Rigid polyurethane (PUR) or polyisocyanurate (PIR) foam boards manufactured through a controlled foaming process, free of CFC and HCFC. The manufactured products are excellent thermal insulators with high mechanical properties, high rigidity and light weight. These materials are widely used as thermal insulators for industrial applications such as: insulated and refrigerated vehicles, pipe insulation for industrial refrigeration, tank and cistern insulation, cryogenic applications, refrigerating chamber floors, etc.