S.C. Code Ann. § 11-35-1825
The State Engineer's Office shall develop a procedure and a list of criteria for prequalifying construction bidders and sub-bidders. The criteria must include, but not be limited to, prior performance, recent past references on all aspects of performance, financial stability, and experience on similar construction projects. A governmental body may use the prequalification process only for projects where the construction involved is unique in nature or over ten million dollars in value as determined by and subject to the approval of the State Engineer's Office. All prequalification projects must be under the supervision of the State Engineer's Office.
When the prequalification process is employed, only those bidders or sub-bidders who are prequalified through this procedure may submit a bid for the project. The determination of which bidders and sub-bidders are prequalified, and entitled to bid, is not protestable pursuant to Section 11-35-4210 or other provisions of this code.