Subor is currently supplying GRP pipes of 4 m in diameter to the 'Kralkizi Dicle Main Channel Second Part Irrigation Project' in Turkey. The pipes are manufactured using a continuous filament winding process.
Subor is currently supplying GRP pipes of 4 m in diameter to the 'Kralkizi Dicle Main Channel Second Part Irrigation Project' in Turkey. The pipes are manufactured using a continuous filament winding process.
Subor has started installing the GRP pipes for the siphon lines.
Subor has started installing the GRP pipes for the siphon lines.

As one of the most important natural resources, water plays a great role both in Turkey and the rest of the world. Today, a vital requirement is the more efficient use of water.

In Turkey, 74% of water useage is for irrigation in agricultural projects and therefore the largest savings must be made in this area. However, when using conventional irrigation systems in Turkey nearly 50% of the water supplied is wasted as a result of leakage in transfer and network lines, evaporation and operational losses. In other words, open system irrigation projects (which are constructed at ground level and open to the atmosphere) consume 2 m3 of water for every 1 m3 reaching the plants. This not only leads to the waste of already restricted water resources, but also to the construction of distribution and drainage networks with larger capacities, eventually leading to increased costs plus additional energy consumption for systems equipped with pumping facilities. On top of this, irrigation projects must pay for the water they use, increasing the importance of saving water.

GRP pipe

The Devlet Su Isleri (DSI) (State Hydraulic Works) Directorate General, part of the Ministry of Environment and Forest, is in charge of the planning, management, development and operation of all of Turkey's water resources. It is responsible for the planning, project development, construction and operation of the potable and freshwater supply and irrigation networks for urban areas with a population over 100 000, along with dams and hydroelectric power plants. DSI is also responsible for the most efficient use of these water resources. Headquartered in Ankara, the organisation consists of regional directorates.

The efforts of the DSI have led to increased awareness of water consumption nationwide, leading to an accelerated switch over to the closed (piped) system in irrigation projects. As a consequence, leakage, evaporation and operational losses in the transfer and network lines will be avoided by the closed pipe system buried several metres underground.

Previously, the only alternative for large diameter pipes in irrigation and small hydro power plant (SHPP) projects was steel. However, issues such as corrosion of metal and concrete based pipes used in infrastructure projects and increased level of service breakdowns, resulting from incorrect installation in particular, have led infrastructure investors to consider new materials. The use of glass fibre reinforced polyester, which is more corrosion resistant than metal, is becoming increasingly widespread in infrastructure applications.

Considering the future needs of the market and at the height of the economic crisis in 2009, Subor Pipe Industry And Trade Inc invested in a new manufacturing line which is capable of producing GRP pipes up to DN 4000 mm in diameter. Subor is a preferred supplier of pipe systems to the irrigation projects overseen by the DSI.

Kralkizi irrigation project

Subor is currently supplying GRP pipes of 4 m in diameter to the 'Kralkizi Dicle Main Channel Second Part Irrigation Project.' This is the first time pipes of this size have been manufactured in Turkey.

This project within the city borders of Diyarbakir comes under the scope of the Southeastern Anatolia Project (GAP) – one of the biggest regional development projects in the world – which has the objective of enhancing the quality of life and the income level of the population in this region. The area of GAP covers the basins of the Euphrates and Tigris and the nine cities (Adiyaman, Batman, Diyarbakir, Gaziantep, Kilis, Mardin, Siirt, Sanliurfa, Sirnak) located in the upper Mesopotamia plains. The most important river in the city of Diyarbakir is the Tigris. The aim of the project is to distribute the water taken from the Kralkizi dam on the Tigris.

Subor signed the contract for this project in May 2010 and, working with contractors Ufuk Insaat and Inelsan Insaat, started manufacturing and installing GRP pipes for the siphon lines.

The DSI Diyarbakir Regional Directorate chose GRP pipes for the siphon lines because of their high corrosion resistance, easy and fast installation, and short manufacturing period. Siphon lines, which generally have a 'V' shape, are used to transfer water from one point to another.

Within the scope of the project there are four GRP siphons of diameter 4 m with a total length of 10 700 m. The first two siphons have a flow rate of 92 m3/s whereas remaining siphons have a flow rate of 52 m3/s. All siphons will be installed as parallel pipeline in order to enable these high flow rates. For the first two siphons, three parallel GRP pipelines will be installed in the same trench, and for siphons no. 3 and 4, two parallel GRP pipelines will be laid in the same trench.

GRP pipes, 4 m in diameter, with pressure classes PN 6-10 and stiffness SN 5000, have already been installed in the construction of siphon no. 3. In total, 3600 m of GRP pipes and fittings were installed in the same trench as two parallel lines. By installing an average of 72 m long double pipeline in a 36 m long trench each day, the construction of siphon no. 3 was realised in a fast and economic way compared to the alternative methods.

In the second phase of the project, Subor has just started installation and backfilling works of siphon no. 2. 3300 m of GRP pipes and fittings will be installed in the same trench as three parallel lines.

In the third phase of the project, siphon no. 1, a total of 3500 m of pipe is going to be installed.

Subor facts & figures

Subor Boru San. Ve Tic. AS was founded in 1996 to manufacture and sell glass fibre reinforced polyester (GRP) pipes. Today, Subor, in partnership with Yapi Merkezi and the Amiantit Group, is a world leading manufacturer of GRP pipes up to 4 m in diameter. Subor has two production plants in Turkey and exports to 30 countries around the world.

Subor has the capacity to produce 1200 km of large diameter GRP pipe per year, with three production lines at its Adapazari plant and one production line at its Sanliurfa plant. Subor has produced over 4500 km of pipe since it was founded, under the license of Flowtite.

Subor is certified to the ISO 9001 Quality Management System, ISO 14001 Environmental Management System and OHSAS 18001 Occupational Health and Safety Quality Management System.

The 12 m long GRP pipes, manufactured at Subor's Sakarya plant, are delivered by low bed trucks to the construction site. There are also elbows of various angles, two specially designed GRP 'T' pieces for the first stage and four for the second stage in the project.

A trench excavation of 11 m is required for a double pipeline; up to 16 m is required for a triple pipeline installed in parallel.

The approximately 7 m deep trench is filled with crushed stone after the completion of the installation and the filling is compressed with a compactor and a roller. In the sections with high groundwater level, geotextiles are used under the pipe and at the trench walls. The trench excavation and filling is carried out by the contractor company, while the pipe installation is performed by the experienced Subor field services team.

The coupling connections of the installed GRP pipes are subjected to leakage tests by Subor field engineers with the use of hydraulic field equipment mounted on wheeler sled. This specially designed portable test equipment allows the internal test of each connection along the line. The installed pipes are tested the same day and backfilling works are carried out accordingly.

Within the completion of this project in 2012 the irrigation issue of the region will be solved and the employment of the population in the region will be promoted. ♦


This article was published in the May/June 2011 issue of Reinforced Plastics magazine.

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