Tenn. Code Ann. § 4-6-118

For the purpose of proper regulation, recording and auditing the various expenditures of the penitentiaries named in § 4-6-102, the managing officers thereof shall prepare, and present to the commissioner of correction in triplicate, not less than fifteen (15) days before the first day of each month and on forms furnished by the commissioner, a detailed estimate of all supplies, materials, improvements and money needed during each month.