TPi October 2009

developments products &

Pressure jacking pipes for sewers

THE municipality of Groningen in the Netherlands has extended its existing sewer main, sized DN 1000 and DN 1200. The gravity sewer main could not cope with high flow rates, for example those occurring during heavy rainfall. To prevent sewage from overflowing and polluting the environment, the authorities decided to convert it into a closed pressure system. With this, and its extension by 2.4km Hobas CC-GRP sewer systems, a capacity of 3,000m 3 /h could be achieved, allowing the line to easily cope with future needs as well as the connection of a further village. Since the line crosses a busy part of the town of Groningen, Hobas proposed the use of CC-GRP pressure pipe systems, which can be installed by open as well as trenchless construction. As Hobas GRP pressure pipes can be jacked, local engineers placing an order for the company’s CC-GRP, worth €1,222,000 for the complete line. This included five jacking sections with Hobas CC-GRP jacking pipes DN 1000 to 1500 and pressure pipes PN 6, DN 1000 and 1600 m DN 1200, as well as flanges, elbows, reducers and tees with stainless steel locked joints. Several obstacles along the pipe route, such as roads and a channel, were overcome by microtunnelling. Due to the requirements of the road authorities, two jacking sections running beneath the highway were realised with cover pipes, which were delivered by Hobas Benelux, and the Hobas CC-GRP pressure pipes were consequently inserted. The largest, THE shortage of clean drinking water is a worldwide problem. It is claimed that more than 55% of drinking water never reaches the home, due to leaking and run-down supply pipes. This situation can be solved at low expense, without digging and without large investment in costly equipment. Tube-In, from MultiLining Products, is a complete system for the rehabilitation of potable water pipes and pressure pipes. Pipes are reconditioned by pulling an armoured polyethylene

with an outer diameter of 1,500mm, was positioned beneath highway A7.

The three other microtunnelling sections were implemented using CC-GRP pressure jacking pipes PN 6 and flush FWC couplings. These ran beneath a gas pipeline, several streets and a navigable channel, where the installation was conducted in 12m depth. A 275m long section with CC-GRP pressure jacking pipes of 1,280mm outer diameter was jacked in a curve radius of 1,300m. The contractor installed an intermediate station that is required for jacking with over 4,000kN. However, due to the smooth and non-absorbing outer surface of Hobas pipes the maximal jacking force did not exceed 1,800kN, and the intermediate station was never in operation. Hobas Engineering GmbH – Austria info@hobas.com www.hobas.com

The Hobas flush couplings used for jacking S S are leak tight and facilitate assembly

Several obstacles along the S S pipe route, such as roads and a channel, were overcome by microtunneling

Rehabilitation of potable water pipes

accurately follows the shape of the old pipe, even through bends.

hose through the leaking water pipe, extending the life of the pipe.

The system is installed by using simple and inexpensive equipment. The pipe is first cleaned to remove any deposits, either with a steel scraper or a Polly- Pig, a cylinder shaped plug that is pressed through the pipe several times by means of water or air. Tube-In is then pulled through the old pipe, and when water pressure is restored, Tube- In will inflate and take the shape of the host pipe.

Tube-In has a wall thickness of 2-3mm and is constructed of a polyethylene inside layer, a strong armour layer and an outside layer of polyethylene. This construction gives a very strong pipe with a clean and smooth inner surface. Tube-In fits most pipe dimensions and may be installed in lengths up to 500m (1,640ft). It can be used in pipes with a pressure up to 20 bar (280 psi), and

MultiLining Products ApS – Denmark multiliner@multiliner.dk

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October 2009 Tube Products International