Fences arent included in Chapter 7A.

Depending on material and location, fencing can increase or decrease the vulnerability of a building to wildfire.

A solid perimeter fence made of noncombustible materials (such as steel or concrete) has been shown to be an effective barrier against a radiant energy exposure from the fire front. Even a wood plank fence, if a high density species is selected, and the boards are closely spaced, can provide some protection to the building from a purely radiant exposure. Depending on the pre-fire exposure, however, vegetative debris at the base of a combustible fence could result in ignition, as would direct flame contact.

[Leonard, J. et al. 2006. Research and Investigation into the Performance of Residential Boundary Fencing Systems in Bushfires, Bushfire CRC, Report CMIT 2006-186]

Ember ignition of dry grass, and spreading uphill to this fence, could result in ignition of the fence. Wood fencing, particularly when smaller members such as the lattice shown here is used, would be susceptible to ignition during wildfires, and the fire could spread laterally to the building.

A wood frame fence with metal wire infill would be safer choice in terms of lateral fire spread. This fence would not provide protection from a radiant exposure.

The solid wood fence shown here could provide some protection from radiant exposure to this home should a neighboring home ignite. However, if it ignites, it would provide the radiant exposure to the home. Use of a noncombustible fence to connect to the home is recommended.

In this fire demonstration, a wood lattice fence, connected to a wood clad wall, was ignited with at burning standard B brand. As is shown in the following photograph, fire did not sustain combustion after the B brand burned out, and did not spread fire to the wall, even though fine combustible debris was stuffed into areas in the lattice fence.

Fire likely did not spread to the wall because of a lack of pre-wildfire exposure prior to the demonstration (elevated temperatures over many days, high winds, low relative humidity, and pre-radiation exposure from the fire). This observation is in agreement with the results of Leonard, et al. (2006). They reported that the moisture content in the near-surface region of the wood was a more factor that the overall average moisture content in determining whether sustained ignition would occur. During a fire demonstration, it is difficult to exposure materials to true wildfire weather.

[Leonard, J. et al. 2006. Research and Investigation into the Performance of Residential Boundary Fencing Systems in Bushfires, Bushfire CRC, Report CMIT 2006-186]

In this fire demonstration, a vinyl lattice fence, connected to a wood clad wall, was ignited with at burning standard A brand. As is shown in the following photograph, fire did not spread to the wall, even though fine combustible debris was stuffed into areas in the lattice fence.

The vinyl lattice fence deformed, but did not sustain combustion after the A brand burned out, and did not spread fire to the combustible wood wall.