Electric Field Vector Mapping (EFVM®) FAQ’s

– What Is EFVM®?
– What are the advantages of EFVM®?
– How does EFVM® work?
– What is the difference between high voltage ELD and low voltage EFVM®?
– Are the any limitations of EFMV®?
– How are results provided to you?
– Why Jersey Infrared Consultants?

What Is EFVM®?

Electric field vector mapping, or EFVM®, is a type of non-destructive testing used to locate a breach or void in a waterproofing membrane. A low-voltage electrical current is used to create an electrical potential between a non-conductive membrane and a grounded conductive deck or substrate.

Used in Europe since the 1980’s, EFVM® was introduced to the United States in the early 2000’s. Since that time, it has gained recognition from waterproofing manufacturers, building owners and property managers among others.

What are the advantages of EFVM®?

There are many advantages to using EFVM® to perform a non-destructive or troubleshooting test of a waterproofing membrane. Testing can be performed on sloped roofs and vertical walls.

Some of the advantages include the following:

  • Able to locate the exact location of the breach or hole
  • Testing can be performed as soon as the membrane is applied
  • Defects can be repaired and retested during the same test visit
  • May be used on IRMA, ballasted, overburden and uninsulated roof systems
  • Locate and repair the breach before water has a chance to enter the roofing system
  • Testing can be performed during adverse weather conditions

How does EFVM® work?

A grid field is established on the area to be tested by laying a low voltage wire directly on the roof surface. Penetrations, such as drains or projections, will be isolated from the grid. An electrical charge is attached to the grid wire, and a spray of water is applied to the membrane. This allows the completion of the electrical circuit between the non-conductive waterproofing membrane and the conductive structural deck.

A watertight membrane will isolate the potential difference. Breaches of holes in the membrane will cause an electrical connection to occur. By using probes, our certified inspectors read the directional flow of the current with a potentiometer to locate the point of entry with pinpoint accuracy.

All breaches are numbered and documented. If qualified personnel are on site at the time of the test, repairs can be made and the area will be retested.

What is the difference between high voltage ELD and low voltage EFVM®?

Electronic Leak detection (ELD), referred to as “high voltage” leak detection, relies on a conductive deck as the ground source and the membrane as the insulator. A broom like device consisting of numerous small conductive bristles is used to “sweep” the roof.

ELD requires that the test area be completely dry and be exposed. A good grounding component, such as a metal drain, flashing or rebar, must be exposed and able to provide a solid connection t the deck material.

Advantages of the EFVM® method include the ability to test under different weather conditions and with certain types of ballast or overburden in place. Current industry practice prefers EFVM over ELD for investigation of possible seam defects. When the testing is completed, the wire grid remains in place and is available should future testing be required.

Are the any limitations of EFVM®?

Roof construction to be considered for EFVM® testing should include metal or concrete deck materials. If the test area has a wood deck or insulation between the deck and the membrane, a mesh of grounding material can be installed just below the waterproofing membrane.

Safe access to all areas to be tested must be provided. Ice, snow, excessive wind, and/or daytime temperatures below 30°F, will result the need to reschedule the test.

What must be provided on site at the time of the test?

When we receive the notice to proceed with your project, we will forward a detailed checklist to guide you through preparing for the test and items needed the day of the test. Typical items we request prior to the test include completion of all membrane work, site-specific requirements, and drawings of the area to be tested.

At the time of the test, the three most important items are (1) adequate hose and water on all areas to be tested, (2) 110v electrical grounded power, and (3) direct access to the areas of the roof where the grid wire will be laid.

How are results provided to you?

One of the advantages of EFVM® testing is that the results are real time. This provides the client the opportunity to make repairs of any located breaches and retest the roof area during the same site visit.

A written report, including documentation of any problems located and any retest results, will be provided. This report will also include a drawing of the roof indicating the location of all findings as well as documenting the location of the wire grid to for ease of future testing.

Why Jersey Infrared Consultants?

The high standards we set for service and reliability have earned us a reputation for excellence. Certified technicians, using state-of-the-art equipment and technology, perform all Electric Field Vector Mapping tests.

Jersey Infrared Consultants’ safety compliance, background check, and drug screening programs are a part of our commitment to providing an unequaled level of client care and quality service.  Our reports are clear, easy-to-understand, and comprehensive. They are delivered in a timely fashion in both written and electronic formats.

Our staff regularly conducts training classes, publishes technical articles, and participates in continuing education, enabling us to remain THE firm to hire for your projects.