ASTM D7909-14
(Guide)Standard Guide for Placement of Blind Actual Leaks during Electrical Leak Location Surveys of Geomembranes
Standard Guide for Placement of Blind Actual Leaks during Electrical Leak Location Surveys of Geomembranes
SIGNIFICANCE AND USE
4.1 Geomembranes are used as low-permeability barriers to control liquids from leaking from landfills, ponds, and other containments. The liquids may contain contaminants that, if released, can cause damage to the environment. Leaking liquids can also erode the subgrade. 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 result even when the quality of the subgrade preparation, the quality of the material placed on the geomembrane, and the quality of the workmanship are not deficient.
4.3 Electrical leak location methods are an effective final quality assurance (QA) measure to locate previously undetected leaks in electrically insulating geomembranes. Practices for these implementations are contained in Guide D6747 and Practices D7002, D7007, D7240, and D7703.
4.4 It is important to realize that the detection of leaks depends not only on the capabilities of the leak location equipment, procedures, and experience of the leak location practitioner but also on local site conditions that are not under the control of the leak location practitioner. In particular, to detect a leak, there shall be an electrical conduction path through the leak and through the materials above and below the leak to allow sufficient electrical current through the leak for detection. For some site conditions, such as a leak not making contact with the subgrade, dry geotextile, or geocomposite above or below the leak; dry materials above or below the leak; degree of isolation between the materials above and below the geomembrane; and other factors, may preclude the detection of leaks. Therefore, the use of a properly placed blind actual leak is also a test of site preparations and conditions.
4.5 It is not necessarily proper to conclude that, if a blind actual leak is not detected, a leak locati...
SCOPE
1.1 This guide is for placing blind actual leaks in geomembranes before performing an electrical leak location survey. The geomembranes can be bare (not covered) or can be covered with water or moist soil.
1.2 This guide is intended to serve as an additional quality control/quality assurance (QC/QA) measure to ensure that leaks through the geomembrane are detectable, site conditions are proper for leak location surveys, and a valid and complete leak location survey is performed. Because various leak location practitioners use a wide variety of equipment to perform these surveys and have a wide range of expertise, placement of blind actual leaks by the owner or owner’s representative helps ensure that the leak location survey is being performed correctly and completely.
1.3 Placing blind actual leaks can also assist in determining whether or not the site conditions permit the flow of electric current through leaks, which is necessary for detecting leaks using electrical methods.
1.4 For clarification, this guide is in addition to the typical placement of the artificial or actual leaks placed as described in the relevant ASTM International standards for the various leak location methods.
1.5 Placing blind actual leaks should be done with the consent and knowledge of all involved parties and specifically the “owner” of the geomembrane. Geomembranes are typically purchased and installed by dedicated geosynthetic installers who “own” the geomembrane until the ownership gets transferred to the end user. A project meeting should be set up with the owner, the consultant, the geosynthetic installers, and the leak location contractor. The intention to use blind leaks should be clearly stated by the owner or consultants or both and the scope and number to be placed should be understood by all parties. The consultant should broadly identify to the lining contractor a location that can be easily repaired after the test. I...
General Information
Standards Content (Sample)
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Designation: D7909 − 14
Standard Guide for
Placement of Blind Actual Leaks during Electrical Leak
1
Location Surveys of Geomembranes
This standard is issued under the fixed designation D7909; 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 is critical that all actual blind holes be included on the liner
documentation and repair record drawing.
1.1 This guide is for placing blind actual leaks in geomem-
branes before performing an electrical leak location survey. 1.6 Leak location surveys can be used on geomembranes
The geomembranes can be bare (not covered) or can be installed in basins, ponds, tanks, ore and waste pads, landfill
covered with water or moist soil. cells, landfill caps, and other containment facilities. The
procedures are applicable for geomembranes made of electri-
1.2 This guide is intended to serve as an additional quality
cally insulating materials. (Warning—The electrical methods
control/quality assurance (QC/QA) measure to ensure that
used for geomembrane leak location could use high voltages
leaks through the geomembrane are detectable, site conditions
resulting in the potential for electrical shock or electrocution.
are proper for leak location surveys, and a valid and complete
This hazard might be increased because operations might be
leak location survey is performed. Because various leak
conducted in or near water. In particular, a high voltage could
location practitioners use a wide variety of equipment to
exist between the water or earth material and earth ground or
perform these surveys and have a wide range of expertise,
any grounded conductor.These procedures are potentially very
placement of blind actual leaks by the owner or owner’s
dangerous and can result in personal injury or death. The
representative helps ensure that the leak location survey is
electrical methods used for geomembrane leak location should
being performed correctly and completely.
be attempted only by qualified and experienced personnel.
1.3 Placing blind actual leaks can also assist in determining
Appropriate safety measures shall be taken to protect the leak
whether or not the site conditions permit the flow of electric
location operators as well as other people at the site.)
current through leaks, which is necessary for detecting leaks
1.7 The values stated in SI units are to be regarded as
using electrical methods.
standard. No other units of measurement are included in this
1.4 For clarification, this guide is in addition to the typical
standard.
placement of the artificial or actual leaks placed as described in
1.8 This standard does not purport to address all of the
the relevantASTM International standards for the various leak
safety concerns, if any, associated with its use. It is the
location methods.
responsibility of the user of this standard to establish appro-
1.5 Placing blind actual leaks should be done with the
priate safety and health practices and determine the applica-
consent and knowledge of all involved parties and specifically
bility of regulatory limitations prior to use.
the“owner”ofthegeomembrane.Geomembranesaretypically
purchased and installed by dedicated geosynthetic installers
2. Referenced Documents
who “own” the geomembrane until the ownership gets trans-
2
2.1 ASTM Standards:
ferred to the end user.Aproject meeting should be set up with
D4439 Terminology for Geosynthetics
the owner, the consultant, the geosynthetic installers, and the
D6747 Guide for Selection of Techniques for Electrical
leaklocationcontractor.Theintentiontouseblindleaksshould
Detection of Leaks in Geomembranes
be clearly stated by the owner or consultants or both and the
D7002 Practice for Leak Location on Exposed Geomem-
scope and number to be placed should be understood by all
branes Using the Water Puddle System
parties. The consultant should broadly identify to the lining
D7007 Practices for Electrical Methods for Locating Leaks
contractor a location that can be easily repaired after the test. It
in Geomembranes Covered with Water or Earth Materials
1
This test method is under the jurisdiction of ASTM Committee D35 on
2
GeosyntheticsandisthedirectresponsibilityofSubcommitteeD35.10onGeomem- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
branes. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved March 1, 2014. Published March 2014. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D7909–14 the ASTM website.
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