Wildland-Urban Interface Code (WUI Code)

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A wildland-urban interface (WUI) code is specifically designed to mitigate the risks from wildfire to life and property. The standards within a WUI code will vary according to the scope that a community is willing to adopt and enforce. Typically, however, a WUI code includes the following topics:

  • Structure density and location: number of structures allowed in areas at risk from wildfire, plus setbacks (distance between structures and distance between other features such as slopes).
  • Building materials and construction: roof assembly and covering, eaves, vents, gutters, exterior walls, windows, non-combustible building materials, and non-combustible surface.  
  • Vegetation management: tree thinning, spacing, limbing, and trimming; removal of any vegetation growing under tree canopies (typically referred to as “ladder fuels”), surface vegetation removal, and brush clearance; vegetation conversion, fuel modifications, and landscaping.
  • Emergency vehicle access: driveways, turnarounds, emergency access roads, marking of roads, and property address markers.
  • Water supply: approved water sources and adequate water supply.
  • Fire protection: automatic sprinkler system, spark arresters, and propane tank storage.
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A WUI code often works in conjunction with other codes, such as the jurisdiction’s fire code and building code. References to these other codes should be included in the WUI code. The local authority responsible for a WUI code is typically the local fire district/department, land use department, or building department. To be successful, the adopting jurisdiction should ensure there is enough internal capacity to enforce the code. 

Model WUI codes can be useful in providing jurisdictions with examples of language for required mitigation and guidance. It is rare that jurisdictions adopt model WUI codes in full; rather, they adopt them in part and/or with local amendments. WUI codes also work best in concert with other voluntary and outreach programs that encourage resident awareness and education.

Implementing a WUI code promotes safer development by ensuring that life and property are uniformly protected from wildfire risk. In addition, WUI codes:

  • Provide a robust, comprehensive, and consolidated set of regulations for developers, contractors, and residents.
  • Complement existing building and fire codes to ensure that additional standards are met.
  • Are based on scientific findings on the effectiveness of ignition loss reduction.
  • While some WUI code requirements may require more upfront financial investment through the building and construction process, codes can reduce long term spending on suppression and rebuilding because features are built to a higher standard and increase a structure’s survivability.
  • WUI codes promote safer development that protects life and property.

This 24-page guide by NFPA provides information on community wildfire safety specifically for planners and regulators.  In 2012, Colorado Springs updated their WUI mitigation requirements by adopting an appendix for the Hillside Overlay Zone that required additional fuels management, fire protection systems, roof coverings, and other hardened structure features. 

Some communities and counties in Colorado have adopted either their own WUI code or parts of the International Code Council’s Wildland-Urban Interface model code (IWUIC). For example, in 2011 Pueblo County adopted most of the IWUIC (2009 edition) as part of their uniform fire code (adopted as the “Fire Codes of Pueblo County”). 

Many other jurisdictions, including Boulder CountyEagle County, and Summit County have integrated wildfire hazard mitigation requirements into their land use regulations and building codes to specify when new construction, additions, or retrofits require additional mitigation. For more examples related to wildfire, see additional examples in the Building Code and Site-Specific Hazard Assessment tools.

WUI codes can also bring a number of challenges, although many of these can be overcome if the community is committed to the process:

  • May bring additional costs to construction, although this varies by jurisdiction.
  • Typically WUI codes only apply to new development and improvements or repairs, leaving existing development still at risk.
  • Adoption can be controversial; successful WUI code adoptions engage a number of stakeholders and the public long before the adoption process began.
  • Enforcement can be challenging and requires adequate internal staff capacity to effectively implement.
Key Facts

Administrative Capacity

Experienced planner; coordination with local fire authority and building department

Mapping

WUI map or hazard ratings required for applicability

Regulatory Requirements

N/A

Maintenance

Yes. Periodic updating encouraged for maps and technical standards

Adoption Required

Yes. Can be integrated into zoning code

Statutory Reference 

N/A

Associated Costs

Varies; may require consultant

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