The Geosynthetics 2013 conference in April brought a wealth of new technologies, methodologies and products to the liner integrity survey community. Two of the most significant advancements in liner integrity technology are described here.
New arc testing equipment was introduced for exposed geomembrane liner integrity surveys. The revolutionary part about this equipment is that its use is no longer limited to specially-made conductive-backed geomembrane. It has the same requirements for a semi conductive layer underneath the geomembrane as the water-based exposed geomembrane methods.
Very little instruction is required to operate the equipment, but the geomembrane must be clean and dry. The maximum spark length is approximately one inch, which means that effort should be made to minimize the wrinkles (if conductive-backed geomembrane is not used).
Figure 1 shows the complete set of equipment that is required to perform the arc testing method, which no longer requires the bulky water distribution hoses of the water-based methods. In the presence of a leak, there is a visual and audio alarm along with the spark. The intensity of the spark can be regulated for different geomembrane thicknesses. The stainless steel bar used to distribute the electricity across the geomembrane can be custom fabricated to various lengths and shapes.
GPS-based data logging will be available soon as an optional feature for the equipment to provide a quality assurance document. An operator only needs to make sure that the equipment is passed over the entire area of the geomembrane. The GPS-based data recording shows the path taken by the operator, ensuring that the entire area was covered, and also shows locations that resulted in sparks, just in case the operator missed any.
This year will mark the creation of a new ASTM standard for all of the exposed geomembrane leak location methods, including the arc testing method. TRI Environmental is now a distributor of the equipment, and has exclusive distribution rights within the United States. Contact firstname.lastname@example.org for more information.
GSE’s Leak Location Liner made its debut, a product specially manufactured to support and enhance liner integrity surveys.The product has been improved from earlier conductive-backed geomembrane products to enable seam testing and dipole testing after placement of cover material.
GSE’s Leak Location Liner not only enables liner integrity surveys where typical geomembrane makes it unfeasible, but it also improves liner integrity survey sensitivity for all applications. The conductive backing makes surveys more sensitive by increasing the conductivity of the overall leak circuit and also by making it possible to locate leaks where holes lack good contact.
Examples of poor leak contact conditions include at the peak of a wrinkle, under the overlap of a fusion weld, and in a location with a depression in the subgrade.
For the latest standards information regarding leak location technologies, please visit the ASTM International Committee D35 home page.
Visit the site of the Arc Tester equipment manufacturer, Sensor Group.
Visit GSE Envrionmental’s website: www.gseworld.com
See also: The latest Leak Location Liner brochure (PDF)