What Does Focused Electrode Leak Location (FELL) Mean?
Focused electrode leak location (FELL) is a trenchless method to accurately locate leaks in non-metallic sanitary sewer pipes. It locates leaks by using a simple focused electrode and analytical software.
FELL can also test the liner permeability and lateral and manhole connections reinstatements in a sewer pipe that has been rehabilitated using trenchless methods such as cured-in-place pipe or sliplining.
Trenchlesspedia Explains Focused Electrode Leak Location (FELL)
Focused electrode leak location is an advanced trenchless inspection method that is fast and accurate in determining leaks, its location and magnitude.
The FELL method involves placing an electrode into the ground near the segment of the pipeline to be tested. A tag line such as a sewer jetting hose attached to a sonde emitting an electric current is passed through the sewer along with a sliding pipe plug.
The sewer line is then filled with water such that all joints and lateral connections are fully immersed. The sonde along with the tag line is pulled through the pipe about 30 feet/minute. The electric current emitted by the sonde is recorded and mapped as per the location of the sonde and digitally displayed on a screen.
In places where there are defects or leaks, the electric signal is able to pass easily and at a higher rate. The plotting is done for electric current vs. longitudinal location.