Leak Detection

Leakage Detection

Water losses can occur at many points within the water supply system. Physical Losses occur mostly in service connections in our country. Generally in urban infrastructure works (wastewater collection, road asphalting, natural gas connections, telephone, electricity etc. connections) excavation etc. Service connections are damaged during the operations and leaks begin to occur. Damaged service connection pipes cannot be repaired at the desired level by the companies carrying out the relevant infrastructure activities. As a result, relatively low flow leaks begin and high volumes of water are lost over many years in poorly repaired service connections. Leakage water does not come to the surface at the connection points where leakage occurs most of the time and disappears by leaking underground.

Leaks frequently occur in plastic (PVC) water pipes used in water distribution networks, which are kept under the sun for a long time. Leaks start from cracks in the pipes and water losses continue for many years until leaks are noticed and repaired. In addition, losses can occur in the old pipes, various valves and connections in the supply and distribution lines.

Properties of Leaks:

Searching, determining, locating and repairing leaks consists of three stages. These stages can be defined as Awareness-A, Location-L and Repair-R, and ALR for short. In this approach, leaks in pipes, overflows in warehouses or losses at different points occur in three stages:

• Time to become aware - the time it takes for the administration to notice the leak.
• Locating time - the time it takes to locate the leak.
• Repair time - the time required for repair or repair.

As the time spent by the administrations to become aware of the water loss / leak, to locate it and to repair it, the volume of water lost increases. It may take weeks or even years until an underground leak is noticed. Therefore, leakage awareness, locating and repair times should be reduced within the strategy of reducing water losses.

Types of Leaks:

It is very important that water administrations understand the formation of different types of leaks within their systems, evaluate the leak flow time and ALR processes and the total volume of physical water losses. Types of leaks are listed below:

• Reported bursts - They are visible and often quickly reported by the public. Recognition time is short for this type of eruptions.
• Bursts that are not reported - Usually occurs underground and do not surface. It is often revealed in leak detection studies and its awareness is long.
• Background leak - Occurs with a combination of very small leaks. Identifying and repairing such leaks individually is both difficult and costly.

Active leak control is a vital application for efficient water loss management as well as being cost effective. Ground microphones electronically amplify the sound / noise caused by the leak. These devices can be installed for use in contact or monitoring mode. The contact mode is used to listen to the fittings and is similar to the electronic listening sticks.

Monitoring mode is used to search for leaks in pipelines between fittings. In this method, the ground microphone is placed at certain distances on the pipeline and the changing noise level is monitored as it approaches the leak point. When the presence of a leak is detected by the acoustic recorders or leak noise correlator, the site team can locate the leak point.