No one catches leaks like ILD®. That’s why we’re the world leader.

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.

  1. Small electrical pulses are directed onto the membrane. The electricity searches for a ground connection.
  2. If the membrane is watertight, the electricity is isolated and does not find a ground connection.
  3. If the membrane is not watertight, the electricity makes a ground connection and is pulled toward positive poles.

A. Small electrical pulses are directed onto the membrane. The electricity searches for a ground connection.

B. If the membrane is watertight, the electricity is isolated and does not find a ground connection.

C. If the membrane is not watertight, the electricity makes a ground connection and is pulled toward positive poles.

TOP 10 ADVANTAGES OF USING EFVM®:

  1. Pinpoints the exact location of any membrane breaches
  2. Defects can be repaired and retested the same day
  3. Non-destructive to the membrane
  4. Requires only a limited use of water
  5. Eliminates removal of overburden to locate a breach
  6. Can be performed in inclement weather
  7. Can be performed on sloped structural decks
  8. Overburden installation can proceed immediately after or during test
  9. Membrane performance can be monitored through the overburden
  10. Effective on vertical surfaces
  • Developed by ILD® Germany in the early 1990s, EFVM® quickly became a valuable tool for leak investigations on existing systems. Introduced to North America in 2001, the EFVM® testing procedure has become the standard for waterproofing verification.
  • ILD® has tested over 200 million square feet of membrane worldwide (including hot or cold liquid applied membranes, coatings, and various sheet membranes). Our certified inspectors perform non-destructive integrity tests on new or existing waterproofing membranes and containment liners using our pinpoint-accurate EFVM® technology.
  • Only ILD® technicians are trained and certified in performing EFVM® testing, providing superior detection of all waterproofing defects and breaches (particularly in cases where water exit location may not correspond with point of entry).