Preventing Failure: Leakage detection technologies and methods

Leakage detection technologies and methods

Pipelines are widely used for the transportation of fresh water to households, commercial and industrial consumers. The structure of pipelines is designed to withstand several environmental loading conditions to ensure safe and reliable distribution from the point of production to the shore or the distribution depot. However, leaks in pipeline networks are one of the major causes for concern as they can lead to serious ecological disasters, human casualties and financial losses.

The government and urban local bodies are making continuous efforts to reduce pipeline leakages by using the latest technologies that will allow inspectors to precisely determine the location and the severity of the leakage. Industries are also becoming receptive to the idea of deploying advanced technologies to treat effluents, as well as recycling and reusing them for industrial purposes and greenbelt development. Further, the detailed mapping of assets and underground utilities, and the deployment of leakage control technologies are being undertaken to curb losses due to the increasing level of non-revenue water.

Different methods are being adopted for detecting leakages in the pipeline network. Acoustic detection remains the primary means of detecting and locating pipeline leaks. Acoustic leak detection is described as the systematic method of using listening equipment to survey the distribution system, identify leak sounds and pinpoint the exact locations of hidden underground leaks. The exterior methods mainly involve the use of specific sensing devices to monitor the external part of the pipelines. The operational principle, strengths and weaknesses of these methods are discussed in the subsequent sections. The fibre optic method involves the installation of fibre optic sensors along the exterior of the pipeline. They can be installed as distributed or point sensors to extensively detect the physical and chemical properties of hydrocarbon spillage along the pipelines. Further, sensors, ultrasonic flow meters and bulk meters need to be installed at all points of the distribution chain. Smart Ball is being used by utilities to detect very small leak points. Tethered acoustic leak and air pocket inspection technology also helps detect leakages in pipelines.

The Indian states have adopted various techniques to detect pipeline leakages. The Kerala Water Authority (KWA) has adopted the Sahara Drag chute and Smart Ball leak detection technologies for easier and more effective detection of leakages. KWA uses Smart Ball technology for detecting leakages in the water network. Bengaluru is using WaterOn, an app that allows individual households to keep track of water usage and curb wastage for 45 days. The Gurugram Metropolitan Development Authority has implemented a centralised integrated water management system to identify the demand for potable water, check illegal supply and analyse incremental supply.

Leak localisation is essential in pipeline monitoring as it will speed up the repair process. Mobile sensor nodes with built-in GPS have been deployed to determine and report the geographical location of pipeline leakages. The use of mobile sensor nodes in pipeline environments is essential as it can enhance coverage and help the network recover from any failure that partitions the whole network into multiple disconnected subnetworks. However, the cost of implementation of these sensor nodes with GPS capability is extremely high.

Metering is another important aspect of water projects. The absence of water meters has been a root cause for issues such as high non-revenue water, unchecked leakages and overflows, and unauthorised and reckless water consumption. The Municipal Corporation of Greater Mumbai (MCGM) has launched a portal called MCGM GIS, which will give an overall geographical view of the city on a map and allow users to check plot reservations, and progress of road works and pipelines passing through a particular area. At the same time, developers can access information about existing pipeline networks to prevent damages. GIS technology helps find the exact location of faults in the pipes, and is thus effective in detecting leakages.

In sum

Leak detection is a field that continues to grow and advance with the use of both established technology and emerging methods. The performance of the various pipeline leakage detection methods varies depending on the approaches, operational conditions and pipeline networks. Leak localisation and estimation of the leakage rate are both important as they facilitate spillage containment and maintenance at an early stage to avoid any serious damage to the environment.