Protecting Wood Utility Poles From Wildfire

Protecting wood utility poles from wildfire

12 March 2013

USA — According to the National Oceanic and Atmospheric Association (NOAA), 2012 was the warmest year on record in the continental United States. With overall temperatures climbing and snow levels nearing record lows, 2013 is shaping up to be a hot, dry year. In fact, according to the National Drought Mitigation Center, at least 10 states are already experiencing exceptional drought conditions. As drought conditions worsen and temperatures rise, the likelihood of wildfires increases. Last year, 67,000 wildfires burned more than 9.2 million acres across the U.S., according to the National Interagency Fire Center (NIFC).

It’s imperative that electric utilities and other pole owners take action to reduce their risk of fire damage to poles and the subsequent outages caused by pole failures. Good right-of-way practices, including regular trimming, clearing and herbicide application go a long way in helping prevent damage. Many utilities choose to take those practices a step further by grubbing poles, which includes removing all brush around the pole’s base. Removal of the fuel source at the pole’s base reduces the likelihood the pole will catch fire; it provides no protection for the pole, however, if it does catch fire.

Effective Fire Protection

There are many products that protect wood poles from fire damage. These products can generally be classified into one of three categories: coatings, wraps or barriers. All three are designed to protect poles from fire damage, but they vary in application method, cost and function. As pole owners prepare to evaluate available products, it’s important to ensure the product of choice does not inhibit other vital maintenance practices. Products that prevent future inspection and remedial treatment of the pole, for example, can be counter-productive. While they may protect the pole from fire, they prevent proper maintenance of the pole, which effectually shortens the pole’s service life. A fire retardant should possess the following characteristics to be considered effective:

Breathable: An effective product should allow the pole to breath. Products that do not allow the pole to breathe will encapsulate moisture, promoting decay and subsequently decreasing the service life and safety of the pole.
Gaffable: The product should not render the pole unclimbable. Products that render the pole unclimbable can cause problems for linemen who need to ascend the pole for any number of reasons. If the product is not climbable, extra expense will be incurred to install removable steps, and pole owners will need to work through additional safety procedures to perform above ground maintenance.
Long-lasting: The potential of the product to withstand multiple burns or to be easily repaired in the field makes it more cost-effective for pole owners. Products that are only effective for one burn can be a cost-effective strategy when fire is imminent, but they will need to be replaced following an event or the pole will be vulnerable to the next fire. And, if the product cannot be field-repaired because of damage or wear, the pole will again be vulnerable to fire damage. To provide long-term protection, coatings need to have high adhesion qualities. Poles that have been heavily treated with an initial treatment of creosote or pentachlorophenol can sometimes bleed excess preservative, preventing long-term adhesion. An effective application should be properly designed for the type of structure on which it will be used.

One thousand one hundred poles coated with a latex-based fire retardant withstood trial by fire in Arizona.

Safe to Apply: Products that contain solvents, plasticizers or known carcinogens can pose a risk to the applicator. Proper review of the product’s material safety data sheet (MSDS) prior to purchase will provide education about the dermal, eye and respiratory protection required to safely apply the product. Pole owners should also be aware of the potential environmental impact a product can have, such as volatile organic compound (VOC) levels and any associated over-spray issues.
Easy to Install: Products that are difficult to install or have a complex installation process usually are ineffective from a cost-benefit perspective. Products that require cumbersome equipment, two-part sprayers, respirators, specialized training or have a short pot life-the application life of the product once mixed-can make field application difficult and acceptance by utility line crews improbable. While it’s ideal to apply fire protection as part of routine maintenance, emergency situations often arise and require products that can be applied or installed quickly, leaving little time for specialized training. Wraps and barriers are traditionally most effective in emergency situations because they do not require cure time or a waiting period before they are viable.

Trial by Fire: Successful Fire Mitigation

Winds, drought and high temperatures make the southwest U.S. susceptible to wildfires during the summer months. In an effort to prevent pole failures and subsequent power loss because of fire damage, an Arizona electric cooperative elected to apply a latex-based, fire protective coating to a number of its wood poles. Just as crews began coating poles, a wildfire broke out in the Coronado National Forest. Rather than coating the poles originally selected, the cooperative chose to change course and coat the poles in the path of the fire.

Crews selected a starting point at a safe distance in front of the fire and began grubbing and coating poles. Crews applied the protective product to 1,100 poles. The fire blazed for more than a week, scorching 27,000 acres. In its 42-square miles path, the fire claimed 60 homes, 14 buildings, four businesses and 220 uncoated poles-but failed to claim a single one of the 1,100 poles with the fire protective coating.

Conclusion

The risks associated with pole ownership are numerous, and fires will continue to threaten service interruptions and cause physical damage to outside facilities. With a little research, pole owners will find there are a number of available fire retardant products that can be used as part of a cost-effective strategy to mitigate damage caused by fires.

24. November 2017/by GFMCadmin