What are the A-level ceiling materials used in four-star hotels?

Light steel keel and paper gypsum board, according to national regulations, if gypsum board is used together with metal components of light steel keel, it can be classified as A-grade materials, and water-based latex paint is classified as A-grade. In fact, Class A materials are incombustible materials. So most of them can use something else. Don't use wood, paper or chemical plastics, because there is a lot of smoke, and fire prevention is absolutely forbidden.