For those dry places where wildfires will become more prevalent, keeping houses safe is critical. You want to keep flying embers from getting through your attic vents and starting the whole house on fire.
But if you think about it, attic and foundation vents are a contradiction. The vents are necessary to allow free movement of air, which helps prevent mold inside. On the other hand, these vents allow in burning embers during a wildfire. Thus, the requirement that wire mesh be installed over the vents.
But here is the real dilemma: The smaller the mesh on the vent cover (quarter-inch mesh is required by many building codes), the better the protection from embers. But the smaller the mesh, the worse for air flow and greater the tendency to get clogged.
And even the quarter-inch mesh does not prevent some firebrands (chunks of burning wood) from burning through the mesh.
"Quarter-inch mesh cannot stop embers and flames during wildfires," said Stephen Quarles, a wood durability advisor for University of California Cooperative Extension. "This is an example of conflict in code preferences between building and fire officials. Smaller mesh screens would do a better job of keeping out fire and embers, but these same screens plug up more easily."
Brent Berkompas, a city of San Bernardino, Calif., firefighter, has had many occasions to think about this issue, particularly when fighting big wildfires in 2003 and 2007 and watching homes burn from the inside out after embers got into the attic or crawl space. So he came up with a solution.
Berkompas' invention, Brandguard vents, are baffled vent covers, made of 26-gauge galvanized steel, that allow air to flow freely but block embers from passing through, he says.
Here's a story on the vents in Fire Engineering magazine.