Protecting Wood Utility Poles from Wildfire

Over the last 20 years, the average number of acres burned by wildfires has grown from 2 million acres per year to 8 million acres per year (Wildfires Today).  As wildfires become more destructive, 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.  It goes without saying that 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 base of a pole.  Removal of the fuel source at the base of the pole reduces the likelihood that the pole will catch fire; however, it provides no protection for the pole in the event that it does catch fire.

Effective Fire Protection
There are a number of products designed to protect wood poles from damage caused by fire.  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.  For example, products that prevent future inspection and remedial treatment of the pole 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 in order to be considered truly 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 un-climbable.  Products that render the pole un-climbable 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 much 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.  Likewise, if the product cannot be field-repaired in the event of damage or wear, the pole will again be vulnerable to fire damage.  To provide long-term protection, coatings need to have excellent 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 it will be used on.

Safe to Apply - Products that contain solvents, plasticizers, or known carcinogens can pose a risk to the applicator.  Proper review of the product's 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 VOC levels and any associated over-spray issues.

Easy to Install - Products that are difficult to install or have a complex installation process typically turn out to be very 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.

Comparison of Fire Protection Products for Wood Poles

COATINGS

WRAPS

BARRIERS

Favorable Characteristics

Latex Coating

Intumescent Coating

Epoxy Coating

Latex Wrap

Copper-Poly Wrap

Metal Shield

Breathable

Gaffable

Withstands multiple burns

Field repairable

Quick & easy to install*

       No specialized training req.

       No 2-part sprayer required

       No respirator or mask req.

Suitable for emergencies**

*Easy setup, quick preparation and application time, and product easily transported from pole to pole.
**No cure time or waiting period required before product is viable.

Trial by Fire: Successful Fire Mitigation
Winds, drought, and high temperatures make the southwest United States extremely susceptible to wildfires during the summer months.  In an effort to prevent pole failures and subsequent power loss due to 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, 4 businesses, and 220 un-coated poles but failed to claim a single one of the 1,100 poles with the fire protective coating.  Click here to learn more about latex-based 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 that there are a number of fire retardant products available that can be used as part of a cost-effective strategy to mitigate damage caused by fires.