Case

Norway: Connecting cities with new main water supply

Ringsaker municipality, Norway, has approximately 33,500 inhabitants and covers an area of 1,281 square kilometres. The municipality is expanding and thus the need for water is growing

To meet the demands, a water main running from the city of Moelv to the city of Rudshøgda is renewed with manholes and service points. The long term goal is to connect the entire municipality from Moelv to the city of Brumunddal with public water.

The reason for Ringsaker municipality's upgrade of the water supply is among other things the increase of industrial companies in Rudshøgda, and growth along the lake Mjøsa also adds to the increasing demand for water. In addition to the need for potable water and water for industrial use, high demands are also placed on the waterline’s capacity in connection with irrigation and firefighting.

To stay ahead of the development, Ringsaker municipality has started building a new and modern water connection from the water works in Moelv and up to Rudshøgda. In the long run, the intention is to connect the entire municipality from Moelv to Brunmunddal in a dual-line.



“We renew pipelines and basins based on points of distribution. To begin with, this will increase the capacity up to Rudshøgda. The connection towards Brumunddal is also of societal significance in the long term which is why we use dimensions that, if necessary, can supply the entire region from one of the water works. This holds both safety and practical advantages,” explains Fahle Karlsen, Project Manager in Ringsaker municipality.

The existing pipeline is from the 1970s. Now the connections will be 400/500 mm throughout the entire distance, and all minor pipelines will be connected to eight new manholes with new fittings.

"It is a large and important project for the municipality and it is highly important for the water connection in the future,” says Karlsen.
Two stages
The work is divided into two stages, and it also includes renewal of main pipelines for wastewater and rainwater. New pipes will be installed from the pumping station for wastewater to the wastewater treatment plant in Moelv, while new connection pipes are installed for rainwater, which is separated and sent to trenches and further out in the terrain.

The work takes place in a junction where roughly 10,000 cars pass every day, which put great demands on the contractor, Maskinanlegg AS in Brumunddal. “To work in high-density housing areas pose challenges. We have to adapt to traffic and the existing infrastructure. Among other thing, we have to drill our way under the main road to make room for a wastewater pipeline. It was also our intention to install water pipelines below Moelva. We tried with 120 meters controlled drilling mainly due to environmental considerations. Now we will have to dig,” says Jon Ola Eid from Maskinanlegg AS, Brumunddal.

The reason for Ringsaker municipality's upgrade of the water supply is among other things the increase of industrial companies in Rudshøgda, and growth along the lake Mjøsa also adds to the increasing demand for water. In addition to the need for potable water and water for industrial use, high demands are also placed on the waterline’s capacity in connection with irrigation and firefighting.

Eight manholes
Eight manholes with valves are installed as part of the overall renovation of the water pipeline in order to ensure smooth operations and provide access to minor branches of the pipeline. A flexible AVK combi-cross DN 400 is installed in each of the manholes in a distance of approximately 160 meter from each other. The manholes are connecting the existing water distribution with the new water pipeline.

“This combi-cross is an advanced and user-friendly fitting. An example is the full bore centre part and a centre cap with standard flanges for DN 100 fire hydrants, which can easily be connected with optional valves in sizes 150, 200, 250, 300 or 400 mm,” says Martin Rud, Market Manager at AVK Norge AS.

The advantage of this solution is that it is possible to mount a blind cover on one or more of the outlets. It has a threadless connection output which can be used for different purposes. The cover can be rotated so the location of this output can be either on the top or bottom of the line, or in any other position that the client may want depending on the application.

Also for firefighting
The assembly between the centre part and the valves is based on a thoroughly tested system which is also used within firefighting.

“This is tested according to the requirements on EN 1074-2, both for strength and tightness testing of pipes with operating pressure up to PN16,” says Martin Rud. The centre cap can be removed for easy access to pigging or for inspection and maintenance of pipelines.

“This is the only combi-cross on the market that has a DN 400 centre part and DN 400 valves. Just like the AVK combi-cross in DN 100 – DN 300, the anchoring points are placed on the centre part independent from the valves or flanges. The anchor is therefore 100 % intact even if a coupling or valve is demounted on one or more outlets,” says Martin Rud. All the valves have a full bore corresponding with the flange size.

“Whether you choose a DN 150 or DN 400 valve, they have the same overall face-to-face length and a common centre line throughout the installation,” explains Martin Rud. The valves are moulded with a lifting eye ensuring that the valve is automatically centered when mounted in connection with renovation or expansion.

Service and three-way
Service connection valves are mounted vertically behind the flange on all the valves. Passage through the ductile valve bodies is smooth and without internal thread, with an epoxy coating according to GSK.

“The combi-cross comes with AVK´s three-way ball valve that ensures water circulation in the ball when it is in closed position. This is particularly advantageous when service valves can be exposed to frost,” explains Martin Rud.

This type of valve has been used in Norway for many years and is certified by SINTEF (an independent research organisation) for use as service connection valve.

One of the manholes is also equipped with an Auma actuator from Sigum Fagerberg for immediate remote operation when needed.

All components and materials for both stages are supplied by Brødrene Dahl in Hamar and the project manager is Kurt Nyhagen.

“It is very important that we have a professional wholesaler with us, and Kurt Nyhagen is very attentive which ensures that we can work efficiently,” says Jon Ola Eid from the contractor, Maskinanlegg AS in Brumunddal.

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