In a recent 10-yr. period, wildfires have impacted an average of 7.5 million acres of land each year throughout the United States.(1) Eight of the top ten costliest wildland fires in the US have occurred in the last decade; all 10 were in California.(2) Do you have a vested interest in one of the 2 million properties in California, or in one of the other 2.4 million properties in the United States that are at high to extreme risk to wildfires?(3)
If you are curious about wildland fire exposures and what can be done to mitigate them, continue reading. This article will identify wildland fire risks, preparation steps, and how to respond in the event of a wild fire.
What is a wildland fire? Per NFPA 1140, Standard for Wildland Fire Protection, a wildland fire is “a fire that originates in or extends to vegetative fuels and that can involve structures or other combustible materials.” Wildland fires include brush fires, grass fires, bushfires, and forest fires.
NFPA 1140, Chapters 24 through 26 apply to “all existing structures […] located in a wildland/urban interface area…” and allows the authority having jurisdiction (AHJ) to determine the requirements needed per site. Section 18.104.22.168 requires that all buildings within 30 ft. of a vegetated slope have mitigation measures “as determined by the AHJ”. NFPA 1140 provides general location requirements, but fails to provide the criteria necessary to determine if a building or site is exposed.
The January 2022 version of FM Global Property Loss Prevention Data Sheet 9-19, Wildland Fire, better identifies when to assess for wildland fire exposures. Such as those within 200 ft. of a brushland or grassland, or half a mile of any forest or woodland area. It also provides visuals and tables to assist in determining the exposure. The notable changes in this revision include:
- Increased brush/grassland fire exposure from 100 ft. to 200 ft. to account for ember attack
- Added recommendations for exterior walls that are exposed to ember attack
- Added a recommendation for pre-incident planning and relocated the guidance to FM Global Property Loss Prevention Data Sheet 10-1, Pre-Incident and Emergency Response Planning)
- Added a recommendation to remove all combustible vegetation within 5 ft. of important building and equipment
- Simplified radiant heat tables
- Added a recommendation to consider the water supply for new construction
- Provided visual examples of vegetation type, land slope and separation distances
- Updated guidance on exposure sprinkler protection
Ideally, your location would be greater than 200 ft. from a brush/grassland area, and greater than 0.5 mi. from any forest or woodland area. If the location must be in a wildland exposed area, site selection is key to mitigate potential exposures. It is important to evaluate for radiant heat and/or direct flame impingement exposures when located within 510 ft. of forest/woodland areas. Evaluate when located within 200 ft. of brush/grassland areas as well. Be sure to keep the building(s), equipment, and yard storage at a safe distance.
Using passive protections can mitigate identified exposures. This can include removing the vegetation, or using fire-resistive or other non-combustible construction. Other passive protections include providing measures to prevent embers from entering the building, and avoiding combustible yard storage. Installing underground power lines also mitigates identified exposures.
If passive protection does not reduce the wildfire exposure to acceptable levels, move to an active protection approach. Active protection includes sprinklers for the exposed windows/walls. Design guidelines for exposure sprinkler protection are provided in NFPA 13, Standard for the Installation of Sprinkler Systems, and Data Sheet 9-19.
When it comes to pre-incident fire planning, NPFA 1140 focuses on wildland firefighting and not what you can do at your facility in the event of a wildland fire. Developing a plan that lists specific duties, as recommended in FM Global Property Loss Prevention Data Sheet 10-1, Pre-incident and Emergency Response Planning, will help prevent significant damage to your property and the potential impact to your business. Other steps to mitigate the potential for damage include, but are not limited to, the following:
- Monitoring for wildland fires
- Removing combustible yard storage and debris
- Clearing the roof drains/gutters
- Closing all building openings
- Shutting down HVAC systems
- Backing up servers
- Coordinating with the responding fire service
Review the response plan, the exposure(s), and ensure that all resources are still available prior to the wildland fire season. Clear and/or maintain the vegetation near buildings, yard storage, and equipment as needed.
Are you exposed? Regional wildfire maps can identify if a given facility is within a known wildfire region, but they can’t quantify exposures. Contact Risk Logic to have an engineering analysis of your facility to see if you are exposed to a potentially devastating wildland fire.
- Hoover, K and Hanson, L (2021, October 4) Wildfire Statistics. Congressional Research Service https://sgp.fas.org/crs/misc/IF10244.pdf
- CalFire (2022, January 13) Top 20 Largest California Wildfires https://www.fire.ca.gov/media/4jandlhh/top20_acres.pdf
- Wildfire Risk Analysis. https://www.verisk.com/insurance/campaigns/location-fireline-state-risk-report/
NFPA 13, Standard for the Installation of Sprinkler Systems
NFPA 1140, Standard for Wildland Fire Protection
FM Global Property Loss Prevention Data Sheet 9-19, Wildland Fire
FM Global Property Loss Prevention Data Sheet 10-1, Pre-incident and Emergency Response Planning