Utility pole performance: effect of service life on surface hardness and preservative retention of CCA-treated pine poles
Ruddick, J.N.R.; Jonsson, E.B.; Nilsson, E.M.A.
Forest Products Journal 41(6): 21-27
Red pine and jack pine poles treated with chromated copper arsenate (CCA) and in service for up to 43 years did not show any change in surface hardness from that found in newly installed poles. Enhancement of the surface hardness of poles caused by CCA treatment will remain for the duration of their service life. Leaching of preservative from the aboveground portion of the poles was very small, approximately 0.5 kg/m3 for copper and 2 kg/m3 for arsenic in jack pine and not detectable in red pine. The composition and retention of CCA-type A in treated jack pine poles that had been in service 30 to 40 years was compared with literature data for conventional leached material. The results revealed no unusual losses, even though the region of Ontario would be affected by acid rain. Surface hardness of utility poles is an important parameter that affects the acceptability of the pole as being safe to climb during line maintenance. The current investigation was designed to evaluate how the surface hardness of preservative-treated utility poles is affected by the type of preservative and the age of the poles. CCA-treated red pine and jack pine poles that had been in place for up to 43 years were located in Bell Canada's system in Ontario, and screened for use in the project. A survey of poles in three locations was made, and data were collected on surface hardness using a 6-Joule Pilodyn. Other information recorded included the wood species, information from the brand, and the moisture content (using a resistance-type moisture meter). Core samples were removed from each pole to determine wood density and preservative retention.