Fire Safe Marin

Depending on the type of glass, a window that is exposed to flames may break after only 1 to 3 minutes of exposure to intense heat or flames and allow flames and embers inside. Testing has shown that single-pane windows are highly vulnerable to breaking when exposed to wildfire conditions. Glass in windows breaks because of extreme temperature differences, which develop between the exposed glass and the glass protected by the window framing material, when exposed to the heat from a wildfire (or the heat from your neighbor's burning home).

Homes ignite in one of three ways: embers/firebrands, radiant heat exposure, or direct flame contact. An example of an ember ignition is when wind-blown embers accumulate on combustible materials such as a wood shake roof. An untreated wood shake or shingle roof covering is the greatest threat to a home. Roof covering fire ratings are Class A, B, C, or unrated; with Class A providing the best performance. Common Class A roof coverings include asphalt fiberglass composition shingles, concrete, and flat/barrel-shaped tiles.

Watch FIRESafe MARIN's new video, narrated by Dr. Stephen Quarles, on protecting attached decks from wildfires. Summertime often means cookouts on the deck and gatherings with friends. But did you know that choosing the right kind of materials to build your deck and keeping it clear of combustible materials (both on the top and underneath) are critical steps in reducing the risk of a wildfire damaging your home? Watch this video to see how different types of decking materials and combustible materials on top of the deck performed in wildfire testing.

Embers are the most important cause of home ignition. Recent research indicates that two out of every three homes destroyed during the 2007 Witch Creek fire in San Diego County were ignited either directly or indirectly by wind-dispersed, wildfire-generated, burning or glowing embers (Maranghides and Mell 2009) and not from the actual flames of the fire. These embers are capable of igniting and burning your home in several ways. In order to have a wildfire-safe home, two equally important factors must be implemented: 1) the wise selection of building materials and designs that will help the home resist the wildfire; and 2) the home must have adequate defensible space, based on the wise selection, placement, and maintenance of near-home vegetation.

A wildfire-safe home must be resistant to ignition from wind-blown embers. Even if the flames never reach your home, it must be able to withstand exposure to millions of tiny embers that can be carried a mile or more in front of a wildfire. To provide maximum wildfire protection for your home, a combination of near-home vegetation management, appropriate building materials, and related design features must be used. These points are summarized the excellent University of California publication, "Home Survival in Wildfire-Prone Areas: Building Materials and Design Considerations."