ASTM E2551-18
(Test Method)Standard Test Methods for Humidity Calibration (or Conformation) of Humidity Generators for Use with Thermogravimetric Analyzers
Standard Test Methods for Humidity Calibration (or Conformation) of Humidity Generators for Use with Thermogravimetric Analyzers
SIGNIFICANCE AND USE
5.1 These test methods calibrate or demonstrate conformity of the humidity level in a purge gas generated by a humidity generator at a fixed temperature. Such calibration or demonstration of conformity may be required by quality initiatives.
5.2 Conformance demonstrates that the humidified purge gas is within some established limits.
5.3 Calibration provides an offset and or slope value that may be used for establishing the relative humidity scale of the apparatus.
SCOPE
1.1 These test methods describe the humidity calibration (or conformance) of humidity generators for use with thermogravimetric analyzers and other thermal analysis apparatus. The humidity range covered is 5 % relative humidity (% RH) to 95 % RH and the temperature range is 0 °C to 80 °C.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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.
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Designation: E2551 − 18
Standard Test Methods for
Humidity Calibration (or Conformation) of Humidity
1
Generators for Use with Thermogravimetric Analyzers
This standard is issued under the fixed designation E2551; 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 E1582 Test Method for Temperature Calibration of Thermo-
gravimetric Analyzers
1.1 These test methods describe the humidity calibration (or
conformance) of humidity generators for use with thermogra-
3. Terminology
vimetric analyzers and other thermal analysis apparatus. The
3.1 Specifictechnicaltermsusedinthisstandardaredefined
humidity range covered is 5 % relative humidity (% RH) to
in Terminologies E473 and E1142. These terms include first-
95 % RH and the temperature range is 0 °C to 80 °C.
deviation-from-baseline, isohume, relative humidity, thermal
1.2 The values stated in SI units are to be regarded as
curve, and thermogravimetric analysis.
standard. No other units of measurement are included in this
3.2 Definitions of Terms Specific to This Standard:
standard.
3.2.1 water activity, n—the ratio of actual partial pressure of
1.3 This standard does not purport to address all of the
water to the saturated water vapor pressure at the same
safety concerns, if any, associated with its use. It is the
temperature, expressed as a decimal fraction.
responsibility of the user of this standard to establish appro-
3.2.1.1 Discussion—Water activity is also known as relative
priate safety, health, and environmental practices and deter-
pressure in some applications areas.
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor-
4. Summary of Test Method
dance with internationally recognized principles on standard-
4.1 Humidity generators are devices aimed at producing a
ization established in the Decision on Principles for the
specific level of humidity in the purge gas used by thermogra-
Development of International Standards, Guides and Recom-
vimetric analyzers or other thermal analysis apparatus. The
mendations issued by the World Trade Organization Technical
requested humidity levels may be held constant (isohume) or
Barriers to Trade (TBT) Committee.
increased or decreased in a continuous or stepped fashion.
2. Referenced Documents
4.2 The humidified purge gas is submitted to a thermogra-
2
2.1 ASTM Standards:
vimetric analyzer in which the weight of a hygroscopic
D1193 Specification for Reagent Water
material is observed. The relative humidity (or activity) of the
E177 Practice for Use of the Terms Precision and Bias in moisture in the purge gas is stepped or scanned through a
ASTM Test Methods
humidity range. At a fixed humidity of the purge gas, the test
E473 Terminology Relating to Thermal Analysis and Rhe- specimen deliquesces and gains weight. In Test MethodA, the
ology
humidity of the onset of this weight gain is taken as the
E691 Practice for Conducting an Interlaboratory Study to humidity calibration point. In Test Methods B and C, the rate
Determine the Precision of a Test Method
of weight change is zero at the humidity calibration point.
E1142 Terminology Relating to Thermophysical Properties
5. Significance and Use
5.1 These test methods calibrate or demonstrate conformity
of the humidity level in a purge gas generated by a humidity
1
These test methods are under the jurisdiction of ASTM Committee E37 on
generator at a fixed temperature. Such calibration or demon-
ThermalMeasurementsandarethedirectresponsibilityofSubcommitteeE37.10on
stration of conformity may be required by quality initiatives.
Fundamental, Statistical and Mechanical Properties.
Current edition approved Oct. 1, 2018. Published October 2018. Originally
5.2 Conformance demonstrates that the humidified purge
approved in 2007. Last previous edition approved in 2013 as E2551 – 13. DOI:
gas is within some established limits.
10.1520/E2551-18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.3 Calibration provides an offset and or slope value that
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
may be used for establishing the relative humidity scale of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. apparatus.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E2551 − 18
6. Interferences 7.3 Thermogravimetric Analyzer (TGA)—The essential in-
strumentation required to provide the mini
...
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: E2551 − 13 E2551 − 18
Standard Test MethodMethods for
Humidity Calibration (or Conformation) of Humidity
1
Generators for Use with Thermogravimetric Analyzers
This standard is issued under the fixed designation E2551; 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 ThisThese test method describesmethods describe the humidity calibration (or conformance) of humidity generators for use
with thermogravimetric analyzers and other thermal analysis apparatus. The humidity range covered is 5 to 95 % % relative
humidity (% RH) to 95 % RH and the temperature range is 0 °C to 80°C.80 °C.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 There are no ISO equivalents to this standard.
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 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.
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.
2. Referenced Documents
2
2.1 ASTM Standards:
D1193 Specification for Reagent Water
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E473 Terminology Relating to Thermal Analysis and Rheology
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1142 Terminology Relating to Thermophysical Properties
1
ThisThese test method ismethods are under the jurisdiction of ASTM Committee E37 on Thermal Measurements and isare the direct responsibility of Subcommittee
E37.10 on Fundamental, Statistical and Mechanical Properties.
Current edition approved April 1, 2013Oct. 1, 2018. Published May 2013October 2018. Originally approved in 2007. Last previous edition approved in 20072013 as E2551
– 07.13. DOI: 10.1520/E2551-13.10.1520/E2551-18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. 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
---------------------- Page: 1 ----------------------
E2551 − 18
E1582 Test Method for Temperature Calibration of Thermogravimetric Analyzers
3. Terminology
3.1 Specific technical terms used in this standard are defined in Terminologies E473 and E1142. These terms include thermal
curvefirst-deviation-from-baseline, isohume, relative humidity, thermal curve, and thermogravimetric analysis.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 relative humidity, n—the ratio of actual partial pressure of water to the saturated water vapor pressure at the same
temperature, expressed as a percentage.
3.2.1 water activity, n—the ratio of actual partial pressure of water to the saturated water vapor pressure at the same temperature,
expressed as a decimal fraction.
3.2.1.1 Discussion—
Water activity is also known as relative pressure in some applications areas.
3.2.3 first-deviation-from-baseline, n—the relative humidity or water activity at which a deflection from the established baseline
is first observed.
4. Summary of Test Method
4.1 Humidity generators are devices aimed at producing a specific level of humidity in the purge gas used by thermogravimetric
analyzers or other thermal analysis apparatus. The requested humidity levels may be held constant (isohum)(isohume) or increased
or decreased in a continuous or stepped fashion.
4.2 The humidified purge gas is submitted to a thermogravimetric analyzer in which the w
...
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