Second in a series of articles on “Living With Wildfires”
May 2008 | by Dismas Abelman
Last month I described the conditions that lead to large-scale fires in the San Diego region. Fuel, topography and weather all affect a fire but we are able to modify only the first of these factors. I described the need for a fuel-modification plan around homes living in the Wildland Urban Interface (WUI) and the benefit of minimizing combustible materials around all homes in Del Mar.
Buildings are the other part of the fuel chain. These are the homes in which we live. Our houses are constructed in a way to keep the elements away from our family and us. In the past fire safety was given very little regard. Over the years each state has developed a code for the construction standards of buildings that will provide for the safety of the occupants. The State of California has also developed additional codes for homes constructed in the Wildland Urban Interface (WUI). These codes are more restrictive than codes for the urban portions of the state and currently apply to homes in Crest Canyon and along the canyon rim. Homes built and maintained in this area are required to have a vegetation management plan that will provide for a defensible space. In addition to the defensible space homes need to be constructed in such a way as to maximize the potential for protection in a wildfire.
The roof is the most vulnerable part of the home in terms of exposure to fire approaching from an external source. A roof will be exposed to direct fire contact, radiant heat from a fire burning close to the house, embers traveling on the wind and convected heat from fires burning up a hill toward the structure. Thus wood-shake shingle roofs are not permitted in areas that are prone to fire danger. Any of the external fire sources can ignite a wood-shake shingle roof and become a free-burning fire. Once involved, there is very little the firefighters can do without a large number of apparatus and personnel. This is typically not the case in a wildfire situation. A roof must provide the first line of defense from an oncoming fire.
Another way to protect a home that could be exposed to a wildfire is to enclose the roof eaves. This is the area that extends away from the house on the underside of the roof. A lesson that has been learned through the numerous wildfires is that an exposed eave can allow fire to start through direct flame contact as well as an ember traveling on the wind. These embers can find cracks or crevices and allow the fire to start and burn a building from the outside in. Another method for fire or an ember to get into your home is through attic venting. These are the openings that allow air to flow into and out of your attic. While necessary for the health of your home, if not properly protected, these openings can allow an ember to ride the wind into an attic space and start a fire. Again, once this fire has started, it will take a large number of resources to get it under control.
Windows should be dual glazed or paned and constructed in a manner that will withstand heat and fire. When purchasing new windows specifically ask about these features, quality can differ greatly from manufacturer to manufacturer. Finally pay attention to fences. If a wood fence is desired, make sure the five feet that come into contact with the house are constructed with non-combustible materials.
The Del Mar Fire Department will send someone to your home to help you determine actions you can take to make it more fire safe. Please call the Fire Department at 755-1522 if you have any questions or would like to schedule an appointment.
Dismas Abelman is Deputy Fire Chief/Fire Marshal, Del Mar and Solana Beach Fire Departments.
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