Aluminium is A1 rated under the Euroclass system. The best aluminium decking systems are A2 fire rated. Specifically, a decking board, like Alupave, will achieve an A2-s1,do fire classification.
Fire ratings can vary per decking brand so always ensure you check with the manufacturer. A high-quality decking range, such as Alupave Decking, should achieve the full A2 fire rating, however, not all do!