Basic approach to the risk assessment of natural gas pipelines

Evaluation of the limiting distance between a high-pressure natural gas pipelines and different types of neighbouring structures is undertaken by means of a risk assessment. The limiting distance is derived from the value of acceptable societal risk. The greater the distance between a structure and a high-pressure natural gas pipeline, the less societal risk exists. Given the density of structures (e.g. buildings, traffic routes, plants) in the Czech Republic, the limiting distances between structures and high-pressure natural gas pipelines are set to fulfil the acceptable societal risk criterion. The Technical University of Liberec has developed a methodology for assessing the risk associated with the release of gas from a high-pressure natural gas pipelines. A series of analyses and model calculations were undertaken to determine the impact of the consequences of a natural gas leak to people inside and outside the neighbouring structures. Model calculations were based on the probabilities of a natural gas leak, weather conditions, physical processes associated with natural gas leaks and other factors. The pipeline route was considered as a linear source of risk. Solutions and model calculations are therefore different from the methods used for point source risks such as LPG and CNG tanks. This article describes the basic approach for evaluating the limiting distance. These results were used in the Czech codes of practice applicable to the design of high-pressure natural gas pipeline routes and structures near them.