Mesa staff propose moving to 2024 building and fire codes with local amendments; new rules address battery energy storage systems

City building and fire officials presented a proposed update from the 2018 to the 2024 editions of the International Building and Fire Codes, and described local amendments meant to reflect Valley practices, conserve water and strengthen public-safety responses to emerging technologies such as battery energy storage systems (BESS).

John Sheffer, deputy director and building official, told the council the 2024 codes "address new technologies," including safety guidance for battery systems, and would keep Mesa consistent with most other Valley cities that have moved to the newer code cycle. He said the change would not create new permit types or fees but would add new code requirements for future construction.

Sheffer outlined small-business-friendly amendments: raising thresholds for separate male/female restrooms from 15 to 25 occupants, raising drinking-fountain and service-sink thresholds, and adopting reduced plumbing fixture flow rates (for example, 1.28 gallons-per-flush toilets) to encourage water conservation. He also discussed an optional accessibility guideline for houses and a modest estimated energy-efficiency improvement tied to the 2024 codes.

Fire Marshal Sean Alexander described fire-safety amendments and operations-related changes. He said Mesa would limit the firefighter air-replenishment system requirement to high-rise buildings (defined as 75 feet or taller) rather than mid-rise structures, and seek three-dimensional construction models from developers on commercial buildings three stories and above to support firefighter orientation and future personnel-tracking systems.

On BESS, staff proposed adopting the latest NFPA 855 safety guidance and adding Mesa-specific site-design rules intended to reduce the likelihood that a thermal-runaway event spreads across very large installations. Alexander told the council the city's approach is to enable vehicle-mounted operations and to break very large sites into smaller blocks with apparatus access and horizontal separation so crews can concentrate flows on adjacent containers while allowing a burning container to exhaust rather than sending firefighters into extreme risk.

Staff said they had engaged the development advisory forum, the Home Builders Association, SRP and energy-efficiency organizations and received letters of support, and they proposed an adoption schedule with introduction on Dec. 1 and action on Dec. 8, 2025, and an effective date in early 2026 to align with an ISO reassessment. The council asked staff to make sure business groups (including the Mesa Chamber of Commerce) received briefings; staff said they would.