Wildfire Ember Highlights
http://www.xactware.com — Xactware is one of the founders of the Institute for Business & Home Safety’s new state-of-the-art, multi-peril research center in Chester Country, N.C. At this facility, researchers simulate disaster conditions — including heavy winds, droplet-sized rain, realistic hailstones, and firebrand/ember generation — to test building materials and structure components. They record the tests on high-speed, high-definition cameras to analyze the results.
In this experiment, researchers recreated an ember storm to study how a typical home holds up in wildfire conditions. The U.S. Forest Service and the International Association of Fire Chiefs have verified that the ember storm simulation is a realistic demonstration of a typical wildfire event.
For more information about IBHS, check out http://www.disastersafety.org.
A full transcript of the video is provided below.
Insurance Institute for Business & Home Safety
Ember Storm Demo
Wildfire test structure in the IBHS Research Center’s large lab. The structure is designed to demonstrate vulnerabilities of a typical home.
Researchers load a combustible mix of pine bark mulch and wood dowels into the burn chamber of each ember generator.
Plants and landscaping material, such as mulch, are placed around the test house, as they would be in the real world, to demonstrate ignition potential.
The ember storm is created using five ember generators. Each generator has three stacks to deliver embers into the wind field. Embers are pushed through the stacks using large fans attached to the burn chambers.
The Research Center’s large 105-fan array created winds of 10 to 20 miles per hour, which produced the ember shower attacking the house.
Vegetative debris (pine straw) ignites in gutters as a result of the ember attack. The vinyl gutter melts and falls, the aluminum gutter stays intact, and the dry grassy vegetation becomes fully involved in flames.
The asphalt shingle roof shown here is a Class A rated roof, which is the best type of roof in a wildfire prone area. Burning pine straw in the valley of the roof will not penetrate the roof allowing flames or sparks into the attic; this prevents internal ignition.
The untreated wood shake roof is vulnerable to spot fires. As embers burn through the roof, they can cause internal ignition, leading to the destruction of the home.
Dry vegetation has ignited in the indented corner; this fire then ignites the highly flammable wood lap siding. A vortex of fire is created in the corner by turbulent winds—an effect which often accompanies wildfire.
Two other types of wall siding are demonstrated here: the left side is fiber cement siding (this is only slightly damaged, despite significant exposure to fire, and the right side is vinyl siding, which is melted away.
This attic gable end vent has a 1/8-inch mesh screen, yet embers still penetrate and float into the attic, where they likely would catch on combustible material.
The fiberglass window screen allows some ember penetration. As the screen melts on flame contact, an opening is created which allows embers and flames to penetrate the home and catch on combustible material, such as curtains or carpeting.
The ember storm created in the IBHS Research Center has been validated by wildfire experts from the U.S. Forest Service and the International Association of Fire Chiefs as a realistic demonstration of a typical wildfire event.