Development of Flowstop Systems for Large Diameter Polyethylene Mains

摘要

The economic success of BG Transco Plc,(formerly British Gas) during the last three decades stems from the mid-sixties discovery of natural gas fields below the North Sea.The subsequent development and exploitation of that resources has depended on a number of key decisions.The decisions to create a national high pressure gas grid and to convert all consumers from towns gas to natural gas created the modern industry,but a third decision has had an equally revolutionary effect on the technology employed and that was the decision to utilize polyethylene (PE) pipework for low pressure distribution purposes.Developments in polyethylene (PE) pipe technology have led to an ongoing increase in the size of pipes being laid in the UK.Currently,pipes up to 630mm (PE80) and 400mm (PE100) have been commissioned.However,in an emergency situation there may be a requirement to perform a flow stop operation on pipes of these diameters.This paper reviews new developments with regard to flow stopping on PE mains with emphasis on the problems of dealing with large diameter pipes safety and effectively.