Pipeline Leak Detection

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PARSAN represents the complete range of services associated with innovative Leak Detection Systems to identify Visible & Invisible leaks to reduce the leakages in water supply in cities. The services broadly cover Zone measurement using immobile or mobile meters and localizing leaks with the help of acoustic signals. The whole leak detection system is integrated with GIS system to develop further applications.

Installing underground pipes and fittings of a drinking water network system generates significant costs for the utilities. Leaks on pipe networks waste precious resources, with the water losses requiring substantial additional financial resources for water purification purposes and for the operation of oversized network structure (pumps, pipes, reservoirs, etc.). Already minor leaks can cause massive financial losses. Therefore, any damage on a pipe network has to be detected and remedied as quickly as possible.

In general, the leakage-borne noise is used to locate a leakage on a pipe. As soon as a liquid escapes a pipe at a damaged spot, shock waves are generated which travel along the water column in both directions in a sinusoidal way. Wherever these shock waves collide with the pipe material, the pipe material is stimulated to vibrate. These mechanical vibrations are called structure-borne sound waves. The farther the waves travel, the less intensive they become. And finally, there is a point where the shock waves do no longer make the pipe material vibrate and thus do no longer generate any noise. This, of course, strongly depends on the kind of soil, its compaction level, the pipe material, the operation pressure, and some other factors.

Leak Detection Method

In general, leakage detection activities are separated into zone measurement, leakage pre-locating, and pinpointing. We at PARSAN offer all three types of leakage detection from one source.

Zone measurement allows quantifying a leak by measuring the zero-consumption status at night (2:00 – 4:00am) thus identifying those areas hosting the biggest leaks. Natural zone limiters are applied to monitor the feeding quantities through firmly installed, immobile meters in basins and at pump stations. If immobile meters cannot be installed in a section or zone, mobile flow-rate meters are applied to measure the flow of fluid.

Pre-locating means roughly localizing leaks by systematically listening to pipe network contact points which are directly accessible such as hydrants or valves. The principle is relatively simple: more intensive noise = leak is closer, less intensive noise = leak is farther away. This principle allows narrowing a leak to a certain section between two contact points. The accuracy achieved is usually not sufficient to start excavating. Therefore, subsequent pinpointing is recommended.

Pinpointing. The area which has already been pre-selected through correlator, testrod microphone, and noise logger activities is now listened to with an electro-acoustic listening device in order to pinpoint the exact leakage spot by locating the highest noise level. The device accuracy usually limits excavating to a minimum and thus provides resource-optimized network maintenance.

PARSAN also specialized in using geophysical tools like ground penetrating radar and geophones to detect pipeline leakages in difficult conditions where conventional methods like Leak noise correlator etc.

Highly sensitive geophones are planted along the pipeline route to listen to noise created by leaking water. The technique does not require pipe to be exposed at any place and has the advantage in completely buried pipe sections.

Ground Penetrating Radar detects the minor changes in soil permittivity due to leaking fluid.