air Force - 68
FSC 91GP
Approved for public release; distribution
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Designation: D 2500 – 99 An American National Standard
British Standard 4458
Standard Test Method for
1
Cloud Point of Petroleum Products
This standard is issued under the fixed designation D 2500; 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 (e) indicates an editorial change since the last revision or reapproval.
This test method was adopted as an ASTM-IP Standard.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope lowest. The size and position of the cloud or cluster at the cloud
point varies depending on the nature of the specimen. Some
1.1 This test method covers only petroleum products that
samples will form large, easily observable, clusters, while
are transparent in layers 40 mm in thickness, and with a cloud
others are barely perceptible.
point below 49°C.
3.1.1.2 Discussion—Upon cooling to temperatures lower
NOTE 1—The interlaboratory program consisted of petroleum products
than the cloud point, clusters of crystals will grow in multiple
of Test Method D 1500 color of 3.5 and lower. The precisions stated in this
directions; for example, around the lower circumference of the
test method may not apply to samples with ASTM color higher than 3.5.
test jar, towards the center of the jar, or vertically upwards. The
1.2 This standard does not purport to address all of the
crystals can develop into a ring of cloud along the bottom
safety concerns, if any, associated with its use. It is the
circumference, followed by extensive crystallization across the
responsibility of the user of this standard to establish appro-
bottom of the test jar as temperature decreases. Nevertheless,
priate safety and health practices and determine the applica-
the cloud point is defined as the temperature at which the
bility of regulatory limitations prior to use. For specific hazard
crystals first appear, not when an entire ring or full layer of wax
statements see Notes 3–6.
has been formed at the bottom of the test jar.
3.1.1.3 Discussion—In general, it is easier to detect the
2. Referenced Documents
cloud point of samples with large clusters that form quickly,
2.1 ASTM Standards:
such as paraffinic samples. The contrast between the opacity of
D 1500 Test Method for ASTM Color of Petroleum Prod-
the cluster and the liquid is also sharper. In addition, small
2
ucts (ASTM Color Scale)
brightly-reflective spots can sometimes be observed inside the
3
E 1 Specification for ASTM Thermometers
cluster when the specimen is well illuminated. For other more
2.2 IP Standard:
difficult samples, such as naphthenic, hydrocracked, and those
4
Specifications for IP Standard Thermometers
samples whose cold flow behavior have been chemically
altered, the appearance of the first cloud can be less distinct.
3. Terminology
The rate of crystal growth is slow, the opacity contrast is weak,
3.1 Definitions of Terms Specific to This Standard:
and the boundary of the cluster is more diffuse. As the
3.1.1 cloud point, n—in petroleum products, the tempera-
temperature of these specimens decrease below the cloud
ture of a liquid specimen when the smallest observable cluster
point, the diffuse cluster will increase in size and can form a
of wax crystals first appears upon cooling under prescribed
general haze throughout. A slight haze throughout the entire
conditions.
sample, which slowly becomes more apparent as the tempera-
3.1.1.1 Discussion—To many observers, the cluster of wax
ture of the specimen decreases, can also be caused by traces of
crystals looks like a patch of whitish or milky cloud, hence the
water in the specimen instead of crystal formation (see Note 4).
name of the test method. The cloud appears when the tempera-
With these difficult samples, drying the sample prior to testing
ture of the specimen is low enough to cause wax crystals to
can eliminate this type of interference.
form. For many specimens, the crystals first form at the lower
circumferential wall of the test jar where the temperature is 4. Summary of Test Method
4.1 The
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