Since our discussions in open session of Working Group II at Peebles, a number of workers in Australia have collaborated in comparing the efficacy of X-ray, sonic testing, or resistivity measurements for detecting internal defects in poles. The purpose of this circular is to draw to your attention some of the results, in summary form. No attempt has been made to compare techniques. More detailed accounts may be published at some future time by the individual workers concerned. Forty condemned eucalyptus telegraph poles were assessed by traditional inspection methods (hammer sounding and boring), X-ray scanning, Resotest Pole-Check sonic tester, and Shigometer resistivity technique. The work was planned and carried out by Messrs Johnstone and Gardner (Forest Commission of N.S.W., Wood Technology and Forest Research Division), Messrs McKitterick and Seaman (Telecom Australia) and Dr. Thornton of this Division who collaborated in examining 22 of the poles with the Shigometer. The results are summarised in the Table and some of the more interesting poles are shown in the figures. Unfortunately, details of the X ray scanning are not available for dissemination at this stage and therefore they have been omitted from the Table. For interpretation of the data obtained with the Shigometer, Dr. Thornton has combined the instrument's readings with application of it's probe to detect sound wood, i.e. less than 40 mm of sound wood remaining together with readings which suggest the presence of internal defects results in the pole being condemned. Note also in the case of the Resotest Pole-Check a suspect reading means that the poles should be re-assessed by traditional boring and sampling. Dr. Thornton and I wish to stress that we believe the instruments used in this study are valuable as aids to the linesman/pole inspector; we consider that no system should be put forward as the sole indicator of whether a pole has failed or not.

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