If leak detection was performed when the membrane was initially installed, a wire loop may have been permanently installed under the overburden to facilitate testing at a later date.  If not, a wire loop is placed on either the surface of the overburden or intermittently buried at a shallow depth within the overburden.

The overburden is thoroughly saturated with water in order to ensure that the entire overburden assembly becomes conductive and can support the flow of an electrical current to the membrane below.

One of the two leads from a power supply is connected to this wire loop conductor. The other lead is connected to the structural deck.

As a result, an electrical potential difference is created between the membrane surface, which is wet, and the structural deck, which is “earthed” or grounded – essentially producing two opposing electric plates.

A 16-probe receiver is placed on the saturated surface of the overburden in an approximately 3’ x 3’ pattern.

If readings indicative of a breach are found, additional adjacent readings are taken until an area of concern can be mapped out on the overburden’s surface.

This area of concern is marked on the overburden’s surface, providing a frame of reference for the area of overburden to be removed. Because testing is not occurring directly on the membrane, these areas can range from 10-100 SF in size.

Once the membrane is exposed, standard ELD can be completed directly on the membrane, pinpointing any potential breaches.

Once the breach is located, it is marked on the membrane, photographed, and cataloged for reporting purposes.

We generate and submit a detailed report of our findings, that includes general project information, noted site conditions (with photographs), breach photographs and measured locations. A digital drawing is submitted with the report that highlights the area(s) tested, with all breach locations plotted.