Codes - As introduced, revises authority of state fire marshal to prescribe rules relating to minimum statewide building construction safety standards, specifically for fire prevention for multi-family dwelling units. - Amends TCA Title 68, Chapter 120.

HB 2551 amends Tennessee building codes to clarify the state fire marshal's authority regarding safety standards for multi-family dwellings with two to six units. The bill explicitly prohibits the fire marshal from requiring automatic fire sprinkler systems in these buildings, while allowing local governments to adopt their own mandatory sprinkler requirements using the NFPA 13D standard. Key provisions include requiring separate exits for each dwelling, two-hour fire-resistant walls between units, and limiting structures to three stories. This directly affects local governments (cities/counties) that adopt building codes and developers constructing small multi-family housing projects, effective July 1, 2026.