External Corrosion Direct Assessment (ECDA) is a four stage process used to manage the integrity of a pipeline from the threat of external corrosion. The four stages are defined as:
The purpose of ECDA is to manage the threat of external corrosion without making recourse to in-line inspection techniques and/or hydrostatic pressure testing. Consequently use is made of above ground survey results or other techniques for identifying locations of the various types of damage. A key element of ECDA is the use of excavations to ensure that necessary repairs are undertaken and to validate the findings of the defect detection techniques. Excavations are generally recognised as significant cost items.
Using our approach we not only fulfil the requirements of the appropriate recommended practises, but by using a detailed and mathematically robust reliability-based technique, we provide the pipeline operator with transparent and detailed safety justifications that:
Optimise the number of excavations required and provide a clear visualisation of the how the integrity level changes following the completion of each excavation
Determines the time interval to the next assessment that is necessary to maintain an acceptable level of integrity
AFAA have developed very sophisticated in-house software for undertaking ECDA studies, it has been subjected to extensive validation and verification processes.