System Maintenance & Performance # 2004 Milan
The United Kingdom has one of the oldest and most developed gas transportation systems in the world. Today, its policy is to use polyethylene (PE) as the preferred material for the safe and efficient transportation of natural gas for operating pressures up to 7 Bar. Transco are the largest gas transporter in the UK with 258,000 kilometres of distribution gas pipeline (up to 7bar operating pressure) comprising of 130,000 kilometres of PE and 128,000 kilometres of iron and steel pipelines (mains). The distribution system provides gas to 20 million service installations. In a liberalised gas market the replacement of iron mains is subject to strict regulation that provides a business strategy to reduce costs, maximise asset value and increase system integrity. The use of PE pipe in conjunction with ‘no-dig’ technologies has significantly contributed to this strategy over the past decade. Sealback™ is a remote live transfer technique that has been developed for the rehabilitation of low-pressure iron gas mains that are situated in locations which have restricted access. Illustration of the ‘Sealback™’ system This paper describes the Sealback™ system, which has been successfully developed in the UK and provides an update of Serviflex™ – A flexible solution for the renovation of small diameter service pipes, first reported at PPX, Gothenburg in 1998.