An industrial park shall contain not less than twenty (20) acres and shall be developed by a single entity. Lots may be sold to separate users but the sale of lots must be accompanied by protective covenants ensuring a high level of architecture, site improvements and their continued maintenance. Covenants shall include, at a minimum, a property owners' association, provisions for maintenance of individual sites and common areas, standards for finishing of buildings, and design standards for signs. Such covenants shall be submitted with the application for an industrial park zoning classification.