Articles & Case Studies


Posted: Monday 6th October 2014

With its unique combination of ground microphone and tracer gas detector, the latest Seba HL 5000 H2 water leak locator from Megger allows leaks in buried water pipes to be located quickly, reliably and accurately, thereby minimising the extent and cost of excavations as well cutting the time needed to find and repair the leak.

The acoustic detector provided in the HL 5000 H2 uses novel DSA (dual segment analysis) technology to minimise the effects of background noise that might otherwise mask the sound of the leak. After processing, the resulting high-quality audio is delivered to the instrument’s headset for comfortable monitoring by the operator.

The audio signal is also analysed to produce a bar-chart display that simultaneously shows the results obtained at up to nine measuring points. The location of the leak is unambiguously indicated by the measuring point where the height of the bar is largest.

For very small leaks and those where local conditions make acoustic leak pinpointing difficult, the tracer gas facility offered by the HL 5000 H2 provides a convenient alternative.

The pipe under investigation is filled with tracer gas (95% nitrogen, 5% hydrogen) through a hydrant or house connection. This gas escapes at the leak and, thanks to its low specific density, it rises quickly and vertically, penetrating virtually all materials, including concrete and tarmac. When the tracer gas reaches the surface, directly above the leak, it can readily be detected with the sensitive electronic gas sensor that is supplied with the HL 5000 H2.

Other innovative features of this versatile instrument include an acoustic line location mode which, when used in conjunction with a “pipe pecker”, allows the location and route of plastic pipelines to be readily determined.

The HL 5000 H2 also provides an integrated logging function for both sound and tracer gas concentration. This allows reading to be recorded for 3, 15 or 30 minutes while, for example, the water supply is turned off and on again. For a genuine leak, this should produce a large change in both sound and gas readings. If this change is not observed in the recordings, the “leak” is confirmed as spurious without wasting time and money on expensive and unnecessary excavations.

Seba HL5000 H2 leak locators from Megger feature compact and lightweight yet robust construction, which means that they are convenient and comfortable to use even for extended periods.

They are supplied in the form of a complete kit that, in addition to the instrument itself, includes headphones, a ground microphone, an active universal microphone with magnet and probe tip, and a hydrogen sensor with rod. Also included are tripod adapters, connecting leads, a carrying strap and a durable equipment case to house all of the other items.

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August 2021

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