California Building Code Section 403 governs high-rise buildings (over 75 ft above lowest fire-truck access level). Data centers regularly trip these thresholds. Required: redundant emergency power (60 min minimum, typically diesel + UPS in concert with N+1 redundancy), smoke control system per 909, voice/alarm communication per 907.5.2.2, fire service elevators per 403.6, and a fire command center per 911. Mission-critical occupancies often layer in Group H requirements for battery rooms (gaseous hazard category). Plan reviewers in SF, San Jose, Santa Clara County require N+1 UPS + N+1 generator + 96-hour fuel on-site for any building registered as Tier III or above.