Apparatus and method for detecting holidays in liners

A method of detecting holidays in a liner having uneven contours, comprising the steps of:

• creating a circuit for current from a generator to a first contact with said liner to a second contact spaced from said first contact to said generator, said second contact being an electric reference for said generator;
• pulsing current from said generator to said liner first contact as said first contact is moved over and maintains uniform contact with said liner, wherein said liner is a geomembrane on a geotechnical site, and said first contact is a flexible moveable contact that conforms to the uneven contours of said liner, wherein the first contact includes a truck rolling on guide wheels and a plurality of conductive rollers spaced along a flexible conductive cable supported between said guide wheels;
• detecting a plurality of at least one electric signal associated with said pulsing current from said electric reference;
• continuously processing a selected recent plurality of said detected electric signals to generate a baseline value for said at least one electrical signal, wherein a detected electric signal having a value on one side of the baseline is deemed to indicate no holiday and an electric signal having a value on the other side of the baseline is deemed to indicate a holiday;
• and
• actuating a holiday signal when at least one of said detected electric signals has a value on said other side of said baseline.