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How do you Detect a Leak in a Plastic Pipe?

At one time, nearly every pipe that a leak expert would encounter would be made from some kind of metal. But as the awareness of the benefits of plastic pipes become common, so did their use. And while there are many benefits to plastic pipes, one of the biggest problems can be that the usual methods of leak detection don’t work as well in plastic pipes. So what is the best solution to detect a leak?

Acoustic issues

The classic way of detecting a leak is through the use of acoustic leak detection equipment. But this type of equipment was developed for metal pipes where the sounds would help the equipment isolate where the problem was. When that same equipment is applied to a leak in a plastic pipe, there is a completely different acoustic characteristic – plastic pipes are ‘quieter’ and don’t transmit sounds the way that metal ones do.

Studies in the US on the use of acoustic leak detection in plastic pipes found a number of problems. For example, usually the frequency range set by the correlator was too high – this means that the people detecting the leak couldn’t hear the sounds they needed to diagnose where the problem was. It also found that many accelerometers that were used to sense vibrations would only detect large leaks in plastic pipes and completely miss smaller ones.

Lack of noise

Another issue came from the experience of the leak detection experts themselves. It is common knowledge that if there is no noise from a pipe, there is no leak but when this was applied to a plastic pipe, the situation wasn’t always true. Leak signals from plastic pipes were found to be lower than 50 Hz – sounds too low for the human ear to pick up. This means operators were missing the sounds of the leaks simply because their ears weren’t equipped to hear the signalling sound.

Rods and aquaphones are also commonly used for leak detection but issues were discovered with these when applied to plastic pipes. Both were only effective when within a short distance of the leak – less than five metres in most cases. This meant that high resolution surveys were being used to supplement the traditional systems but these are very time consuming and extending the length of disruption for the job.

Hydraulic leak detection

One type of system that has been shown to work well with plastic pipes is hydraulic systems. This type of system, such as the Ferret leak detection device, uses water pressure to find the leak and can work just as well in plastic pipes as in metal ones.

A robust balloon, known as the Ferret Head, is put in the pipe and attached to an umbilical cord. Once inflated, water cannot pass. The Ferret Head is pushed along the pipe and when it reaches the leak, water gushes out of the leak due to the water pressure built up behind it. This means operators don’t need to rely on hearing the leak and allows for a precise location due to the built-in tracing equipment within the Ferret Leak Locator.

This system allows operators to easily detect leaks in plastic pipes and doesn’t require any of the acoustic based technology that has previously caused so many false results. To learn more about how the Ferret Leak Locator works and how it could help streamline your job times, you can find step by step tutorials on our website. Alternatively, get in touch with us by calling us on 0800 292 2835 or fill in our contact form and we will get back to you.

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