New Standard Practice for Electrical Leak Location of Covered Geomembranes

It has been over fifteen years since the publication of the first version of ASTM D7007 for the standard practice for locating leaks in installed geomembranes covered with liquid and/or earthen material. Since then, the standard remains largely unchanged and is now outdated with the advancement of the practices and the development of new technologies. Some of the issues with ASTM D7007 include: (i) it provides little information on how to properly prepare a site for a dipole survey, despite being the key aspect for a successful survey. (ii) The procedures to determine measurement density do not fully incorporate the procedures needed to effectively locate a real hole in the liner. (iii) The procedures are ineffective in controlling the survey extent and precision of measurement locations. (iv) Finally, only general survey parameters are required to be presented in the dipole survey report and providing survey data is optional and it may be with raw data files. Accordingly, a new standard practice, ASTM D8265, incorporating new technologies, such as GPS-based data acquisition and voltage mapping, and improved methodologies was approved by the ASTM committee D35 in June 2019. The ASTM D8265 updates the practices in ASTM D7007 to the state-of-the-art methodologies that have significantly improved the effectiveness of dipole surveys, making them more precise, accurate and transparent. This paper details the new standard practice ASTM D8265 and how it differs from ASTM D7007. Case studies are presented, showing how the new practice improves the effectiveness and the documentation of the method.