International Conference on pipeline inspection

new techniques rather than have some 20 papers on minor aspects. One such review came from V.V. Klyuev of the Moscow Research Institute of Introscopy, who discussed the possibilities for NDT of new physical techniques such as NMR, synchotron radiation and the Barkhausen effect. The social programme, as indicated above, was lavish and varied, ending with gastronomic feats at Chateau Pontet Canet. Other functions featured speeches which had their serious side, as when the Chancellor of the Universities of

inspection, and, for in-service inspection, the necessity of not only locating but also of accurately sizing defects to discriminate between innocuous and potentially hazardous defects. These proved to be general themes in the conference.

Aquitaine stressed that France had no natural resources except the quality of its production and its technological ideas. He lamented the lack of interest which the Universities showed in NDT. I can say Amen to both these remarks.

A F, B r o w n

The Conference Proceedings are available from CGI~ 50-52 Boulevard Gallien~ 92133 Issy-lesMoulineaw¢ France

International Conference on Pipeline Inspection Edmonton, Alberta, Canada, 1 3 - 1 6 J u n e 1 9 8 3 Hopefully this will prove to be the first in a series of international conferences on pipeline inspection rather than a unique event since the conference was highly successful. There were nearly 300 participants from 17 countries, representing an unusually wide breadth of expertise in NDT inspection techniques. The conference sessions covered the full gamut from standards and regulations through mill and field inspection to in-service pipeline inspection, each session being introduced by judiciously selected keynote speakers. Because of the wide range of topics, the excellent introductory review papers and the generally high technical level of the contributed papers, the proceedings are likely to become the standard introductory reference book on pipeline inspection techniques and the list of attendees included will doubtless become an historical 'who's who'. The main concern of the conference was gas pipelines. Modern lines are as large as 1.2 m in diameter and are made with high strength steels (480 MPa yield strength) and may be operated with wall stresses of up to 80% of yield strength. They may be hydrostatically tested to as high as 110% of yield strength. Although, to the general public, pipelines may appear as massively strong steel structures they are, in effect,

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pressure vessels, and verv sophisticated inspection techniques are used in the manufacture of pipe joints, the construction of pipelines and the subsequent inspection of all welds by certified inspectors working to accepted standards. Although a number of incidents and failures were shown as illustrations at the conference, the pipeline industry has in fact an exceptionally good safety record thanks to its emphasis on quality, workmanship, integrity and reliability assured by inspection. The inspection methods discussed at the conference included the entire range of NDT techniques, namely dye penetrant and magnetic particle techniques, radiographic and ultrasonic inspection, magnetic flux leakage, eddy current and acoustic emission detectors, supported by diagnostic techniques ranging from conventional metallurgical microscopy to scanning electron microscopy and microprobe analysis. The opening keynote address by E. Shelton of Nova, an Alberta Corporation (Canada), gave an admirable introductory overview of the various inspection techniques used to ensure pipeline integrity and reliability. In response to questioning, Shelton gave suggested priorities as the development and acceptance of alternatives to field radiography, such as ultrasonic techniques for line construction

The introductory session on 'Standards and regulations' served a valuable purpose since a major component of engineering is the application of experienced judgement. Standards and regulations represent our cumulative body of mature engineering experience and accepted sound professional practice. Both the conference speakers and the numerous committee members who labour to distil this important consensus of our experience deserve thanks for their efforts. In turn, the conference itself should have significant impact on the further refinement and acceptance of our regulations and standards to keep pace with continued developments in NDT and inspection practices. The general impression from the session on 'Mill inspection' was very positive and it seemed almost that non-destructive inspection might eventually make hydrostatic testing almost superfluous. P.A. Peters of Mannesmannrohren-Werke (FRG) stressed the achievement of quality by production and the use of computer-controlled NDT to allow feedback at the earliest possible stage and to ensure accurate product identification. A. GilroyScott from Canuck Inspection (Canada) described the possibility of real-time radiography of circumferential welds and showed some dramatic examples of computer enhanced real-time radiography. A. Palynchuk (Western Instruments, Canada) gave some investigative examples of scanning electron micrographs and microprobe analyses, making the point that improved inspection generally gives improved yields through feedback to product control. Two excellent presentations on ultrasonic inspection described the optimization of parameters such as refracted beam angle (T. Okamura of Nippon Steel, Japan) and the use of acoustic focussing lenses (C. Kittmer, Atomic Energy of Canada), and showed how effective ultrasonic inspection can be particularly for planar defects such as lack of sidewall fusion at welds

NDT INTERNATIONAL. OCTOBER 1983

which is difficult to detect radiographicaUy. The Canmet stress diffractometer, which uses a miniature x-ray tube to measure lattice strain, exemplified the present or even future state-of-theart Whilst this session on mill inspection techniques showed that significant advances in radiography, particularly real-time presentation and computer enhancement, were being made, the impression was that there was great interest and effort being devoted to ultrasonic techniques and that we may expect to see them in greater use in the near future. Eddy-current inspection devices for tubes were descn'.bed by G. Schroeder of Institut Dr Forster (FRG), who also showed an impressive computer-controlled automatic test line using, successively, eddy current, leakage flux and ultrasonic detectors. The speakers on 'Field inspection' showed rather more 'incidents' and defect problems, partly because both construction and inspection is naturally more difficult under field conditions but also because a rejection rate of 1%, for example, may be reasonable in mill production where there may even be a demand for lower quality product for less demanding use, whilst the same rejection rate occuring in line construction could cause very serious repair problems. Keynote speaker J.T. Justice (TransCanada Pipelines) and R.I. Coote (Nova) highlighted many of the relative advantages and problems of radiography and ultrasonic inspection, and these were amplified by several subsequent speakers, notably R. Van Agthoven (RTD) who described the Rotoscan high-speed ultrasonic inspection tool for girth welds, which has been field tested in Canada recently, including explosively fabricated girth welds (described by A. Loyer, CIL). M. Macecek from Techno Scientific (Canada) argued the superiority of ultrasonics for determining flaw depths by using time-of-flight measurements. The general consensus might be summarized that whilst radiography can typically detect cavities and porosity better than ultrasonics, ultrasonics is generally superior for planar defects such as cracks. Realtime computer enhanced radiography offers potentially better and more useful interpretation but any

alternative to conventional radiography must also give hard copy permanent reproducible records. Modern ultrasonic techniques are often capable of detecting more small defects but many of these are less likely to cause fracture and the application of acceptance criteria established on the basis of radiographic inspection techniques may be inappropriate and require the repair of needlessly large numbers of non-critical'defects. Fracture mechanics should be used to assess fitness for service. To the observer it would appear that the experiences and comparison tests of radiographic and ultrasonic techniques to determine their different attributes were a major contribution to the conference. Standards, which are designed for safety, will need revision to reflect this growing experience and to ensure that full use is made of the special attributes of ultrasonic inspection techniques whilst recognizing that the most appropriate technique will depend on the particular application. The final day was devoted to inservice inspection, and provoked some lively discussion by magnetic leakage flux and eddy-current proponents. R.W.E. Shannon (British Gas) gave the keynote address which clearly showed the very impressive efforts they are devoting to their on-line inspection and pig development programme. He endorsed leakage flux detectors for metal loss detection, as did subsequent speakers L. Goulet (Tuboscope, USA) and A. Teitsma (TransCanada), but of course the preference really depends on the type of defect likely to occur and eddy-current detectors are excellent for crack detection, as shown by H. Goedecke (Pipetronix, FRG) and Y. Uchida (Nippon Kokan KK., Japan). Special techniques presented included acoustic emission for flaw detection (K. Tanaka, Nippon Steel) and for leak detection (M.N. Bassim, University of Manitoba, Canada), magnetometer monitoring of bending stresses and infra-red spectral signature correlation for airborne remote leak sensing (H.S. Lee, Moniteq, Canada). K.HSgmoen (Det norske Veritas) described their automated underwater ultrasonic inspection system for the detailed examination of interior corrosion on risers and lines. This has been in use in the North Sea since 1981.

NDT INTERNATIONAL. OCTOBER 1983

It would seem that the conditions for on-line inspection and the variety of possible defects giving concern have provoked some very ingenious technological approaches. The session and the conference closed with dramatic pictures of some sensational recent failures and a heartfelt plea for the further application of pipeline techniques. Despite this finale we should remember that the pipeline industry has an enviable safety record and that this has been achieved largely as a result of the development and application of the inspection techniques discussed at this conference. The technical sessions of the conference were extremely successful and the highlights were the presentations and comparisons of ultrasonic and radiographic inspection methods, for mill and field weld inspection, and the reports of on-line inspection pig development programmes, which may still prove to be in their infancy. Despite this, for many people an even more important aspect of the conference was the opportunity to meet with other experts in their own field and in other areas of pipeline inspection. In many cases the faces may have been new but the reputations were already mutually respected so that the opportunity to exchange experiences, ideas and views was eagerly taken, and new professional friendships made. The organization and format of the conference gave excellent opportunities for these personal exchanges, which were probably the most valuable part and are likely to be a real stimulus for future efforts and developments in pipeline inspection. Those who missed the conference are strongly advised to study the proceedings and to attend the next time.

D.L Atherton

The Conference Proceedingscan be obtained through Dr D.K Male Conference Secretary, Canada Centre for Mineral and Energy Technology, 555 Booth Street Ottawa, Ontario KIA OG1, Canada 301