(1) At or before the issuance of bonds the city legislative body or the fiscal court of the county, as the case may be, shall, by ordinance or resolution, set aside and pledge the income and revenue of the industrial building into a separate and special fund to be used and applied in payment of the cost thereof and in the maintenance, operation and depreciation thereof. The ordinance or resolution shall definitely fix and determine the amount of revenue necessary to be set apart and applied to the payment of principal and interest of the bonds, and the proportion (if any) of the balance of the income and revenue to be set aside as a proper and adequate depreciation account, and the remaining proportion of such balance shall be set aside for the reasonable and proper operation and maintenance of the industrial building.
(2) The rents to be charged for the use of the building shall be fixed and revised from time to time so as to be sufficient to provide for payment of interest upon all bonds and to create a sinking fund to pay the principal thereof when due, and to provide for the operation and maintenance of the building and an adequate depreciation account, if any depreciation account has been established.