Tenn. Code Ann. § 68-122-103

No boiler that does not conform to the rules and regulations formulated by the board governing new construction and installation shall be installed and operated in this state after twelve (12) months from the date upon which the first rules and regulations under this part pertaining to new construction and installation shall have become effective, unless the boiler is of special design or construction, and is not covered by the rules and regulations, nor is in any way inconsistent with such rules and regulations, in which case a special installation and operating permit may, at its discretion, be granted by the board.