Utility Poles that Can Beat the Warmth

Wildfires burned more than 2.5 million acres of land in California in 2021 and, with high heat and record drought in the forecast, the state could be facing similar losses in 2022. To reduce fire risk and improve the resiliency of electrical grids, California’s utility companies are beefing up their mitigation efforts, trimming trees, burying electrical lines and, in some cases, replacing wood electrical poles with fire-retardant FRP poles.

Composites manufacturing companies have been selling FRP utility poles in various parts of the US for almost a quarter century, and now utilities in fire-prone areas have an even greater incentive to use them. Creative Pultrusions, part of the Creative Composites Group (CCG), has developed an FRP pole with a highly fire-retardant composite sleeve that protects the base pole and improves its ability to withstand the fierce wildfire temperatures.

“Our poles have always been fire-resistant. They meet the UL 94 VO classification, which means they will self-extinguish on a vertical burn,” explains Dustin Troutman, CCG’s director of marketing and product development.

Over the years, the company has continued to research combinations of thermoset resins and fire-resistant additives to improve composite poles’ fire resistance. In early 2020, the company introduced its new line of FireStrong™ poles, which feature the FRP sleeve. The FireStrong composite material has been engineered to withstand three minutes of temperatures at 2100 degrees Fahrenheit – the conditions that can be created by the brush, grass and chaparral shrub fires that are typical in California and other Western states.

The composite sleeve is unique because it not only insulates and cools the pole, but also protects it. The heat from a fire triggers an endothermic chemical reaction in the sleeve which produces water that absorbs thermal energy and insulates the pole. The outer sleeve protects the FireStrong pole from reaching temperatures that would cause permanent strength loss.

At the request of a utility company customer, CCG added a temperature measurement device into the pole to get an accurate read on what happens to it during a fire.

“The utility company wanted a way to inspect the poles post-fire to determine what kind of strength retention they had,” says Troutman. “So, we incorporated a permanent measuring device that continuously monitors the temperature of the surface of the FRP pole and records the maximum temperature it reaches. Based on that temperature exposure, the utility can determine whether to replace the pole or continue to use it because they know the strength is fine.” A utility can check the recorder, positioned on the pole approximately two feet above the ground line, by removing an access cover.

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