Utility poles are an expensive item when you own millions of them. The expected, or design lifespan of an 11,0m – 160/180mm pole should be in the region of 25 years if properly treated. That means the outer 25 -75mm of the pole has sufficiently dropped in moisture content to allow pressure-treated preservative into the wood structure. The science states that you cannot compress a liquid, therefore if the moisture is still too high, you will not succeed in penetrating the circumference with an uninterrupted envelope of preservative, and to a specified depth. This leads to premature failure of the unit due to decay or insect damage, eventually rendering the pole unfit for service. During a well-structured inspection service routine, these issues can be identified. Applying a diffusible wood preservative can assist the factory primary treatment to maintain the integrity of the pole, should the inspection not reveal critical faults.