What is type 4 construction?

Type IV construction is that type of construction in which the building elements are solid wood or non-combustible materials and have fire resistance ratings according to Table 601. Many type 4 buildings were built before the 1960s with large pieces of wood. These buildings, easily recognizable by firefighters, have wooden walls and ceilings seen in barns, factories and old churches. They owe their robust structure to the wood connected by metal plates and bolts.

While well-maintained type 4 buildings resist fire, the age of some of these buildings poses significant difficulties for firefighters. Type IV buildings are largely constructed of large pieces of wood, connected by metal plates and bolts. This was common practice before 1960, making heavy wood constructions very easy to spot. Old churches, factories and barns usually fall into this category.

There is a list of 26 items found in Section 603 that refers you to other sections of the code that allow you to use the materials listed in this section. Type IV buildings have exterior walls and incombustible interior elements. These buildings are made of solid or laminated wood. All wooden elements must meet dimensional requirements.

Wooden columns, beams, and beams must be at least 8 inches thick. Heavy floor and ceiling planks must be at least 6 inches thick. If these types of buildings catch fire, they require large volumes of water to be extinguished, but they resist fire well and do not collapse easily due to their structural mass. Although type 3 buildings contain fire-resistant materials, their roof systems burn out quickly and their fire-cut beams pose a hazard to firefighters.

Although Chapter 5 of the International Building Code (IBC) covers the size and height of a building based on its construction type and occupancy classification, this publication will only cover what are the different types of building classifications. Structural elements associated with Type I construction generally receive fire protection for three to four hours. A garage generally wouldn't require such a high construction type rating and can be built with a lower construction type rating to minimize the cost of construction. Some type 1 buildings have climate control systems and self-pressurized staircases to prevent fires from spreading.

Therefore, the type of construction is based on the period of time it takes each element of the building to resist a fire or continue to perform its structural function. Knowing the different types of construction promotes safety during and after the construction of a building. Type A refers to “protected buildings”, while type B exists in reference to “unprotected buildings”. That said, many Type III buildings contain connected attics or horizontal empty spaces, increasing the likelihood of a fire spreading.

Ventilation in this type of building is not an option, because the roof must also be composed of non-combustible materials. This type of construction has brick or block walls with a wooden roof or floor assembly that is not protected against fire. However, those who work in it know that the industry is still very organized, divided into specific types of construction and processes. This type is called “fireproof” not because of its resistance to fire, but because of the fuel provided by the building.

Building codes classify all structures, from type 1 to type 5, and this type of building reveals crucial information, such as fire resistance. .