Papers # 2016 Berlin

The S-bend installation method is the reason for the successful worldwide development of the market for marine PE pipelines over the last 50 years. Small and medium sized PE pipes can safely be installed using the S-bend installation method; however, difficulties increase as pipe sizes increase. In order to ensure a safe installation of pipes larger than 2000 mm, PE pipe and resin manufacturers must contribute to the development of the method, and supply expertise to contractors and the end user, as they did in the 1960s and 1970s when the S-bend method was originally developed. The technical support given to contractors and end users will be of utmost importance for the further growth of the market for large diameter marine PE pipelines.

PE pipes have been used for marine pipeline installations since the early 1960s. Today, solid wall PE pipes are by far the most frequently used material for marine pipelines. The main reason for the successful development of the market is the use of the S-bend installation method. This method involves floating the air-filled PE pipeline on the surface of the sea, and then submerging it by filling it with water from one end. During installation the pipe is significantly bent, and subjected to stresses and strains. For most pipelines, the stresses experienced during installation will be far higher than those experienced for the remainder of the pipe’s service life. Typically, the axial stress in a solid wall PE pipe may reach 6 -12 MPa during the installation phase. A solid wall PE pipe can accommodate such stresses, but for thin walled pipes (SDR>26) a significant out of roundness will occur when the pipe is bent. The out of roundness will highly influence the kinking risk for the pipe when bent. Today, solid wall PE pipes are manufactured in sizes up to 2500 mm in diameter, but the extrusion technology and PE material properties set limits for the wall thickness. These limits mean that large diameter pipes must be made to relatively high SDR ratings, and thus are more sensitive to kinking than smaller, more thick walled pipes. In order to safeguard the S-bend installation and avoid kinking failures of the pipes at installation the pipe supplier must be able to calculate the bending at installation, and be able to give technical support to designers, contractors and end users.

This paper highlights the experience of the S-bend installation method, how pipe bending can be calculated, and the necessity of accurate E-modulus data for PE100 materials at high stress levels. The latter is important for assessing safety margins at Sbend installations, and enables the pipe manufacturers to provide better design support to further develop the market for large diameter marine PE pipelines

Related keywords : Design, installation, intake, PE pipe, outfall.
Please note that the whole article content is available on PPCA website onlySource : 2016 Berlin

Related papers


Author(s) : Ilija Radeljic, Ingemar Björklund 2018 Las-Vegas

Installations of solid wall HDPE pipes are becoming more difficult and riskier with the increase in diameter (OD2000+ mm), length of strings (1000+ meters) and reduction in the wall thickness (SDR26-30). To gain a better understanding of the limits of the final pipe assembly prior to the sinking, a laboratory tests in...

Europe's largest-ever PE pipe project - The Montpellier Sea Outfall

Author(s) : Blomster, Baeckman, Ettinger 2004 Milan

Only ten years ago, steel was the dominant material in marine outfall projects. Technological advances in raw material supply, more sophisticated extrusion technology and know-how development in submerging of pipelines has however changed this situation. In 2002 Pipelife Norge A/S won Europe's largest-ever...

Performance of Buried Large Diameter Structured Wall PE Pipes

Author(s) : Andtbacka, Bjorklund, Lofmark, Thorstensson 2004 Milan

The performance of buried large diameter structured wall PE pipes has been studied by following the development of the deflection in four different large diameter PE pipes installed in Finland and Sweden. The pipes studied have had an internal diameter of 2000-2400 mm and a ring stiffness of 4-8 kN/m2. Two of the...

Relining of a large Diameter Water Main in Kolkata Using Solid Wall PE Pipes

Author(s) : Bjorklund, Leowpenwong 2004 Milan

An old 1550 mm diameter heavily corroded water pipe, was in March 2003 relined in Kolkata, India by using 1400 mm SDR 30 PE pipework. In all, 1 km of pipe was rehabilitated. To facilitate the installation of the PE pipe and maximize the insertion lengths, extensive planning for a slip-lining operation was carried out....

Strength Investigation of Large Diameter PE 100 Low Sag Pipe

Author(s) : Janson, Bergstroem, Baeckman, Blomster 2004 Milan

When performing strength quality control of PE pressure pipes made of new grades it is important to take the creep vs. time into consideration and not only the common stress vs.time behaviour. Thus, it is just the relation between linear strain and logarithmic time, which will within a reasonable testing time help us...

Plastics Pipes in Water Distribution Systems. A Study of Failure Frequencies

Author(s) : Bjorklund 1992 Eindhoven

Investigations of failure frequencies in municipal water distribution networks have been performed on several occasions over the past 15 years in Sweden. In a follow-up study, reasons for failure in PVC and PE water pipes during the period 1986-1990 have been studied. It was found that PVC pipes manufactured after...

Members of the Association

BOREALISBOROUGEINEOS O&PIRPCKorea Petrochemical IND. Co., LTDLyondellBasellPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE