ASTM E77-14(2021)
(Test Method)Standard Test Method for Inspection and Verification of Thermometers
Standard Test Method for Inspection and Verification of Thermometers
SIGNIFICANCE AND USE
4.1 The test method described in this standard will ensure that the thermometers listed in Specifications E1 and E2251 will indicate temperatures within the maximum scale errors listed, be compatible with the apparatus, and serve the purpose for which they were designed.
4.2 Thermometers that do not pass the visual and dimensional inspection tests may give erroneously high or low temperature readings, or may not fit into existing equipment used in ASTM methods. For accurate temperature measurements the scale readings of the thermometer should be verified as described in this test method.
SCOPE
1.1 This test method covers visual and dimensional inspection and test for scale accuracy to be used in the verification of liquid-in-glass thermometers as specified in Specifications E1 and E2251. However, these procedures may be applied to other liquid-in-glass thermometers.2
Note 1: The use of NIST SP250-232 is recommended.
1.2 Warning—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:E77 −14 (Reapproved 2021)
Standard Test Method for
Inspection and Verification of Thermometers
ThisstandardisissuedunderthefixeddesignationE77;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers visual and dimensional inspec-
E1Specification for ASTM Liquid-in-Glass Thermometers
tion and test for scale accuracy to be used in the verification of
E344Terminology Relating to Thermometry and Hydrom-
liquid-in-glass thermometers as specified in Specifications E1
etry
andE2251.However,theseproceduresmaybeappliedtoother
E2251Specification for Liquid-in-Glass ASTM Thermom-
liquid-in-glass thermometers.
eters with Low-Hazard Precision Liquids
NOTE 1—The use of NIST SP250-23 is recommended.
1.2 Warning—Mercuryhasbeendesignatedbymanyregu- 3. Terminology
latoryagenciesasahazardoussubstancethatcancauseserious
3.1 Definitions:
medicalissues.Mercury,oritsvapor,hasbeendemonstratedto
3.1.1 The definitions given in Terminology E344 apply.
be hazardous to health and corrosive to materials. Use caution
Some that are considered essential to this standard are given
when handling mercury and mercury-containing products. See
below.
the applicable product Safety Data Sheet (SDS) for additional
3.1.2 calibration, n—of a thermometer or thermometric
information. The potential exists that selling mercury or
system, the set of operations that establish, under specified
mercury-containing products, or both, is prohibited by local or
conditions, the relationship between the values of a thermo-
national law. Users must determine legality of sales in their
metric quantity indicated by a thermometer or thermometric
location.
system and the corresponding values of temperature realized
by standards.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.1.2.1 Discussion—(1) The result of a calibration permits
either the assignment of values of temperature to indicated
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- values of thermometric quantity or determination of correc-
tions with respect to indications. (2) A calibration may also
mine the applicability of regulatory limitations prior to use.
determine other metrological properties such as the effect of
1.4 This international standard was developed in accor-
influence quantities. (3) The result of a calibration may be
dance with internationally recognized principles on standard-
communicatedinadocumentsuchasacalibrationcertificateor
ization established in the Decision on Principles for the
acalibrationreport.(4)Thetermcalibrationhasalsobeenused
Development of International Standards, Guides and Recom-
to refer to the result of the operations, to representations of the
mendations issued by the World Trade Organization Technical
result, and to the actual relationship between values of the
Barriers to Trade (TBT) Committee.
thermometric quantity and temperature.
3.1.3 complete-immersionthermometer,n—aliquid-in-glass
thermometer, not specified in ASTM documents, designed to
This test method is under the jurisdiction of ASTM Committee E20 on
Temperature Measurement and is the direct responsibility of Subcommittee E20.05 indicate temperature correctly when the entire thermometer is
on Liquid-in-Glass Thermometers and Hydrometers.
exposed to the temperature being measured.
Current edition approved May 1, 2021. Published June 2021. Originally
ε1
approved in 1949. Last previous edition approved in 2014 as E77–14 . DOI:
10.1520/E0077-14R21.
2 3
“Liquid-in-Glass Thermometer Calibration Service,” NIST Special Publication For referenced ASTM standards, visit the ASTM website, www.astm.org, or
250-23, 1988. Available from U.S. Government Printing Office, Superintendent of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:// Standards volume information, refer to the standard’s Document Summary page on
www.access.gpo.gov. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E77−14 (2021)
3.1.4 partial-immersion thermometer, n—a liquid-in-glass resistance is determined by comparison with a standard
thermometer designed to indicate temperature correctly when resistor, using a potentiometer, a Kelvin-type double bridge, or
the bulb and a specified part of the stem are exposed to the aWheatstonebridge,(preferablyoftheMuellertype)oranAC
temperature being measured. resistance bridge. Temperatures may then be calculated using
suitable resistance-temperature equations. In order that it shall
3.1.5 total-immersion thermometer, n—a liquid-in-glass
be satisfactory for such use, the thermometer should meet the
thermometer designed to indicate temperature correctly when
requirement that the ratio of resistances at the steam and ice
just that portion of the thermometer containing the liquid is
pointsshallbegreaterthan1.3925.Morecompleteinformation
exposed to the temperature being measured.
on the construction and use of primary standard thermometers
3.2 Definitions of Terms Specific to This Standard: 4
may be obtained from NIST SP250-22.
3.2.1 referencepoint,n—atemperatureatwhichathermom-
5.5 Secondary Standard Thermometers—Secondary stan-
eter is checked for changes in the bulb volume.
dardthermometersaremoresuitableforroutinework,andmay
3.2.2 verification, n—the process of testing a thermometer
beofvarioustypesasdescribedbelow.Theyaresimplertouse
for compliance with specifications.
than a primary standard thermometer with its accessory
3.2.3 verification temperatures, n—the specified tempera-
equipment,thelatterbeingcapableofanorderofprecisionand
tures at which thermometers are tested for compliance with
accuracy far in excess of that attainable with liquid-in-glass
scale error limits.
thermometers. The choice of a secondary standard will be
governed by various factors. The following criteria should, in
3.2.4 Other descriptions of terms relating to thermometers
so far as possible, be satisfied: The standard should be a
are included in Sections 3 and 17 of Specification E1.
calibratedthermometerofequalorpreferablyhighersensitivity
4. Significance and Use
thanthethermometertobeverified,anditshouldbecapableof
giving results of an equal or preferably higher order of
4.1 The test method described in this standard will ensure
accuracy and also of an equal or preferably higher order of
that the thermometers listed in Specifications E1 and E2251
reproducibility or precision. Scale corrections should always
will indicate temperatures within the maximum scale errors
be applied in the use of these standards. Secondary standards
listed, be compatible with the apparatus, and serve the purpose
may be of the following types.
for which they were designed.
5.5.1 Direct-reading Resistance Thermometers—Direct-
4.2 Thermometers that do not pass the visual and dimen-
reading resistance thermometers are available commercially,
sional inspection tests may give erroneously high or low
are very convenient to use, and have the advantage over the
temperature readings, or may not fit into existing equipment
primary type that temperature indications are given directly in
used in ASTM methods. For accurate temperature measure-
theinstrumentreading.Theyshouldbecompletelyrecalibrated
ments the scale readings of the thermometer should be verified
every 6 to 12 months, depending upon the temperatures of
as described in this test method.
usage. Ice points should be taken every three months.
5.5.2 Liquid-in-glass Thermometers—Liquid-in-glass
5. Apparatus
thermometers, when used as secondary standards, may be
5.1 Graduated Metal Scales or Templates—Maximum and
classified into two groups, those intended for testing general
minimum specified linear dimensions are measured with
purposetotalorpartial-immersionthermometers,andthosefor
graduated metal scales and templates on which lines are ruled
testing special use partial-immersion thermometers.
atsuitabledistancesfromreferencepointscorrespondingtothe
5.5.2.1 Total-immersion Thermometers—In the case of gen-
maximumandminimumvaluesoftheseveralspecifieddimen-
eral purpose total-immersion thermometers, the sensitivity of
sions.
the thermometers to be tested will govern the choice of
5.2 Micrometers and Ring Guages—Specified diameters of
standard. For thermometers graduated in 1, 2, or 5° divisions,
ASTM thermometers are checked using micrometers, or more
a set of well-made thermometers will be adequate when
conveniently with ring gauges consisting of metal plates in
calibrated and used with applicable corrections. For fraction-
which holes have been formed corresponding to the maximum
ally graduated thermometers a calibrated set of the following
and minimum values of the several specified dimensions. The
thermometers is recommended. Specifications for theseASTM
thickness of such gauges should approximate the diameters of
Precision Thermometers appear in Specification E1.
the holes to minimize errors resulting from the axis of the
ASTM
thermometer stem being other than normal to the plane of the
Ther- Length,
Range Celsius Divisions
mometer mm
gauge. When specified, diameters may also be checked with
Number
conventional snap gauges having plane parallel working faces.
62C −38 to +2 °C 0.1 °C 380
5.3 Comparators—Comparators are required for verifica-
63C −8 to +32 °C 0.1 °C 380
tionofscaleaccuracyofliquid-in-glassthermometers.Suitable
64C 25 to 55 °C 0.1 °C 380
types are described in Appendix X1.
5.4 Primary Standard Thermometer—The primary standard
“Platinum Resistance Thermometer Calibrations,” NIST Special Publication
thermometer in the range from−183 to 630 °C (−297 to
NIST Special Publication 250-22.Available from U.S. Government Printing Office,
1166°F)istheplatinum-resistancethermometer.Temperatures
Superintendent of Documents, 732 N. Capitol St., NW, Washington, DC 20401-
are not measured directly with this instrument. Its electrical 0001, http://www.access.gpo.gov.
E77−14 (2021)
process below the freezing point of the liquid, care should be
ASTM
Ther- Length,
exercised to warm the stem sufficiently during the melting
Range Celsius Divisions
mometer mm
process so that no solidification occurs in the stem; otherwise
Number
65C 50 to 80 °C 0.1 °C 380
thebulbmayburstorthecapillarymaysplitinternallybecause
66C 75 to 105 °C 0.1 °C 380
of the expansion forces generated in the bulb.
67C 95 to 155 °C 0.2 °C 380
68C 145 to 205 °C 0.2 °C 380 6.1.1.1 If a mercury separation is observed in the stem,
69C 195 to 305 °C 0.5 °C 380
several different ways are suggested for joining the columns,
70C 295 to 405 °C 0.5 °C 380
dependingontheconstructionofthethermometerandthetype
ASTM
of separation. If a small portion of the liquid has separated at
Ther- Length,
Range Fahrenheit Divisions
mometer mm
the top of the column and the thermometer is provided with an
Number
expansion chamber, the liquid usually can be joined by
62F −36 to +35 °F 0.2 °F 380 carefully and slowly heating the bulb until the separated
63F 18 to 89 °F 0.2 °F 380
portion is driven into the expansion chamber. Never heat the
64F 77 to 131 °F 0.2 °F 380
bulb in an open flame.When the column itself follows into the
65F 122 to 176 °F 0.2 °F 380
66F 167 to 221 °F 0.2 °F 380 chamber, the separated portion usually will join onto the main
67F 203 to 311 °F 0.5 °F 380
column. A slight tapping of the thermometer against the palm
68F 293 to 401 °F 0.5 °F 380
of the hand will facilitate this joining. This method should not
69F 383 to 581 °F 1.0 °F 380
70F 563 to 761 °F 1.0 °F 380
be employed for high-temperature thermometers (above
The foregoing set is calibrated for total immersion.With the 260°C or 500 °F), because the heating of the bulb, which is
exception of the first two, each thermometer is provided with
necessary to drive the liquid into the expansion chamber, may
anauxiliaryscaleincluding0°C(32°F),thusprovidingmeans
overheat the glass and either break the bulb, because of the
for checking at a fixed point, which should be done each time
pressureofthegas,ordestroytheaccuracyofthethermometer
the thermometer is used. The change in ice-point reading
by expanding the bulb. Thermometers that have a contraction
should then be applied to all readings. It is only necessary to
chamber below the lowest graduation are likely to develop
have a liquid-in-glass thermometer completely calibrated one
separations either in the chamber or above it. It is frequently
time. Recalibration is performed as described in 6.3.8.
possibletojoinsuchseparationsbycoolingthethermometerso
5.5.2.2 Partial-immersion Thermometers— General pur-
that the separated portion as well as the main column both
pose partial-immersion thermometers, as commonly listed in
stand in the chamber. Tapping the tube against the hand or the
manufacturers’ catalogs according to their own specifications,
bulb on a soft spongy material, such as a rubber stopper,
are normally bought and sold without specification of the
usually will bring the liquid together. For more stubborn
temperatures of the emergent column for the various tempera-
separations it may be necessary to cool the bulb in dry ice to a
tureindicationsofthethermometers.Insuchcases,verification
point low enough to bring all of the liquid into the bulb itself.
is usually carried out for the emergent column temperatures
Bysoftlytappingonasoftspongymaterialoragainstthehand
prevailing with the verification equipment being employed.
it usually is possible to bring the liquid together in the bulb.
5.5.2.3 Special Use Partial-immersion Thermometers—
The bulb should be allowed to warm up slowly. The liquid
Special use partial-immersion thermometers, such as those
should emerge into the bore with no separation.
covered in Specification E1, have specified emergent mercury
6.1.1.2 In organic-liquid-filled thermometers distillation
columns or stem temperatures. These thermometers can be
may occur, with subsequent condensation of the colorless
used as standards to calibrate other thermometers similar in all
parent liquid in the upper part of the thermometer. Such
details of con
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