What defines a "Firewall" in building construction?

A "Firewall" in building construction is specifically designed to prevent the spread of fire between areas of a building or between buildings. This type of wall is built using materials and techniques that can withstand fire for a specified period, thereby protecting adjacent structures or compartments from flames and heat. The primary function of a firewall is to create a barrier that limits the movement of fire, smoke, and heat, contributing to the overall safety of the building and its occupants.

While other options mention different types of walls, they do not align with the fire-resistive purpose that defines a firewall. For example, a wall separating two blocks does not necessarily address fire safety, a wall for aesthetic purposes serves no structural or protective function in the context of fire safety, and a wall surrounding an entire building may not have the fire-resistive capabilities required to be considered a firewall. The essential characteristic of a firewall is its role in enhancing fire safety, which is why the correct definition centers on its ability to prevent the spread of fire.