San Diego County building codes tested in wildfires

San Diego County building codes tested in wildfires

26 September 2011

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USA — Two devastating wildfires only four years apart gave San Diego County officials an unprecedented opportunity to measure whether changes in building codes and planning requirements designed to mitigate wildfire disasters actually made any difference.

The conclusion? “They worked,” said Jeff Murphy, deputy director of the county’s Department of Planning and Land Use.

Such an experiment is not possible in Texas, where counties have very limited authority over development within their boundaries. But in Southern California, counties have taken the lead in trying to reduce fire damage in the wild land-urban interface, the rural areas where human development brushes up against nature and where wildfire danger is the greatest.

In 2001, after a series of smaller wildfires, San Diego officials added building codes designed to make new homes in rural areas better able to repel fires, such as ignition-resistant decking and fire-repellent roofing. The new rules also required homeowners to make the areas around their residences less flammable, such as setting minimum distances that had to be cleared of vegetation.

Two years later the effectiveness of the new standards were tested in the Cedar Fire, which destroyed about 14 percent of the approximately 15,000 homes in the burn area. Yet only 4 percent of homes built under the new rule were lost.

It wasn’t a perfect test; fire can move in random ways that has nothing to do with building codes. But a regional task force looking at fire safety determined that regulators needed to go even further.

“If the needless loss of structures and lives is going to be stopped in San Diego County, we have to muster the ‘political will’ to adopt and enforce effective wildland-urban interface codes,” the 2004 report concluded.

So that year the planners tweaked the code even more, adding minimum distances that new homes must be set back from open spaces. Attic vents were closed, and gutters had to be installed so as to shed flammable leaves and debris. Homes outside the reach of hydrants were required to have up to 10,000 gallons of stored water for firefighters.

When another series of wildfires raged across the county in October 2007, incinerating 1,500 homes, the planners took another tally. This time, of the structures that had been built according to the revised 2004 codes, only 2 percent burned, compared with 13 percent of all the homes in the burn area.

“When the fires died, crews found signs of hope inside the charred perimeter — evidence that county actions to improve building codes and policies had better protected people and property,” Murphy wrote in a 2009 paper for the American Planning Association. “The evidence lay in the wreckage, or in the lack of it.”

San Diego’s planners haven’t focused only on building codes; developers of new subdivisions must also pass a strict fire-proofing site review if they want to earn the county’s sign-off on their projects.

Among other questions, they must answer where water to fight a fire will come from, who will maintain defensible space and how architects have arranged houses to mitigate burning. For example, “They have to take into account topography,” Murphy said. “Lots of folks want to be right on the edge of a hillside. But that’s not the best place for fire prevention.”

Still, San Diego officials say that protecting communities from catastrophe ultimately comes down to the commitment of individual property owners.

Unfortunately, “there is an apparent apathy on the part of the public when it comes to preparing for disasters,” the 2004 report said. “It is easier to ignore emergency preparedness or to think that it only happens to the other person, than to put in the time and effort to prepare for the unexpected.”

“People’s memories fade over time,” said Andy Parr, fire chief of Lakeside, which lost 300 homes in the 2003 fire. “I tell people, ‘You suffered a gigantic loss — don’t you get it? ‘ But I still have a fire prevention problem. I have to go out and pound on doors and say, ‘Cut your grass!'”

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