Researching ways to extend utility pole service life
Wood poles have been used to support electric transmission and telecommunication lines since the late 1800's. These poles have provided long reliable service under a variety of environmental conditions. Originally, utilities used naturally durable wood species such as American chestnut and cedar. The loss of chestnut to disease and the limited supply of cedar wood forced many utilities to substitute less durable species such as pine or Douglas-fir. These species required supplemental preservative application to provide long-term service life and encouraged the development of a wood-treatment industry, specifications for proper preservative use, and later, inspection programs to ensure poles retained adequate strength to support their design loads.
For many years, detection and control of decay in utility poles posed a major challenge for utilities, but the development of fumigants in the late 1960's opened many new avenues to prolong the useful life of wood. Oregon State University (OSU) had long been active in utility pole issues, but the development of fumigants led to a increasing emphasis on improving the performance of wood poles and finally, in 1980 to the establishment of Utility Pole Research Cooperative (Co-op). Originally established to develop new fumigants and assess the effects of air seasoning on pole properties, the Co-op has changed its focus over the past 37 years to address a variety of wood-related issues that improve the performance of wood, making utilities more competitive.
Current Co-op work is divided into a series of overall objectives that include:
- Identifying and evaluating methods for controlling internal decay in poles
- Identifying methods for field treatment of surface damage to treated wood
- Developing improved specifications for wood poles
- Evaluating the effectiveness of external groundline treatments
- Developing information on performance of new preservatives for wood poles
Each year, OSU prepares an annual report detailing the activities and research progress of the Co-op, presents these data to the advisory committee at an annual meeting, and receives feedback on the research direction. The goal is to allow members to have maximum project input.
Co-op research is divided into a number of objectives, which have changed throughout the years as they have been completed or new problems arise. The current objectives for the 2017-2021 five-year cycle are:
Develop improved treatments for internal decay in utility poles
Develop methods for preventing decay in field drilled bolt holes
Evaluate external barriers, preservative pastes and bandages
Improve specifications of wood poles
Evaluate capability of non-destructive pole inspection devices
Performance of topical fire retardants under field conditions
Assess potential for preservative migration from poles in storage and in service
Identify methods for effectively recycling post-service utility poles and crossarms
Develop readily accessible information on various aspects of wood pole management
Develop information on above ground issues in aging utility structures and identify solutions
Assess the benefits of maintenance decisions over multiple inspection cycles
Assess the effects of solvent additives on preservative performance
UPRC research led to the development of pole fumigants and we continue to test new and existing formulations. Recent work has led to specifications for throughboring poles and we continue to conduct novel studies to enhance wood durability.
The most recent two Co-op Annual Reports are restricted to members only, but previous reports as well as journal publications are available for download or ordering.