ASTM D4787-13(2018)
(Practice)Standard Practice for Continuity Verification of Liquid or Sheet Linings Applied to Concrete Substrates
Standard Practice for Continuity Verification of Liquid or Sheet Linings Applied to Concrete Substrates
SIGNIFICANCE AND USE
5.1 The electrical conductivity of concrete is primarily influenced by the presence of moisture. Other factors, which affect the electrical continuity of concrete structures, include the following:
5.1.1 Presence of metal rebars,
5.1.2 Cement content and type,
5.1.3 Aggregate types,
5.1.4 Admixtures,
5.1.5 Porosity within the concrete,
5.1.6 Above or below grade elevation,
5.1.7 Indoor or outdoor location,
5.1.8 Temperature and humidity, and
5.1.9 Age of concrete.
5.2 The electrical conductivity of concrete itself may be successfully used for high-voltage continuity testing of linings applied directly with no specific conductive underlayment installed. However, the voltage required to find a discontinuity may vary greatly from point to point on the structure. This variance may reduce the test reliability.
5.3 Although the most common conductive underlayments are liquid primers applied by trowel, roller, or spray, and which contain carbon or graphite fillers, others may take the form of the following:
5.3.1 Sheet-applied graphite veils,
5.3.2 Conductive polymers,
5.3.3 Conductive graphite fibers,
5.3.4 Conductive metallic fibers, and
5.3.5 Conductive metallic screening.
5.4 Liquid-applied conductive underlayments may be desirable as they can serve to address imperfections in the concrete surface and provide a better base for which to apply the lining.
5.5 This practice is intended for use only with new linings applied to concrete substrates. Inspecting a lining previously exposed to an immersion condition could result in damaging the lining or produce an erroneous detection of discontinuities due to permeation or moisture absorption of the lining. Deposits may also be present on the surface causing telegraphing. The use of a high voltage tester on a previously exposed lining is not recommended because of possible spark through which will damage an otherwise sound lining. A low voltage tester can be used but could ...
SCOPE
1.1 This practice covers procedures that may be used to allow the detection of discontinuities in nonconductive linings or other non-conductive coatings applied to concrete substrates.
1.2 Discontinuities may include pinholes, internal voids, holidays, cracks, and conductive inclusions.
1.3 This practice describes detection of discontinuities utilizing a high voltage spark tester using either pulsed or continuous dc voltage.
Note 1: For further information on discontinuity testing refer to NACE Standard SP0188-2006 or Practice D5162.
1.4 This practice describes procedures both with and without the use of a conductive underlayment.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.6 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 a specific hazard statement, see Section 7.
1.7 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:D4787 −13 (Reapproved 2018)
Standard Practice for
Continuity Verification of Liquid or Sheet Linings Applied to
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Concrete Substrates
This standard is issued under the fixed designation D4787; 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. Referenced Documents
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2.1 ASTM Standards:
1.1 This practice covers procedures that may be used to
allow the detection of discontinuities in nonconductive linings D5162 Practice for Discontinuity (Holiday) Testing of Non-
conductive Protective Coating on Metallic Substrates
or other non-conductive coatings applied to concrete sub-
strates. G62 Test Methods for Holiday Detection in Pipeline Coat-
ings
1.2 Discontinuities may include pinholes, internal voids,
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2.2 NACE Standards:
holidays, cracks, and conductive inclusions.
SP0188-2006 Discontinuity (Holiday) Testing of Protective
1.3 This practice describes detection of discontinuities uti-
Coatings
lizing a high voltage spark tester using either pulsed or
continuous dc voltage.
3. Terminology
NOTE 1—For further information on discontinuity testing refer to
3.1 Definitions of Terms Specific to This Standard:
NACE Standard SP0188-2006 or Practice D5162.
3.1.1 conductive underlayment, n—a continuous layer ap-
1.4 This practice describes procedures both with and with- pliedtothepreparedconcretesurfacepriortotheapplicationof
out the use of a conductive underlayment. a nonconductive lining layer(s) that will allow high voltage
spark testing for discontinuities in the lining, as it will conduct
1.5 The values stated in SI units are to be regarded as
the current present when the spark is generated.
standard. The values given in parentheses are for information
3.1.2 current sensitivity, n—some high voltage testers have
only.
adjustable current sensitivity that can be used to prevent low
1.6 This standard does not purport to address all of the
levels of current flow activating the audible alarm. The alarm
safety concerns, if any, associated with its use. It is the
sensitivity control sets the threshold current at which the
responsibility of the user of this standard to establish appro-
audible alarm sounds. If the high voltage can charge the lining,
priate safety, health, and environmental practices and deter-
a small amount of current will flow while this charge is
mine the applicability of regulatory limitations prior to use.
established. If the lining contains a pigment that allows a
For a specific hazard statement, see Section 7.
low-level leakage current to flow from the probe while testing
1.7 This international standard was developed in accor-
the threshold current can be set so that the alarm does not
dance with internationally recognized principles on standard-
sound until this current is exceeded, that is, when a holiday or
ization established in the Decision on Principles for the
flaw is detected. Increasing the current threshold setting makes
Development of International Standards, Guides and Recom-
the instrument less sensitive to this low level current flow,
mendations issued by the World Trade Organization Technical
decreasing the current threshold setting makes the instrument
Barriers to Trade (TBT) Committee.
more sensitive to current flow.
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This practice is under the jurisdiction of ASTM Committee D01 on Paint and For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Related Coatings, Materials, and Applications and is the direct responsibility of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Subcommittee D01.46 on Industrial Protective Coatings. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Sept. 1, 2018. Published September 2018. Originally the ASTM website.
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approved in 1988. Last previous edition approved in 2013 as D4787 – 08 (2013). Available from NACE International (NACE), 1440 South Creek Dr., Houston,
DOI: 10.1520/D4787-13R18. TX 77084-4906, http://www.nace.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D4787−13 (2018)
TABLE 1 Suggested Voltages for High Voltage Spark Testing
3.1.3 discontinuity, n—a localized lining site that has a
dielectric strength less than a determined test voltage. Total Dry Film Thickness
Suggested Inspection, V
mm mils
3.1.4 high voltage spark tester, n—an electr
...
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