... with a high strength adhesive composite.The core material of color steel fireproof rock wool insulation color steel ... workshop ceiling, cut off, ect. Through the refractory limit of detection of national testing center, the refractory time is 80 minutes. ... Giordano SPA Determination, rock wool sandwich panel and wallboard refractory of limit 100mm thickness (REI), 120 minutes; 75mm thickness (REI) ...