Power and telecom poles used to support overhead power and telephone lines were from the outset made from wood. Wood is generally readily available all over the world, lightweight, strong, non-conducting and when preservative treated durable. More recent changes in legislation affecting wood preservatives and shorter lifespan in tropical locations have led many utilities to look at potentiality longer lasting alternative materials such as reinforced concrete, galvanised steel and composites. But do these materials really give a longer lifespan than wooden poles? First a brief look at the pros and cons of each material Concrete For Against Uniform appearance Very heavy difficult to handle , Strong Higher cost than wooden pole, Rot Proof Can be difficult to fix to Termite Proof Reinforcing corrodes resulting in failure Fire resistance Uses large quantities of energy D angerous at roadside when struck by vehicles Galvanised Steel For Against Uniform appearance Conducts electricity Strong Higher cost than wooden pole, Rot Proof Can be difficult to fix to Termite Proof C orrosion causes failure Fire resistance Generally good roadside Composites, Fibre Glass etc For Against Uniform appearance Poor fire resistance Strong Much higher cost than wooden pole, Rot Proof L arge quantities of energy in production Termite Proof osmosis can reduce strength over time Low weight Insulator Wood For Against Readily available Prone to decay when poorly protected Strong Prone to termite attack when poorly protected Low weight Fire resistance limitations when not protected Insulator Low unit cost Known and proven Environmentally friendly, grows on trees G ood failure mode when struck by vehicles Inspection From the above we can see that all materials have different failure modes that mean regular inspection is required after the initial 10 to 15 years if pole failure is to be avoided with timely replacement. Lifetime Cost For any utility lifetime cost is the key deciding factor when looking at alternative pole materials and this cost is generally calculated based on initial cost and projected lifespan for a given material. The challenge here is in knowing the lifespan for poles made from each of the different materials and this is where things become more challenging with a lack of published data offset by manufacturers claims for lifespan. A study undertaken in Australia gives data on expected lifespan based on real life experience over many years. The graph below shows the results. Source; Pole Service Life – An Analysis of Country Energy Data (Australia) Nathan Spencer Koppers Wood Products Pty. Ltd., Sydney, Australia firstname.lastname@example.org Leith Elder Country Energy, Goulburn, Australia email@example.com In concrete poles the typical failure mode is corrosion of the reinforcing bars, for steel poles ground line corrosion is common over time and for wood ground line decay and termite attack are the common failure modes. The results clearly show that standard treated wooden poles whilst generally outperforming concrete lag behind steel poles. But when taking account of initial cost it is clear that wood is still a good all round choice, It is readily available, low in cost, lightweight, easy to handle and work and available in a wide range of sizes to suit pretty much all needs. In the last 20 years there has been a growing adoption and use of technology to overcome woods greatest weakness which is decay and termite attack at the vulnerable ground line section of the pole. It is at this part of the pole that conditions are perfect for wood decay and termite attack, the section of pole deeper in the ground and above ground often having a service life 3 or 4 times longer than the ground line section. To prevent degradation and failure at this point composite heat applied sleeve products such as Polesaver offer an excellent solution, they isolate the wood from all the factors necessary for ground rot and termite attack including moisture thus dramatically extending the pole life at low unit cost. With a typical expected pole service life similar to that of steel poles the use of ground line sleeves have given wood another lease of life as the material of choice for utility poles.