Leak detection in Roskilde
In the oldest part of the city, a hole becomes a passage
Excavation work in Roskilde's medieval city centre is not just a question of getting a machine there. In the oldest part of the city, an intervention can trigger archaeological considerations, and then the schedule will be different from the one given by the contractor. On top of that, traffic flow in narrow streets, where there must be room for deliveries and pedestrians while work is being done.
Restoration is pulling in the same direction. A paving stone or granite slab must be laid back as it was, and that is a different job than pouring asphalt into a hole. Therefore, the measurement must be completed before the excavation permit is applied for, and the position must be narrow enough for the application to describe a single location.
How close a point can be placed from the surface
How precisely we can pinpoint the location depends on the method and what the pipe is in. Acoustic listening with a ground microphone typically narrows down to an area where the sound image is strongest, and on cast iron and steel the sound carries a long way. Correlation calculates the position based on the time difference between two recordings at each end of the section, and on long, straight sections it gives a narrow answer.
If it needs to be tighter, we inject tracer gas into the pressurized pipe. The gas is harmless, seeps out through the leak and up through the ground or the joints of the coating, and the surface is systematically scanned with a detector. Here we are talking about an accuracy of a few centimeters. This is the method we choose when the consequences of digging incorrectly are great.
Leak detection in Roskilde in pedestrian streets and narrow streets
The measurement does not require any blocking. We work from the surface and from the network's own measurement points: wells, valves and taps. This makes it possible to measure in a pedestrian zone or a narrow street in the middle of the day without blocking deliveries or pedestrians.
On the other hand, noise sets limits. A pedestrian street during opening hours is a difficult acoustic environment, and therefore we often take acoustic measurements early in the morning or late at night, when background noise is low. Trace gas is less sensitive to noise and can be used during opening hours if that is the way things are supposed to go.
Leak detection in Roskilde before applying for a digging permit
When the map material doesn't fit — and in older city centers this is the rule rather than the exception — we trace the route of the pipe and mark it on the terrain. This way you know whether the pipe is under the roadway or the sidewalk, how deep it is supposed to be, and where it crosses other pipes.
This has a direct impact on what needs to be presented before digging. An application based on a marked route and a measured position describes a small, limited intervention instead of a stretch that needs to be explored. It is also easier to coordinate with other line owners when the route is known and district heating and cables are located in the same narrow margin.
Part of the value lies in being able to clear a stretch before someone spends hours on an application. If your own team wants to do it, the search equipment for the purpose is available through us, both for sale and on lease, and the practice of reading a sound image correctly is part of the basic course at DWI Leak Academy. We are still called in when the position needs to be narrow enough for a digging permit in the old city center.
What the numbers say when the repair is done
Once your contractor has repaired the line, we can check the line again and see if the loss has disappeared. On a supply network that is worked on over time, however, it is the zone-by-zone figures that drive the decisions: they can be followed year by year and included in the calculation of NRW, so that the development can be read on the part of the network that was worked on, and not just on the total pumped out figure.
For a municipality or utility, it also has a practical side. If each location is documented, the excavation work in the city center can be planned together instead of coming one at a time, and the restoration can be agreed with the contractor who will be laying the pavement in advance.
What the municipality and the utility get
After a task, you will have the position marked on site and the measurements documented with the method and the conditions under which the measurements were made. If we have carried out a cable search, you will receive the progress so that it can be included in your own map material.
Neither excavation nor repair is our responsibility. We locate and document, mark the terrain, and the repair is carried out by your own contractor or plumber, with whom we are happy to speak directly about where the cut should be made. Emergency telephone number +45 70 23 98 98 is open, and an operator can often be with you the same day.
With tracer gas we are talking a few centimeters. With acoustics and correlation it becomes a narrow range, the width of which depends on the pipe material, distance between measurement points and noise conditions at the site. We always state the accuracy of the measurement.
Yes. There is no need to block off or dig while we are measuring. Noise can make acoustic measurements difficult in the middle of the day, so we typically take them early or late, while trace gas detection can be done while the street is in use.
Our documentation describes the measured position and, if we have traced the line, its course. This makes it possible to apply for a limited intervention rather than a search route. The application itself is the responsibility of you or your contractor.
Yes. We check the site and measure the night consumption in the zone again. If there is still a loss, we continue the search, because there is often more than one leak on an old section.
Yes, and that's often where we start. Cable tracing provides the actual course marked in the terrain, and only then do we measure. Otherwise, you risk listening in the wrong place.
Contact DWI
Contact us for competent advice, leak detection and pipe location for your waterworks or water supply. We also assist commercial customers and private households with professional solutions.
