There is a list of 26 items found in Section 603 that points you to other sections of the code that allow you to use the materials listed in this section. Type V construction is where the structural elements, the outer walls and the inner walls are of any material allowed by the code, combustible or non-combustible. A Type I-B building (the “basic Type I construction”) can be 160 feet tall with 12 to 16 floors. The type of activities carried out within a structure can help determine if Type V timber frame construction is an option.
When it comes to Type I construction, firefighters must be aggressive in securing stairwells and evacuating victims from the structure. While the building elements in a Type I building must be non-combustible materials, Section 603 provides a list of where combustible materials can be used in a Type I building. The many nuances of a building's use and size requirements can complicate matters and create confusion as to what type of construction is the most suitable. But those who work in it know that the industry is still very organized, divided into specific types of construction and processes.
Determining which of the five types of construction your project falls under is a key decision as part of the scoping process with your construction manager and building designer. Construction materials and practices used in Type I construction provide the highest level of fire protection. The most common types of roof systems in a commercial Type 3 construction environment include parallel cable truss and panel roof systems. Size requirements are similar to those of Type III and, although construction materials are classified as non-combustible, they provide less fire resistance than Type I, and the spread of fire would likely cause more damage.
Although Chapter 5 of the International Building Code (IBC) covers how large and tall a building is allowed to be based on its type of construction and occupancy classification, this publication will only cover what the different types of building classifications are. That said, many Type III buildings contain connected attics or horizontal empty spaces, making it more likely that a fire will spread. A building is best identified during pre-planning, but there are different characteristics that will help firefighters identify the type of building when they stop at the scene.