ASTM D1293-18
(Test Method)Standard Test Methods for pH of Water
Standard Test Methods for pH of Water
SIGNIFICANCE AND USE
5.1 The pH of water is a critical parameter affecting the solubility of trace minerals, the ability of the water to form scale or to cause metallic corrosion, and the suitability of the water to sustain living organisms. It is a defined scale, based on a system of buffer solutions2 with assigned values. In pure water at 25°C, pH 7.0 is the neutral point, but this varies with temperature and the ionic strength of the sample.5 Pure water in equilibrium with air has a pH of about 5.5, and most natural uncontaminated waters range between pH 6 and pH 9.
SCOPE
1.1 These test methods cover the determination of pH by electrometric measurement using the glass electrode as the sensor. Two test methods are given as follows:
Sections
Test Method A—Precise Laboratory Measurement
8 to 15
Test Method B—Routine or Continuous Measurement
16 to 24
1.2 Test Method A covers the precise measurement of pH in water utilizing at least two of seven standard reference buffer solutions for instrument standardization.
1.3 Test Method B covers the routine measurement of pH in water and is especially useful for continuous monitoring. Two buffers are used to standardize the instrument under controlled parameters, but the conditions are somewhat less restrictive than those in Test Method A. For on-line measurement, also see Test Method D6569 which provides more detail.
1.4 Both test methods are based on the pH scale established by NIST (formerly NBS) Standard Reference Materials.2
1.5 Neither test method is considered to be adequate for measurement of pH in water whose conductivity is less than about 5 μS/cm. Refer to Test Methods D5128 and D5464.
1.6 Precision and bias data were obtained using buffer solutions only. It is the user's responsibility to assure the validity of these test methods for untested types of water.
1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.
1.8 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.
1.9 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: D1293 − 18
Standard Test Methods for
1
pH of Water
This standard is issued under the fixed designation D1293; 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 priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 These test methods cover the determination of pH by
1.9 This international standard was developed in accor-
electrometric measurement using the glass electrode as the
dance with internationally recognized principles on standard-
sensor. Two test methods are given as follows:
ization established in the Decision on Principles for the
Sections
Development of International Standards, Guides and Recom-
Test Method A—Precise Laboratory Measurement 8 to 15
Test Method B—Routine or Continuous Measurement 16 to 24 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.2 Test MethodAcovers the precise measurement of pH in
water utilizing at least two of seven standard reference buffer
2. Referenced Documents
solutions for instrument standardization.
3
2.1 ASTM Standards:
1.3 Test Method B covers the routine measurement of pH in
D1066 Practice for Sampling Steam
water and is especially useful for continuous monitoring. Two
D1067 Test Methods for Acidity or Alkalinity of Water
buffers are used to standardize the instrument under controlled
D1129 Terminology Relating to Water
parameters, but the conditions are somewhat less restrictive
D1193 Specification for Reagent Water
thanthoseinTestMethodA.Foron-linemeasurement,alsosee
D2777 Practice for Determination of Precision and Bias of
Test Method D6569 which provides more detail.
Applicable Test Methods of Committee D19 on Water
1.4 Both test methods are based on the pH scale established
D3370 Practices for Sampling Water from Closed Conduits
2
by NIST (formerly NBS) Standard Reference Materials.
D5128 Test Method for On-Line pH Measurement of Water
1.5 Neither test method is considered to be adequate for
of Low Conductivity
measurement of pH in water whose conductivity is less than
D5464 Test Method for pH Measurement of Water of Low
about 5 µS/cm. Refer to Test Methods D5128 and D5464.
Conductivity
D6569 Test Method for On-Line Measurement of pH
1.6 Precision and bias data were obtained using buffer
E70 Test Method for pH of Aqueous Solutions With the
solutions only. It is the user’s responsibility to assure the
Glass Electrode
validity of these test methods for untested types of water.
1.7 The values stated in SI units are to be regarded as
3. Terminology
standard. The values given in parentheses are mathematical
3.1 Definitions:
conversions to inch-pound units that are provided for informa-
3.1.1 For definitions of terms used in this standard, refer to
tion only and are not considered standard.
Terminology D1129.
1.8 This standard does not purport to address all of the
3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the
3.2.1 pH, n—the negative logarithm of the hydrogen ion
responsibility of the user of this standard to establish appro-
activity in an aqueous solution or the logarithm of the
reciprocal of the hydrogen ion activity.
3.2.1.1 Discussion—The pH of an aqueous solution is de-
1
These test methods are under the jurisdiction of ASTM Committee D19 on
rived from E, the electromotive force (emf) of the cell:
Water and are the direct responsibility of Subcommittee D19.03 on Sampling Water
and Water-Formed Deposits, Analysis of Water for Power Generation and Process
Use, On-Line Water Analysis, and Surveillance of Water.
Current edition approved Jan. 15, 2018. Published January 2018. Originally
3
approved in 1953. Last previous edition approved in 2011 as D1293 – 11. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/D1293-18. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
Wu, and Koch, “Standard Reference Materials: Standardization of pH Standards volume information, refer to the standard’s Document Summary page on
Measurements,” NBS Special Publications No. 260-53, 1988. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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...
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: D1293 − 12 D1293 − 18
Standard Test Methods for
1
pH of Water
This standard is issued under the fixed designation D1293; 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
1.1 These test methods cover the determination of pH by electrometric measurement using the glass electrode as the sensor. Two
test methods are given as follows:
Sections
Test Method A—Precise Laboratory Measurement 8 to 15
Test Method B—Routine or Continuous Measurement 16 to 24
Sections
Test Method A—Precise Laboratory Measurement 8 to 15
Test Method B—Routine or Continuous Measurement 16 to 24
1.2 Test Method A covers the precise measurement of pH in water utilizing at least two of seven standard reference buffer
solutions for instrument standardization.
1.3 Test Method B covers the routine measurement of pH in water and is especially useful for continuous monitoring. Two
buffers are used to standardize the instrument under controlled parameters, but the conditions are somewhat less restrictive than
those in Test Method A. For on-line measurement, also see Test Method D6569 which provides more detail.
2
1.4 Both test methods are based on the pH scale established by NIST (formerly NBS) Standard Reference Materials.
1.5 Neither test method is considered to be adequate for measurement of pH in water whose conductivity is less than about 5
μS/cm. Refer to Test Methods D5128 and D5464.
1.6 Precision and bias data were obtained using buffer solutions only. It is the user’s responsibility to assure the validity of these
test methods for untested types of water.
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this The values
given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not
considered standard.
1.8 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.9 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:
D1066 Practice for Sampling Steam
D1067 Test Methods for Acidity or Alkalinity of Water
D1129 Terminology Relating to Water
1
These test methods are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D19.03 on Sampling Water and
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and Surveillance of Water.
Current edition approved Jan. 1, 2012Jan. 15, 2018. Published January 2012January 2018. Originally approved in 1953. Last previous edition approved in 20052011 as
D1293 – 99(2005).11. DOI: 10.1520/D1293-11.10.1520/D1293-18.
2
“Standard Reference Materials: Standardization of pH Measurements” Wu and Koch, NBS Special Publications No. 260-53, 1988.Wu, and Koch, “Standard Reference
Materials: Standardization of pH Measurements,” NBS Special Publications No. 260-53, 1988.
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’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 ----------------------
D1293 − 18
4
D1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits (Withdrawn 2003)
D1193 Specification for Reagent Water
D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
D3370 Practices for Sampling Water from Closed Conduits
D5128 Test Method for On-Line pH Measurement of Water of Low Conductivity
D5464
...
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