Architects can help reduce fire risk
In this story from AIA partner James Hardie, find out how architects can use their products to enhance fire safety
California architect Annie Chu, FAIA, begins each new project in the same way. Chu uses an online system to investigate the home site’s fire risk and the measures required to mitigate it.
Prolonged drought and steep topography surrounding Los Angeles, where Chu works as a principal of Chu + Gooding Architects, make the area particularly vulnerable to wildfire. But it’s not just Californians who face risks.
In 2016 wildfires destroyed 3,192 homes across the country, according to data from the National Interagency Fire Center. Tennessee, site of the Gatlinburg fires, was the hardest-hit state, with 2,121 homes lost.
And this number is probably low because of gaps in the way federal and state agencies and local fire departments collect data, explains Michele Steinberg, manager of the Wildfire Division of the National Fire Protection Association, a nonprofit organization that creates codes and standards used by local governments and firefighters.
“The trend over the last 25 years is for the severity of fires to increase,” Steinberg says. “We aren’t necessarily seeing more fires every year, but we are seeing bigger and bigger fires.”
With erratic global weather patterns, “There is a risk everywhere across the United States,” Steinberg says.
While many people envision the destructive power of a raging fire, the real threat comes from embers that float through the air before and after fires—as many as six embers per square foot, says Bill Stewart, co-director of the Center for Forestry and Center for Fire Research and Outreach at the University of California, Berkeley.
“[The site’s fire risk] is the first thing we look at. Everything else comes after that.”- Annie Chu, FAIA
The home of one of Chu’s clients was under construction in 2007 when fire swept through the area where it was being built. Fortunately, the home was unharmed, but this close call is something she still remembers.
“[The site’s fire risk] is the first thing we look at,” she says. “Everything else comes after that.”
While no home is fireproof, architects can take steps to increase the likelihood that homes they design will survive.
Roofing materials are rated by Underwriters Laboratories as class A, B, C, or non-rated, with class A providing the most fire resistance.
Choose tiles and other fire-rated building materials that interlock tightly and are installed over a fire-resistant base. Slate, clay, and concrete roof tiles, and steel and copper shingles, typically perform well.
Steeply pitched roofs are better than flat ones, as embers tend to roll off before they burn through.
Exterior materials and siding
Noncombustible material such as fiber cement siding, stucco, brick, adobe, and concrete block provide protection. Embers can become trapped in the underside of overhangs, so these areas need fire protection as well.
Vents present another area of exposure and should be covered with fine mesh. Bathroom, dryer, and kitchen vents should have automatic back-draft dampers.
Generally considered the weakest point in home’s fire-resistant armor, windows can shatter due to high temperatures, allowing fire to quickly penetrate the interior. Double-pane windows perform better than single-pane versions, Stewart says. Roll-down metal fire doors are an option in high-risk areas.
Layout and landscaping
Driveways, walkways, and landscaping can put space between a home and fire-prone wild areas or outbuildings. Plants with high moisture content in their leaves are less likely to burn, as are those that don’t accumulate much seasonal debris. On the flip side: Junipers, pines, spruces, and firs have resins that can fuel fire.
And don’t forget simple housekeeping steps. Inform homeowners that they need to clean gutters regularly and move stacks of firewood and other flammable materials safely away from their home.
James Hardie fiber cement building products are a solution for building fire-resistant homes, and are noncombustible when tested in accordance with ASTM E136. They are approved for use by the California State Fire Marshal in Wildland Urban-Interface zones.
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