ASTM E104-20a
(Practice)Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions
Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions
SIGNIFICANCE AND USE
5.1 Standard value relative humidity environments are important for conditioning materials in shelf-life studies or in the testing of mechanical properties such as dimensional stability and strength. Relative humidity is also an important operating variable for the calibration of many species of measuring instruments.
SCOPE
1.1 This practice describes one method for generating constant relative humidity (rh) environments in relatively small containers.
1.2 This practice is applicable for obtaining constant relative humidities ranging from dryness to near saturation at temperatures spanning from 0 °C to 50 °C.
1.3 This practice is applicable for closed systems such as environmental conditioning containers and for the calibration of hygrometers.
1.4 This practice is not recommended for the generation of continuous (flowing) streams of constant humidity unless precautionary criteria are followed to ensure source stability. (See Section 9.)
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 Warning—Saturated salt solutions are extremely corrosive, and care should be taken in their preparation and handling. There is also the possibility of corrosive vapors in the atmospheres over the saturated salt solutions.2
1.7 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. For more specific safety precautionary information see 1.6 and 10.1.
1.8 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
Buy Standard
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: E104 − 20a
Standard Practice for
Maintaining Constant Relative Humidity by Means of
1
Aqueous Solutions
This standard is issued under the fixed designation E104; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 This practice describes one method for generating con-
mendations issued by the World Trade Organization Technical
stant relative humidity (rh) environments in relatively small
Barriers to Trade (TBT) Committee.
containers.
1.2 This practice is applicable for obtaining constant rela-
2. Referenced Documents
tive humidities ranging from dryness to near saturation at
3
2.1 ASTM Standards:
temperatures spanning from 0 °C to 50 °C.
D1193 Specification for Reagent Water
1.3 This practice is applicable for closed systems such as
D1356 Terminology Relating to Sampling and Analysis of
environmental conditioning containers and for the calibration
Atmospheres
of hygrometers.
3. Terminology
1.4 This practice is not recommended for the generation of
continuous (flowing) streams of constant humidity unless 3.1 Definitions—For definitions of other terms used in this
precautionary criteria are followed to ensure source stability. practice, refer to Terminology D1356.
(See Section 9.) 3.1.1 non-hygroscopic material, n—material which neither
absorbs nor retains water vapor.
1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4. Summary of Practice
standard.
4.1 Standard value relative humidity environments are gen-
1.6 Warning—Saturated salt solutions are extremely
erated using selected aqueous saturated salt solutions.
corrosive, and care should be taken in their preparation and
handling.Thereisalsothepossibilityofcorrosivevaporsinthe
5. Significance and Use
2
atmospheres over the saturated salt solutions.
5.1 Standard value relative humidity environments are im-
1.7 This standard does not purport to address all of the
portant for conditioning materials in shelf-life studies or in the
safety concerns, if any, associated with its use. It is the
testing of mechanical properties such as dimensional stability
responsibility of the user of this standard to establish appro-
and strength. Relative humidity is also an important operating
priate safety, health, and environmental practices and deter-
variable for the calibration of many species of measuring
mine the applicability of regulatory limitations prior to use.
instruments.
For more specific safety precautionary information see 1.6 and
10.1.
6. Interferences
1.8 This international standard was developed in accor-
6.1 Temperature regulation of any solution-head space en-
dance with internationally recognized principles on standard-
vironment to 60.1 °C is essential for realizing generated
relative humidity values within 60.5 % (expected).
1
This practice is under the jurisdiction ofASTM Committee D22 on Air Quality
6.2 Some aqueous saturated salt solutions change composi-
and is the direct responsibility of Subcommittee D22.11 on Meteorology.
tion following preparation by hydrolysis or by reaction with
Current edition approved Nov. 1, 2020. Published December 2020. Originally
approved in 1951. Last previous edition approved in 2020 as E104 – 20. DOI:
10.1520/E0104-20A.
2 3
Opila, R., Jr., Weschler, C. J., and Schubert, R., “Acidic Vapors Above For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Saturated Salt Solutions Commonly Used for Control of Humidity,” IEEE Trans. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Components, Hybrids and Manufacturing Technology, Vol 12, No. 1, March 1989, Standards volume information, refer to the standard’s Document Summary page on
pp. 114–120. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E104 − 20a
TABLE 1 Humidity Fixed Point (HFP) Salt Solutions
HFP Designation Salt Name Chemical Symbol Temperature Range (°C)
HFP4 Cesium fluoride CsF 15 to 80
HFP7 Lithium bromide LiBr 5 to 80
HFP12 Lithium chloride LiCl 5 to 80
HFP23 Potassium
...
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: E104 − 20 E104 − 20a
Standard Practice for
Maintaining Constant Relative Humidity by Means of
1
Aqueous Solutions
This standard is issued under the fixed designation E104; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This practice describes one method for generating constant relative humidity (rh) environments in relatively small containers.
1.2 This practice is applicable for obtaining constant relative humidities ranging from dryness to near saturation at temperatures
spanning from 0 °C to 50°C.50 °C.
1.3 This practice is applicable for closed systems such as environmental conditioning containers and for the calibration of
hygrometers.
1.4 This practice is not recommended for the generation of continuous (flowing) streams of constant humidity unless precautionary
criteria are followed to ensure source stability. (See Section 9.)
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 Warning—Saturated salt solutions are extremely corrosive, and care should be taken in their preparation and handling. There
2
is also the possibility of corrosive vapors in the atmospheres over the saturated salt solutions.
1.7 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. For more specific safety precautionary information see 1.6 and 10.1.
1.8 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
3
2.1 ASTM Standards:
D1193 Specification for Reagent Water
1
This practice is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.11 on Meteorology.
Current edition approved March 1, 2020Nov. 1, 2020. Published April 2020December 2020. Originally approved in 1951. Last previous edition approved in 20122020
as E104 – 02 (2012).E104 – 20. DOI: 10.1520/E0104-20.10.1520/E0104-20A.
2
Opila, R., Jr., Weschler, C. J., and Schubert, R., “Acidic Vapors Above Saturated Salt Solutions Commonly Used for Control of Humidity,” IEEE Trans. Components,
Hybrids and Manufacturing Technology, Vol 12, No. 1, March 1989, pp. 114–120.
3
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’sstandard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E104 − 20a
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
3. Terminology
3.1 Definitions—For definitions of other terms used in this practice, refer to Terminology D1356.
3.1.1 non-hygroscopic material, n—material which neither absorbs nor retains water vapor.
4. Summary of Practice
4.1 Standard value relative humidity environments are generated using selected aqueous saturated salt solutions.
5. Significance and Use
5.1 Standard value relative humidity environments are important for conditioning materials in shelf-life studies or in the testing
of mechanical properties such as dimensional stability and strength. Relative humidity is also an important operating variable for
the calibration of many species of measuring instruments.
6. Interferences
6.1 Temperature regulation of any solution-head space environment to 60.1°C 60.1 °C is essential for realizing generated relative
humidity values within 60.5 % (expected).
6.2 Some aqueous saturated salt solutions change composition following preparation by hydrolysis or by reaction with
environmental component
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.