About 70% of the earth’s surface is covered by water while only 3% of this water is considered available freshwater either as surface water or groundwater.

That makes freshwater a precious water resource and needs to protect and save every drop from it.

To achieve this goal, it’s very important to maintain and regularly check your water system including the water pipeline and water distribution network to be free from any water leakage.

As water distribution pipes lose around 20-30% of their water content and the losses exceed 50% in the older ones especially systems that have poor management and maintenance.

That is why we use water leak detection.

Now the question is what is leak detection? why do we need it? and the different technologies behind it.

What is leak detection?

Leak detection is a process for detecting, monitoring and measuring the unexpected entrance or escape of fluids and gases from pressurized systems.

Due to pressure variations between two regions, leaks can travel from the interior of a component or machine to the outside.

while a leak detector is a device that has a sensor to monitor and detect the losses of the water or fluids in the system.

Hamilton defined leak detection as a combination of three key phases known as localizing, locating and pinpointing, shortened as LLP.

After detecting a leak, localizing means restricting it down to a single segment of the network or a specific district-metered area.

The second phase is locating and it is the first phase in which the leak’s location is determined.

The leak is estimated to be within a 30 km radius of the site, according to Hamilton.

According to Hamilton, the third phase would be pinpointing.

Pinpointing is another process in which an estimate for the exact site of the leak is calculated within a 20-cm radius.

Leaks are frequently the result of corrosion, in which a metal container erodes to the level that the contained liquid leaks.

Corrosion is a result of poor management or maintenance of the distribution pipes or changes in the properties of the water such as changes in water pH that tends to erode the pipe material.

Why leak detection is needed?

Water leakage detection is needed because of the following points:

To ensure water safety

Leakage in a pipe can allow pathogenic and other microorganisms to enter the pipe from the surrounding environment and contaminate water.

Save the surrounding environment

Water leaking from wastewater pipes will contaminate the groundwater with pathogenic, heavy metals and other materials harmful to the environment.

Damaging other properties

A ground leak can cause severe damage to a home or building’s foundation over time, increase moisture inside the structure and stimulate the development of mold and other pests.

All of these issues could be quite costly to resolve.

However, water pipe failures can cause damage to nearby buildings.

Maximizing water usage

Water leak detection can achieve the maximum benefit from the water supply system.

Reliable Water Supply

Many firms and industries require a sufficient amount of water to run their operations.

However, if the water supply and pressure become unstable, emergency services such as the fire department could be seriously harmed.

Categories of leak detection models

The two categories of leak-detecting systems are as follows:

Systems for detecting static leaks

These are systems that depend on sensors and data collectors installed inside the water network as well as valves and are capable of relaying periodic data to the network management office.

This information can be used to locate, localize and pinpoint leaks.

Systems for detecting dynamic leaks

These are systems that conduct investigations by moving leak detection devices to suspected leakage areas.

As a result, they initially rely on suspicion of an existing leak.

Another strategy is to conduct regular surveys around cities to detect leaks as soon as possible.

These systems can detect leaks and rapidly localize and pinpoint them.

Technologies for detecting leaks

Listening devices

To monitor underground water pipelines from the surface, both electrical and mechanical geophones are applied.

The main advantages of using these devices are: inexpensive to buy, simple to set up, high sensitivity and high accuracy as they can detect the location of leakage exactly.

Geophones and Hydrophones are the main approaches used to identify leak origin and leak locations by depending on high acoustic signals sent by the release of pressurized fluids.

Both of them depend on the proficiency and experience of the operator.

extended earpieces are another listening device that is suited for metallic pipelines.

Depending on human senses and interpretation and affection by external mechanical noise are the major problems of these devices which can be improved by lowering their impact.

Leak noise loggers

Leak Noise loggers are installed in pipe holes without the need for trenching or drilling and they can be used for permanent, semi-permanent, or water leak surveying.

Noise loggers work by employing advanced algorithms to compare the sound produced by regular operations to that of the leak, allowing leaks to be identified as soon as they occur.

The significant benefits of this system are the capability to preprogram the correlation and analysis, which allows for faster analysis and detection, as well as the ability to analyze at night, which decreases noise that may impact the loggers and can be done without the use of people.

Moreover, this method is used in highly pressurized water networks, allowing for the expanded propagation of leak signals.

Moreover, many loggers can be used concurrently to offer multiple detections for more accurate findings.

Infrared thermography

Thermography (IR) cameras measure and image the infrared radiation emitted by an object.

It is capable of detecting temperature differences on the surface of the pavement caused by water leaks.

This method has been evaluated on non-metallic pipelines and provided accurate results.

The surrounding weather, as well as changes in soil conditions and temperature, have a significant impact on the performance of the result.

Tracer gas

Tracer gases are a leak detection technique that involves injecting harmless and insoluble gas into leaks.

These gases contain ammonia, halogens and helium, with helium being the most sensitive.

This gas tends to escape through the leak as it is light in weight, which can be detected by a detector to identify the leak.

Tracer gas technology is suitable for all pipe materials and they are not widely utilized in bigger pipelines due to the high cost of putting a large amount of gas into the system.

Ground-penetrating radar

Ground Penetrating Radar (GPR) technology uses electromagnetic waves and transmits them into the ground to locate leaks by imaging the underground environment, including the pipe and the leak.

The benefits of this technology are its ability to identify leaks regardless of pipe material, for any diameter size, the device’s ability to be simply transported between sites and it doesn’t require experience or training to operate it.

Leak detecting robots

Several robotic devices have been developed to inspect pipes and locate leaks in sewers.

These devices can be either wireless or corded.

However, certain leak detection robots can also repair leaks.

The “smart ball” is one example offered in leak-detecting robots.

Smart-Ball is a free-swimming technology that was designed to detect leaks in big flowing water pipelines.

Small ball devices are small in size which made them flexible to enter multiple sizes of pipelines and detect tiny leaks.

Wireless micro-electro-mechanical systems (MEMS)

Micro-Electro-Mechanical Systems (MEMS) are mechanical and electro-mechanical devices and structures that are microfabricated.

They are composed mainly of Micro-Sensors, Micro-Actuators, Micro-Electronics and Micro-Structures.

Micro-Electro-Mechanical Systems are characterized by low cost and high sensitivity to signal anomalies.

Data analysis-based methods

Those methods depend on data analysis and range from data analysis to artificial intelligence-based methods.

Regression analysis is one of the most common methodologies.

Regression analysis requires a large number of data points representing various characteristics of a chosen research.

Another common method is artificial neural networks (ANN).

Which is a directed learning approach as it depends on high-quality collected data to develop a baseline.

Factors to take into consideration

A leak detector’s effectiveness for a certain application might be affected by a combination of factors.

1-Size of the potential leak

2-The physical specifications of the system

3-The type of tracer fluid being used

4-The purpose of the detection device

5-Leak location

References

[1] 7 Reasons Water Leak Detection is Important, 28Jun, Leak Master [online] Available at: https://www.leaknet/blog/7-reasons-water-leak-detection-is-important/

[2] Samer El-Zahab & Tarek Zayed, 11 June 2019, Smart Water volume 4, Article number: 5 (2019) [online] Available at: https://smartwaterspringeropen.com/articles/10.1186/s40713-019-0017-x#Sec3

[3] Principles of Leak Detection, Thomas net [online] Available at: https://www.thomasnet.com/articles/instruments-controls/leak-detection-principles/