ASTM D7240-06(2011)

Geomembranes are used as barriers to prevent liquids from leaking from landfills, ponds, and other containments. For this purpose, it is desirable that the geomembrane have as little leakage as practical.

The liquids may contain contaminants that if released can cause damage to the environment. 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.

Geomembranes are often assembled in the field, either by unrolling and welding panels of the geomembrane material together in the field, or unfolding smaller flexible geomembranes in the field.

In exposed geomembrane applications, geomembrane leaks can be caused by poor quality of the subgrade, accidents, poor workmanship, and carelessness.

Electrical leak location methods are an effective final quality assurance measure to locate previously undetected leaks.

1.1 This standard is a performance-based practice for using the spark test to electrically locate leaks in exposed geomembranes with an insulating layer that are in intimate contact with a conductive layer. For clarity, this document uses the term ‘leak’ to mean holes, punctures, tears, cuts, cracks and similar breaches over the partial or entire area of an installed geomembrane (as defined in 3.2.3).

1.2 This test method can be used on exposed geomembranes installed in basins, ponds, tanks, ore and waste pads, landfill cells, landfill caps, and other containment facilities. This standard is applicable for geomembranes in direct and intimate contact with a conductive surface or with a conductive layer integrally included.

1.3 SAFETY WARNING: The electrical methods used for geomembrane leak location use high voltage, low current power supplies, resulting in the potential for electrical shock. The electrical methods used for geomembrane leak location should be attempted by only qualified and experienced personnel. Appropriate safety measures must be taken to protect the leak location operators as well as other people at the site.

1.4 This standard does not purport to address all of the safety and liability concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.