Red-Alert Pre-Plan Form

Type 1 structures are high-rises, and they’re the stoutest of all construction types when exposed to fire. High-rises are usually defined as buildings more than 75 feet tall, with some agencies making amendments for buildings that are 35–55 feet tall. Type 1 structures are constructed of concrete and protected steel (steel coated with a fire-resistant material, most often a concrete mixture), and are designed to hold fire for an extended amount of time in order to keep the fire at bay in the room and/or floor of origin.Type 2 construction is typically found in new buildings and remodels of commercial structures. The walls and roofs are constructed of non-combustible materials. Specifically, walls are usually reinforced masonry or tilt slab, while roofs have metal structural members and decking. The top of these roofs are often covered with lightweight concrete, foam, an insulated membrane or a combination of these materials. Because most of these buildings are newer builds, they’re usually up to code and include fire suppression systems. And because metal roofs may fail with heat—not just from direct fire—expect early collapse, especially in some of the bigger buildings that have a substantial fire load.Type 3 buildings can be of either new or old construction, and they have non-combustible walls and a wood roof. Older construction buildings may consist of unreinforced masonry and have a conventionally framed roof, while newer buildings will have lightweight roof systems supported by reinforced masonry or tilt slab. The most common types of roof systems in a commercial setting of Type 3 construction include parallel cord truss and panelized roof systems.Type 4 construction is found in older buildings and utilizes large dimensional lumber for structural members and interior elements.Type 5 construction is found in many modern homes. The walls and roofs are made of combustible materials—most commonly wood. If the walls are wood-framed, the roof usually is as well. Rooftops are ceramic tile or asphalt shingles placed over lightweight trusses and OSB.