ASTM E1502-98
(Guide)Standard Guide for Use of Freezing-Point Cells for Reference Temperatures
Standard Guide for Use of Freezing-Point Cells for Reference Temperatures
SCOPE
1.1 This guide describes the essential features of freezing-point cells and auxiliary apparatus, and the techniques required to realize freezing points in the temperature range from 29 to 1085°C.
1.2 Detailed design and construction are not addressed in this guide.
1.3 This guide is intended to describe good practice and establish uniform procedures for the realization of freezing points.
1.4 This guide emphasizes principles. The emphasis on principles is intended to aid the user in evaluating cells, in improving technique for using cells, and in establishing procedures for specific applications.
1.5 For the purposes of this guide, the use of freezing-point cells for the accurate calibration of thermometers is restricted to immersion-type thermometers that, when inserted into the reentrant well of the cell, (1) indicate the temperature only of the isothermal region of the well, and (2) do not significantly alter the temperature of the isothermal region of the well by heat transfer.
1.6 This guide does not address all of the details of thermometer calibration.
1.7 This guide is intended to complement special operating instructions supplied by manufacturers of freezing-point apparatus.
1.8 The following hazard caveat pertains only to the test method portion, Section 7, of this guide. This standard does not purport to address all of the safety problems, 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.
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Designation: E 1502 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Guide for
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Use of Freezing-Point Cells for Reference Temperatures
This standard is issued under the fixed designation E 1502; 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.
INTRODUCTION
During freezing, pure material transforms from the liquid state to the solid state at a constant
temperature known as the freezing point. The freezing points of highly purified materials can serve as
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reference temperatures, and in fact, the International Temperature Scale of 1990 (ITS-90) relies on
the freezing points of some highly purified metals as defining fixed points. Freezing points can be
realized in commercially available systems incorporating freezing-point cells. When the cells are
properly made and used, they establish useful reference temperatures for the calibration of
thermometers and for other industrial and laboratory purposes; with care, the freezing points of highly
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purified materials can be realized with an uncertainty of a few millikelvins or less.
1. Scope instructions supplied by manufacturers of freezing-point appa-
ratus.
1.1 This guide describes the essential features of freezing-
1.8 The following hazard caveat pertains only to the test
point cells and auxiliary apparatus, and the techniques required
method portion, Section 7, of this guide. This standard does not
to realize freezing points in the temperature range from 29 to
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purport to address all of the safety concerns, if any, associated
1085 °C.
with its use. It is the responsibility of the user of this standard
1.2 Detailed design and construction are not addressed in
to establish appropriate safety and health practices and
this guide.
determine the applicability of regulatory limitations prior to
1.3 This guide is intended to describe good practice and
use.
establish uniform procedures for the realization of freezing
points.
2. Referenced Documents
1.4 This guide emphasizes principles. The emphasis on
2.1 ASTM Standards:
principles is intended to aid the user in evaluating cells, in
E 344 Terminology Relating to Thermometry and Hydrom-
improving technique for using cells, and in establishing pro-
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etry
cedures for specific applications.
E 644 Test Methods for Testing Industrial Resistance Ther-
1.5 For the purposes of this guide, the use of freezing-point
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mometers
cells for the accurate calibration of thermometers is restricted
to immersion-type thermometers that, when inserted into the
3. Terminology
reentrant well of the cell, (1) indicate the temperature only of
3.1 Definitions:
the isothermal region of the well, and (2) do not significantly
3.1.1 reference temperature, n—a fixed, reproducible tem-
alter the temperature of the isothermal region of the well by
perature, to which a value is assigned, that can be used for the
heat transfer.
calibration of thermometers or other purposes.
1.6 This guide does not address all of the details of
3.1.2 Additional terms used in this guide are defined in
thermometer calibration.
Terminology E 344.
1.7 This guide is intended to complement special operating
3.2 Definitions of Terms Specific to This Standard:
3.2.1 first cryoscopic constant, A, n—a constant of propor-
tionality between the freezing point depression of, and concen-
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This guide is under the jurisdiction of ASTM Committee E-20 on Temperature
tration of impurities in, a sample of reference material, given
Measurement and is the direct responsibility of Subcommittee E20.07 on Funda-
by the ratio of the molar heat of fusion of the pure material, L,
mentals in Thermometry.
to the product of the molar gas constant, R, and the square of
Current edition approved Oct. 10, 1998. Published March 1999. Originally
the thermodynamic temperature of fusion, T, of the pure
published as E 1502–92. Last previous edition E 1502–92.
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Preston-Thomas, H., “The International Temperature Scale of 1990 (ITS-90),”
material (freezing point):
Metrologia, Vol 27, No. 1, 1990, pp. 3–10. For errata see ibid, Vol 27, No. 2, 1990,
p. 107.
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In this guide temperature intervals are expressed in kelvins (K) and millikelvins
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(mK). Values of temperature are expressed in degrees Celsius (°C), ITS-90. Annual Book of ASTM Standards, Vol 14.03.
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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 1502
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A 5
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