BEST PRACTICE IN PIPELINE DEFECT ASSESSMENT
Defects in pipelines can be introduced during manufacturing (e.g. laminations), transportation (e.g. fatigue cracking), fabrication (e.g. weld defects) and installation (e.g. dents), and can occur both due to deterioration (e.g. corrosion) and due to external interference (e.g. gouges and dents). To ensure the integrity of the pipeline, operators must be able to both detect and assess the significance of pipeline defects. Furthermore, the importance of accurate engineering models, for which the model uncertainty has been quantified, is important when applying risk-based (structural reliability) methods to pipelines. The past 40 years has seen the development of 'fitnessfor-purpose' methods for assessing the significance of pipeline defects. However, there is no definitive guidance that draws together all of the assessment techniques, or assesses each method against the published test data, or recommends best practice in their application. This paper describes the findings of a recent literature review and defines the objectives of the next phase of a Joint Industry Project which is being sponsored by thirteen international oil and gas companies (BG Technology, BP, CSM, DNV, EMC, Gaz de France, Health and Safety Executive, MOL, PII, SNAM, Statoil, Toho Gas and Total Oil Marine). The deliverable will be a Pipeline Defect Assessment Manual, which will provide the best available techniques for the assessment of pipeline defects.
The significance of embedded non-planar defects in transmission-pipeline girth welds. II
A literature review and description of the European pipeline research group's (ERPG) guidelines on acceptability and limits of non-planar defects in transmission-pipeline girth. In this part, the authors explained the EPRG's interests in this field, and examined current girth-weld defect-acceptance criteria.
Formation of unexpected ions from a first-generation polyamidoamine dendrimer by use of methanol: an artefact due to electrospray emitter corrosion?
We report the formation of unexpected ions during the analyses of a first-generation polyamidoamine dendrimer in negative ion mode using an ion trap equipped with an electrospray ionisation source. These surprising ions corresponded to an increase of 12 m/z units over those expected. The formation of the unexpected ions was dependent on the tuning of the solution flow rate and the capillary high voltage. In addition, measurements of unusual value of the current suggested that a reaction was occurring in the corona plasma. The influence of methanol in this phenomenon was demonstrated by using CD(3)OH in the sample preparation. We propose two structures to explain the observed adduct based on the results of MS(2) experiments and by referring to previous work dealing with 12 m/z units addition. We showed that a corona discharge caused by alterations taking place to the electrospray capillary emitter was the origin of these unexpected ions. Finally, we discuss the mechanism involved in the formation of the ions and we propose means to control such artefacts.