Any school facilities modernized under WAC 392-347-015 must be used for at least five years beyond the completion of modernization. School directors will pass a resolution and submit it to the superintendent of public instruction that the modernized facility will be used for instructional purposes for five years after the completion of the project. If the school facility is not used for instructional purposes during this five-year period, the amount of state funding assistance allocated and spent for the modernization project must be returned to the state school building construction fund. The five-year use requirement and the five year prohibition against additional modernization funding shall be waived in the event that a facility is rendered permanently unusable before the end of the five-year period by an unforeseen natural event. The definition of "unforeseen natural event" shall be as set forth in RCW 28A.150.290.