Transmission Poles by Croft
Proven strength and known performance has made CroftPoles™ a safe option with utility companies internationally. Tests carried out by the New Zealand Forest Research Institute on the durability of preservative treated utility poles confirm our own research but carry more weight due to their unbiased nature.Although a number of different species and treatment types were used in New Zealand, the most pertinent of those surveyed were the C.C.A. treated pine and the Creosote treated douglas fir. Of the 287 C.C.A treated pine poles included in the survey (installed from 1958 to 1974) only two had failed. Of the 371 Creosote treated poles in use from 1951 to 1962, 108 had failed through decay with another 5 showing significant decay.
Results have shown that poles treated appropriately will have expected average service lives in excess of 50 years. Durability monitoring to date has shown that the best performance has been achieved with pine poles treated with C.C.A. or pentachlorophenol oil. However, there are economic and environmental disadvantages associated with the latter. The best option for wooden softwood poles are therefore pines treated with C.C.A.
It is perhaps no coincidence that C.C.A. treatment of pine is the only treatment of utility poles undertaken in New Zealand today and it is unlikely to change in the foreseeable future.