ASTM D8551-24

Standard Practices for Permanent Monitoring Systems for Electrical Leak Detection and Location

SIGNIFICANCE AND USE
4.1 Geomembranes are used as impermeable barriers to prevent liquids leaking out of landfills, ponds, and other containment facilities. In addition, geomembranes are also used to prevent external liquids leaking into to these types of facilities (for example, floating covers, landfill caps, and roofs of storage tanks). The liquids may contain contaminants that, if released, can cause damage to the environment or damage to the contents where protection is against leakage into the facility. In the case of a landfill cap, leakage increases the amount of leachate that the landfill can produce. Leaking liquids can erode the subgrade, causing further damage. Leakage can result in product loss or otherwise prevent the installation from performing its intended containment purpose. For these reasons, it is desirable that the geomembrane have as little leakage as practical.  
4.2 Geomembrane leaks can be caused by poor quality of the subgrade, poor quality of the material placed on the geomembrane, accidents, poor workmanship, manufacturing defects, and carelessness.  
4.3 The most significant causes of leaks in geomembranes that are covered with only water are related to construction activities, including pumps and equipment placed on the geomembrane, accidental punctures, punctures caused by traffic over rocks or debris on the geomembrane or in the subgrade, and ruptures caused by settlement during filling.  
4.4 The most significant cause of leaks in geomembranes covered with earthen materials is construction damage caused by machinery that occurs while placing the earthen material on the geomembrane. Such damage also can breach additional layers of the lining system such as geosynthetic clay liners.  
4.5 As a practical measure, other electrical leak location methods (see Guide D6747) should be used in conjunction with the permanent monitoring system to eliminate leaks in the installed geomembrane(s) as part of facility construction. Such methods must include testing ...
SCOPE
1.1 These practices describe standard procedures for using electrical methods to locate leaks in geomembranes covered with liquid, earthen materials, waste, and/or any material deposited on the geomembrane.  
1.2 These practices are intended to ensure that permanent leak detection and location systems are effective, which can result in complete containment (no leaks in the geomembrane).  
1.3 Not all sites will be easily amenable to this method, but some preparation can be performed in order to enable this method at nearly any site as outlined in Section 6. If ideal testing conditions cannot be achieved (or designed out), the method can still be performed, but any issues with site conditions must be documented.  
1.4 Permanent monitoring systems for electrical leak detection and location can be used on geomembranes installed in basins, ponds, tanks, ore and waste pads, landfill cells, landfill caps, and other containment facilities including civil engineering structures. The procedures are applicable for geomembranes made of materials such as polyethylene, polypropylene, polyvinyl chloride, chlorosulfonated polyethylene, bituminous material, and other sufficiently electrically insulating materials.  
1.5 Any permanent electrical monitoring system must detect the occurrence of a leak through the geomembrane, and it must last longer than the monitored geomembrane by nature of the concept. Therefore, all buried components and mechanical and electrical connections must be made of material either the same as the geomembrane, in case of sensors situated above geomembrane, or made from a material with a longer lifespan in cases where they are situated under the monitored geomembrane.  
1.6 Permanent electrical monitoring systems are comprised of either large mesh pads separated by nominal spaces, or a grid of sensors situated either below the geomembrane or above the geomembrane or in both positions (below and above the ge...

General Information

• Status: Published
• Publication Date: 31-Jan-2024
• Technical Committee: D35 - Geosynthetics
• Drafting Committee: D35.10 - Geomembranes

Relations

• Refers: ASTM D7007-24 - Standard Practices for Electrical Methods for Locating Leaks in Geomembranes Covered with Water or Earthen Materials
• Effective Date: 01-Mar-2024
• Refers: ASTM D4439-24 - Standard Terminology for Geosynthetics
• Effective Date: 01-Feb-2024
• Refers: ASTM D4439-23b - Standard Terminology for Geosynthetics
• Effective Date: 15-Jul-2023
• Refers: ASTM D7007-16 - Standard Practices for Electrical Methods for Locating Leaks in Geomembranes Covered with Water or Earthen Materials
• Effective Date: 01-Jan-2016

Overview

ASTM D8551-24: Standard Practices for Permanent Monitoring Systems for Electrical Leak Detection and Location establishes procedures for using electrical methods to locate leaks in geomembrane-lined containment systems. Geomembranes serve as impermeable barriers, commonly used in landfills, ponds, tanks, and other containment facilities to prevent leakage of potentially harmful fluids. Permanent electrical leak detection and monitoring systems ensure the ongoing integrity of these barriers by providing real-time detection and precise location of leaks, enabling rapid remediation and minimizing environmental risks.

Key Topics

• Significance of Permanent Monitoring:
  • Geomembrane leaks may occur due to poor subgrade quality, improper installation, accidental damage, or manufacturing defects.
  • Leaks can lead to environmental contamination, loss of valuable materials, undermining of containment function, and increased operational costs.
  • Using permanent electrical monitoring enables detection, location, and remediation of leaks throughout the lifecycle of the containment facility.
• Electrical Leak Detection Methods:
  • Electrical systems can monitor geomembrane integrity under various cover materials such as liquids, soil, or waste.
  • Detection systems may consist of grids of sensors (point or zonal) installed above, below, or on both sides of the geomembrane, or the use of large mesh pads.
  • Sensors must be constructed from corrosion-resistant and durable materials, designed to last longer than the monitored geomembrane.
• System Design Considerations:
  • Proper site preparation is essential for effective leak detection, including the elimination of conductive paths other than leaks.
  • All sensor and electrode positions should be precisely recorded to support accurate leak localization.
  • System sensitivity and detection precision are influenced by sensor grid density and the electrical properties of the cover and subgrade materials.
• Installation and Operation:
  • Commissioning practices require thorough pre-cover testing with supplemental methods and strict documentation procedures.
  • The system supports continuous monitoring and must be robust against environmental, chemical, and mechanical influences over long operational periods.
  • Proper commissioning ensures zero-leak conditions and facilitates ongoing leak detection during operational and post-closure phases.

Applications

• Landfills: Protecting groundwater and surrounding environments from landfill leachate by ensuring continuous geomembrane integrity.
• Lined Ponds and Basins: Preventing leakage of industrial or municipal water, wastewater, or process liquids.
• Waste Containment Pads: Used in mining and industrial sectors to prevent hazardous fluid escapes from ore or waste storage areas.
• Storage Tanks and Covered Structures: Ensuring the integrity of floating covers, tank roofs, and landfill caps by detecting external and internal leaks.
• Civil Engineering Structures: Supporting the safe operation of critical containment infrastructure, including impoundments and engineered environmental barriers.

The usage of permanent electrical leak detection provides regulatory compliance, minimizes environmental impact, and extends the lifespan of containment systems. Early detection of leaks reduces repair costs and prevents the need for extensive remediation or facility shutdowns.

Related Standards

• ASTM D4439 - Terminology for Geosynthetics
• ASTM D6747 - Guide for Selection of Techniques for Electrical Leak Location of Leaks in Geomembranes
• ASTM D7002 - Practice for Electrical Leak Location on Exposed Geomembranes Using the Water Puddle Method
• ASTM D7007 - Practices for Electrical Methods for Locating Leaks in Geomembranes Covered with Water or Earthen Materials
• ASTM D7703 - Practice for Electrical Leak Location on Exposed Geomembranes Using the Water Lance Method
• ASTM D7909 - Guide for Placement of Intentional Leaks During Electrical Leak Location Surveys of Geomembranes
• ASTM D7953 - Practice for Electrical Leak Location on Exposed Geomembranes Using the Arc Testing Method
• ASTM D8265 - Practices for Electrical Methods for Mapping Leaks in Installed Geomembranes

Incorporating ASTM D8551-24 within quality management systems strengthens leak detection protocols and supports sustainable, responsible management of containment facilities.

Keywords: electrical leak detection, geomembrane integrity, ASTM D8551-24, permanent monitoring systems, environmental containment, landfill liner inspection, geosynthetics leak detection, electrical sensor grid, regulatory compliance.

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: D8551 − 24
Standard Practices for
Permanent Monitoring Systems for Electrical Leak Detection
and Location
This standard is issued under the fixed designation D8551; 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 the geomembrane). In specific cases, sensors may be situated
only at the perimeter of the monitored lined facility.
1.1 These practices describe standard procedures for using
electrical methods to locate leaks in geomembranes covered 1.7 The values stated in SI units are to be regarded as
with liquid, earthen materials, waste, and/or any material standard. No other units of measurement are included in this
deposited on the geomembrane. standard.
1.2 These practices are intended to ensure that permanent 1.8 The electrical methods used for geomembrane leak
leak detection and location systems are effective, which can location should be attempted only by qualified and experienced
result in complete containment (no leaks in the geomembrane). personnel. Appropriate safety measures should be taken to
protect the leak location operators, as well as other people at
1.3 Not all sites will be easily amenable to this method, but
the site.
some preparation can be performed in order to enable this
1.9 This standard does not purport to address all of the
method at nearly any site as outlined in Section 6. If ideal
safety concerns, if any, associated with its use. It is the
testing conditions cannot be achieved (or designed out), the
responsibility of the user of this standard to establish appro-
method can still be performed, but any issues with site
priate safety, health, and environmental practices and deter-
conditions must be documented.
mine the applicability of regulatory limitations prior to use.
1.4 Permanent monitoring systems for electrical leak detec-
1.10 This international standard was developed in accor-
tion and location can be used on geomembranes installed in
dance with internationally recognized principles on standard-
basins, ponds, tanks, ore and waste pads, landfill cells, landfill
ization established in the Decision on Principles for the
caps, and other containment facilities including civil engineer-
Development of International Standards, Guides and Recom-
ing structures. The procedures are applicable for geomem-
mendations issued by the World Trade Organization Technical
branes made of materials such as polyethylene, polypropylene,
Barriers to Trade (TBT) Committee.
polyvinyl chloride, chlorosulfonated polyethylene, bituminous
material, and other sufficiently electrically insulating materials.
2. Referenced Documents
1.5 Any permanent electrical monitoring system must detect
2.1 ASTM Standards:
the occurrence of a leak through the geomembrane, and it must
D4439 Terminology for Geosynthetics
last longer than the monitored geomembrane by nature of the
D6747 Guide for Selection of Techniques for Electrical Leak
concept. Therefore, all buried components and mechanical and
Location of Leaks in Geomembranes
electrical connections must be made of material either the same
D7002 Practice for Electrical Leak Location on Exposed
as the geomembrane, in case of sensors situated above
Geomembranes Using the Water Puddle Method
geomembrane, or made from a material with a longer lifespan
D7007 Practices for Electrical Methods for Locating Leaks
in cases where they are situated under the monitored geomem-
in Geomembranes Covered with Water or Earthen Mate-
brane.
rials
1.6 Permanent electrical monitoring systems are comprised
D7703 Practice for Electrical Leak Location on Exposed
of either large mesh pads separated by nominal spaces, or a
Geomembranes Using the Water Lance Method
grid of sensors situated either below the geomembrane or
D7909 Guide for Placement of Intentional Leaks During
above the geomembrane or in both positions (below and above
Electrical Leak Location Surveys of Geomembranes
These practices are under the jurisdiction of ASTM Committee D35 on
Geosynthetics and are the direct responsibility of Subcommittee D35.10 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Geomembranes. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Current edition approved Feb. 1, 2024. Published February 2024. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D8551-24. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8551 − 24
D7953 Practice for Electrical Leak Location on Exposed measurements include but are not limited to: burns, circular
Geomembranes Using the Arc Testing Method holes, linear cuts, seam defects, tears, punctures, and material
D8265 Practices for Electrical Methods for Mapping Leaks defects.
in Installed Geomembranes
3.2.12 measurement, n—for the purposes of this standard, a
measurement is an electrical evaluation of a geomembrane-
3. Terminology
lined containment facility to check for leaks in the geomem-
brane.
3.1 For general definitions related to geosynthetics, see
3.2.13 measurement area, n—the portion of the
Terminology D4439.
geomembrane-lined containment facility subjected to an elec-
3.2 Definitions of Terms Specific to This Standard:
trical leak location measurement.
3.2.1 actual leak, n—for the purposes of this standard, the
3.2.14 monitoring, n—for the purpose of this standard,
term “actual leak” is used for a leak to distinguish it from an
monitoring is a repeated measurement of the measurement area
artificial leak.
to enable the detection of leaks as and when they occur.
3.2.2 anomaly (anomalies, pl), n—electrical measurement
3.2.15 point sensor, n—a sensor placed in a discrete location
caused by some aberration in the measurement area, which
of a gridded network.
may or may not be a leak.
3.2.16 potential, n—electrical voltage measured relative to a
3.2.3 artificial leak, n—for the purposes of this standard, an
reference point.
artificial leak is the temporary use of a sensor electrode or
3.2.17 power source, n—the direct current (DC) power
supply electrode, which is used to electrically mimic a leak in
supply used by leak location practitioners and permanent
the lining system and is used to confirm functionality without
systems in order to create a voltage differential across the
creating an actual leak in the lining system.
geomembrane.
3.2.4 blind leak, n—for the purposes of this standard, a blind
3.2.18 primary geomembrane, n—the geomembrane consti-
leak is a circular hole in the geomembrane intentionally placed
tuting the first containment layer in a lining system containing
by the owner or owner’s representative in a location unknown
multiple geomembranes.
to the leak location practitioner.
3.2.19 probe(s), n—a conductive object used to make elec-
3.2.5 conductive-backed geomembrane, n—a specialty
trical measurements.
geomembrane featuring a conductive backing.
3.2.20 return electrode, n—the electrode that is used as
3.2.6 conductive geotextile, n—a specialty geotextile manu-
reference pole to the current source electrode and it is placed
factured to be electrically conductive for use in multilayer
outside of measurement area, or on the opposite side of the
geosynthetic arrangements.
geomembrane as the current source electrode.
3.2.21 sensing electrode(s), n—see sensor; alternative noun
3.2.7 dipole measurement, n—an electrical measurement
used by leak location practitioners.
made on or in a partially conductive material using closely
spaced sensors carried over the covering layer and placed at
3.2.22 sensor(s), n—the electrodes that are used as receptors
equal centers to measure the entire surface for evidence of
of the electric leak location signals for measuring either voltage
anomalies (see Practices D7007 and D8265).
(V) or current (A). They are placed either below the geomem-
brane or above the geomembrane or on both sides of geomem-
3.2.8 earthen material, n—sand, gravel, clay, silt, combina-
brane. These are usually manufactured using conductive and
tions of these materials, waste materials, or similar materials
corrosion-resistant material such as 316L stainless steel or
with an approximate conductivity <50 kΩ/m.
titanium, or alternatively of semiconductive HDPE.
3.2.9 electrically isolated conductive-backed geomembrane
3.2.23 site response current, n—the value of current, typi-
installation, n—an installation of conductive-backed geomem-
cally expressed in milliamps, resulting from applying a voltage
brane that achieves a continuously conductive surface on the
to a current source electrode inserted into the material covering
bottom layer while electrically isolating the bottom conductive
the geomembrane in the measurement area with the current
layer from the top insulating layer of the entire geomembrane
return electrode connected to the underlying conductive layer
installation.
in case of multiple geomembranes or to the earth in case of
3.2.10 known leak, n—for the purposes of this standard, a
single geomembrane construction.
known leak is a circular hole in the geomembrane intentionally
3.2.24 source electrode, n—the electrode used to apply
placed by the owner or owner’s representative per Guide
current to the material above the geomembrane.
D7909.
3.2.25 zonal sensors, n—a form of sensor that is not a point
3.2.11 leak, n—for the purposes of this standard, a leak is
sensor but instead covers a large area and is formed of
any opening, perforation, breach, slit, tear, puncture, crack, or
electrically conductive mesh, which has a ratio of 1:1 (leak
seam breach in the lining system. Moisture/humidity or direct
location resolution to physical sensor size).
mineral contact should be present through a “leak” in order to
4. Significance and Use
produce an anomaly. Scratches, gouges, dents, or other aber-
rations that do not completely penetrate the geomembrane are 4.1 Geomembranes are used as impermeable barriers to
not considered to be leaks. Types of leaks detected during prevent liquids leaking out of landfills, ponds, and other
D8551 − 24
containment facilities. In addition, geomembranes are also reason for not applying this method. However, history has
used to prevent external liquids leaking into to these types of shown that it may be better to know, in order to minimize
facilities (for example, floating covers, landfill caps, and roofs late-life remedial work, by repairing leaks in a sector of a site
of storage tanks). The liquids may contain contaminants that, if rather than entirely exhuming and relocating (waste, for
released, can cause damage to the environment or damage to example) to a new site.
the contents where protection is against leakage into the
4.8 A permanent electric leak location monitoring system
facility. In the case of a landfill cap, leakage increases the
must last longer than the geomembrane it is designed to
amount of leachate that the landfill can produce. Leaking
monitor, otherwise failure caused by degradation of that
liquids can erode the subgrade, causing further damage.
material will not be detected. To achieve this, all buried
Leakage can result in product loss or otherwise prevent the
components and the associated electrical connections must be
installation from performing its intended containment purpose.
designed in such a way as to achieve this and additionally must
For these reasons, it is desirable that the geomembrane have as
avoid metallic corrosion of the buried components and/or
little leakage as practical.
critical connections.
4.2 Geomembrane leaks can be caused by poor quality of
the subgrade, poor quality of the material placed on the 5. Summary of the Permanent Electrical Leak Location
Methods
geomembrane, accidents, poor workmanship, manufacturing
defects, and carelessness.
5.1 There are three types of measurement employed when
monitoring geomembrane integrity:
4.3 The most significant causes of leaks in geomembranes
5.1.1 Voltage measurement (mV and V),
that are covered with only water are related to construction
5.1.2 Current measurement (mA), and
activities, including pumps and equipment placed on the
5.1.3 Hybrid (current and voltage measurement are both
geomembrane, accidental punctures, punctures caused by traf-
used).
fic over rocks or debris on the geomembrane or in the
subgrade, and ruptures caused by settlement during filling.
5.2 There are three types of system configurations by which
the above mentioned measurements can be taken:
4.4 The most significant cause of leaks in geomembranes
5.2.1 Point sensors (mV, V, and mA),
covered with earthen materials is construction damage caused
5.2.2 Zonal sensor (mV, V, and mA), and
by machinery that occurs while placing the earthen material on
5.2.3 Hybrid (zonal sensor and point sensors).
the geomembrane. Such damage also can breach additional
layers of the lining system such as geosynthetic clay liners.
5.3 When there are leaks in the geomembrane, electrical
current flows through the leaks, which produces high current
4.5 As a practical measure, other electrical leak location
density and a localized anomaly in the voltage potential
methods (see Guide D6747) should be used in conjunction with
distribution in the material above the geomembrane. Electrical
the permanent monitoring system to eliminate leaks in the
measurements are made to locate those areas of high current
installed geomembrane(s) as part of facility construction. Such
density that can correspond to the presence of leaks.
methods must include testing of the exposed geomembrane
before covering and before commissioning a permanent moni-
5.4 The electric current is used as a direct testing and
toring system. Then the permanent monitoring system can be
monitoring parameter to detect and/or locate position of leaks
used in conjunction with other cover geomembrane testing
by the specific technology used.
methods to quickly detect and locate all leaks caused by the
5.5 Measurements are typically made either pole-pole or
covering process.
pole-dipole array or on a grid pattern. For point sensor systems,
they are always recorded and then organized into an electrical
4.6 Permanent electric leak location monitoring methods are
used to first detect and then subsequently locate leaks for repair map of the measurement area (this is not the case for zonal
sensing).
during the whole life of the geomembrane. They are designed
to detect and locate leaks at the end of the construction phase
5.6 An electrical map created from the electrical measure-
and during the operational and closure phases and also to
ments is adjusted in order to clearly display a characteristic
monitor any post-closure phases. These practices can easily
leak signal, and the measurement area is analyzed for the
achieve a zero-leak condition at the conclusion of the measure-
presence of any signals characteristic of a leak.
ment(s) at the end of the construction phase. If any of the
5.7 Electrical measurements can be carried out at any time
requirements for measurement area preparation and testing
and it does not depend on thickness of covering material.
procedures is not adhered to, however, then leaks can remain in
the geomembrane after the construction phase completion
5.8 Zonal sensor systems utilize a direct detection method.
measurement. On some sites it may not be practicable to
Each zonal sensor is a known size at a known location, which
achieve, but the closer the site can be designed (and carefully
enables simultaneous detection and location of a leak within a
constructed to that design), the closer it will reach the ideal
few seconds of the leak occurring in a fully autonomous
zero-leak condition.
manner.
4.7 Through the life of the facility monitored by an electric 5.9 Geomembranes of EPDM are not able to be tested by
leak location system, leaks that are detected can be repaired. this or other covered geomembrane electric leak location
Often the difficulties of carrying out a repair are cited as a methods.
D8551 − 24
6. Design power source is connected to a return electrode in contact with
the subgrade, or electrically conductive material under the
6.1 The design process should involve the electric leak
geomembrane (in the case of multilayered geomembrane
location system designer who should identify all the areas from
arrangements). This creates a voltage differential between the
the proposed site drawings where there is insufficient conduc-
material over the geomembrane and the material under the
tivity. In addition, all places and points where the electric leak
geomembrane. There can be one or more source electrodes
location signals (applied electrical potential or electrical cur-
regularly or irregularly covering the monitored area. The
rent) can escape via conductive paths should be identified.
density depends on the conductivity of the cover material and
Once identified, the design should be altered so that these
any multiplier used to create redundancy to increase system
incompatible conditions can be eliminated.
resilience. Positions of each source electrode must be precisely
6.2 Different types of sensors can be used for measurements
recorded as X-Y coordinates, preferably using a GPS total
(whether these are point sensors or zonal sensors). They must
station (65 mm).
be made of a material that is demonstrably resistant to the
6.11 Sufficiently electrically conductive material must be
corrosive environment in which they are to be placed and must
present and in direct contact with the monitored geomembrane
meet the same requirements for longevity as the geomembrane
(above and below the geomembrane), for example, suitable
itself, with a minimum operating life of more than 30 years.
electrically conductive earthen material, GCL, or liquid. Fro-
6.3 Point sensors can be placed under or above the geomem-
zen earthen materials are not sufficiently electrically conduc-
brane to be monitored, but should be placed as close as
tive when the whole cross section is frozen. In the case of bare
possible to the geomembrane.
geomembrane, the measurement area can be flooded with
water in order to perform this test method. The geomembrane
6.4 Point sensors can arranged in either a regular or irregu-
should be subjected to a hydraulic gradient across the geomem-
lar grid or a mixture, however, the whole monitored area needs
brane so that if a hole or breach exists in the geomembrane it
to be covered, preferably with a margin beyond the perimeter
will leak either shortly before or during the testing. The
because measurement is taken in pairs so effectively the last
material creating the subgrade of the geomembrane should be
measurement by length or width is effectively halfway between
as homogenous as possible. Anomalous features such as
the sensors.
trenches or pipes are allowed, but may produce anomalous
6.5 The spacing of point sensors affects the precision of leak
electrical readings. The material covering the geomembrane
location, but most importantly it also greatly affects the
has no restrictions other than suitable electrical conductivity.
sensitivity for detection of any leak. Higher grid density results
6.12 For single geomembrane installations, the material
in greater sensitivity and higher leak location precision,
covering the geomembrane must be completely isolated from
however, there are diminishing returns and the cost curve is
the material underneath the geomembrane. This is typically
exponential. Optimum grid spacing to ensure detection of leaks
achieved through an isolation trench around the entire perim-
is always possible and has been found to be 5 m by 5 m for
eter of the measurement area. It can also be achieved with a
sites with normal electrical properties. Grid spacing of point
welded flap of geomembrane that separates the cover material
sensors should therefore always comply with the following
inside the measurement area from the material outside, or the
table in terms of resistivity of the covering, subgrade, or
geomembrane can be extended through the anchor trench to
conductive geosynthetic material (depending on what is in
daylight above the earthen materials. Any conductive path(s)
contact with the point sensors):
such as metal pipe penetrations, grounded pumps, and batten
Less than 5 kOhm Greater than 5 kOhm
10 m by 10 m 5 m by 5 m strips on concrete must be isolated or insulated from the water
or earthen material over the geomembrane. The only path for
6.6 All types of sensors and electrodes shall have their
electrical current flow must be through leaks in the geomem-
positions precisely registered as X-Y coordinates.
brane under the level of water or earthen materials covering the
6.7 Typically the precision associated with the location of
geomembrane in the measurement area.
leaks is 610 % of the grid spacing of point sensors when
6.13 There must be a sufficiently conductive material di-
installed in accordance with 6.5.
rectly below the electrically insulating geomembrane being
6.8 The design of the installed grid of sensors must take into
tested. Typically, leak location m
...