Which type of construction is classified as heavy timber?

Heavy timber construction is classified as Type IV. This type of construction is characterized by the use of large wooden beams and columns, typically made from solid wood with a minimum dimension that allows the material to be classified as heavy timber. This construction type is notable for its durability and resilience in the event of a fire. The large dimensions of the timber allow for longer burn times before the structural integrity is compromised, effectively providing time for occupants to evacuate and for firefighters to respond.

In fire protection terms, heavy timber construction offers a degree of fire resistance that is not present in lighter construction types, which can contribute to fire spread more rapidly. The large timbers are less likely to fail than smaller wooden components, making Type IV buildings significant in terms of safety during firefighting operations.

Other classifications may refer to different types of materials and structural principles that do not include the use of heavy timber elements. For detailed understanding, recognizing the specific attributes of each construction type is essential for firefighting operations, as they affect both the fire behavior and the strategies employed by firefighters.