Small-Scale Testing of Passive Fire Protection Systems for Structures on the Wildland-Urban Interface

The average intensity and frequency of wildland fires have been on the rise over the years due to climate change. This, in combination with recent expansion and growth of rural areas, has led to an increased risk of wildfire damage for structures in the wildland-urban interface (WUI). This paper proposes a permanent passive fire protection system that is built into the structure. A flame-resistant material would be attached to the sheathing underneath the roofing and siding material. This system would allow the easily replaceable exterior components of the structure to burn while leaving the interior of the structure protected. Small-scale models were tested to compare the performance of five different flame-resistant materials, including structural wrap, ceramic fiber, Pyrogel, Kaowool, and intumescent paint. Post-burn charring evaluations and temperature analyses were conducted to determine which types of material and siding were most effective at protecting the small-scale models. Pyrogel outperformed the other materials but is by far the most expensive. The ceramic fiber material was the second most effective flame-resistant material overall and might have the potential to be as effective as Pyrogel if used in conjunction with the other materials tested, though further testing of material combinations would be needed to validate this supposition. The results of this project clearly demonstrated the feasibility of using a permanent passive fire protection system to protect structures in the WUI.