In a study conducted in collaboration with the University of North Carolina at Charlotte, IBHS evaluated the long‐term effectiveness of two fire‐retardant gels when applied to a wood‐based substrate. Gels are a type of coating meant to provide protection for a short period, a few hours, and are typically applied manually just prior to the arrival of a wildfire. The gels act as a protective heat sink on the material they are applied to, reducing the impact of the thermal exposure and therefore potential to ignite.
The operating principle of these fire‐retardant gels is based on hydration. Therefore, their effectiveness is reduced as the gels lose moisture. Fully hydrated, both gels tested can increase the time‐to‐ignition from 15 seconds to over 7 minutes. However, in a realistic wildland fire scenario of 15 percent relative humidity and a wind speed of 10 m/s (approximately 22 mph) both gels reach 50 percent dehydration in less than 1.5 hours and full dehydration in 7 hours.