EVFM Testing
The Watertite EVFM technique uses water as an electrically conductive medium; therefore, it is essential that the surface to be tested is wet. If it is not raining at the time of the survey, then water needs to be sprayed over the area. Once the area is suitable for the test, the Watertite technician installs an un-insulated wire loop around the perimeter of the area and connects the electrical pulse generator to the wire. The electrical pulse generator delivers a 40-volt potential for one second every three seconds. The pulsating potential on the wet roof surface forms an “electrical plate.” The grounded structural deck is the other “electrical plate,” while the membrane separating the two plates acts as the insulator. If moisture enters a breach in the membrane, an electrical contact is established between the two plates (i.e., an electrical ground).
Using a potentiometer connected to two probes, the Watertite technician steps into the electric field and places the probes on the surface. If there is a breach in the membrane, the dial on the potentiometer will move either to the left or to the right. The Watertite technician can then follow the direction of the electric field to the membrane breach. Because of the high electrical resistance through the roof, the magnitude of the electrical current is relatively small.
The benefits for EVFM can be summarized as follows:
• Ability to locate defects precisely and non-destructively.
• Ability to re-test repairs immediately.
• Can be used after cover systems are installed, especially with “green roof” landscapes – where a permanent wire is left in place.
• Eliminates the hazard of overloading structural decks during testing, since ponding water is not part of the testing procedure.
• Can be used on sloped roof surfaces where flood testing is impossible.
The benefits for EVFM can be summarized as follows:
• Ability to locate defects precisely and non-destructively.
• Ability to re-test repairs immediately.
• Can be used after cover systems are installed, especially with “green roof” landscapes – where a permanent wire is left in place.
• Eliminates the hazard of overloading structural decks during testing, since ponding water is not part of the testing procedure.
• Can be used on sloped roof surfaces where flood testing is impossible.
Leak Detection
Integrity testing and leak detection is the 'holy grail' of building envelope work and membrane repairs. To have an assurance that the portions of a building that are expected to get wet due to weather are in a condition to prevent water transmission to the interior is the goal of every property manager, as well as every builder. Finding test methods to give that assurance, has evolved over the decades, Electric Vector Frequency Mapping (EVFM) testing provides more accurate results, and in less time. EVFM 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 EVFM test can read through the overburden and ballast, while still providing perfectly accurate results.
Watertite can perform Electric Vector Frequency Mapping (EVFM) Membrane Testing in nearly all conditions, and on nearly any surface. As it uses the exact conditions to do the testing as what the membrane is designed to withstand. What better way to get peace of mind when it comes to quality control testing or troubleshooting problems in waterproofing membranes.
Watertite can perform Electric Vector Frequency Mapping (EVFM) Membrane Testing in nearly all conditions, and on nearly any surface. As it uses the exact conditions to do the testing as what the membrane is designed to withstand. What better way to get peace of mind when it comes to quality control testing or troubleshooting problems in waterproofing membranes.
Contact Us
For any enquiries in regards to EVFM testing please fill out the form below and one of our friendly staff will be in contact with you shortly or feel free to call on 03 9645 6308.
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