In a move intended to reduce the spread of wildfire within Woodside, the Town Council on June 12 introduced an ordinance mandating town-wide use of ignition-resistant materials when significant changes are made to the exteriors of homes, garages and other non-agricultural buildings.

The council will hold a public hearing June 26, when it is likely to vote to adopt the ordinance. If approved a second time, the ordinance becomes law in 30 days.

The ordinance, which passed on a unanimous vote with members Anne Kasten and Dave Burow absent, amends the state fire code already adopted by the town to specify when a remodeling project is significant enough to require the use of ignition-resistant exterior siding, and vents that prevent the entry of burning embers.

The siding rule comes into effect upon replacement of 80 percent or more of the existing siding. Ember-resistant vents are necessary when exterior siding and/or roofing work includes buying new vents, according to a staff report.

Ember-resistant vents comes with varying levels of sophistication. There are designs that close at a particular temperature; another design traps embers. An inexpensive alternative is one-millimeter screening, a system tested by the National Institute of Standards and Testing, Fire Marshal Denise Enea of the Woodside Fire Protection District told the council.

Go to this link to see a demonstration of fire embers igniting a house, including embers passing through an unprotected vent.

The difference in cost between ember-resistant and ordinary vents for a typical roof- or siding-replacement project is about $1,000, according to the staff report.

Go to this link for information on building materials approved by the California Department of Forestry and Fire Prevention.

"Ventilation is important," said Mayor Dave Tanner, a builder. "If you're sucking up embers, you're going to catch your house on fire. At least put the screen in there. It'll save the house."

The new regulations do not apply to agricultural buildings such as barns and stables, which tend to be highly ventilated by design and not amenable to standard fire-prevention practices.

The ordinance also incorporates state vegetation management standards for reducing the danger of a fire gathering momentum from burning brush and shrubbery.

The Woodside fire district has its own standard that expands on the state's defensible space rules by requiring an additional 30 feet of cleared land along a property's perimeter. The vegetation of concern includes "flashy fuels" such as weeds and annual grasses, and easily ignited dead plants and litter.

The Woodside fire district covers Woodside, Portola Valley and nearby unincorporated communities, including Ladera, Vista Verde Los Trancos Woods and Emerald Hills.

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