In terms of integrity assessment, the pipeline industry has come a long way in 40 years, developing systems to detect, locate, size, and assess the significance of many types of features. These methods will continue to evolve, but the biggest gains will come from obtaining, retaining, and using data for our pipelines. Bob Andrews draws on his 40 years of experience in the integrity field to discuss a few of these developments and the pain points that, if not addressed, will put a stop to the trend of integrity management improvement.
In those days, fracture mechanics was still in its infancy, a specialist subject for research, particularly in the nuclear and aerospace industries. Work conducted in the US and the UK had produced the first methods for assessing defects such as cracks and corrosion in pipelines. This introduced the industry to the concept of “fitness for purpose,” in which the acceptance of a crack (although now we have to call them imperfections) was based on the actual loads and actual material properties rather than arbitrary limits.
At the time, fitness for purpose was a new concept, and there were concerns that this would encourage poor workmanship and poor quality. These concerns delayed the publication of the first codified guidance for fitness-for-purpose assessments, PD 6493, by several years. PD 6493:1980 contained 51 pages; the 2013 edition of the successor document, BS 7910, now a full British Standard, contains 486 pages. In 1980, it was possible to assess a defect “by hand” using the graphs in the document; now we have to use computer programs. PD 6493 has been joined by similar (and in some cases longer) standards, including API 579 and DNVGL-RP-F108. These are supported by standards for materials testing.
A quantitative integrity assessment requires inspection information on the size of the features. It has been well said that in 90% of the cases, you assess an inspection report, not the actual defect, as the actual defect dimensions are not known. Inspection technology for pipelines has also changed. Forty years ago, British Gas was beginning to develop the first high-resolution MFL tools. ROSEN had yet to be founded. We now have a range of ILI tools that can detect and size cracks, locate the position of a buried pipeline, and then make it possible to estimate strains and find dents. This progress has been aided by developments in other, apparently unrelated, areas such as solid-state memory (so we can reliably store data on board the tool) and battery technology (to power the tool).
All these developments notwithstanding, we still have problems in our integrity assessments with basic inputs such as a lack of knowledge of the material properties, the management of records, and the use of empirical assessment methods. It is understandable that, for older pipelines, we do not have the data that modern assessment methods require – an engineer building a pipeline in the 1970s would have needed a very powerful crystal ball to know what tests would be required for assessment methods developed 40 years later. In fact, it is a testament to the engineering and construction prowess of many pipeline systems that so many of them are still successfully operating today. The recent introduction of inline inspection technologies, such as the ROMAT system, which can provide some information on material properties, is a potentially valuable capability for pipelines with limited material data.
However, the industry is not always making the best use of data that could be obtained by, for example, testing material removed in diversions or repairs. Furthermore, data and information has been lost in some cases, or, at best, has become more difficult to locate and use, during company takeovers or restructurings. Cost-cutting is often at the root of these changes, and the value of material data and records may not be apparent to managers and executives driving a reorganization. Contrary to the belief of some, it is not all “on the web.”
I have also seen a similar issue with the loss of engineering experience and expertise in company “downsizings” and “rightsizings” – when did we last see a company upsizing? The effects on expertise and corporate knowledge are, I think, being masked in the short term by experienced engineers being reemployed by consulting companies, which means they are still available to the industry. In the longer term, this is not sustainable, and we need to address it. Initiatives such as ROSEN’s Education Services and the Young Pipeliner groups that started in Australia and have now spread to other continents are a good starting point. The more fundamental problems of corporate culture and an aging workforce are going to be more difficult to solve.
To conclude these thoughts: the pipeline industry has developed its own methods and adapted general standards for assessing and managing integrity over 40 years. These methods will continue to evolve, but the biggest gains will come from obtaining and retaining data for our pipelines.