ASTM D6743-06
(Test Method)Standard Test Method for Thermal Stability of Organic Heat Transfer Fluids
Standard Test Method for Thermal Stability of Organic Heat Transfer Fluids
SIGNIFICANCE AND USE
Heat transfer fluids degrade when exposed to sufficiently high temperatures. The amount of degradation increases as the temperature increases or the length of exposure increases, or both. Due to reactions and rearrangement, degradation products can be formed. Degradation products include high and low boiling components, gaseous decomposition products, and products that cannot be evaporated. The type and content of degradation products produced will change the performance characteristics of a heat transfer fluid. In order to evaluate thermal stability, it is necessary to quantitatively determine the mass percentages of high and low boiling components, as well as gaseous decomposition products and those that cannot be vaporized, in the thermally stressed heat transfer fluid.
This test method differentiates the relative stability of organic heat transfer fluids at elevated temperatures in the absence of oxygen and water under the conditions of the test.
The user shall determine to his own satisfaction whether the results of this test method correlate to field performance. Heat transfer fluids in industrial plants are exposed to a variety of additional influencing variables. Interaction with the plant’materials, impurities, heat build-up during impaired flow conditions, the temperature distribution in the heat transfer fluid circuit, and other factors can also lead to changes in the heat transfer fluid. The test method provides an indication of the relative thermal stability of a heat transfer fluid, and can be considered as one factor in the decision-making process for selection of a fluid.
The accuracy of the results depends very strongly on how closely the test conditions are followed.
This test method does not possess the capability to quantify or otherwise assess the formation and nature of thermal decomposition products within the unstressed fluid boiling range. Decomposition products within the unstressed fluid boiling range may represent a significant po...
SCOPE
1.1 This test method covers the determination of the thermal stability of unused organic heat transfer fluids. The procedure is applicable to fluids used for the transfer of heat at temperatures both above and below their boiling point (refers to normal boiling point throughout the text unless otherwise stated). It is applicable to fluids with maximum bulk operating temperature between 260°C (500°F) and 454°C (850°F). The procedure shall not be used to test a fluid above its critical temperature. In this test method, the volatile decomposition products are in continuous contact with the fluid during the test. This test method will not measure the thermal stability threshold (the temperature at which volatile oil fragments begin to form), but instead will indicate bulk fragmentation occurring for a specified temperature and testing period. Because potential decomposition and generation of high pressure gas may occur at temperatures above 260°C (500°F), do not use this test method for aqueous fluids or other fluids which generate high-pressure gas at these temperatures.
1.2 DIN Norm 51528 covers a test method that is similar to this test method.
1.3 The applicability of this test method to siloxane-based heat transfer fluids has not been determined.
1.4 &si-value;
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 warning statements, see 7.2, 8.8, 8.9, and 8.10.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6743–06
Standard Test Method for
1
Thermal Stability of Organic Heat Transfer Fluids
This standard is issued under the fixed designation D6743; 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* D2887 Test Method for Boiling Range Distribution of
Petroleum Fractions by Gas Chromatography
1.1 Thistestmethodcoversthedeterminationofthethermal
D4175 Terminology Relating to Petroleum, Petroleum
stability of unused organic heat transfer fluids. The procedure
Products, and Lubricants
is applicable to fluids used for the transfer of heat at tempera-
2.2 DIN Norms:
turesbothaboveandbelowtheirboilingpoint(referstonormal
51528 Determination of the Thermal Stability of Unused
boiling point throughout the text unless otherwise stated). It is
3
Heat Transfer Fluids
applicable to fluids with maximum bulk operating temperature
between 260°C (500°F) and 454°C (850°F). The procedure
3. Terminology
shall not be used to test a fluid above its critical temperature. In
3.1 Definitions:
this test method, the volatile decomposition products are in
3.1.1 thermal stability, n—the resistance to permanent
continuous contact with the fluid during the test. This test
changes in properties caused solely by heat. D4175
method will not measure the thermal stability threshold (the
3.2 Definitions of Terms Specific to This Standard:
temperature at which volatile oil fragments begin to form), but
3.2.1 decomposition products that cannot be vaporized,
instead will indicate bulk fragmentation occurring for a speci-
n—materials from the thermally stressed heat transfer fluid,
fied temperature and testing period. Because potential decom-
from which those fractions that can be vaporized are removed
position and generation of high pressure gas may occur at
by distillation procedures, that are quantitatively determined as
temperatures above 260°C (500°F), do not use this test method
residues in a bulb tube distillation apparatus.
for aqueous fluids or other fluids which generate high-pressure
3.2.2 fluid within the unstressed fluid boiling range, n—any
gas at these temperatures.
fluid components with boiling point between the initial boiling
1.2 DIN Norm 51528 covers a test method that is similar to
point and final boiling point of the unstressed fluid.
this test method.
3.2.3 gaseous decomposition products, n—materials with
1.3 The applicability of this test method to siloxane-based
boiling points below room temperature, at normal pressure,
heat transfer fluids has not been determined.
such as hydrogen and methane, that escape upon opening the
1.4 The values stated in SI units are to be regarded as
test cell and that can be determined by measuring the mass
standard. The values given in parentheses are for information
immediately thereafter.
only.
3.2.4 high boiling components, n—materials from the ther-
1.5 This standard does not purport to address all of the
mally stressed heat transfer fluid, with boiling points above the
safety concerns, if any, associated with its use. It is the
final boiling point of the unstressed heat transfer fluid, but
responsibility of the user of this standard to establish appro-
which can still be separated by distillation from the heat
priate safety and health practices and determine the applica-
transfer fluid by means of classical separation procedures.
bility of regulatory limitations prior to use. For specific
3.2.5 low boiling components, n—materials from the ther-
warning statements, see 7.2, 8.8, 8.9, and 8.10.
mally stressed heat transfer fluid, with boiling points below the
2. Referenced Documents initial boiling point of the unstressed heat transfer fluid.
2
3.2.6 mass percentage of high boiling components, n—the
2.1 ASTM Standards:
percentage of thermally stressed heat transfer fluid with a
boiling point above the final boiling point of the unstressed
1
This test method is under the jurisdiction of ASTM Committee D02 on
fluid.
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
3.2.7 mass percentage of low boiling components, n—the
D02.L0.06 on Nonlubricating Process Fluids.
percentage of thermally stressed heat transfer fluid with a
Current edition approved Dec. 1, 2006. Published January 2007. Originally
´1
approved in 2001. Last previous edition approved in 2001 as D6743–01 . DOI: boiling point below the initial boiling point of the unstressed
10.1520/D6743-06.
fluid.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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Standards volume information, refer to the standard’s Docume
...
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