Masonry and concrete walls are classified as firewalls rated at how many hours?

Masonry and concrete walls are typically classified as firewalls rated for 4 hours due to their capacity to withstand high temperatures and prevent the spread of fire for an extended period. This fire-resistance rating is crucial in building construction as it allows for additional time for occupants to evacuate the building and provides firefighters a window to control the fire without compromising structural safety. The 4-hour rating reflects the materials' inherent properties, which include low thermal conductivity and high mass, contributing to their effectiveness in containing fire. Understanding these fire ratings is essential for ensuring that buildings comply with safety codes and standards, ultimately protecting lives and property.