# Structure fire

A structure fire is a fire involving the structural components of various types of residential, commercial or industrial buildings, such as barn fires. Residential buildings range from single-family detached homes and townhouses to apartments and tower blocks, or various commercial buildings ranging from offices to shopping malls. This is in contrast to "room and contents" fires, chimney fires, vehicle fires, wildfires or other outdoor fires.
Structure fires typically have a similar response from the fire department that include engines, ladder trucks, rescue squads, chief officers, and an EMS unit, each of which will have specific initial assignments. The actual response and assignments will vary between fire departments.
It is not unusual for some fire departments to have a predetermined mobilization plan for when a fire incident is reported in certain structures in their area. This plan may include mobilizing the nearest aerial firefighting vehicle to a tower block, or a foam-carrying vehicle to structures known to contain certain hazardous chemicals.

## Types (United States)

In the United States, according to NFPA, structures are divided into five construction types based on the severity of the fire hazard:
| Type I: Fire Resistive | Typically used in high-rises. The material comprising the structure is either inherently able to withstand significant exposure to fire (concrete), or in which a fire resistive covering is applied to steel structural members. |
| Type II: Non-combustible | Typically used in strip shopping center malls. Roofs are constructed out of steel rafters. |
| Type III: Ordinary construction | Brick and mortar walls, wood frame floors. City rowhouses are where this type of construction is most often found. |
| Type IV: Heavy timber | Often used in churches or other community-based buildings. |
| Type V: Wood frame | Typically used in recent construction of single-family dwellings, townhouses, garden apartments with four floors or less. |
* Remains of a structure fire on Cotton Avenue, Macon, Georgia, US. c. 1876
* A burned-out house

## Causes of house fires
### Canada

Information from Canada's National Fire Information Database shows these ignition sources for residential fires in 2014.
Residential fire sources of ignition, 6 jurisdictions, 2014 :
| Ignition source | Examples | Percentage |
| Cooking equipment | stoves, hot plates, BBQs, deep fryers | 33% |
| Smoker's material and open flame | cigarettes, lighters, matches, candles, lanterns, blow torches | 24% |
| Heating equipment | central heating, space heaters, wood stoves, fireplaces | 14% |
| Electrical distribution equipment | permanent electric wiring, extension cords, batteries | 11% |
| Appliances and household equipment | televisions, household appliances | 7% |
| Exposure | fire spread from other buildings or outdoors | 7% |
| Other electrical equipment | power tools, lamps, computers | 4% |
| No igniting object | lightning | 1% |
A 2023 update from Statistics Canada confirmed that cooking equipment and smoker's material continued to be the top causes of residential fires, at 32% and 25% of total incidents respectively.

### United States

Data from the U.S. Fire Administration's National Fire Incident Reporting System shows that cooking has consistently been the leading cause of residential building fires.
Residential building fire causes, 2017-2019 :
| Cause | Examples | Percentage |
| Cooking | stoves, ovens, cooking fires | 50.9% |
| Heating | furnaces, boilers, water heaters, portable heaters, chimneys | 9.3% |
| Other Unintentional, Careless | product misuse, discarded materials, heat source too close to combustibles | 7.4% |
| Electrical Malfunction | electrical wiring, lighting fixtures | 6.7% |
| Intentional | deliberately set fires | 4.3% |
| Open Flame | candles, matches, lighters, embers | 4.3% |
| Other Heat | fireworks, heat/sparks from friction | 3.4% |
| Appliances | most electronic and electrical appliances | 3.0% |
| Equipment Misoperation, Failure | equipment malfunction or operation deficiency | 2.3% |
| Smoking | cigarettes and other smoking materials | 2.0% |
| Exposure | heat spread from another hostile fire | 1.8% |
| Natural | spontaneous ignition, chemicals, storms | 1.7% |
| Other Equipment | computer, telephone, special or unspecified equipment | 1.3% |
| Cause under investigation | cause still undetermined | 1.3% |
| Playing with Heat Source | children or others playing with fire | 0.4% |