What is the
International Wildland-Urban Interface Code?

The International Wildland-Urban Interface Code (IWUIC) establishes requirements for land use and the built environment within designated Wildland Urban Interface (WUI) areas using prescriptive and performance provisions. The IWUIC establishes minimum special regulations for the safeguarding of life and property from the intrusion of wildfire and:

  • Regulates ignition-resistant construction techniques and defensible space as well as fire department access and available water supplies for fire suppression.
  • Focuses on preventing ignition of buildings and vegetative fuels from direct exposure to wildfire and fire exposure from adjacent structures.
  • Helps prevent structure fires in the WUI from spreading to wildland fuels, even in the absence of fire department intervention.

Key Components

  • Ignition-Resistant Construction
    Building materials and assemblies designed to resist ignition from embers, radiant heat and direct flame contact. Includes roofing, siding, vents and decks that meet performance standards for wildfire exposure.
  • Defensible Space
    A buffer zone around a structure where vegetation and combustible materials are managed to reduce fire intensity and provide safe access for firefighting. Typically includes zones within 0–30 feet and 30–100 feet from the structure.
  • Emergency Vehicle Access
    Design standards for roads, driveways, and turnarounds that ensure fire apparatus can reach structures safely and efficiently during wildfire events. Includes minimum width, grade, and clearance requirements.
  • Water Supply
    Minimum requirements for on-site or nearby water availability for firefighting, including hydrants, tanks, or natural sources. Ensures adequate flow and pressure for suppression operations.
  • Fire Sprinklers
    Automatic fire suppression systems installed in structures to control or extinguish fires before they spread. Required in certain hazard zones or for specific occupancy types under the IWUIC.
  • Chimneys with Spark Arrestors
    Devices installed at the top of chimneys to prevent embers or sparks from escaping and igniting nearby vegetation or structures. Required for wood-burning appliances in WUI zones.
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ICC 605

ICC 605, Standard for Residential Construction in Regions with Wildfire Hazard is currently under development (not yet approved). This standard will specify enhanced prescriptive methodologies of wildfire-resistant design and construction details for new and existing buildings and other structures in wildfire hazard areas. The standard will provide prescriptive details for walls, floors, roofs, foundations, windows, doors and other applicable components of construction and a methodology for the identification, assessment and retrofit of existing residential dwellings to protect homes in wildfire hazard areas.

Understanding the International Wildland-Urban Interface Code

The IWUIC establishes requirements for land use and the built environment within designated wildland-urban interface areas using prescriptive and performance provisions. The code is intended to work as a system of its requirements, providing a comprehensive and holistic approach to enhancing building resilience from wildfires.

The key components of the IWUIC include:Graphic showing key components of the International Wildland-Urban Interface Code

  1. Ignition-Resistant Construction
  2. Defensible Space
  3. Emergency Vehicle Access
  4. Water Supply
  5. Fire Sprinklers
  6. Chimney's with Spark Arrestors

The IWUIC is a model code intended to supplement the adopted building and fire codes of a jurisdiction. The unmitigated use of property in WUI areas is a potential threat to life and property – from fire and resulting erosion from burning vegetation. The IWUIC establishes minimum requirements for the safeguarding of life and property from the intrusion of fire from wildland fire exposures and fire exposures from adjacent structures and prevents structure fires from spreading to wildland fuels, even in the absence of fire department intervention. Safeguards to prevent the occurrence of fires and to provide adequate fire protection facilities are provided through a tiered approach commensurate with the relative level of hazard present.

In addition to protecting individual livelihoods, the IWUIC also supports community resilience. An adverse event, like a wildfire, reveals the importance of both a coordinated approach to resilience across multiple community functions and the impacts that can occur across local economies. The IWUIC recognizes the benefits of a holistic approach to addressing risks and enhancing community resilience. Protection from wildfires relies on a community-wide approach that engages multiple actors. Reliance on building-level measures alone will not provide the level of protection necessary.

Among management options offered to help mitigate the U.S. wildfire problem, the National Cohesive Strategy suggests that focusing on building codes, specifically the adoption and enforcement of the IWUIC, supports the goal of making homes and other buildings more resistant to ignition. Unlike other model codes produced by the International Code Council, the IWUIC focuses on protecting life and property from a very specific threat.

Fire Resistant Construction Codes Working Together

The IWUIC works in conjunction with other codes including the International Building Code (IBC), International Residential Code (IRC), International Fire Code (IFC) and International Property Maintenance Code (IPMC) to provide requirements in areas vulnerable to wildfire. These requirements directly influence the resilience of buildings and communities in the WUI.

Graphic showing the International Building Code, International Residential Code, International Wildland-Urban Interface Code, International Fire Code and International Property Maintenance Code

Key requirements for building or retrofitting a house to comply with the IWUIC include:

  • Adding fire-resistant windows, doors and cladding.
  • Adding a non-combustible roof and keeping it clear of pine needles and other flammables.
  • Removing woodpiles and other fuels from near your home.
  • Cutting back vegetation surrounding the house.