What distinguishes Type III construction?

Type III construction is characterized by its use of materials that combine both combustible and non-combustible components, which is often referred to as "ordinary construction." This type of construction typically involves exterior walls made of non-combustible materials, like masonry or concrete, while the interior framing is usually composed of wood or other combustible materials. This distinction is important because it influences fire behavior and the building's overall safety profile. The mixture of materials makes Type III construction vulnerable to fire, particularly in its combustible interior elements, while still providing some fire resistance through its exterior walls.

In other construction types, such as Type I (which is entirely non-combustible) or Type II (which also has non-combustible components but may allow for some combustibles), the characteristics differ significantly. Heavy timber used in some types of construction, like Type IV, distinguishes it from Type III. Similarly, while Type III construction can be found in residential buildings, its definition is not confined to this purpose alone, allowing it to be used for various structures. Thus, the correct understanding of Type III construction lies in recognizing it as "ordinary construction," as it reflects the blend of combustible and non-combustible materials that defines this category.