ASTM C1789-24
(Test Method)Standard Test Method for Calibration of Hand-Held Moisture Meters on Gypsum Panels
Standard Test Method for Calibration of Hand-Held Moisture Meters on Gypsum Panels
SIGNIFICANCE AND USE
5.1 This Standard Test Method is intended for use in calibrating hand-held meters to accurately read from approximately 30 % to 90 % ERH. Moisture content is related to the ERH or Aw of a material.
5.2 Hand-held meters provide a rapid means of sampling the moisture content of gypsum boards and panels during manufacture and for field inspection during and after building construction. However, these measurements are inferential, that is, electrical parameters are measured and compared against a calibration curve to obtain an indirect measure of moisture content. The electrical measurements are influenced by the actual moisture content, a number of other gypsum board and panel variables, environmental conditions, the geometry of the measuring probe, and the design of the meter. The maximum accuracy can only be obtained by an awareness of the effect of each parameter on the meter output and correction of readings as specified by these test methods.
5.3 Electrical conductance and dielectric meters are not necessarily equivalent in their readings under the same conditions. When this test method is referenced, the type of meter that is being used must be reported with the relevant ranges for precision and bias as specified in this standard.
5.4 Both types of meters are to be calibrated with respect to ERH as described in this standard.
SCOPE
1.1 This test method applies to the calibration of hand-held moisture meters for gypsum board, glass faced gypsum panels and fiber-reinforced gypsum panels by means of electrical conductance and dielectric meters. The test uses wetted test specimens which are dried down in at least five (5) steps to determine the moisture content based on the weight loss in comparison to the dry weight. The test also supplies the ERH values for each of the drying steps.
1.2 This test method has not been evaluated for the influence of paint or wall covering materials on the indicated moisture content of a gypsum board or panel substrate.
1.3 The values stated in SI (metric) 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.
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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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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: C1789 − 24
Standard Test Method for
Calibration of Hand-Held Moisture Meters on Gypsum
1
Panels
This standard is issued under the fixed designation C1789; 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* C1177/C1177M Specification for Glass Mat Gypsum Sub-
strate for Use as Sheathing
1.1 This test method applies to the calibration of hand-held
C1178/C1178M Specification for Coated Glass Mat Water-
moisture meters for gypsum board, glass faced gypsum panels
Resistant Gypsum Backing Panel
and fiber-reinforced gypsum panels by means of electrical
C1278/C1278M Specification for Fiber-Reinforced Gypsum
conductance and dielectric meters. The test uses wetted test
Panel
specimens which are dried down in at least five (5) steps to
C1396/C1396M Specification for Gypsum Board
determine the moisture content based on the weight loss in
D4442 Test Methods for Direct Moisture Content Measure-
comparison to the dry weight. The test also supplies the ERH
ment of Wood and Wood-Based Materials
values for each of the drying steps.
D4444 Test Method for Laboratory Standardization and
1.2 This test method has not been evaluated for the influ-
Calibration of Hand-Held Moisture Meters
ence of paint or wall covering materials on the indicated
3
2.2 ASHRAE Standard:
moisture content of a gypsum board or panel substrate.
2009 ASHRAE Handbook – Fundamentals, Chapter 1 –
1.3 The values stated in SI (metric) are to be regarded as
Psychrometrics, American Society of Heating, Refrigerat-
standard. The values given in parentheses are mathematical
ing and Air-conditioning Engineers
conversions to inch-pound units that are provided for informa-
tion only and are not considered standard.
3. Terminology
1.4 This standard does not purport to address all of the
3.1 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the
3.1.1 absolute humidity, d , n—the ratio of the mass of water
v
responsibility of the user of this standard to establish appro-
vapor to the total volume of the moist air sample.
priate safety, health, and environmental practices and deter-
3.1.2 admittance, n—inverse of impedance, a measure of
mine the applicability of regulatory limitations prior to use.
how easily an electric current can flow through a material.
1.5 This international standard was developed in accor-
3.1.3 conductance meters, n—conductance meters are those
dance with internationally recognized principles on standard-
that measure predominantly ionic conductance between points
ization established in the Decision on Principles for the
of applied voltage, usually dc.
Development of International Standards, Guides and Recom-
3.1.3.1 Discussion—Conductance meters generally have
mendations issued by the World Trade Organization Technical
pins that penetrate into the material being measured. Direct-
Barriers to Trade (TBT) Committee.
current conductance meters are commonly referred to as
2. Referenced Documents “resistance” meters. Most commercial conductance meters are
12 4
2 high-input impedance (about 10 Ω), wide-range (10 to
2.1 ASTM Standards:
12
10 Ω) ohmmeters. Their scales are generally calibrated to
C473 Test Methods for Physical Testing of Gypsum Panel
read directly in moisture content (oven-dry mass basis) for a
Products
particular calibration material and at a specific reference
temperature.
1
This test method is under the jurisdiction of ASTM Committee C11 on Gypsum
3.1.4 dew-point temperature, t , n—the temperature at
d
and Related Building Materials and Systems and is the direct responsibility of
which a sample of moist air being cooled at constant pressure
Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.
Current edition approved April 1, 2024. Published April 2024. Originally
and moisture content reaches 100 % relative humidity.
approved in 2013. Last previous edition approved in 2018 as C1789 – 14 (2018).
DOI: 10.1520/C1789-24.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Available from American Society of Heating, Refrigerating, and Air-
Standards volume information, refer to the standard’s Document Summary page on Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA
the ASTM website. 30329, http://www.ashrae.org.
*A Summary of Changes section appears at the end of this st
...
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: C1789 − 14 (Reapproved 2018) C1789 − 24
Standard Test Method for
Calibration of Hand-Held Moisture Meters on Gypsum
1
Panels
This standard is issued under the fixed designation C1789; 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 Scope*
1.1 This test method applies to the calibration of handheldhand-held moisture meters for gypsum board, glass faced gypsum panels
and fiber-reinforced gypsum panels by means of electrical conductance and dielectric meters. The test uses wetted test specimens
which are dried down in at least 5 five (5) steps to determine the moisture content based on the weight loss in comparison to the
dry weight. The test also supplies the ERH values for each of the drying steps.
1.2 This test method has not been evaluated for the influence of paint or wall covering materials on the indicated moisture content
of a gypsum board or panel substrate.
1.3 The values stated in SI (metric) 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.
1.4 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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:
C473 Test Methods for Physical Testing of Gypsum Panel Products
C1177/C1177M Specification for Glass Mat Gypsum Substrate for Use as Sheathing
C1178/C1178M Specification for Coated Glass Mat Water-Resistant Gypsum Backing Panel
C1278/C1278M Specification for Fiber-Reinforced Gypsum Panel
C1396/C1396M Specification for Gypsum Board
D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
D4444 Test Method for Laboratory Standardization and Calibration of Hand-Held Moisture Meters
1
This test method is under the jurisdiction of ASTM Committee C11 on Gypsum and Related Building Materials and Systems and is the direct responsibility of
Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.
Current edition approved Oct. 1, 2018April 1, 2024. Published October 2018April 2024. Originally approved in 2013. Last previous edition approved in 20142018 as
C1789 – 14. DOI: 10.1520/C1789-14R18.14 (2018). DOI: 10.1520/C1789-24.
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.
*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
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C1789 − 24
3
2.2 ASHRAE Standard:
2009 ASHRAE Handbook – Fundamentals, Chapter 1 – Psychrometrics, American Society of Heating, Refrigerating and
Air-conditioning Engineers
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 absolute humidity, d , n—the ratio of the mass of water vapor to the total volume of the moist air sample.
v
3.1.2 admittance, n—inverse of impedance, a measure of how easily an electric current can flow through a material.
3.1.3 conductance meters, n—conductance meters are those that measure predominantly ionic conductance between points of
applied voltage, usually dc.
3.1.3.1 Discussion—
Conductance meters generally have pins that penetrate into the material being measured. Direct-current conductance meters are
commonly referred to as "resistance"“resistance” meters. Most commercial conductance meters are high-input impedance (about
12 4 12
10 Ω), wide-range (10 to 10 Ω) ohmmeters. Their scales are generally calibrated to read directly in moisture content (oven-dry
mass basis) for a particular
...
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