Cause Analysis of Gas Leaks and Methods to Limit Leakage

Hydrocarbon gas leaks create potential dangerous situations with major accidents representing worst case scenarios. Smaller gas leaks are also unwanted as they represent risk of escalation and often lead to shut down or reduced production. Small gas leaks also represent in total a significant amount of gas which is detrimental to our atmosphere. Gassco supplies about 20 % of the natural gas consumed in Europe. Economic loss is a direct consequence initiated by shutdown or reduced production, as well as reliance regarding deliveries towards gas customers. The natural gas industry continuously invests considerable resources into prevention of gas leaks. Regarding the subject of hydrocarbon leaks, there exists an abundance of information, reports, procedures and suggestions. There is not always coherence between the available information so the essential for any operator in the industry is to select the relevant, and most important, information to ensure a safe operation. The discussion in this report has shown the complexity of hydrocarbon gas leaks. There are technical, human, and organizational factors contributing to the undesirable risk of gas leaks within the Gassco operatorship. Certain technical components more prone to leak are valves, flanges, gaskets, and heat exchangers. It is therefore important to ensure joint integrity on the facilitation and the execution level. Approximately 20 % of technical leak sources are due to technical degrading. Corrosion under insulation (CUI) has been introduced as an integrity challenge in this area. In order to improve integrity of process facilities it is necessary for Gassco to invest in measures to improve or reduce technical degrading, such as continuous programs for monitoring, inspection and maintenance. As the human factor is underlying cause of the majority of gas leaks the main focus area for Gassco is to get an overview of organizational factors creating risk. Within this area of concern there should be an increased investment in exchange of experience with more frequent workshops as a proposed measure. Reducing risk of possible misinterpretations of governing documents should also be assessed. Within gas detection there are some methods with distinct characteristics. Infrared technology enables visualization of fugitive emissions and continuous monitoring. The handheld gas camera FLIR GD320 is an efficient method of inspection. The stationary Gas Vision System appears to have potential to become an essential part of monitoring process facilities. Based on the discussion in this report it becomes natural to conclude that the most important safety barrier within the natural gas industry is the human factor. There has been an increased focus on the human factor in recent years with positive results of improvement. However, the industry aims at continuing the positive trend.