ILD® IS THE WORLD LEADER IN ELECTRIC FIELD VECTOR MAPPING (EFVM®) TECHNOLOGY. WE CREATED IT. WE OWN IT.
EFVM® is a low-voltage leak test method that creates an electrical potential difference between a non-conductive membrane surface and conductive structural deck or substrate, which is earthed or grounded. EFVM® is unique in its ability to test the integrity of waterproofing membranes with overburden or ballast. This non-destructive method is important for green roofing systems because the EFVM® test can read through the overburden and ballast, while still providing perfectly accurate results.
HOW EFVM® WORKS
An electric field is created by applying water on the surface of the membrane and using the water as a conductive medium. The EFVM® equipment delivers a low voltage pulsating electrical charge between the non-conductive waterproofing membrane and the conductive structural deck.
A watertight membrane will isolate the potential difference, while breaches in the membrane will cause an electrical connection to occur. Our certified inspectors read the directional flow of the current with a potentiometer to locate the point of entry with pinpoint accuracy.
The EFVM® technicians then complete the test by conducting a visual inspection of all wall junctions, perimeter details, and membrane penetrations. All breaches are numbered to allow for repairs by the waterproofers onsite and are retested to confirm watertightness. A report follows with picture documentation of every breach and a detailed drawing noting the wire placement and breach locations.
Small electrical pulses are directed onto the membrane. The electricity searches for a ground connection.
If the membrane is watertight, the electricity is isolated and does not find a ground connection.
If the membrane is not watertight, the electricity makes a ground connection and is pulled toward positive poles.