Influence of a statutory one-call system on the risk of natural gas pipelines

摘要

In the Netherlands, natural gas is transported through about 12,000 km of high-pressure underground pipelines. Pipeline ruptures are the primary risk of natural gas pipelines and are mainly due to external interference and the risk reducing measures that could be applied focus on this failure cause. An important measure is the introduction of a statutory one-call system which replaces the current voluntary system. An analysis of helicopter patrols and incident reports showed that the voluntary one-call system was used in only about 65% of the digging activities. The analysis also showed that about half of the incidents occurred even when the digging activities were reported. An important cause of the latter incidents is that the digging activities took place without supervision of the pipeline operator involved. Important factors in this lack of supervision are the pressure to begin the digging activities as soon as possible and forgetting to communicate the time at which an activity is to start. The statutory one-call system therefore requires all digging activities to be reported and prohibits digging activities near pipelines containing hazardous substances without the pipeline operator being involved. It is estimated that the statutory one-call system will reduce the number of incidents due to external interference by a factor of 2.5.