Tenn. Code § 62-32-213
This part and the rules promulgated under this part shall have uniform force and effect throughout the state. No political subdivision of this state may adopt and enforce any order, ordinance, rule or regulation requiring any person to obtain any form of permission from the political subdivision to act as a fire extinguisher firm. A political subdivision may require a fire extinguisher system contractor to pay for and obtain a permit for the installation of fire extinguisher systems and require the installation to conform with applicable building codes and requirements; however, the political subdivision may not impose on fire extinguisher system firms qualification or financial responsibility requirements other than proof of a valid certificate of registration issued under this part.
T.C.A. § 62-32-213