Model building codes are created by Standards Developing Organizations and are updated regularly, including incorporating building science advances and changes to underlying engineering standards. Jurisdictions can adopt model building codes and sometimes make amendments that may strengthen or weaken the performance of homes built according to the building code.

The International Code Council (ICC) and the National Fire Protection Association are two major model building code organizations. The ICC develops the International Residential Code (IRC) that governs the construction of approximately 80% of U.S. single-family houses, two-family houses, and townhouses with three or more units. ICC also develops the International Building Code (IBC) that governs new construction of all other types of structures, including multifamily homes like apartments, commercial buildings, and structures outside the scope of the IRC.

While the IRC does not have comprehensive tornado or wildfire-resistant requirements, some provisions can increase safety against these perils. For example, the high wind requirements for windborne debris regions can significantly increase a home’s protection from tornadoes. However, tornado winds can exceed the anticipated design wind speeds for high-wind construction measures. For this reason, tornado storm shelters and safe rooms should be considered as they provide near-absolute life-safety protection, even in extreme tornadoes up to 250 mph. The 2024 IBC addresses tornado resilience through a new standard and new requirements.

While the IRC does not comprehensively address wildfire, some provisions increase wildfire protection for homes, including those addressing the spread of fires from house to house. Examples include the IRC provisions on Fire-Resistant Construction (Section R302) and fire ratings for roof coverings. The International Wildland-Urban Interface Code and the Standard for Wildland Fire Protection (NFPA 1140) are two Wildland-Urban Interface (WUI) Codes designed to reduce wildfire risk.