How a building is constructed determines not only its stability but also how firefighters access it in case of a fire emergency. Ideally, the type of construction depends on the building materials used, and the purpose the building is meant to serve. The construction material used and the management of the construction project will affect the extent of damage should there be a fire breakout.
The right type of construction depends on the purpose and function of a building. The materials used should factor the potential occurrence of a fire outbreak, among other hazards.
Below are six different types of construction.
1. Fire-Resistive Construction
This type of construction is found on high rise structures. Of all construction types, it’s the most resistive in case of a fire break out. High rise buildings are those that are over 75 feet high, although some agencies include buildings between 35 and 55 feet high in this category. These structures are constructed using protected steel and concrete.
Protected material is coated with a fire-resistant substance, in most cases, a mixture of concrete. These buildings are designed to contain an emergency fire for a long time and keep it from spreading. The idea is to contain the fire in the area or floor of origin as long as possible.
2. Non-Combustible Construction
These types of construction can be found in remodelled commercial buildings and new structures. The walls and roofs are built with non-combustible materials. The roof’s decking and members feature a tilt slab or reinforced masonry. Rooftops are normally covered with an insulated foam, membrane, lightweight concrete, or a combination of any of these materials. Mostly, non-combustible buildings are recent construction and usually adhere to the local building codes.
They also have elaborate fire depression systems. Since metal roofs are often affected by heat, both indirect and direct heat, large buildings on fire are likely to collapse pretty fast. If you are a firefighter called to put out a fire in a new commercial building, expect to find a non-combustible construction. To determine whether a building is made of non-combustible material, always sound the walls first.
3. Combustible Construction
Also known as “ordinary,” these types of construction can be found in either old or new buildings. They feature a wood roof and non-combustible materials. Old buildings feature conventionally framed roof and unreinforced masonry, while the lightweight roof systems on new buildings are reinforced and supported by tilt slab or masonry. For commercial construction, the dominant roof systems feature panelized roofs and parallel cord trusses. Firefighters entering an old style building should be on the lookout for clues such as arched lintels, collar ties, and king’s rows.
Such buildings feature conventionally framed roofing materials. When going to the roof of a building that does not have signs of unreinforced masonry, a firefighter must first sound the walls to establish the wall type. New buildings use parallel and panelized cord trusses that often fail unexpectedly in a direct fire impingement. Be it lightweight or conventional, vertical ventilation is very effective on ordinary construction types.
4. Heavy Timber Construction
The heavy timber construction can be found in old buildings. It uses large dimensional lumber for interior elements and structural members. Heavy timber buildings are extremely stable, even when on fire. It is however critical for firefighters to approach them with caution since they are usually poorly maintained, have weathering issues, or termites, conditions that could lead to quick collapse.
You can easily identify these buildings by the large lumber used to build walls and the expansive roofs that feature long roof spans. In most cases, these buildings are likely to have been built before 1960 when most construction featured metal plates and bolts connectors. These buildings have thicker-than-usual decking that makes it extremely challenging to drill or saw in a ventilation hole in case of a fire.
5. Wood-Framed Construction
Most modern homes feature wood-framed construction. The roofs and walls comprise combustible materials that are usually made of wood. The rooftops are mounted with asphalt shingles or ceramic tiles that are placed on OSB and lightweight trusses. In most cases, lightweight construction is bound to collapse in just a few minutes after catching fire.
It is therefore important to sound the walls of such a building before climbing to the rooftop. If it has a busy attic, consider using alternatives to rooftop ventilation such as asphalt or tile rooftops. Since the roofs are constructed with wood, the shingles can act as ventilation, but remove tiles first if they are installed.
6. Pre-Engineered Construction
This type of construction consists of factory-built steel buildings that are transported and assembled on site. With pre-engineered constructions, a contractor designs and builds the building. Warehouses and industrial structures are a perfect fit for this type of construction since it is cheap and can be quickly erected or dismantled and moved to another location. The advantage of pre-engineered construction is that it is quick to set up and also highly affordable in comparison to other construction types.