Which wall type requires a 4-hour fire rating?

Masonry walls typically require a 4-hour fire rating due to their composition and structural integrity. This fire rating is crucial in ensuring that these walls can withstand fire exposure for an extended period, providing a barrier that helps to contain the spread of fire and protect life and property.

Masonry is made from durable materials such as brick, concrete, and stone, which inherently have better fire-resistance properties compared to other materials. The thickness and density of these walls contribute to their ability to resist heat and prevent the passage of flames, smoke, and toxic gases.

In comparison, while gypsum walls are known for fire resistance, they generally have lower fire ratings than masonry walls. Wooden partition walls lack the necessary fire resistance characteristics entirely, resulting in much lower fire ratings. Steel walls, although they have good structural integrity and can be treated for fire resistance, often have different fire rating requirements depending on their design and application.

Thus, masonry walls are the correct choice for this question regarding a 4-hour fire rating, as they are specifically designed and constructed to meet these stringent fire safety standards.