Introduction: The study will apply to the whole of the buried above 7 bar pipeline Network belonging to National Grid Gas Distribution and Transmission. The study will only consider natural landslides, i.e. it will not include landslides due to made up earthworks such as embankments and other man made hazards such as dams. It will also exclude impacts within the boundary fence of installations.

Objectives:

The objectives of the study are to enable National Grid to better quantify the risk of natural landslides affecting its high pressure gas network.  This will support its asset management and risk assessment processes allowing National Grid to quantify the risk to the general public at specific locations and also to understand any potential impact on gas supplies.  As a result of this work National Grid will be able to decide on locations where it may be appropriate to undertake monitoring to detect any potential earth movement, or undertake remedial measures to mitigate the impact of a natural landslide.

Expected Benefits: The successful completion of this project will result in a landslide domain map based on data supplied by the British Geological Survey for the geographical area of the National Grid pipeline network. A risk model will be developed that will allow National Grid to determine the likelihood of pipeline failure due to natural landslides at any given point on its above 7 bar pipeline network. The risk model will take account of the key pipeline parameters (i.e. wall thickness, diameter, pressure, and grade) and also take account of any known weld quality issues. The risks will be quantified for both pipeline leaks and pipeline ruptures.