Tennessee Code Title 6. Cities and Towns § 6-36-115

(a) All materials, supplies and equipment shall be purchased by the director of schools in accordance with procedures approved by the board of education, except that centralized purchasing with the city administration may be utilized where it is mutually agreed upon by the council and board or their delegated representatives.

(b) The board of education or director of schools, in making purchases and contracts, shall be subject to the provisions of this charter relating to purchases and contracts by the city council and city manager, with the board of education standing in the stead of the council and the director of schools standing in the stead of the city manager.

(c) No purchase, expenditure or contract shall be made in excess of available school funds.