ASTM E2251-14(2021)
(Specification)Standard Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
Standard Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
ABSTRACT
This specification covers liquid-in-glass ASTM thermometers using low hazard thermometric liquids. The gas filling above the liquid shall be nitrogen or other suitable inert gas. The filling gas shall be chosen to have very low solubility in the thermometric fluid. The stem shall be made of suitable thermometer tubing and shall have a plain front and enamel back. The bulb shall be made of glass and the following distances between graduations and the bulb, and between graduations and enlargements in the capillary, are minimum limits acceptable. All graduation lines, figures, and letters shall be clearly defined, suitably colored, and permanent. The width and the sharpness of the graduation lines shall be designed in accordance with necessary space between the graduations and the desired accuracy of interpolation. The middle of the graduation line shall be accurately determinable. In addition, the graduation lines shall be straight, of uniform width, and perpendicular to the axis of the thermometer. On partial immersion thermometers an immersion line shall be permanently marked on the front of the thermometer at the distance above the bottom of the bulb as specified. The immersion inscription shall be written in capital letters and abbreviated. The terminal number shall be in full when there are one or more numbered graduations between it and the next full number. The special inscription specified shall be marked on the thermometer in capital letters and Arabic numbers without the use of periods.
SCOPE
1.1 The purpose of this standard is to specify liquid-in-glass ASTM thermometers using low hazard thermometric liquids defined in this standard.
1.2 This standard specifies liquid-in-glass thermometers graduated in degrees Celsius or degrees Fahrenheit that are frequently identified and used in methods under the jurisdiction of the various technical committees within ASTM. The current approved thermometers are listed in Table 1.
1.3 The technical requirements for the thermometric liquids used in the thermometers in Table 1 are specified in Annex A1. Tests for conformity to the technical requirements are also found in Annex A1.
Note 1: It has been found by experience that ASTM Thermometers, although developed in general for specific tests, may also be found suitable for other applications, thus precluding the need for new thermometer specifications differing in only minor features. However, it is suggested that technical committees contact E20.05 before choosing a currently designated thermometer for a new method to be sure the thermometer will be suitable for the intended application.
1.4 For full rationale, see Appendix X1.
1.5 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.
1.6 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:E2251 −14 (Reapproved 2021)
Standard Specification for
Liquid-in-Glass ASTM Thermometers with Low-Hazard
Precision Liquids
This standard is issued under the fixed designation E2251; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 Thepurposeofthisstandardistospecifyliquid-in-glass
E1Specification for ASTM Liquid-in-Glass Thermometers
ASTM thermometers using low hazard thermometric liquids
E77Test Method for Inspection and Verification of Ther-
defined in this standard.
mometers
1.2 This standard specifies liquid-in-glass thermometers
E344Terminology Relating to Thermometry and Hydrom-
graduated in degrees Celsius or degrees Fahrenheit that are
etry
frequentlyidentifiedandusedinmethodsunderthejurisdiction
E563Practice for Preparation and Use of an Ice-Point Bath
of the various technical committees withinASTM.The current
as a Reference Temperature
approved thermometers are listed in Table 1.
3. Terminology
1.3 The technical requirements for the thermometric liquids
3.1 Definitions—ThedefinitionsgiveninTerminologyE344
usedinthethermometersinTable1arespecifiedinAnnexA1.
apply.
Tests for conformity to the technical requirements are also
found in Annex A1.
3.2 Definitions of Terms Specific to This Standard:
NOTE 1—It has been found by experience that ASTM Thermometers,
3.2.1 bulb length, n—the distance from the bottom of the
although developed in general for specific tests, may also be found
bulb to the junction of the bulb and the stem tubing.
suitableforotherapplications,thusprecludingtheneedfornewthermom-
3.2.2 contraction chamber, n—an enlargement of the
eter specifications differing in only minor features. However, it is
suggested that technical committees contact E20.05 before choosing a
capillary, located below the main scale or between the main
currently designated thermometer for a new method to be sure the
scale and the auxiliary scale, that serves to reduce the scale
thermometer will be suitable for the intended application.
lengthortopreventcontractionofalltheliquidcolumnintothe
1.4 For full rationale, see Appendix X1.
bulb.
1.5 This standard does not purport to address all of the 3.2.3 diameter, n—thelargestoutsidedimensionoftheglass
tubing as measured with a ring gage.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2.4 expansion chamber, n—an enlargement at the top of
priate safety, health, and environmental practices and deter-
the capillary to provide protection against breakage caused by
mine the applicability of regulatory limitations prior to use.
excessive gas pressure.
1.6 This international standard was developed in accor-
3.2.5 faden thermometer, n—a thermometer with a long,
dance with internationally recognized principles on standard-
thin bulb used to determine emergent stem temperatures.
ization established in the Decision on Principles for the
3.2.6 intervalerror,n—thedeviationofthenominalvalueof
Development of International Standards, Guides and Recom-
a temperature interval from its true value; either for the total
mendations issued by the World Trade Organization Technical
range(totalinterval)orforapartoftherange(partialinterval).
Barriers to Trade (TBT) Committee.
3.2.7 low-hazard liquid, n—a liquid that is biodegradable,
non-hazardousandconsiderednon-toxicinthermometerquan-
tities.
This specification is under the jurisdiction of ASTM Committee E20 on
Temperature Measurement and is the direct responsibility of Subcommittee E20.05
on Liquid-in-Glass Thermometers and Hydrometers. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2021. Published December 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2003. Last previous edition approved in 2014 as E2251–14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E2251-14R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2251−14 (2021)
NOTE 2—It is the responsibility of the manufacturer to determine the
8. Capillary Clearances
suitability of a liquid for this standard. In marking the thermometer with
8.1 The following distances between graduations and the
theASTMdesignationthemanufacturerisconfirmingthattheliquidinthe
bulb, and between graduations and enlargements in the
thermometerisnon-hazardousasdefinedbycurrentOSHA(Occupational
Safety and Health Administration) standards and non-toxic in thermom-
capillary, are minimum limits acceptable for thermometers in
eter quantities per current definitions of the United States Environmental
this standard.
Protection Agency.
NOTE 6—In order for a thermometer to be usable over its entire
3.2.8 thermometric liquid, n—the liquid in a liquid-in-glass
graduated range, graduation marks must not be placed too close to any
thermometer that indicates the value of temperature.
enlargement in the capillary. Insufficient immersion of the thermometric
liquid in the main bulb or capillary enlargement, graduation marks placed
3.2.9 top of the thermometer, n—the top of the finished
over parts of the capillary that have been changed by manufacturing
instrument.
operations, or graduations so close to the top of the thermometer that
3.2.10 total length, n—overall length of the finished instru-
excessive gas pressure results when the thermometric liquid is raised to
ment. this level, may lead to appreciable errors.
8.1.1 A 13-mm length of unchanged capillary between the
3.3 Other terms may be found in the Terminology sections
bulb and the immersion line or lowest graduation, if the
of Specification E1 and Test Method E77.
graduation is not above 100°C (212°F); a 30-mm length if the
4. Specifications
graduation is above 100°C (212°F).
8.1.2 A 5-mm length of unchanged capillary between an
4.1 The individual thermometers shall conform to the de-
enlargementandthegraduationnextbelow,exceptatthetopof
tailed specifications given in Table 1, the general requirements
the thermometer.
specified in Sections5–15, and Annex A1 and Annex A2.
8.1.3 A 10-mm length of unchanged capillary between an
NOTE 3—Thermometers manufactured to previous revisions of this
standard shall retain the same ASTM status as those meeting current enlargement,otherthanthebulb,andtheimmersionlineorthe
specifications.
graduation next above, if the graduation is not above 100°C
NOTE 4—The encapsulation (jacketing) of the glass of liquid-in-glass
(212°F); a 30-mm length if the graduation is above 100°C
thermometers with polyflourinated hydrocarbons will change their perfor-
(212°F).
mance and physical characteristics, including, but not limited to, response
8.1.4 A 10-mm length of unchanged capillary above the
time, accuracy, and physical dimensions. Therefore, under no circum-
stancesshouldanencapsulatedorotherwisemodifiedASTMthermometer
highest graduation, if there is an expansion chamber at the top
beusedinperformingteststhatspecifytheuseofanASTMthermometer.
of the thermometer; a 30-mm length if there is no expansion
chamber. For the purposes of this requirement, “an expansion
5. Type
chamber” is interpreted as an enlargement at the top end of the
5.1 Each thermometer in Table 1 shall be of the liquid-in-
capillary bore that shall have a capacity equivalent to not less
glass type filled with a low hazard thermometric liquid that
than 20 mm of unchanged capillary.
meetsthespecificationsinAnnexA1.Thegasfillingabovethe
8.2 Due to a change in the methods used for scale
liquid shall be nitrogen or other suitable inert gas. The filling
placement, it is possible to manufacture thermometers that
gas shall be chosen to have very low solubility in the
comply with the specifications given in Table 1, but not meet
thermometric fluid.
the requirements for capillary clearances given above. In any
case, the distances given in this section are the governing
6. Stem
factor. Under no circumstances shall the scales on thermom-
6.1 Stem—The stem shall be made of suitable thermometer
eters be placed closer than these minimum distances.
tubing and shall have a plain front and enamel back.
9. Graduations and Inscriptions
6.2 Top Finish—The top of all thermometers specified in
Table1shallhaveaplainroundedfinish,exceptthefollowing,
9.1 All graduation lines, figures, and letters shall be clearly
whichshallhavethetopfinishindicatedbelow.Anyspecialtop
defined, suitably colored, and permanent. The width and the
finish shall be included in the total length of the thermometer.
sharpness of the graduation lines shall be designed in accor-
6.2.1 Special Finish:
dance with necessary space between the graduations and the
6.2.1.1 Any finish suitable for assembly in a standard
desiredaccuracyofinterpolation.Themiddleofthegraduation
304.8-mm (12-in.) non-sparking metal armor with open face;
line shall be accurately determinable.
in a cup case assembly; or in a flushing case assembly as
9.1.1 A suitably etched thermometer with the etched lines
defined in standards the thermometers are used in:
and figures filled with a suitable colorant shall be considered
Thermometers S58C, S58F, S59C, S59F, S130C, S130F
permanentlymarkedprovideditpassesthetestforpermanency
of pigment in Specification E1.
7. Bulb
9.2 Graduation Lines—All graduation lines shall be
7.1 The bulb shall be made of glass having a viscosity of at
straight, of uniform width, and perpendicular to the axis of the
14.6 13.4
least10 poisesat490°C(914°F)andatleast10 poisesat
thermometer. The width of the graduation lines shall be as
520°C (968°F).
follows:
NOTE5—Thermometersmadewithbulbglasseshavingpropertiesclose
9.2.1 Group 1—Maximum line width 0.10 mm; for ther-
to these minimum requirements should not be subjected to temperatures
mometers that may read to fractions of a division, often with
above 405°C (760°F) or be continuously exposed to temperatures above
370°C (700°F). magnifying aids:
E2251−14 (2021)
12. Bulb Stability
Thermometers S56C, S56F, S62C, S62F, S63C, S63F, S64C, S64F,
S65C, S65F, S66C, S66F, S67C, S67F, S91C, S116C, S117C,
S120C 12.1 Notestforbulbstabilityisnecessaryforanythermom-
eterscurrentlyinthisstandard.However,shouldtherebeinthe
9.2.2 Group 2—Maximum line width 0.15 mm; for ther-
future, the bulb stability test as found in Specification E1 shall
mometersthatmaybereadtothenearesthalfdivisionorwhere
be used.
the congestion of scale dictates the use of a scale to moderate
fineness:
13. Scale Error
Thermometers S5C, S5F, S12C, S12F, S15C, S15F, S18C, S18F,
S22C, S22F
13.1 Thermometers shall be verified and calibrated at the
9.2.3 Group 3—Maximum line width 0.20 mm; for ther-
temperatures specified in Table 4. Partial immersion thermom-
mometers with more open scales, usually read to the nearest
eters shall be calibrated for the emergent stem temperatures
division, often times under adverse conditions where a bold
specified in Table 4 using faden thermometers.
graduation is therefore desired:
13.1.1 At the time of purchase, the scale errors must be
Thermometers S58C, S58F, S59C, S59F, S130C, S130F
within the maximum scale error found in Table 1. The
9.3 Immersion Line—On partial immersion thermometers
indications of many high temperature and fractionally gradu-
an immersion line shall be permanently marked on the front of
ated thermometers may change with time and continued use,
thethermometeratthedistanceabovethebottomofthebulbas
due to minute changes in bulb volume. Periodic verification of
specified in Table 1 within a tolerance of 60.5 mm. The
thesethermometerseitherovertheentirescaleorreverification
immersion inscription shall be written in capital letters and
at the reference temperature (ice point or steam point), in
abbreviated (for example, 76 mm immersion shall be written
accordance with procedures set forth in Test Method E77,is
76 MM IMM.)
recommended.
9.4 Terminal Numbers—The terminal number shall be in
fullwhenthereareoneormorenumberedgraduationsbetween 13.2 Due to the application requirements for range and
it and the next full number. This rule need not necessarily be
construction of the following thermometer(s) do not have
followed for:
reference points such as ice and steam points:
9.4.1 Precision Thermometers:
S91C
S65F, S66F, S67C, and S67F
14. Case and Instructions
9.5 Scale Below Zero—When a scale extends both above
and below 0°C or 0°F, the two parts of the scale shall be
14.1 Each thermometer shall be supplied in a suitable case
differentiatedbysomemeans.Examplesofsuitablemeansare:
on which shall appear the following marking (except when a
9.5.1 Different colorants for the graduations for the two
transparentcaseisused):theletters“ASTM,”thethermometer
parts of the scale,
number (S59C, S59F, etc.), and the temperature range.
9.5.2 Different style of numerical characters for the two
parts of the scale, and
14.2 Each thermometer shall be supplied with suitable user
9.5.3 Use of minus signs before appropriate numbers below
instructions. See Appendix X2 for Sample User Instructions.
0°C or 0°F.
15. Methods of Verification and Calibration
10. Special Inscription
15.1 Thermometers shall be verified and calibrated at the
10.1 The special inscription specified in Table 1 shall be
specified immersion in accordance with Test Method E77. For
marked on the thermometer in capital letters and Arabic
partial immersion thermometers careful consideration to emer-
numbers without the use of periods. Include year of current
gent stem temperatures shall be observed.
revision in theASTM designation (for exampleASTM S56C-
03).
10.1.1 Eachthermometershallbepermanentlymarkedwith
a unique serial number and the manufacturer’s tradename or
mark.
10.1.2 Each thermometer shall have the average coefficient
of thermal expansion of the liquid permanently marked.
10.1.3 When the length of the thermometer permits, the
words “TOTAL IMMERSION” may also be inscribed on the
back of thermometers calibrated for total immersion.
11. Permanency of Pigment
11.1 Thetestforpermanencyofpigmentshallbeperformed
on any convenient portion of the scale section of the thermom-
eter.Thepigmentshallnotchalk,burnout,orloosenasaresult
of this test (see Specification E1).
E2251−14 (2021)
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