Wildland-Urban Fire Research Homepage
Wildland-urban ignition research indicates that a home's characteristics and the area immediately surrounding a home within 100 to 200 feet principally determine a home's ignition potential during a severe wildland fire. I refer to this area that includes a home and its immediate surroundings as the home ignition zone.
The link address is: http://www.firelab.org/fbp/fbresearch/wui/home.htm