A structure fire includes the partial or complete burning of any type of residential, commercial or industrial building. We’re talking about homes, offices, stores, warehouses, factories or any type of building or their frameworks.
Structural fires are categorized differently than chimney fires, room-and-contents fires, vehicle fires, wildfires, or other outdoor fires.
For anyone who has experienced a fire in their home or at work, they understand how the damage to the premises is much wider than the actual burn areas, since smoke and water damage can be quite significant.
FIRE DEPARTMENT RESPONSE TO STRUCTURAL FIRES
Fire departments often respond to structure fires with a similar protocol. Often the following units are sent: fire engines, ladder trucks, rescue squads, chief officers, and an Emergency Medical Technician (EMT) unit. Each have specific assignments once they are sent. However, response details will vary among fire departments.
For many structural fires, shutting off gas and electricity at the location are typically an early priority for arriving fire crews.
If hazardous materials (hazmat) are known to be stored, or discovered, at a location, then additional specific procedures and equipment are required by firefighters. For example, a foam-carrying vehicle may be sent to structures known to store hazardous chemicals.
INTERIOR/EXTERIOR STRUCTURE FIRES
Structure fires may be attacked with either “interior” or “exterior” resources, or both.
- Interior crews, using the “two in, two out” rule, may extend fire hose lines inside the building, locate the fire and cool it with water. “Two in, two out” means firefighters never go into a dangerous situation in a fire or rescue incident alone. Two firefighters should be positioned outside the hazard area to initiate a rescue of the firefighters inside, in the event that they get into trouble.
- Exterior crews may direct water into windows and other openings, or against any nearby fuels exposed to the initial fire. However, hose streams directed into the interior through exterior wall apertures may conflict and jeopardize interior fire attack crews, so close coordination is vital.
FIRE RESISTANT BUILDINGS
Buildings that are made of flammable materials such as wood are different from fire-resistant building materials such as concrete. Generally, a “fire-resistant” building is designed to limit fire to a small area or floor. Other floors may be safe by preventing smoke inhalation and damage.
All buildings on fire, or suspected of being on fire, must be evacuated, regardless of fire rating.
FIRE STRUCTURE VENTILATION
Some fire fighting tactics may appear to be destructive, but often serve specific needs. For example, in order to provide ventilation for fires, firefighters are forced to either break open holes in the roof or floors of a structure (called vertical ventilation), or break open windows and walls (called horizontal ventilation) to remove smoke and heated gases from the interior of the structure.
Such ventilation methods are also used to improve interior visibility to locate victims more quickly.
Ventilation helps preserve the life of trapped or unconscious individuals as it releases the poisonous gases from inside the structure.
Vertical ventilation is vital to firefighter safety in the event of a flashover or backdraft scenario.
FLASHOVERS AND BACKDRAFTS
Flashover is one of the most-feared phenomena among firefighters. Firefighters are taught to recognize the signs and symptoms of flashovers and to avoid backdrafts.
Flashover by definition is “the sudden involvement of a room or an area in flames from floor to ceiling caused by thermal radiation feedback.” Thermal radiation feedback is the energy of the fire being radiated back to the contents of the room from the walls, floor, and ceiling. This radiation of energy to the contents of the room will raise ALL the contents to their ignition temperature. When the contents of the room suddenly and simultaneously ignite, this is flashover. This means that flashover is a temperature-driven event.
A backdraft is a smoke explosion that can occur when additional air is introduced into a smoldering fire and heated gases enter their flammable range and ignite with explosive force. A backdraft is an “air-driven event,” unlike a flashover, which is a “temperature driven.” The fact that most fires are air regulated and not fuel regulated makes the understanding of backdrafts so important.
Flashovers, due to their intense heat (900–1200° Fahrenheit) and explosive temperaments, are commonly fatal to firefighter personnel.
Precautionary methods, such as smashing a window, reveal backdraft situations before firefighters enter the structure to attack the fire head-on.
Releasing flammable gases through the roof eliminates the possibility of a backdraft, and the removal of heat can reduce the possibility of a flashover.
Firefighters exercise certain routines, including opening closed doors to buildings and compartments on fire, known as door entry procedures, ensuring fire crew safety where possible.
Firefighter safety is the number one priority.