What is the typical dimension of Class 4 load-bearing wooden columns?

The typical dimensions for Class 4 load-bearing wooden columns are commonly recognized as 12 inches by 12 inches. This sizing is used because Class 4 construction involves heavy timber or solid wood components, which need to bear significant loads and resist fire effectively. The 12 x 12 dimensions provide a sufficient cross-sectional area to support structural loads while also facilitating better fire resistance compared to smaller dimensions.

While other dimensions may be used in different contexts or specific applications, 12 x 12 is standard and widely accepted in the context of Class 4 construction due to its balance between strength and fire performance. Understanding these dimensions is crucial for fire officers, as they relate to building construction types and their associated fire behavior and risks.