Within the past few years, solutions to these limitations have been found that make ELD even more versatile and valuable than ever before. (For a more in-depth look at this topic, see “Electronic Leak Detection: High vs. If the deck is wooden, or the membrane is conductive (such as black EPDM) the assembly will typically not be testable. For instance, they require a conductive roof deck-such as metal or concrete-and a non-conductive roof membrane. These test methods do have limitations, though. As the operator “sweeps’ the surface of the membrane, any moisture or breach in the membrane will complete the circuit between the measuring device and the roof deck.īallasted and green roofs typically use low-voltage testing, while roofs with exposed membranes in dry climates typically find high-voltage methods a better choice. One electrical lead is connected to the roof decking, and the other is attached to device resembling a push broom with copper bristles. High-voltage electrical testing requires a membrane that is perfectly dry and completely exposed. Used in place of wire mesh, it will alert building maintenance to any breach in the roof membrane. The technician uses specialized probes, resembling ski poles, to determine the direction of the current and determine the location of the defect.Įlectronic -conductive primer is applied to the roof deck of the Royal Alberta Museum. Any gap in the membrane will create an electric short. Testing involves stretching a wire around the roof perimeter and wetting the top of the membrane to create an upper electrical “plate.” The structural deck acts as the lower electrical plate, and the roof membrane located in between acts as the insulator. The low-voltage testing method-technically “low-voltage impedance testing”-is the most widely-used method for detecting roof leaks in Europe, and has proven so effective that manufacturers, including Sika Sarnafil, Carlisle Construction Materials and Kemper now accept or even require ELD as an integrity test before issuing a warranty for newly installed materials. “Electronic leak detection goes by several trade names-such as low voltage vector mapping, EFVM, ELD Fusion, Integriscan, and so forth-but it all stems from the same basic technology: utilizing electricity to precisely locate membrane breaches.” “There’s a revolution going on in the art of leak detection,” says Peter Brooks, president and CEO of IR Analyzers/Vector Mapping. (For a comprehensive comparison of various leak detection technologies, see “Rooftop Leak Detection” in the Winter 2010 issue of this magazine.) Even pinhole leaks invisible to the naked eye can be identified, and repairs can be made on the spot and immediately retested to ensure watertight results. Both identify breaches by monitoring electric fields set up above and below the membrane surface. The other uses low voltage and a wet membrane. The high voltage method requires a dry, exposed membrane. There’s actually two different types of ELD. In the early 2000s, electronic leak detection (ELD) became available in North America, and has proven to be faster, more accurate, and more affordable than other testing methods. Infrared thermography and nuclear moisture testing are effective, but actually identify water-soaked insulation, rather than the source of the problem, which has to be done visually. Flood testing, which long ago was the only option, was replaced decades ago by better methods. The obvious solution is to regularly test the roof membrane for leaks, and repair as needed. These leaks end up costing American businesses billions of dollars annually, with damage ranging from minor water stains and electrical outages to complete structural failure. The National Roofing Contractors Association (NRCA) estimates that up to 40% of flat roofs develop serious problems within one year of installation. Leaky roofs are a serious but surprisingly common problem.
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