Conductance Leak Location
The principle of the Electronic leak testing method is the establishment of an electrical potential between the electrically insulating waterproof membrane and the conductive underlying substrate.
Electric conductance leak location requires that the substrate material directly below the membrane be sufficiently conductive for the test method employed. In most instances, a concrete substrate is sufficiently conductive to allow this method. In certain membrane assemblies, where the substrate is nonconductive, it is possible to install a conductive material directly under the membrane to facilitate testing.
Low Voltage Methods
(Electric Field Vector Mapping EFVM)
When testing using a low voltage electrical potential, a thin controlled covering of water on the surface forms the conductive path horizontally across the membrane to any membrane breach. At a breach location, an electrical path to the substrate is formed through the water connecting to the substrate below. A sensitive receiver detects the leakage current and alerts the operator to the exact location of this connection.
Membrane on Concrete (Conductive Substrate)
NO MESH REQUIRED
EFVM® electronic leak detection can be performed after the installation of the membrane.
The concrete and reinforcing steel create an electrical potential difference, Moisture penetration can be located quickly and cost-effectively repaired.
Membrane on Plywood (Non-Conductive Substrate)
VMG™ Vector Mesh Grid REQUIRED
To facilitate EFVM® testing being carried out to membrane on a plywood substrate, VMG™ Vector mesh is to be fixed to the plywood prior to membrane installation. VMG™ is a stainless steel 50mm x 50mm grid that is a patented conductive medium. The conductor wire is placed on top of the membrane delivering direct current tension to the surface. Even in the case of minimal contact with moisture, the system closes the electrical circuit. Moisture penetration can be located quickly and cost-effectively repaired.
Membrane on Insulation or Warmroof (Non-Constructive Substrate)
VMG™ Vector Mesh Grid REQUIRED
To facilitate EFVM® testing of membrane on Insulated Warmroof, VMG™ Vector mesh is to be fixed to the Insulation board prior to membrane installation. VMG™ is a stainless steel 50mm x 50mm grid that is a patented conductive medium. The conductor wire is placed on top of the membrane delivering direct current tension to the surface. Even in the case of minimal contact with moisture, the system closes the electrical circuit. Moisture penetration can be located quickly and cost-effectively repaired.
Membrane on Foil Faced Insulation Warmroof (Conductive)
Conductive Foil Tape REQUIRED
To facilitate EFVM® testing of membrane on Foil Faced Insulated Warmroof, Foil Faced PIR boards are connected with Conductive Foil Tape to create a continuous conductive medium.
The conductor wire is placed on top of the membrane delivering direct current tension to the surface. Even in the case of minimal contact with moisture, the system closes the electrical circuit. Moisture penetration can be located quickly and cost-effectively repaired.
