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
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.