What is the key characteristic of Type IV construction?

Type IV construction is characterized by its use of heavy timber framing, which sets it apart from other construction types. This method utilizes large timber members that can provide notable structural integrity and fire resistance. Heavy timber materials are often assumed to have a lower combustion rate compared to lighter materials, which contributes to a slower rate of fire spread and improved overall fire safety.

The robust nature of heavy timber can help maintain the building's structural integrity longer during exposure to fire, thus allowing for better evacuation times and reducing the likelihood of sudden failures. Therefore, Type IV construction is frequently designed to exploit these benefits, emphasizing strength and fire resistive properties, which are inherent in the characteristics of heavy timber.