A combustion chamber (3) for a power plant gas turbine assembly (1) wherein the combustion chamber comprises an outer casing (7) and a plurality of heat shielding tile devices (8) supported by the outer casing; wherein at least one shielding tile device comprises: a metallic tile body (9) having an inner face (10) configured for facing the hot gas flow inside the combustion chamber and an opposite outer face (11) configured for facing a plenum obtained between the outer casing and the metallic tile body and fed by cooling air; a first plurality of first cooling pipes (12) fed by the cooling air wherein the first cooling pipes are arranged parallel each other forming a first layer (16) on the outer face of the metallic tile body; a second plurality of second cooling pipes (13) fed by the cooling air wherein the second cooling pipes are arranged parallel each other forming a second layer (17) on the first plurality of first cooling pipes.