How to Extend Wood Pole Life

I read an interesting article in TD World about a Finnish electric utility that deployed storm hardening tactics designed to extend wood pole life.  Unique methods to harden poles would make for an interesting case study of sorts for the EPP blog!

Tactics to Extend Wood Pole Life

The Finnish utility – Rovakaira Networks Construction Ltd. – is particularly focused on pole degradation from ground rot.  Generally, the area on a pole that is underground or above the ground is not as susceptible to decay as the part of the pole that comes into direct contact with the decaying organisms present in the soil.  Thus, this ground line section is the focus of the hardening techniques. 

The utility annually inspects all of its poles that are more than 35 years old, but in recent years it has sought to be more proactive when it comes to hardening the poles.  This is especially important given that the utility’s service area is located in an artic-like climate, and these harsh conditions contribute to pole degradation. 

Aside from the annual inspections, the main hardening tactic that Rovakaira has deployed involves the installation of ground level barrier sleeves to protect the wood from the ground.  This is the primary method the utility is depending on to extend wood pole life.  In fact, the utility claims that these sleeves can double pole life by blocking organisms, oxygen, nitrogen and moisture (moisture presence must be less than 25% to prevent moisture-related decay). 

The sleeves themselves consist of a heat-shrink thermoplastic ground line sleeve lined with a heat-applied thermoplastic bituminous sealant.  When heated, the liner in the sleeve essentially gets shrink-wrapped around the bottom section of the pole to seal it from the elements. 

Although the sleeves increase pole cost by 20%, the resultant doubling of the poles’ useful life more than offsets this additional upfront cost.  To date, the utility has installed more than 4,000 sleeves to extend wood pole life.