In the demonstration area of Klampenborg noise loggers proved helpful at once. Knowledge and technology combined by the LEAKman joint partnership create world class water distribution networks.
In the water supply network of Klampenborg two leaks were identified only a few weeks after the installation of noise loggers. Both of the leaks were fixed within a short period of time and hereby water losses were minimized as well as further collateral damages were avoided.
Novafos and HOFOR – two major water suppliers in the capital region of Denmark – are partners in the LEAKman project. Each company has designated two districts to be full-scale demonstration areas as a part of the project. They are now being transformed into state-of-the-art water distribution networks. During spring 2017 noise loggers were implemented and when completed, the demonstration areas will be covered with 400 permanently deployed noise loggers, 4,800 smart meters, active pressure management, real-time hydraulic modelling and online monitoring of KPI’s.
In Klampenborg, a DMA (District Metering Area) belonging to Novafos, the newly deployed noise loggers proved to be valuable within just a few weeks.
Of the 400 noise loggers, 125 have been installed in Klampenborg DMA. If it had not been for the noise loggers, it would probably have been a while before anyone would have known about the two leaks.
One leak was identified on a pipe in a private installation where the owner is responsible for the repair. In this case, it was fixed in collaboration with Novafos and the repair was carried out within less than three weeks. The second leak was fixed within just one week after identification.
Worst case scenario
Before the noise loggers were installed, leaks were found during manual surveys of the distribution network in Klampenborg. These leak surveys were carried out systematically at least once a year.
This means – in worst case – that the leaks could exist for almost a year before being detected, had it not been for the new loggers since the ALR-time (Awareness, Location & Repair) is drastically reduced. During a year, the water loss from a leak could be significant and the leakage could potentially result in pipe bursts which would cause even more water to be lost as well as more expensive collateral damages to follow. Therefore, active leakage control is an important step on the way to a minimized water loss.
World class water management
The LEAKman partners, Novafos and HOFOR, were already familiar with usage of automatic noise loggers and gate valves. Both water suppliers have previously used this equipment at selected locations. As a part of the LEAKman project, several DMAs in northern Copenhagen are now systematically monitored and on their way to an absolutely exceptional low water loss.
The NRW level in Danish drinking water distribution networks is on average below 10%. This is among the lowest in the world, while unfortunately a lot of drinking water goes to waste in many other countries around the world. Thus, it should be a global focus area to minimize water losses.
How the noise loggers work: Automatic tracking and reporting
- The noise of a leak can often be recognized and separated from other background noises by the loggers.
- Leaks can be identified and locations can be determined from the intensity and the frequency of the noise.
- The noise logger is programmed to measure the noise 10,000 times during a pre-defined period of time, usually from 2 am to 4 am when consumption is low and pressure is high, and background noises are at a minimum level.
- Signals picked up by the noise loggers are sent to the water supply management system as audio files. If a logger has recorded a noise pattern above the configured threshold, a warning or alarm will be raised. Operators will manually pin-point the exact noise location and verify the source to be a leak before sending in the repair team.
- The automatic noise loggers are supplied by LEAKman partner Leif Koch A/S with more than 40 years of experience in leakage management.
Installation of the noise loggers: Custom made valve covers
- With the purpose of being able to isolate a smaller section of the supply network, in case of pipe bursts or replacement of pipes, the Klampenborg network has a number of AVK valves distributed across the entire network.
- This provides an opportunity to place the noise loggers together with these valves.
- As the valves are mounted on the pipes they have direct contact with the pipe wall, and an extension spindle allows the valve to be operated from street level.
- Sound is optimally transported through metal and as the valve and the extension spindle have metallic contact, these are optimal conditions for installation of the noise loggers.
- The extension spindle is usually fixed in a street cover and AVK has developed a plastic cover offering room for storage of equipment such as microphone, data logger, battery and antenna. The plastic cover provides optimal conditions for transmitting the radio signal.
The water distribution network: Using DMAs
- A complete overview of all the details in a massive supply network can be difficult to achieve. Nowadays, it is common practice to divide the distribution network into smaller manageable sections, District Metering Areas (DMA).
- Typically, such DMAs cover from five hundred up to a maximum of five thousand customer points.
- The DMAs need to be well defined and separated in order to make sure, whether water is lost as physical or commercial losses, or if it simply disappears to a neighboring section.
- Usually, the DMAs are separated by cutting pipes that would connect to another section but leaving a smaller number of closed pipes for emergency supply using shut-off valves – typically gate valves. It is extremely important that these valves are reliable and absolutely tight. Reliable, functional and long lasting gate valves are the backbone of any water distribution network.