ASTM E601-15

Standard Guide for Measuring Electromotive Force (emf) Stability of Base-Metal Thermoelement Materials with Time in Air

SIGNIFICANCE AND USE
5.1 This test is important because the accuracy of a temperature measurement by a thermocouple is directly related to the emf stability of the thermoelements.  
5.2 This test is used to verify that the tested thermoelements meet the intended requirements.  
5.3 This test is useful in comparing the emf stability of two base metal thermoelements under the same conditions. The test and reference emf may be measured either simultaneously or alternately.  
5.4 The relative stabilities of base metal thermoelements determined by this test are valid only under the specified test conditions. Results will be affected by changes in any of the following conditions: (1) temperature profile or gradient along the length of the thermoelements; (2) abundance, velocity and composition of the air surrounding the test pieces; (3) thermoelectric inhomogeneity of the test thermoelements; (4) stability of the platinum thermoelement.  
5.5 The test does not address the determination of base metal thermoelement stabilities over a series of temperature changes.  
5.6 The reliability of this test depends on the emf stability of the reference platinum thermoelement. For testing the relative emf stability of base-metal thermoelements, a reference element of platinum that has sufficient thermoelectric stability to determine any significant change in emf of base-metal thermoelements shall be used. To ascertain that the experimental method protects the platinum sufficiently from degradation, the method shall be validated by performing the procedure described in Appendix X1 prior to the actual test.  
5.7 The test result does not apply to applications in which the temperature distribution, for a given measuring junction temperature, changes with time.
SCOPE
1.1 This guide provides a method for measuring the emf stability of base-metal thermoelement materials in air referenced to platinum at specified constant elevated temperatures using dual, simultaneous, emf indicators, or using a single emf indicator, with the test and reference emf measured alternately. This test is conducted over a period of weeks.  
1.2 A calibrated platinum-rhodium/platinum thermocouple is used as a reference standard to establish the test temperature.  
1.3 The useful life of a thermocouple depends on the stability of the emf generated at given temperatures for a required time interval. This method provides a quantitative measure of the stability of individual thermoelements. By combining the results of the positive (P) and negative (N) thermoelements, the stability of a thermocouple comprised of both P and N thermoelements may be obtained. The emf of an individual thermoelement is measured against platinum, which may be the platinum leg of the platinum-rhodium/platinum reference thermocouple, or an additional platinum reference.
Note 1: Some thermoelements may show insignificant emf drift while undergoing relatively rapid oxidation. In these cases, failure of the thermoelement may be indicated only by a large rise in the electrical resistance between joined thermoelements, as measured at the reference junctions.
Note 2: See ASTM MNL 12 for recommended upper temperature limits in air.2
Note 3: This guide is only applicable for initially new thermoelements. Base-metal thermoelements exposed to temperatures above 200°C become thermoelectrically inhomogeneous, and stability testing of inhomogeneous thermoelements will give ambiguous results.  
1.4 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.

General Information

• Status: Historical
• Publication Date: 30-Apr-2015
• ICS: 17.200.20 - Temperature-measuring instruments
• Technical Committee: E20 - Temperature Measurement
• Drafting Committee: E20.11 - Thermocouples - Calibration

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E601 − 15
Standard Guide for
Measuring Electromotive Force (emf) Stability of Base-Metal
1
Thermoelement Materials with Time in Air
This standard is issued under the fixed designation E601; 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 1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This guide provides a method for measuring the emf
ization established in the Decision on Principles for the
stability of base-metal thermoelement materials in air refer-
Development of International Standards, Guides and Recom-
enced to platinum at specified constant elevated temperatures
mendations issued by the World Trade Organization Technical
using dual, simultaneous, emf indicators, or using a single emf
Barriers to Trade (TBT) Committee.
indicator, with the test and reference emf measured alternately.
This test is conducted over a period of weeks.
2. Referenced Documents
1.2 A calibrated platinum-rhodium/platinum thermocouple
3
2.1 ASTM Standards:
is used as a reference standard to establish the test temperature.
E220 Test Method for Calibration of Thermocouples By
1.3 The useful life of a thermocouple depends on the
Comparison Techniques
stability of the emf generated at given temperatures for a
E230 Specification for Temperature-Electromotive Force
required time interval. This method provides a quantitative
(emf) Tables for Standardized Thermocouples
measure of the stability of individual thermoelements. By
E344 Terminology Relating to Thermometry and Hydrom-
combining the results of the positive (P) and negative (N)
etry
thermoelements, the stability of a thermocouple comprised of
E563 Practice for Preparation and Use of an Ice-Point Bath
both P and N thermoelements may be obtained. The emf of an
as a Reference Temperature
individual thermoelement is measured against platinum, which
E1159 Specification for Thermocouple Materials, Platinum-
may be the platinum leg of the platinum-rhodium/platinum
Rhodium Alloys, and Platinum
reference thermocouple, or an additional platinum reference.
2.2 Other Referenced Documents
NOTE 1—Some thermoelements may show insignificant emf drift while
undergoing relatively rapid oxidation. In these cases, failure of the
NIST Monograph 175
thermoelement may be indicated only by a large rise in the electrical
resistance between joined thermoelements, as measured at the reference
3. Terminology
junctions.
NOTE 2—See ASTM MNL 12 for recommended upper temperature
3.1 Definitions—The definitions given inTerminology E344
2
limits in air.
shall apply to this guide.
NOTE 3—This guide is only applicable for initially new thermoele-
ments. Base-metal thermoelements exposed to temperatures above 200°C 3.2 Definitions of Terms Specific to This Standard:
become thermoelectrically inhomogeneous, and stability testing of inho-
3.2.1 emf indicator, n—an instrument that measures the emf
mogeneous thermoelements will give ambiguous results.
and displays the value, for example, a digital voltmeter
1.4 This standard does not purport to address all of the
(DVM).
safety concerns, if any, associated with its use. It is the
3.2.2 emf stability, n—change in emf (or in equivalent
responsibility of the user of this standard to establish appro-
temperature) with time, with the thermocouple junctions held
priate safety and health practices and determine the applica-
at fixed temperatures and with the thermal profile along the
bility of regulatory limitations prior to use.
thermoelements held constant.
3.2.3 half-maximum heated length, n—the distance between
1
This guide is under the jurisdiction of ASTM Committee E20 on Temperature
the tip of the temperature sensor and the position along the
Measurement and is the direct responsibility of Subcommittee E20.11 on Thermo-
couples - Calibration.
Current edition approved May 1, 2015. Published June 2015. Originally
approved in 1977. Last previous edition approved in 2013 as E601 – 07a (2013).
3
DOI: 10.1520/E0601-15. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
2
Manual on the Use of Thermocouples in Temperature Measurement: Fourth contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Edition, Available from ASTM Headquarters, 100 Barr Harbor Drive, West Standards volume information, refer to the standard’s Document Summary page on
Conshohocken, PA 19428, www.astm.org. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E601 − 07a (Reapproved 2013) E601 − 15
Standard Test Method Guide for
Measuring Electromotive Force (emf) Stability of Base-Metal
1
Thermoelement Materials with Time in Air
This standard is issued under the fixed designation E601; 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
1.1 This test method measures emf stability of base-metal thermoelement materials in air referenced to platinum at specified
constant elevated temperatures using dual, simultaneous, emf indicators, or using a single emf indicator, with the test and reference
emf measured alternately. This test is conducted over a period of weeks.
1.2 A calibrated platinum-rhodium/platinum thermocouple is used as a reference standard to establish the test temperature.
1.3 The useful life of a thermocouple depends on the stability of the emf generated at given temperatures for a required time
interval. This method provides a quantitative measure of the stability of individual thermoelements. By combining the results of
the positive (P) and negative (N) thermoelements, the stability of a thermocouple comprised of both P and N thermoelements may
be obtained. The emf of an individual thermoelement is measured against platinum, which may be the platinum leg of the
platinum-rhodium/platinum reference thermocouple, or an additional platinum reference.
NOTE 1—Some thermoelements may show insignificant emf drift while undergoing relatively rapid oxidation. In these cases, failure of the
thermoelement may be indicated only by a large rise in the electrical resistance between joined thermoelements, as measured at the reference junctions.
2
NOTE 2—See ASTM MNL 12 for recommended upper temperature limits in air.
NOTE 3—This test method is only applicable for initially new thermoelements. Base-metal thermoelements exposed to temperatures above 200 °C
become thermoelectrically inhomogeneous, and stability testing of inhomogeneous thermoelements will give ambiguous results.
1.4 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.
2. Referenced Documents
3
2.1 ASTM Standards:
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
E344 Terminology Relating to Thermometry and Hydrometry
E563 Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature
E1159 Specification for Thermocouple Materials, Platinum-Rhodium Alloys, and Platinum
3. Terminology
3.1 Definitions—The definitions given in Terminology E344 shall apply to this test method.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 emf indicator, n—an instrument that measures the emf and displays the value, for example, a digital voltmeter (DVM).
3.2.2 emf stability, n—change in emf (or in equivalent temperature) with time, with the thermocouple junctions held at fixed
temperatures and with the thermal profile along the thermoelements held constant.
1
This test method guide is under the jurisdiction of ASTM Committee E20 on Temperature Measurement and is the direct responsibility of Subcommittee E20.04 on
Thermocouples.
Current edition approved May 1, 2013May 1, 2015. Published May 2013June 2015. Originally approved in 1977. Last previous edition approved in 20072013 as
E601 – 07a.E601 – 07a (2013). DOI: 10.1520/E0601-07AR13.10.1520/E0601-15.
2
Manual on the Use of Thermocouples in Temperature Measurement: Fourth Edition, Available from ASTM Headquarters, 100 Barr Harbor Drive, West Conshohocken,
PA 19428, www.astm.org.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E601 − 15
3.2.3 half-maximum heated length, n—the distance between the tip of the temperature sensor and the position
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