ASTM D7954/D7954M-14
(Practice)Standard Practice for Moisture Surveying of Roofing and Waterproofing Systems Using Non-Destructive Electrical Impedance Scanners
Standard Practice for Moisture Surveying of Roofing and Waterproofing Systems Using Non-Destructive Electrical Impedance Scanners
SIGNIFICANCE AND USE
5.1 Excess moisture trapped in roofing or waterproofing systems can adversely affect performance and lead to premature failure of roofing or waterproofing systems and its components. It also reduces thermal resistance, resulting in reduced energy efficiency and inflated energy costs. Impedance scans can be effective in identifying concealed and entrapped moisture within roofing or waterproofing systems.
5.2 This practice is intended to be used at various stages of the roofing and waterproofing system’s life such as: during or at completion of installation of roofing system to determine if there was moisture intrusion into the roofing system or materials for quality control purposes, at regular intervals as part of a preventative maintenance program, and before re-roofing or repair work to assist in determining the extent of work and replacement materials.
5.3 This practice alone does not determine the cause of moisture infiltration into roofing or waterproofing systems; however, it can be used to help tracing excess moisture to the point of ingress.
SCOPE
1.1 This practice applies to techniques that use non-destructive electrical impedance (EI) scanners to locate moisture and evaluate the comparitive moisture content within insulated low-slope roofing and waterproofing systems.
1.2 This practice is applicable to roofing and waterproofing systems wherein insulation is placed above the deck and positioned underneath and in contact with electrically nonconductive single-ply or built-up roofing and waterproofing membranes and systems such as coal tar, asphalt, modified bitumen, thermoplastics, spray polyurethane foam, and similar electrically nonconductive membrane materials. This practice is also applicable to roofing and waterproofing systems without insulation placed above moisture absorbing decks such as wood, concrete, or gypsum, that are in contact with single-ply or built-up roofing and waterproofing membranes as described above.
1.3 This practice is applicable to roofing and waterproofing systems incorporating electrically nonconductive rigid board insulation made from materials such as organic fibers, perlite, cork, fiberglass, wood-fiber, polyisocyanurate, polystyrene, phenolic foam, composite boards, gypsum substrate boards, and other electrically nonconductive roofing and waterproofing systems such as spray-applied polyurethane foam.
1.4 This practice is not appropriate for all combinations of materials used in roofing and waterproofing systems.
1.4.1 Metal and other electrically conductive surface coverings and near-surface embedded metallic components are not suitable for surveying with impedance scanners because of the electrical conductivity of these materials.
1.4.2 This practice is not appropriate for use with Black EPDM membranes or coatings because of its high dielectric content and will give false positives.
1.4.3 Aluminum foil on top-faced insulation, roofing, or waterproofing membranes gives a false positive reading and is not suitable for surveying with impedance scanners; however, liquid-applied aluminum pigmented emulsified asphalt-based coatings shall not normally affect impedance scanner readings.
1.4.4 See A1.4 for some cautionary notes on roofing anomalies and limitations that affect the impedance test practice.
1.5 Moisture scanners using impedance based technology are classified as EI scanners.
Note 1: The term capacitance is sometimes used when describing impedance scanners. Capacitance scanners are purely capacitive as they do not have a resistive component. Impedance scanners combine both capacitance and resistance for testing; thus, they are well suited to the measurement of different types of materials and constructions found in roofing and waterproofing systems as the combination of both components allows for a more versatile testing, calibration, and measurement arrangement.
1.6 This practice also addresses necessary verif...
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Standards Content (Sample)
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Designation:D7954/D7954M −14
StandardPractice for
Moisture Surveying of Roofing and Waterproofing Systems
1
Using Non-Destructive Electrical Impedance Scanners
This standard is issued under the fixed designation D7954/D7954M; 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 liquid-applied aluminum pigmented emulsified asphalt-based
coatings shall not normally affect impedance scanner readings.
1.1 This practice applies to techniques that use non-
1.4.4 SeeA1.4forsomecautionarynotesonroofinganoma-
destructive electrical impedance (EI) scanners to locate mois-
lies and limitations that affect the impedance test practice.
ture and evaluate the comparitive moisture content within
insulated low-slope roofing and waterproofing systems.
1.5 Moisture scanners using impedance based technology
are classified as EI scanners.
1.2 This practice is applicable to roofing and waterproofing
systems wherein insulation is placed above the deck and
NOTE 1—The term capacitance is sometimes used when describing
positioned underneath and in contact with electrically noncon-
impedance scanners. Capacitance scanners are purely capacitive as they
ductive single-ply or built-up roofing and waterproofing mem- do not have a resistive component. Impedance scanners combine both
capacitance and resistance for testing; thus, they are well suited to the
branes and systems such as coal tar, asphalt, modified bitumen,
measurement of different types of materials and constructions found in
thermoplastics, spray polyurethane foam, and similar electri-
roofingandwaterproofingsystemsasthecombinationofbothcomponents
cally nonconductive membrane materials. This practice is also
allows for a more versatile testing, calibration, and measurement arrange-
applicable to roofing and waterproofing systems without insu-
ment.
lation placed above moisture absorbing decks such as wood,
1.6 This practice also addresses necessary verification of
concrete, or gypsum, that are in contact with single-ply or
impedance data involving invasive test procedures using core
built-up roofing and waterproofing membranes as described
samples.
above.
1.7 This practice addresses two generally accepted scanning
1.3 This practice is applicable to roofing and waterproofing
techniques for conducting moisture surveys using electrical
systems incorporating electrically nonconductive rigid board
impedance scanners:
insulation made from materials such as organic fibers, perlite,
1.7.1 Technique A—Continuous systematic scanning and
cork, fiberglass, wood-fiber, polyisocyanurate, polystyrene,
recording (see 8.2), and
phenolic foam, composite boards, gypsum substrate boards,
1.7.2 Technique B—Grid format scanning and recording
and other electrically nonconductive roofing and waterproofing
(see 8.3).
systems such as spray-applied polyurethane foam.
1.8 This practice addresses some meteorological conditions
1.4 This practice is not appropriate for all combinations of
and limitations for performing impedance inspections.
materials used in roofing and waterproofing systems.
1.4.1 Metal and other electrically conductive surface cover-
1.9 This practice addresses the effect of the roofing or
ings and near-surface embedded metallic components are not
waterproofing construction, material differences, and exterior
suitable for surveying with impedance scanners because of the
surface conditions on the moisture inspections.
electrical conductivity of these materials.
1.10 This practice addresses operating procedures, operator
1.4.2 This practice is not appropriate for use with Black
qualifications, operating methods, scanning, surveying, and
EPDM membranes or coatings because of its high dielectric
recording techniques.
content and will give false positives.
1.4.3 Aluminum foil on top-faced insulation, roofing, or
1.11 Units—The values stated in either SI units or inch-
waterproofing membranes gives a false positive reading and is
pound units are to be regarded separately as standard. The
not suitable for surveying with impedance scanners; however,
values stated in each system may not be exact equivalents;
therefore,eachsystemshallbeusedindependentlyoftheother.
1 Combining values from the two systems may result in non-
ThispracticeisunderthejurisdictionofASTMCommitteeD08onRoofingand
Waterproofing and is the direct responsibility of Subcommittee D08.20 on Roofing conformance with the standard.
Membrane Systems.
1.12 This standard does not purport to address all of the
Current edition approved July 15, 2014. Published August 2014. DOI: 10.1520/
D7954_D7954M-14. safety concerns, if any, associated with its use. It is t
...
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