ASTM E2046-99
(Test Method)Standard Test Method for Reaction Induction Time by Thermal Analysis
Standard Test Method for Reaction Induction Time by Thermal Analysis
SCOPE
1.1 This test method describes the measurement of Reaction Induction Time (RIT) of chemical materials that undergo exothermic reactions with an induction period. The techniques and apparatus described may be used for solids, liquids, or slurries of chemical substances. The temperature range covered by this test method is typically from ambient to 400C. This range may be extended depending upon the apparatus used.
1.2 The RIT is a relative index value, not an absolute thermodynamic property. As an index value, the RIT value may change depending upon experimental conditions. A comparison of RIT values may be made only for materials tested under similar conditions of apparatus, specimen size, and so forth. Furthermore, the RIT value may not predict behavior of large quantities of material.
1.3 The RIT shall not be used by itself to establish a safe operating temperature. It may be used in conjunction with other test methods (for example, E 487, E 537, and E 1981 as part of a hazard analysis of a particular operation.
1.4 This test method may be used for RIT values greater than 15 min (as relative imprecision increases at shorter periods).
1.5 This test method is used to study catalytic and autocatalytic reactions. These reactions depend upon time as well as temperature. Such reactions are often studied by fixing one experimental parameter (that is, time or temperature) and then measuring the other parameter (that is, temperature or time). This test method measures time to reaction onset detection under isothermal conditions. It is related to Test Method E 487 that measures detected reaction onset temperature under constant time conditions
1.6 The values stated in SI units are to be regarded as the standard.
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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 2046 – 99
Standard Test Method for
Reaction Induction Time by Thermal Analysis
This standard is issued under the fixed designation E 2046; 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.
1. Scope D 3350 Specification for Polyethylene Plastics Pipe and
Fittings Materials
1.1 This test method describes the measurement of Reaction
D 3895 Test Method for Oxidative-Induction Time of Poly-
Induction Time (RIT) of chemical materials that undergo
olefins by Differential Scanning Calorimetry
exothermic reactions with an induction period. The techniques
D 4565 Test Methods for Physical and Environmental Per-
and apparatus described may be used for solids, liquids, or
formance Properties of Insulations and Jackets for Tele-
slurries of chemical substances. The temperature range covered
communications Wire and Cable
by this test method is typically from ambient to 400°C. This
D 5483 Test Method for Oxidation Induction Time of Lu-
range may be extended depending upon the apparatus used.
bricating Greases by Pressure Differential Scanning Calo-
1.2 The RIT is a relative index value, not an absolute
rimetry
thermodynamic property. As an index value, the RIT value may
D 6186 Test Method for Oxidation Induction Time of Lu-
change depending upon experimental conditions. A compari-
bricating Oils by Pressure Differential Scanning Calorim-
son of RIT values may be made only for materials tested under
etry
similar conditions of apparatus, specimen size, and so forth.
E 473 Terminology Relating to Thermal Analysis
Furthermore, the RIT value may not predict behavior of large
E 487 Test Method for Constant-Temperature Stability of
quantities of material.
Chemical Materials
1.3 The RIT shall not be used by itself to establish a safe
E 537 Test Method for Assessing the Thermal Stability of
operating temperature. It may be used in conjunction with
Chemicals by Methods of Differential Thermal Analysis
other test methods (for example, E 487, E 537, and E 1981 as
E 967 Practice for Temperature Calibration of Differential
part of a hazard analysis of a particular operation.
Scanning Calorimeters and Differential Thermal Analyz-
1.4 This test method may be used for RIT values greater
ers
than 15 min (as relative imprecision increases at shorter
E 968 Practice for Heat Flow Calibration of Differential
periods).
Scanning Calorimeters
1.5 This test method is used to study catalytic and autocata-
E 1445 Terminology Relating to Hazardous Potential of
lytic reactions. These reactions depend upon time as well as
Chemicals
temperature. Such reactions are often studied by fixing one
E 1858 Test Method for Determining Oxidative Induction
experimental parameter (that is, time or temperature) and then
Time of Hydrocarbons by Differential Scanning Calorim-
measuring the other parameter (that is, temperature or time).
etry
This test method measures time to reaction onset detection
E 1860 Test Method for Elapsed Time Calibration of Ther-
under isothermal conditions. It is related to Test Method E 487
mal Analyzers
that measures detected reaction onset temperature under con-
E 1981 Guide for Assessing the Thermal Stability of Mate-
stant time conditions
rials by Method of Accelerating Rate Calorimetry
1.6 The values stated in SI units are to be regarded as the
standard.
3. Terminology
1.7 This standard does not purport to address all of the
3.1 The specialized terms used in this test method are
safety concerns, if any, associated with its use. It is the
described in Terminologies E 473 and E 1445.
responsibility of the user of this standard to consult and
3.2 Definitions of Terms Specific to This Standard:
establish appropriate safety and health practices and deter-
3.2.1 constant temperature stability (CTS) value, n—the
mine the applicability of regulatory limitations prior to use.
maximum temperature at which a chemical compound or
2. Referenced Documents mixture may be held for a minimum of two hours without
2.1 ASTM Standards:
1 2
This test method is under the jurisdiction of ASTM Committee E–27 on Hazard Annual Book of ASTM Standards, Vol 08.02.
Potential of Chemicals and is the direct responsibility of Subcommittee E27.02 on Annual Book of ASTM Standards, Vol 10.02.
Thermal Stability and Condensed Phases. Annual Book of ASTM Standards, Vol 05.03.
Current edition approved Dec. 10, 1999. Published January 2000. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 2046
exhibiting a measurable exothermic reaction. (See Test Method this test method depends upon the size of the specimen to be
E 487.) used. In general, observation of an exothermic reaction in small
3.2.2 reaction induction time (RIT) value, n—the time a specimens (less than 50 mg) is performed using differential
chemical compound or mixture may be held under isothermal scanning calorimetry or differential thermal analysis equipment
conditions until it exhibits a specified exothermic reaction. and techniques. Large samples (up to 2 g) may be tested using
devices such as the Kuhner Micro CTS apparatus.
4. Summary of Test Method
6.2 The following items are required to obtain the appro-
4.1 A specimen of the chemical compound or mixture is
priate experimental data.
placed in an inert container that is then heated to an operator-
NOTE 1—Commercially available differential scanning calorimetry ap-
selected test temperature of interest. The specimen temperature
paratus may be used. Alternatively, the apparatus may be assembled or
and the difference in heat flow or temperature between the test
fabricated from commercially available components.
specimen and an inert reference are monitored until an exo-
6.2.1 Test Chamber, composed of the following:
thermic reaction is recorded. The time from the attainment of
6.2.1.1 Furnace(s), to provide uniform controlled heating of
the isothermal test temperature until the extrapolated onset to
a specimen and reference to a constant temperature.
the exothermic reaction is taken as the Reaction Induction
6.2.1.2 Temperature Sensor, to provide an indication of
Time.
specimen/furnace temperature to 60.1 K.
4.2 Using fresh specimens measurements at more than one
6.2.1.3 Differential Sensor, to detect a difference in heat
isothermal test temperature may be made.
flow (or temperature) between the specimen and the reference
4.3 The RIT is expressed as time at a specific test tempera-
specimen equivalent to 10 μW or 0.01 mK.
ture. For example:
RIT 5 120 min at 100°C NOTE 2—A reference material is used when differential heat flow or
differential temperature measurements are made. The reference material
5. Significance and Use should match the physical state and heat capacity of the specimen as
closely as practical. Typical reference materials include calcined alumi-
5.1 This test method measures the time to extrapolated onset
num oxide, glass beads, silicone oil, or combinations thereof.
of an exothermic reaction under constant temperature (isother-
6.2.1.4 Means of Sustaining a Test Chamber Environment,
mal) conditions for reactions which have an induction period,
through the use of an air purge gas at a rate of 10 to 100 6 5
for example, those which are catalytic or autocatalytic in nature
mL/min.
or which contain reaction inhibitors.
5.2 The RIT determined by this test method is to be
NOTE 3—Typically, air or inert 99.9+ % pure nitrogen, argon, or helium
considered an index measurement that is useful for comparing
is employed (when oxidation in air is a concern). Unless effects of
moisture are to be studied, use of dry purge gas is recommended.
one material to another at the test temperature of interest and in
NOTE 4—For the Kuhner Micro CTS apparatus, the purge gas is
the same apparatus type only.
provided by operation in a laboratory hood with the door(s) approximately
5.3 This test method is a useful adjunct to dynamic thermal
50 % closed.
tests, such as Test Method E 537, which are performed under
6.2.2 Temperature Controller, capable of heating from am-
conditions in which the sample temperature is increased
bient to 400°C at a rate of up to 20°C/min and maintaining an
continuously at constant rate. Results obtained under dynamic
isothermal temperature constant within that range of 60.4°C
test conditions may result in higher estimates of temperature at
for the duration of the test, or both.
which an exothermic reaction initiates because the detected
6.2.3 Recording Device, either digital or analog, to record
onset temperature is dependent upon the heating rate and
and display any fraction of the differential heat flow or
because dynamic methods allow insufficient time for autocata-
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