Flat Roof Electronic Leak Detection Edinburgh

Electronic Leak Detection (ELD) Explained

Electronic leak detection is a technique used to identify leaks in roofing membranes and other waterproofing systems. It utilizes electrical currents or electromagnetic fields to pinpoint the exact location of a leak. This method is particularly effective for flat roofs, where traditional visual inspections might miss subtle or hidden damage. A prerequisite is however that the substructure is conductive and earthed through foil isolation layers, steel decking or concrete which are earthed. This technique is best suited to large commercial buildings rather than residential. There are two common types of electronic roof leak detection, wet testing or dry testing.

Benefits of Flat Roof Electronic Leak Detection

Flat roof electronic leak detection (ELD) is a cutting-edge technique that offers numerous benefits over traditional leak detection methods such as visual/physical inspection and invasive sampling. Here are six key advantages of utilising ELD for flat roofs:

How Electronic Leak Detection Works

Both wet and dry electronic flat roof leak detection require an earth point making electrical contact with the roof decking structure. Wet roof testing involves using a conductive perimeter wire placed on the surface of the test area. This area is then covered with water and connected to a 'Pulse Generator' that produces a low-voltage current, which spreads over the test area through the water. An earth-return lead connects the Pulse Generator to a known earth point on the building’s structure. Pulses of current are applied across the roof covering via the water on the surface. This current finds a path to the earth through leaks and holes in the non-conductive roofing membrane. For effective testing, the roof’s entire surface must be adequately covered with water to ensure proper current flow. The thickness of the roofing membrane or coating does not affect the wet testing process. A detector unit then measures the current flow and guides the operator to the exact location of any leaks. Dry roof testing involves applying a high-voltage DC current to the roof surface using an electrode, such as a phosphor-bronze brush, connected to a detector unit. As the operator moves the electrode brush over the roof's non-conductive surface, any holes present will complete an electrical circuit. This triggers the detector unit's alarm, indicating the location of the fault. Dry testing is significantly faster than wet testing, but it requires precise measurement of membrane thickness and proper setup of the detector unit. For a successful dry roof leak detection test, the entire roof surface must be completely dry and free from moisture. However, moisture beneath the membrane, resulting from a leak, can actually aid the dry testing process by highlighting the leak more effectively.

Wet Testing Electronic Roof Leak Detection

Wet testing electronic roof leak detection utilizes the 'vector-mapping' or 'earth leakage' technique to detect faults. Water's conductive properties, whether from rain or a hose, enable the flow of electrical current, helping to identify leaks. The method consists of two primary components: a generator unit and a detector unit. The generator unit establishes an electrical field across the roof surface using a 'boundary wire' placed around the perimeter of the test area, connected to the negative terminal of the generator unit. The positive terminal is connected to an appropriate earth on the building's structure. Leaks in the roof membrane allow water to reach the building's structure, creating a short circuit. The detector unit, which connects to two handheld test probes, is used to measure the voltage differential between the probes. This allows the detector unit to guide the operator to the exact location of the leak.

Dry Testing Electronic Roof Leak Detection

Dry testing electronic roof leak detection employs a high-voltage test probe equipped with a copper bristle attachment. This method is designed to identify even the smallest breaches in the roofing membrane, down to pinpoint-sized holes. The process begins with the operator carefully sweeping the copper bristle probe across the roof surface. As the probe moves, it creates an electrical field. When the probe encounters a defect in the membrane, such as a tiny hole, a small spark jumps between the test probe and the grounded roof structure. This spark is a clear indicator of a breach, allowing the operator to accurately pinpoint the exact location of the leak. The high voltage used in this method ensures that even the smallest openings are detected, providing a thorough and precise assessment of the roof's integrity. This technique is particularly effective for detecting leaks in roofs with complex geometries or in areas where visual inspection alone might miss small defects.

Compatible Roof Types for ELD

There are numerous types of membranes and coatings used in roofing. The industry has successfully utilized this type of equipment for many years to identify defects and leaks in flat roofs. Each membrane or coating should be initially checked to ensure that an effective test can be conducted base on the structure, material and thickness. The roof types listed below are known to be compatible with electronic flat roof leak detection. This list is not exhaustive; many other non-conductive roofing materials and build-ups may also be tested using our products: asphalt on concrete; hot melt on concrete; single ply on tissue; single ply on foil backed insulation board.

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