Berkeley’s proposed zone 0 regulation mandates the replacement of sections of fence (or gates) that are attached to the house in the 0-5 ft zone around the structure—by sections made with noncombustible materials.
It does not require anything of unattached sections of combustible fence, or, for that matter, fences outside the 0-5 ft zone. A frequent example of it, in Berkeley, is a fence that remains at a certain distance to the house. How dangerous is this configuration?
This remarkable pair of pictures, provided by Alexander Maranguides, of NIST, from an actual California fire (Camp Fire 2018), shows two moments separated by 2 minutes. On the left, a double privacy fence, running perpendicular to a building, then seemingly parallel to it, never closer to the structure than approximately 6 ft (further out than zone 0) from the building, has ignited over its whole length. Two minutes later, the structure next to it has ignited. The wind appears to be blowing towards the building.
Alexander Maranguides’s provided legend (2025-05-12):
“NIST CAMP FIRE Case Study, report #3, Figure 53. Structure ignition on Dade Ct in Magalia. Images are two minutes apart and show fire spread from surface fuels to fence to vegetation to eaves. The [end of the] combustible fence is estimated to be approximately 1.8 m (6 ft) away from the structure.”
Images: NIST Camp Fire Study, report #3, Fig. 53, courtesy CalFire 2018
Lessons learned:
- in a wildfire, wood fences act like fire wicks, quickly drawing fire across large stretches of property, and can easily constitute a deadly danger to structures, even outside of zone 0.
- EMBER is a minimal necessary set of requirements, and should not be considered sufficient to fulfill the wildfire adaptations required to become hardened neighborhoods. We each need to do EMBER and more.
Important note: it is worth noting that Ventura County, which has consistently been ahead of CA WUI fire code by 20-30 years, believes that fences should be regulated further away from structures than the 0-5 ft zone.
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