What is an essential feature of all fire walls according to safety regulations?

The essential feature of all fire walls according to safety regulations is that they must be constructed from masonry. This requirement ensures that fire walls are built from materials that have the necessary fire resistance and structural integrity to contain fire and prevent its spread from one area to another. Masonry, such as brick or concrete, provides the durability and ability to withstand high temperatures, compliance with fire codes, and contributes to overall building safety.

Other options, while they may be related to building construction or safety, do not meet the critical requirement of fire resistance as mandated for fire walls. For instance, painting or the inclusion of windows does not enhance the primary function of a fire wall, which is to provide a barrier against the passage of flames and smoke. Reinforcing with steel, while useful in some construction contexts, is not a universal requirement for fire walls and could depend on specific building codes or design criteria. Thus, the construction material itself is a fundamental aspect that is emphasized in regulations.