By NFPA's Michele Steinberg
From NFPA's Fire Break blog
A recent article in the Colorado Springs Gazette has some Colorado property owners extremely upset about wildfire mitigation. An insurance spokesperson is quoted as saying, “We recommend cutting all trees within 100 feet of a house,” and then referencing changes in NFPA’s recommendations about wildfire safety and defensible space.
So what does NFPA’s Firewise Communities program actually recommend? And have we changed our recommendations?
For more than 15 years, NFPA’s wildfire safety recommendations have been shaped by fire science research on how homes ignite. Our Firewise Landscaping and Construction Guide, one of our primary information resources, has stated, for some time now, “The primary goal for Firewise landscaping is fuel reduction — limiting the level of flammable vegetation and materials surrounding the home and increasing the moisture content of remaining vegetation. This includes the entire ‘home ignition zone’ which extends up to 200 feet in high hazard areas.” The document then breaks out the home ignition zone concept into intermediary zones, starting with a 30-foot perimeter around the house and attachments. This information is not new…and it hasn’t changed in years and years.
Safety in the "home ignition zone": The concept of the home ignition zone was developed by USDA Forest Service fire scientist Jack Cohen in the late 1990s, following some breakthrough experimental research into how homes ignite due to the effects of radiant heat. The 30-foot number comes from the very minimum distance, on flat ground, that a wood wall can be separated from the radiant heat of large flames without igniting. Because of other factors such as topography, the recommended distances to mitigate for radiant heat exposure actually extend between 100 to 200 feet from the home – on a site-specific basis.