What is the fire resistance rating of the exterior walls of Type IV construction according to PD 1096?

In Type IV construction, often referred to as "Heavy Timber" construction, the exterior walls are designed to perform well in the event of a fire due to the inherent nature of the materials used, which include large timber members. According to PD 1096, the fire resistance rating for the exterior walls of Type IV construction is required to be 4 hours. This elevated rating is intended to enhance the fire safety of the structure, allowing it to withstand exposure to fire for an extended period, thus providing additional protection for both the building occupants and neighboring structures. The thick and solid wood components in Type IV construction contribute significantly to achieving this level of performance, making it a robust choice in fire-prone environments.