ASTM D5682-18(2023)
(Test Method)Standard Test Methods for Electrical Resistivity of Liquid Paint and Related Materials
Standard Test Methods for Electrical Resistivity of Liquid Paint and Related Materials
SIGNIFICANCE AND USE
4.1 These tests are suitable for testing paints adjusted for compatibility with various electrostatic spray coating applications, and by their use, spray performance can be optimized.
SCOPE
1.1 These test methods cover the determination of specific resistance (resistivity) of liquid paints, solvents, and other fluids in the range of 0.6 to 2640 MΩ-cm.
1.2 Test Method A describes a procedure for making resistance tests with a commonly used paint application test assembly (Fig. 1 and Fig. 2).
FIG. 1 Analog Paint Application Test Assembly
FIG. 2 Diagram of Digital Application Test Assembly
1.3 Test Method B describes a procedure for making resistance tests with a conductivity meter (Fig. 3).
FIG. 3 Conductivity Meter
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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
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: D5682 − 18 (Reapproved 2023)
Standard Test Methods for
Electrical Resistivity of Liquid Paint and Related Materials
This standard is issued under the fixed designation D5682; 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 2.2.1 kilohm (KΩ), n—resistance value equal to 1000 Ω
(10 ).
1.1 These test methods cover the determination of specific
2.2.2 megohm (MΩ), n—resistance value equal to 1 000 000
resistance (resistivity) of liquid paints, solvents, and other
Ω (10 ).
fluids in the range of 0.6 to 2640 MΩ-cm.
2.2.3 ohm-centimetre (or megohm-centimetre), n—unit of
1.2 Test Method A describes a procedure for making resis-
specific resistance (resistivity).
tance tests with a commonly used paint application test
assembly (Fig. 1 and Fig. 2).
3. Summary of Test Methods
1.3 Test Method B describes a procedure for making resis-
3.1 Test Methods A and B measure direct current through
tance tests with a conductivity meter (Fig. 3).
concentric cylinder electrodes immersed in a liquid paint
1.4 The values stated in SI units are to be regarded as
specimen.
standard. No other units of measurement are included in this
standard.
4. Significance and Use
1.5 This standard does not purport to address all of the
4.1 These tests are suitable for testing paints adjusted for
safety concerns, if any, associated with its use. It is the
compatibility with various electrostatic spray coating
responsibility of the user of this standard to establish appro-
applications, and by their use, spray performance can be
priate safety, health, and environmental practices and deter-
optimized.
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor-
5. Interferences
dance with internationally recognized principles on standard-
5.1 Contamination of the specimen is the most likely cause
ization established in the Decision on Principles for the
of error. Very small amounts of water, acids, or polar solvents
Development of International Standards, Guides and Recom-
will lower the resistance of high resistivity solvents and paints.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5.2 High humidity is not known to interfere with the test
itself but can lead to water pickup by the specimen. For
2. Terminology
repeatable results, tests should be made under the same
2.1 Definitions:
atmospheric conditions and specimens should be stored and
2.1.1 specific resistance (resistivity), n—the ratio of the d-c
handled so as to keep water pickup to a minimum.
potential gradient in volts per centimetre paralleling the current
5.3 Resistivity varies with temperature. A standard test
flow within the specimen to the current density in amperes per
temperature of 25 °C is recommended. Other temperatures are
square centimetre at a given instant of time and under
possible on agreement between the producer and the user.
prescribed conditions.
5.4 Electrification time must be the same for every test due
2.1.1.1 Discussion—This is numerically equal to the resis-
to ion migrations that cause current flow to decrease with time.
tance between opposite faces of a centimetre cube of the liquid.
Variations with time of electrification can result in appreciable
The units are ohm centimetres (or megohm centimetres).
variation in the test results.
2.2 Definitions of Terms Specific to This Standard:
5.5 Devices described in Test Methods A and B apply
different test voltages (45 V and 15 V, respectively). Because of
These test methods are under the jurisdiction of ASTM Committee D01 on
this, some variation in results may be expected.
Paint and Related Coatings, Materials, and Applications and are the direct
responsibility of Subcommittee D01.24 on Physical Properties of Liquid Paints &
Paint Materials. 6. Reagents and Materials
Current edition approved June 1, 2023. Published June 2023. Originally
6.1 Low Resistivity Cell Constant Standards (see Appendix
approved in 1995. Last previous edition approved in 2018 as D5682 – 18. DOI:
10.1520/D5682-18R23. X1 for cell constant determination method).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5682 − 18 (2023)
FIG. 1 Analog Paint Application Test Assembly
FIG. 3 Conductivity Meter
for all electrostatic applications. To provide greater accuracy in
measuring low resistance paints, the meter is equipped with
dual range selection. Range “A” is .005 to 1 MΩ , Range “B”
is .05 to 20 MΩ. The original version of this device was an
analog instrument with a pointer and scale as shown in Fig. 1
and many such instruments are in use. It has been replaced by
a digital version, a diagram of which is in Fig. 2.
8. Standardization
FIG. 2 Diagram of Digital Application Test Assembly
8.1 For maximum accuracy, the probe should be standard-
ized to determine the exact cell constant. For routine measure-
ments a cell constant (K) of 132 may be used (see Appendix
6.1.1 Potassium Chloride, 1000 μΩ/cm.
X1).
6.2 Cleaning Solvents and Solutions—It is essential to
8.2 The electronic-resistance measuring assembly may be
thoroughly clean the probe before and after tests. The cleaning
checked by use of a standard-resistance decade box ( ⁄2 %
solvent should be chosen on the basis of the paint tested. Due
accuracy or better).
care must be exercised in cleaning to ensure all cleaning
solvents are removed from the probe before reusing. The probe
9. Procedure
must be dry and free from contaminates or results will vary.
9.1 Prior to tests, make sure that the probe is thoroughly
cleaned (see 6.2).
TEST METHOD A
9.2 Insert the paint test probe into the jack in the lower right
7. Apparatus
side of the meter case.
7.1 Paint Application Test Assembly—designed to provide
9.3 Set the scale select switch (top center) to the Scale B
measurement of the electrical resistance of paint formulations
position.
9.4 Move the mode select switch (top right) to the Zero
1000 μΩ/cm test solutions are available from scientific supply companies. Adjust position and rotate the zero adjust knob (top left) until
D5682 − 18 (2023)
the dial indicator needle centers on the adjust position (far 12.3 Immerse the measuring cell into a well-mixed, visually
right). Maximum accuracy will be realized with the meter lying uniform specimen. The specimen should reach the two holes in
flat, m
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