Section 75 ILCS 16/40-10 - Bonds for buildings and equipment(a) If the board of trustees determines that funds for any or all of the purposes authorized in Section 40-5 are to be provided by a bond issue, 30 days after the posting of the notice required under Section 40-5, the board shall by ordinance provide that the bonds of the district be issued for the payment of the cost (estimated as provided in Section 40-5) of erecting or constructing a building, remodeling, repairing, or improving an existing library building, erecting an addition to an existing library building, or purchasing a building, site, or equipment.(b) The ordinance shall also state the time or times when the bonds and the interest on the bonds shall become payable. The whole of the principal of the bonds and the interest on the bonds shall, however, become payable within 20 years, and the interest on the bonds shall not exceed the rate permitted in the Bond Authorization Act. The interest may be made payable at times (annually or semiannually) prescribed by the ordinance.(c) The ordinance shall be irrepealable by the board and shall make provision for the levy and collection annually of a special tax upon principal and interest of the bonds as they mature and collection loss and costs. The tax shall be in addition to that otherwise authorized to be levied and collected for library purposes.