Acoustic Leak Detection: How Does It Work?

Acoustic Leak Detection: How Does It Work?

When water leaks through a cracked or damaged pipe, it makes a specific sound. Well - trained water loss prevention specialists are able to determine not only the existence of a leak, but its exact location, which lets you target repairs and minimize the damage, time, and expense of additional pipe excavation.

One of the most accurate ways to find a leak in a pressurized water pipe is through the use of a sensitive ground microphone or acoustic listening device. The microphone is either used at the surface level, or is dropped into a manhole, and the Leak Detection Project Manager uses headphones to listen to and isolate the leak tone. In pressurized pipes, the sound of a leak is pitched low and has a baritone or “hollow” sound, which comes from the vibration of the leak as it travels down the pipe. Leak detection professionals listen for this distinctive hollow tone because it is almost always present in leaking pipes pressurized at 30 psi and above.

It takes a great deal of training and field experience for a Project Manager to become a water loss and leak detection specialist because you have to train your ears to identify not only the sound of the leak, but ambient noise that can be caused by active sewer and other water pipes, and traffic rolling over the pipe at the street level, among other things, so you can isolate the specific leak tone to pinpoint the leak location.

Aside from the distinctive tone that signals a pressurized water pipe leak, there are a few other signs that can alert a professional to a leak, including:

  • Unusually wet areas, like puddles, outside
  • A sudden drop in water pressure
  • A significant spike in water utility bills
GPRS Water Loss Specialist Utilizing Acoustic Leak Detection Equipment
GPRS Water Loss Specialist Utilizing Acoustic Leak Detection Equipment

Even if all those factors are present, a professional must utilize an acoustic leak detection device to confirm the presence of the leak and to precisely locate it. As previously mentioned, ambient sounds must be factored out. However, a trained leak detection Project Manager must also allow for all of the following factors that can impact what they’re hearing:

  • The severity of the leak or damage to the pipe
  • The location of the pipe
  • The water pressure in the pipe
  • How the pipe was installed or constructed (metal v. PVC v. ceramic, etc.)
  • The depth of the pipe below ground
  • The type of soil covering the pipe
  • The surface cover above ground (asphalt, concrete, grass, landscaping, etc.)

How Do You Operate an Acoustic Leak Detector? Before you attempt to operate an acoustic leak detection device, you first need to have a working knowledge of what makes up leak detection equipment, and how to deploy it in the field.

Typically, acoustic leak detection equipment consists of a microphone like a DXmic, a set of good, noise cancelling headphones, and an electric monitor. An “elephant foot” may be added around the mic to help isolate it from picking up surrounding ambient noise, and to amplify the leak tone.

Often you will hear professionals use the phrase that they’re trying to “pinpoint the leak.” Water leak pinpointing merely describes the process of finding the exact location of a water pipe leak. Typically, wherever the distinctive tone is the loudest will be the closest to the leak. The technician will also refer to the decibel reading on the monitor to determine if the sound is slightly louder in one location over another. When a listening device is very close to a leak, the volume level helps the Project Manager pinpoint its location so it can be repaired with a minimum of disruption and excavation.

It is important to remember, however, that water pipe leaks do not always make noise, or that the sound the leak produces is too low to be detected even with state-of-the-art equipment. For instance, water pooling around the site of a leak can act as an acoustic insulator and muffles the noise. That’s why it is vital to hire only highly trained leak detection and water loss specialists because they have more than one way to pinpoint a subsurface water line leak.

The Advantages of Acoustic Leak Detection

The first and most important advantage of acoustic leak detection is that it is a non-invasive and non-destructive technique, which eliminates the need to dig up pipes or damage structures to check the physical characteristics and health of the water pipeline system. Excavating to check pipes is called “potholing,” and it, along with other invasive assessment techniques, not only require far more time, effort, and expense, but they also require repair and replacement of the damaged ground and structures after completion.

These trial-and-error methods are both costly and time consuming, and may not even locate the source of your water loss. On the other hand, acoustic leak detection, especially when accompanied by leak correlation for confirmation, eliminates unwanted excavation, repairs, and saves you time and money. Acoustic leak detectors, in the hands of skilled professionals, allow facility owners and managers to pinpoint the leak location, cause no damage, and allow you to focus your repairs only on the leak itself.

Finding the exact location of a water pipe leak is the first step in solving the problem. Using acoustic leak detection cuts time in half, and can cut investigation and repair costs even more, proving itself to be the most efficient and cost-effective option to curbing water loss. Call GPRS Leak Detection Services to learn how our elite Project Managers can help you visualize your pressurized pipe infrastructure to pinpoint your leak.