The goal of these tests, says Dustin Troutman, director of market and product development for Creative Pultrusions Inc., has been to prove the survivability of FRP materials compared to traditional materials and construction, in terms of crown fires and brush fires. “Crown fires are when the fire travels across the top of the trees and then the brush fires are when it’s on the bottom,” he says.
Fecht elaborates that utility poles only have to withstand about two minutes of exposure to intense heat to pass this test. A brush fire, he adds, typically resides at a single location for about 30 seconds and for a crown fire in a heavily coniferous forest only 90 seconds.
In 2011, RS Technologies began to undertake its own series of utility pole fire tests under the direction of a fire expert from the University of Alberta, so Fecht was familiar with the process. The initial full-scale test was designed to match the total heat flux (the amount of energy exposure) and flame conditions present in a two-minute fire, which is representative of a severe forest fire. “In following studies conducted with input and participation from California utilities, the testing time was increased to three minutes to represent an extreme fire event,” Fecht says.
Others have made formula adjustments to meet this growing demand. “We went through a lot of different iterations to finally get to the solution that we tested,” Haddad says. Without getting into proprietary detail, he explains that Valmont has added an intumescent material into its pole. “When the intumescent gets hit with the temperature of a fire, it will expand and protect the structural glass,” Haddad says.
The test results were a win for FRP overall. But composites manufacturers already knew their products would prove up to the test, and several are launching new facilities to support the explosion in demand for composite utilities products. For example, over the past five years, Geotek has made significant investments in its capacity and buildings, nearly doubling its manufacturing footprint to keep up with the demand.
Additionally, Valmont is opening its new crossarm and pole manufacturing facility in the second quarter of 2020. The plant will switch from fabricating its fire distribution poles with a centrifugal cast process to a filament wound process because the latter allows for increased throughput.
Understanding Deflection Limits
Haddad says this apples-to-apples style fire testing was eye-opening for utilities and pole fabricators alike. “We learned in this test that the requirements from the utility customers around deflection are actually more important than strength,” he says. “What they’re finding in wildfire areas is the fire either is accelerated because of the wind or it spreads a lot faster because of the high wind. They don’t want the pole really moving at those higher wind speeds.”