Which type of materials should not be used for window treatments above a cooking surface?

The use of flammable materials for window treatments above a cooking surface presents a significant safety risk, making this the correct choice. In kitchen environments where cooking occurs, there is a potential for high heat, splashes, and even flames. If window treatments made from flammable materials such as certain fabrics are exposed to these conditions, they could ignite, leading to dangerous fires and putting occupants at risk.

It's crucial for the window treatments in these areas to be made from non-combustible or flame-retardant materials that can withstand the cooking environment and help prevent any fire hazards. The choice of materials is essential for maintaining safety standards in kitchen design and adhering to building codes.

Other materials, like glass, metal, and plastic, while they may have their own considerations in terms of maintenance, aesthetics, or insulation, do not pose the same level of fire risk directly related to flammability when positioned above a cooking surface. Thus, flammable materials are clearly the most concerning in this context, solidifying their status as the option that should be avoided.