Transmission poles with sub-standard retentions protected by Field Liners outperform standard poles in service
M R Behr, G D Shelver, A A W Baecker
Eucalyptus cloeziana 12m transmission poles were treated with sub-standard creosote retentions of 80kg/m3 and Field Liners were fitted to the poles before they were placed in service at Umbumbulu, Kwazulu Natal. Poles treated with standard creosote retentions of 130kg/m3 but without Field Liners were also placed in service in the same area. Core samples were taken from both groups of poles after 12 month's service and these were analysed for creosote content. It was found that the creosote retentions in the outer 10 mm of the sub-standard poles fitted with Field Liners had increased to mean values of 212.76kg/m3 and 219.24kg/m3 at depths of 100mm and 500mm respectively below the groundline. In contrast, the creosote contents of the standard poles without Field Liners had decreased to mean values of 49.20 kg/m3 and 52.64 kg/m3 at depths of 100mm and 500mm respectively below the groundline. It was also seen that the creosote had migrated under gravity from the tops to the groundlines of the poles. The difference in creosote retentions below the groundlines arose because the mobile creosote migrated out of the poles without Field Liners by leaching into the surrounding soil, whereas such mobility was physically arrested when creosote was confined to the wood in the subsoil sections of poles fitted with Field Liners.
Keywords: TRANSMISSION POLES; CREOSOTE MIGRATION; FIELD LINERS
Conference: 97-05-25/30 Whistler, British Columbia, Canada