Spark Test Method

Whilst the water puddle and dipole methods use geoelectrical techniques to identify faults in standard geomembranes, the spark test method allows technicians to identify leaks during the installation of a different form of conductive geomembranes. These conductive geomembranes are the result of recent innovations in geomembrane manufacturing methods, allowing a conductive layer to be included on one side of the traditional geomembrane layer.
Technicians can also apply the spark test method to traditional geomembranes installed in direct contact with a conductive service.

To apply the spark test method, the geomembrane must be installed with the conductive layer facing downwards. A portable voltage source applies an electrical charge to the geomembrane which in turn acts as a capacitor, storing the electrical charge. When a metal brush is passed over the charged membrane, the stored electrical charge is released through any faults in the membrane as an electrical arc.

This release is detectable by a technician and a single test pass over a conductive membrane gives leak detection technicians an accurate picture of its integrity, identifying faults, splits and tears as small as 1mm2. Groupe Alphard applies the method as standardised by ASTM standard D7240-06.