Tenn. Code Ann. § 64-2-210

All contracts of the authority shall be entered into and executed in such manner as may be prescribed by statutes, regulations and procedures governing contracting by county governments, but no contract or acquisition by purchase of equipment, apparatus, materials or supplies involving more than five hundred dollars ($500), or for construction, installation, repair or improvement of the property or facilities involving more than five hundred dollars ($500) shall be made except after such contract has been advertised for bids. Advertisement is not required when an emergency arises and requires immediate delivery of the supplies or performance of the service.