Rigorous Maintenance Program Reduces Wood Pole Failures

Feb 1, 2006 12:00 PM
by Rich Maxwell, Contributing Editor

Wood poles are one of electric utilities' largest and most visible assets. The majority of these poles, which experts estimate to be between 150 and 200 million, were installed during the boom of the 1950s, 1960s and 1970s. With the current demand for better system reliability and higher utilization of equipment, more and more attention is focused on best practices for extending the life of this aging asset.

The problem with wood poles and budgeting money to preserve and refurbish them is the fact that they don't make much noise; and as with most O&M budget items, the “squeaky wheel gets the grease.” This out-of-site-out-of-mind philosophy is bound to catch up with utilities and sometimes does, causing unpredictable outages and added costs when storms hit.

Systematic Maintenance

Tim Carey of Arch Wood Protection Inc. (Smyrna, Georgia) says utilities have several pole maintenance options:

Do nothing and let nature take its course.
Replace the poles based on age alone.
Passively inspect the poles and record their current status, and ultimately replace them when they fail or when there is money in the budget.
Actively inspect, maintain and refurbish poles on a regular, systematic basis. This is the option Carey recommends to maximize the service life of poles.

Snapping Shoals EMC (SSEMC; Covington, Georgia), which is responsible for 61,000 of the country's aging wood pole population, is one utility that is not “waiting until failure.”

SSEMC serves much of southeastern metro Atlanta and one of the fastest-growing regions in the state, primarily in Rockdale, Henry, Newton, southern DeKalb counties and parts of bordering counties. Thirty years ago, the now 70-year-old utility implemented an aggressive pole maintenance program. SSEMC set out to inspect and treat every pole in its system that was more than 10 years old, every 10 years. “It was a hard lump to swallow, but something needed to be done as some of our poles were already showing signs of failure,” recalls Melvin Allen, SSEMC's operations manager.

During the first 10 years, inspectors found 10% of the poles were beyond repair — “rejects.” Just as it does today, the original program included the inspection, treatment, repair and/or replacement of rejected poles. Over the next 10 years, the numbers started to decline. At the end of the second 10-year inspection and treatment cycle, the reject rates had dropped on average to 6%.

The Program

There are two major components to SSEMC's pole maintenance program, below grade and above grade. Poles are not inspected unless they are 10 years old. Any pole less than 10 years old is visually inspected and documented in the inspector's computer file.

The below-grade inspection consists of:

Excavating to 4 inches around the pole and to a depth of 18 inches
Chipping and shaving of loose or decayed wood
Sounding with a hammer
Treatment by mopping with paste or paste and wrapping with a moisture barrier.

In the event a pole has power or a communication riser, or if the pole is encased with asphalt or concrete and can't be excavated, several larger holes are drilled on the above-grade portion of the pole and an internal fumigant is injected into the pole.

The above-grade inspection consists of:

Sounding with a hammer as high as the inspector can reach
Boring with a drill to try to detect any internal decay pockets
Visual inspection of the pole top, looking for large holes, excessive cracks or twist or lean, excessive loose pole shell and any broken or damaged hardware
Inspection and repair of broken ground wires within reach, excavate buried anchors, excessive galvanized anchor eye and installing of guy markers.

Extending Pole Longevity

Throughout the years, the formula and policy has evolved, but central to SSEMC's inspection program is the treatment of all poles due for inspection. Treatment falls into two main categories: pastes and wraps. Where surface preservative cannot be applied, a fumigant is used to penetrate the pole in response to moisture and temperature.

Some poles that are identified as rejected poles can still be reinforced. To determine if the pole is able to meet minimum-strength requirements, the pole maintenance inspector may choose to perform a more in-depth sound and bore. The inspector's interpretation helps determine whether the pole is a candidate for reinforcing using a steel truss.

All of SSEMC's pole maintenance is outsourced. The contract continues to call for the treatment of all poles that are more than 10 years old, every 10 years. Remedial applications vary depending on previous treatments, soil and environmental conditions, as well as the condition of the pole. SSEMC provides historical data and a mapping of each pole on the system being targeted during the current period. The contractor provides all the labor and materials, and executes the appropriate treatment. The inspector keeps careful records and provides them to SSEMC.

Contractor Turnover

One issue that became more and more of a concern for SSEMC was the turnover of contractors every few years as new contracts were awarded. With several maintenance tasks being outsourced, the process of bidding became a full-time job in itself. And each new bid resulted in the possibility of a different set of contractors on the property. With new contractors came a get-acquainted period and some contractors were better than others. Turnover was a problem for other outsourced services such as vegetation management as well.

In 2001, SSEMC had had enough. Too many new faces on the right of way, and the cost of bidding and overseeing several contractors caused SSEMC management to decide to consolidate its bidding process. At first it was a challenge to find contractors who were qualified to do the diverse scope of work included in the contract. However, after several qualified bidders were found, SSEMC announced the broader RFQ.

The new contract, which was expanded to three years, has been successful in more ways than one. McCulloch Utility Services Inc. of South Carolina was awarded the contract for not only pole maintenance but also other rights-of-way services such as herbicide vegetation control and URD transformer pad inspection and maintenance. While on the rights of way, crews look for defective insulators and lightning arrestors, mounting hardware, and other components that have been identified as causes of outages or other system problems. Unit prices are established and McCulloch crews perform repairs as they are identified.

McCulloch crews also inspect service wire, rights-of-way issues, low clearances, and loose or missing transformer hanger bolts, and gather information about foreign attachments (phone, CATV or both) and attachments that have been removed from existing stub poles.

To balance out the seasonal work, McCulloch crews work primarily on the vegetation management part of the contract during the summer. Spring and fall are dedicated to pole treatment as well as pad inspection and maintenance.

“Pay Now” Pays Off

Has the vigorous pole maintenance program paid off? At the completion of the third 10-year cycle, SSEMC pole rejects have dropped to less than 1%. The recent consolidation of transformer pad maintenance and herbicide vegetation control into one contract with the pole maintenance contract also has added to the savings. And single-sourcing has further reduced overhead costs. In a time when every budget dollar counts, SSEMC is a good example of finding ways to do it right the first time.

POLE INSPECTION REPORT

The contractor performs a rigorous inspection based on available standards from ANSI and others. All pertinent information about each designated pole is recorded on a report approved by Snapping Shoals EMC.

According to Snapping Shoals, the report includes, but is not limited to, the following when applicable: