The HOIS recommended practice for in-service computed radiography of pipes

摘要

The comparatively new technology of computed radiography (CR) for NDT imagingrnhas a number of advantages over traditional film-based radiography including reducedrnexposure times, and greater dynamic range. In addition, it does not require facilities forrnthe development of radiographic film, which can be difficult to install and maintain,rngiven the often restricted deck facilities space in an offshore environment. However therntechnology associated with CR is substantially more complex than film, and, in thernabsence of any internationally recognised standards for in-service radiographicrninspection, the quality of the resulting CR images can be variable.rnTo improve the quality control of this form of inspection, the HOIS JIP has developed arnrecommended practice covering CR for the in-service inspection of pipes for wall lossrntype flaws (corrosion, erosion). This project involved a series of experimental trials tornfirst develop and then validate the recommendations, and also quantitatively comparernthe characteristics of different commercially available CR systems.rnThe results of the CR trials undertaken during this project and the mainrnrecommendations of the recommended practice are described.