Tennessee Code Title 68. Health, Safety and Environmental Protection § 68-122-208

It is unlawful for any person, corporation, partnership or firm to engage in the work of repairing or erecting steam boilers, steam kettles, pressure tanks, or steam generators in this state without a valid license as provided under this part. Any violation of this part is a Class C misdemeanor. Each day of such violation constitutes a separate offense. This does not apply to any person repairing such equipment whenever a licensed repair worker cannot be readily obtained, and an emergency exists.