The 'external interference', also known as 'third party damage', stands out as one of the main causes of failures in onshore pipelines. External interference can cause, among others, damage identified as dents, gouges or both, and punctures, also known as 'mechanical damage'. In technical literature there are some semi-empirical analytical methods that aim to assess the fitness for purpose of pipelines with dent and gouge damage. As the equations suggested by these methods differ, the question hangs on "what" method would give a more accurate result when applied. Therefore, this paper presents the results of a comparative technique analysis for some of these methods currently available, concerning the theoretical basis, availability of required data and accuracy in predicting the nominal stress caused by the failure pressure. The results show that there is great similarity between these methods showed that all are essentially based on classical fracture mechanics, and that the 'original semi-empirical dent and gouge fracture method' developed by British Gas stands out as the "most recommended" to assess the fitness for purpose of pipelines with 'dent and gouge' damage type.
Onshore Pipeline; External Interference; Damage Dent and Gouge; Fitness-For-Purpose Assessment
