U.S. Department of Homeland Security • U.S. Fire Administration 

National Fire Data Center • Emmitsburg, Maryland 21727 

www.usfa.fema.gov/statistics/

Topical Fire reporT SerieS Volume 12, Issue 4 / June 2011

Large Loss Building Fires

These topical reports are designed to 

explore facets of the U.S. fire problem as 

depicted through data collected in the U.S. 

Fire Administration’s (USFA’s) National 

Fire Incident Reporting System (NFIRS). 

Each topical report briefly addresses the 

nature of the specific fire or fire-related 

topic, highlights important findings from 

the data, and may suggest other resources 

to consider for further information. Also 

included are recent examples of fire incidents that demonstrate some of the issues 

addressed in the report or that put the 

report topic in context.

Findings

■ An estimated 900 large loss building fires are reported to U.S. fire departments each year 

and cause an estimated 35 deaths, 100 injuries, and $2.8 billion in total loss.

■ Exposures are the leading cause of large loss building fires (22 percent). 

■ Attics, typically vacant spaces above the top story, are the primary origin of all large loss 

building fires (7 percent), along with cooking areas or kitchens (6 percent).

■ Large loss building fires are most prevalent in May (10 percent) and July (10 percent).

■ A peak in large loss building fires is seen between the hours of 1 a.m. and 4 a.m.

■ Forty-eight percent of large loss fires occur in residential buildings.

From 2007 to 2009, an estimated 900 large loss building 

fires were reported by U.S. fire departments annually. 

These fires caused an estimated 35 deaths, 100 injuries, and 

$2.8 billion in property damage.1,2,3 In this topical report, 

large loss building fires were defined as fires that resulted in 

a total dollar loss of $1 million or more.4

Even though large loss fires made up less than 1 percent 

of all building fires from 2007 to 2009, they accounted for 

26 percent of all building fire dollar loss during the 3-year 

period. These fires, though small in number, caused a large 

amount of property damage each year.

Many factors contribute to why these fires become so 

large in size and ultimately result in larger dollar losses. 

Detection time, building construction/design, building contents, and the response time have an impact on the overall 

size and damage produced by a fire. Detection time refers to 

how long it takes to notice that a fire is burning—a key factor for which there is no available data. Large loss fires tend 

to start in many locations where detection may be difficult, 

like attics or storage areas, and most commonly occur in the 

early morning hours. These two factors, the location and 

the time of day, can contribute to a longer detection time 

and ultimately a larger fire resulting in more damage. 

The way a building is constructed or designed can affect 

how a building may burn. In this topical report, the 

building’s construction or design was to blame for the 

growth and spread of the fire in 95 percent of the incidents. 

The most common place where the building construction 

or design failed was in the roof (27 percent). In the case of 

residential buildings, modern day roofs are typically built 

using trusses which are made of a lighter weight material. 

Truss roofs tend to burn more quickly than conventional 

roofs, which are made of more solid, robust materials.5

When one truss fails in the roof, the adjacent trusses tend to 

fail, resulting in a domino effect, which can cause an entire 

collapse of the structure.6

 This collapse typically causes significant damage to the property and contents below. 

Building contents can play a key role in how quickly a 

fire may spread. Residential buildings which made up 48 

percent of all large loss fires, contain furniture, decorative furnishings like drapes and rugs, and in some areas, 

flammable materials, that can contribute to a larger fire. 

Nonresidential buildings, like warehouses, storage areas, 

eating and drinking establishments, or detached garages, 

may contain a large number of combustibles or materials 

that burn fairly quickly. These combustibles can inhibit the 

fire department’s ability to extinguish the blaze and sometimes cause the fire to consume the entire building.7

 Even 

though nonresidential buildings made up 52 percent of all 

large loss fires, they accounted for 59 percent of all large 

loss fire dollar loss.
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 2

The overall response time is another factor that can contribute to how much damage a building may receive. The 

response times in rural areas can be long because a building 

may be located farther away from the closest fire station. 

Urban areas, however, are affected more by traffic patterns, ongoing construction, pedestrians, street layouts 

(dead ends, curvilinear streets, traffic calming devices such 

as speed bumps, and the like).8

 All of these daily aspects 

of urban living can affect how long it may take for the fire 

department to reach a burning building. The analysis of 

response times can be complex and was not undertaken in 

this short report.

On a fraction of the incident reports sent to the National 

Fire Incident Reporting System (NFIRS), the desired information for many data items either is not reported or is 

reported as “unknown.” This lack of data masks the true 

picture of the fire problem. In some cases, even after the 

best attempts by fire investigators, the information is truly 

unknown. In other cases, the information reported as 

unknown in the initial NFIRS report is not updated after 

the fire investigation is completed. When the unknowns 

are large, the credibility of the data suffers. Fire departments need to be more aware of the effect of incomplete 

data reporting and need to update the initial NFIRS report 

if additional information is available after investigation. The 

issues that arose while producing this topical report are 

discussed in a later section.

This topical report addresses the characteristics of large loss 

building fires reported to NFIRS from 2007 to 2009. The 

NFIRS data are used for the analyses presented throughout 

the report. For the purpose of the report, the term “large 

loss fires” is synonymous with “large loss building fires.” 

“Large loss fires” is used throughout the body of this report; 

the findings, tables, charts, headings, and footnotes reflect 

the full category “large loss building fires.”

The large loss fire incidents reported to NFIRS contain a 

notable number of exposure fires—fires which are the 

result of another fire. Exposure fire incidents have a majority of the same information as the originating incident, 

which can skew some of the analyses. In those analyses, 

such as time of alarm, only the originating incidents were 

examined and are so noted in the tables or graphics that 

accompany the analyses.

Type of Fire

Confined and Nonconfined Fires

Building fires are divided into two classes of severity in 

NFIRS: “Confined fires,” which are those fires confined to 

certain types of equipment or objects, and “nonconfined 

fires,” which are not. Confined building fires are small fire 

incidents that are limited in extent, staying within pots 

or fireplaces or certain other noncombustible containers.9

Confined fires rarely result in serious injury or large content 

losses, and are expected to have no significant accompanying property losses due to flame damage.10 Nonconfined 

fires account for all large loss building fires.11 The subsequent analysis of large loss fires in this report, therefore, 

includes only nonconfined fires.

Occupied and Nonactively Occupied Fires

Buildings can be defined as being occupied or nonactively 

occupied. An occupied building is defined as “occupied or 

operating,” while a nonactively occupied building is defined 

as “under construction,” “idle, not routinely used,” “under 

major renovation,” “vacant and secured,” “vacant and not 

secured,” or “being demolished.” In large loss building 

fires, a majority of the large loss fires occurred in occupied 

buildings (84 percent) while a smaller, yet still considerable proportion of large loss fires, occurred in nonactively 

occupied (“vacant”) buildings (16 percent). Contrary to 

some expectations, fires in nonactively occupied buildings 

are a smaller percentage of large loss fires than they are of 

nonconfined building fires overall (20 percent).

Type of Property

Buildings are classified into 12 major property types: 

assembly, eating and drinking establishments, educational, 

institutional, residential, stores and office buildings, basic 

industry, manufacturing, storage, detached garages, outside 

or special property, and other unspecified property.

Residential buildings account for the largest percent (48 

percent) of large loss building fires as shown in Table 1. 

One- and two-family dwellings (29 percent), multifamily 

dwellings (16 percent), and hotel/motel, commercial (2 

percent) account for the majority of fires in this category.

Stores and office buildings account for 16 percent of large 

loss building fires. Mercantile, business, other (3 percent), 

motor vehicle or boat sales, services, repairs (3 percent), 

business offices (2 percent), and food and beverage sales, 

grocery store (2 percent) are the leading property types in 

this category.

Manufacturing is the third leading property type at 10 percent. The remaining property types account for 25 percent 

of large loss building fires.
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 3

Table 1. Large Loss Building Fires by Property Type

Property Type Percent of Large Loss Building Fires

Residential 48.4

Stores and Offices 16.2

Manufacturing 10.2

Storage 7.1

Assembly 5.4

Eating and Drinking 4.6

Basic Industry 2.7

Educational 2.3

Other 1.4

Institutional 1.3

Outside or Special Property 0.3

Detached Garages 0.1

Total 100.0

Source: NFIRS 5.0.

Note: Property use codes for the above property types can be found in the National Fire Incident Reporting System Complete Reference Guide, July 2010, http://www.nfirs.fema.gov/documentation/reference/

NFIRS_Complete_Reference_Guide_2010.pdf. 

Loss Measures

Table 2 presents losses, averaged over the 3-year period, of 

reported large loss building fires.12 As shown in Table 2, not 

only do large loss fires have substantial dollar loss, they also 

result in more fatalities and injuries per thousand fires than 

nonlarge loss building fires.

Table 2. Loss Measures for Large Loss, Nonlarge Loss, and All Building Fires 

(3-year average, 2007–2009)

Measure Large Loss Building Fires Nonlarge Loss Building Fires All Building Fires

Average Loss:

Fatalities/1,000 fires 29.1 4.5 4.5

Injuries/1,000 fires 93.3 24.5 24.7

Dollar loss/fire $2,591,930 $14,280 $19,250

Source: NFIRS 5.0.

Notes: Average loss for fatalities and injuries is computed per 1,000 fires; average dollar loss is computed per fire and is rounded to the nearest $10. Dollar loss has also been converted to reflect total loss per fire 

in 2009 dollars. 

When Large Loss Building Fires Occur

As shown in Figure 1, large loss building fires occur most 

frequently in the early morning hours, peaking from 1 to 4 

a.m. They then gradually decline throughout the midmorning hours until 7 a.m. A sharp decrease is seen from 7 to 

9 a.m. with the lowest point being reached between 8 to 

9 a.m. The fire incidences then slightly rise and fall for the 

rest of the morning until a small peak is seen between 1 

and 2 p.m. A slight decrease is seen between 2 to 3 p.m., 

before gradually increasing again until 6 p.m. The fire incidences then slightly fall before peaking again between 8 to 

11 p.m. A decrease is then seen from 11 p.m. to midnight. 

Starting at midnight, the numbers of fires increase again 

until the peak period begins at 1 a.m. The peak period (1 to 

4 a.m.) accounts for 18 percent of all large loss fires.13
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 4

Figure 1. Large Loss Building Fires by Time of Alarm (2007–2009)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

11PM-Mid

10PM-11PM

9PM-10PM

1PM-2PM

2PM-3PM

3PM-4PM4PM-5PM

5PM-6PM

6PM-7PM

7PM-8PM

8PM-9PM

12PM-1PM

10AM-11AM

11AM-12PM

9AM-10AM

Mid-1AM

1AM-2AM2AM-3AM3AM-4AM4AM-5AM5AM-6AM6AM-7AM

7AM-8AM

8AM-9AM

Time of Alarm

Percent of Large Loss Building Fires

5.3

6.6

6.2

5.6

5.0

4.7 4.6

2.4 2.1

2.9 3.0 2.9

4.2

4.7 4.5

4.8

3.8

2.9

3.8 3.8 4.0

4.7

4.3

3.1

Source: NFIRS 5.0.

Note: For those large loss fires that were the result of an exposure to an existing fire, only originating incidents were used to determine time of alarm. 

Figure 2 illustrates that large loss building fires peak twice 

during the year, once in the spring/early summer and again 

in the winter. The spring/summer peak, which is the highest peak, occurs during the months of May (10 percent) and 

July (10 percent). The second peak in large loss fires is seen 

during the months of December (9 percent) and January 

(9 percent). The lowest number of fire incidents is seen in 

November.

Figure 2. Large Loss Building Fires by Month (2007–2009)

Month of Year 

Percent of Large Loss 

Building Fires

0.0

2.0

4.0

6.0

8.0

10.0

12.0

November

December

October

September

August

July

April

May

June

March

February

January

8.8 8.3 7.9 8.5

9.8

8.4

9.5

8.6

6.9 7.2 6.7

9.3

Source: NFIRS 5.0.

Note: For those large loss fires that were the result of an exposure to an existing fire, only originating incidents were used to determine the incident month. 

Causes of Large Loss Building Fires

Twenty-two percent of all large loss fires with cause information provided are exposure fires as shown in Figure 3. 

The next 3 leading causes combined account for 32 percent 

of large loss fires: electrical malfunctions (12 percent), 

other unintentional, careless actions (11 percent), and 

intentionally set fires (9 percent).14 In 41 percent of all large 

loss fires, the cause is unknown. This large percentage of 

unknown causes may be due to the fact that these fires 

grow so large and are widespread that it may be difficult 

for a firefighter to determine the exact fire cause. As noted 

in the next section, 88 percent of large loss fires extend 

beyond the floor of origin.
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 5

Figure 3. Large Loss Building Fires by Cause (2007–2009)

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0

Unknown

Investigation with Arson Module

Other Unintentional, Careless

Equipment Misoperation, Failure

Exposure

Natural

Other Equipment

Other Heat

Open Flame

Appliances

Electrical Malfunction

Cooking

Heating

Smoking

Playing with Heat Source

Intentional

Percent of Large Loss Fires 

with Cause Determined

Percent of Large Loss Fires

9.2

5.4

0.6

0.4

3.9

2.3

2.5

1.5

1.2

0.7

12.1

7.2

2.0

1.2

7.0

4.2

6.3

3.7

5.0

3.0

7.2

4.3

22.3

13.2

4.0

10.8

6.4

5.7

3.4

2.4

40.8

Percent of Large Loss Building Fires

Causes Source: NFIRS 5.0.

Notes: Causes are listed in order of the U.S. Fire Administration (USFA) Cause Hierarchy for ease of comparison of fire causes across different aspects of the fire problem. Fires are 

assigned to 1 of 16 cause groupings using a hierarchy of definitions, approximately as shown in the chart above. A fire is included in the highest category into which it fits. If it does 

not fit the top category, then the second one is considered, and if not that one, the third, and so on. For example, if the fire is judged to be intentionally set and a match was used 

to ignite it, it is classified as intentional and not open flame because intentional is higher in the hierarchy.

Fire Spread in Large Loss Building Fires

Eighty-eight percent of large loss fires extend beyond the 

floor of origin (Table 3), while only 12 percent of the fires 

are contained to the floor of origin or smaller area. By 

comparison, nonlarge loss fires are limited in fire spread. 

A much smaller percent of nonlarge loss fires (20 percent) 

extend beyond the floor of origin, while a larger percent (80 

percent) are contained to the floor of origin or smaller area. 

Table 3. Fire Spread for Large Loss and Nonlarge Loss Building Fires (2007–2009)

Fire Spread Percent of Large Loss Percent of Nonlarge Loss

Beyond floor of origin 87.8 20.3

Contained to floor or smaller area 12.2 79.7

Source: NFIRS 5.0.

Where Large Loss Building Fires Start 

(Area of Origin)

Seven percent of large loss building fires start in the attic or 

vacant, crawlspace above the top story (Table 4). Cooking 

areas, kitchens (6 percent) are the next leading areas of 

fire origin. Fires that begin in storage areas (5 percent), on 

exterior balconies, unenclosed porches (5 percent), or in 

processing/manufacturing areas, workrooms (5 percent) are 

the next leading areas of fire origin.
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 6

Table 4. Leading Areas of Fire Origin in Large Loss Building Fires (2007-2009)

Areas of Fire Origin Percent (Unknowns Apportioned)

Attic: vacant, crawlspace above top story 7.4

Cooking area, kitchen 5.7

Storage area, other 5.3

Exterior balcony, unenclosed porch 5.2

Processing/Manufacturing area, workroom 5.0

Source: NFIRS 5.0.

Note: Only originating incidents were used to determine area of fire origin.

Unfortunately, information on the items first ignited could 

not be provided as more than half of the incidents, 55 percent, specified “unknown” as the item first ignited. 

How Large Loss Building Fires Start 

(Heat Source)

Figure 4 shows sources of heat categories in large loss fires. 

The “heat from powered equipment” category, predominately 

electrical distribution-related equipment, accounts for 33 

percent of all large loss fires. Within this category, electrical arcing accounts for 12 percent, heat from other powered 

equipment accounts for 8 percent, sparks, embers, or flames 

from operating equipment account for 7 percent, and radiated 

or conducted heat from operating equipment account for 7 

percent of all large loss fires. 

The “heat spread from another fire” category accounts for 25 

percent of large loss fires. This category includes heat spread 

from another fire, other (16 percent), flying brand, ember, or 

spark (7 percent), heat from direct flames or convection currents, and radiated heat from another fire (1 percent each).

The heat source was coded as “undetermined” in 50 percent of 

the large loss fire incidents in NFIRS submitted between 2007 

and 2009.

Figure 4. Sources of Heat Categories in Large Loss Building Fires (2007–2009)

0.0 10.0 20.0 30.0 40.0 50.0 60.0

Undetermined

Explosive, fireworks

Multiple heat sources including multiple ignitions

Other heat source

Chemical, natural heat source

Hot or smoldering object

Heat from open flame or smoking materials

Heat spread from another fire

Heat from powered equipment

Percent of Large Loss Fires with 

Heat Source Determined

Percent of All Large Loss Fires

33.2

16.7

25.4

12.8

15.3

7.7

10.3

5.2

6.3

3.2

5.4

2.7

1.7

0.9

2.3

1.2

49.6

Percent of Large Loss Building Fires

Source: NFIRS 5.0.

Factors Contributing to Ignition in Large 

Loss Building Fires

Table 5 shows the categories of factors contributing to ignition in large loss fires. By far, the leading category is “fire 

spread or control” (34 percent). Exposure fires (30 percent), fire spread or control, other (3 percent), and rekindle 

(1 percent) account for the majority of the fires in this 

category. 

The “misuse of material or product” category is a contributing factor in 27 percent of large loss fires. Abandoned or 

discarded materials or products (8 percent), heat source 

too close to combustibles (7 percent), misuse of material 

or product, other (4 percent), cutting or welding too close 

to combustibles (3 percent), and flammable liquid or gas 

spilled (2 percent) are the leading specific factors contributing to ignition in this category.

The category “electrical failure, malfunction” is the third 

leading factor at 17 percent. The remaining categories are 

contributing factors in 31 percent of large loss fires. 
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 7

Table 5. Factors Contributing to Ignition for Large Loss Building Fires by Major Category 

(Where Factors Contributing to Ignition are Specified, 2007–2009)

Factors Contributing to Ignition Category Percent of Large Loss Building Fires

Fire spread or control 33.5

Misuse of material or product 26.9

Electrical failure, malfunction 16.8

Other factors contributing to ignition 8.2

Mechanical failure, malfunction 7.7

Natural condition 7.5

Operational deficiency 5.7

Design, manufacture, installation deficiency 1.6

Source: NFIRS 5.0.

Notes: 1) Includes only incidents where factors that contributed to the ignition of the fire were specified.

 2) Multiple factors contributing to fire ignition may be noted for each incident; total will exceed 100 percent. 

Factors Contributing to Fire Suppression 

in Large Loss Building Fires

Figure 5 shows the categories of factors contributing to fire 

suppression in large loss building fires (all of which are 

nonconfined fires) and nonconfined nonlarge loss building 

fires. The leading category for both large loss and nonconfined nonlarge loss fires is “building construction or 

design.” The percentage of factors contributing to fire suppression in this category are much higher, 95 percent, for 

large loss building fires than for nonconfined nonlarge loss 

building fires (59 percent). “Delays” are the second leading category for large loss and nonconfined nonlarge loss 

building fires. This category makes up 37 percent of large 

loss and 38 percent of nonconfined nonlarge loss building 

factors contributing to fire suppression. 

Figure 5. Factors Contributing to Fire Suppression for Large Loss Building Fires 

and Nonconfined Nonlarge Loss Building Fires by Major Category 

(Where Factors Contributing to Fire Suppression are Specified, 2007–2009)

0.0 20.0 40.0 60.0 80.0 100.0

Egress/Exit problems

Fire suppression factor, other

Act or omission

Protective equipment

Natural conditions

Onsite materials

Delays

Building construction or design

Percent of Large Loss 

Building Fires

Percent of Nonconfined 

Nonlarge Loss Building Fires

94.5

59.1

36.7

38.3

20.8

13.9

15.7

14.7

7.0 

8.8

3.6

4.9

2.7

2.5

7.4

4.5

Percent of Large Loss and Nonconfined Nonlarge Loss Building Fires

Source: NFIRS 5.0.

Notes: 1) Includes only incidents where factors that contributed to the suppression of the fire were specified.

 2) Multiple factors contributing to fire suppression may be noted for each incident; total will exceed 100 percent. 

 3) For those large loss fires and nonconfined nonlarge loss fires that were the result of an exposure to an existing fire, only originating incidents were used in the suppression factor 

analysis. 
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 8

Alerting/Suppression Systems in Large 

Loss Building Fires

Smoke Alarm Data

Smoke alarm data presented in Table 6 and Table 7 are the 

raw counts from the NFIRS data set and are not scaled to 

National estimates of smoke alarms in large loss fires. In 

addition, NFIRS does not allow for the determination of the 

type of smoke alarm—that is, if the smoke alarm was photoelectric or ionization—or the location of the smoke alarm 

with respect to the area of fire origin.

Overall, smoke alarms were present in 38 percent of large 

loss fires and were known to have operated in 25 percent of

the fires. By comparison, smoke alarms were present in 39 

percent of nonconfined nonlarge loss fires and operated in 

22 percent. In 22 percent of large loss fires, there were no 

smoke alarms present. In another 40 percent of these fires, 

firefighters were unable to determine if a smoke alarm was 

present (Table 6). 

Smoke alarms are present more often in large loss residential building fires than in nonresidential large loss building 

fires (47 percent versus 30 percent).

Table 6. NFIRS Smoke Alarm Presence in Large Loss Building Fires (NFIRS, 2007-2009)

Presence of Smoke Alarms Count Percent

Present 693 38.0

None present 402 22.1

Undetermined 727 39.9

Total Incidents 1,822 100.0

Source: NFIRS 5.0.

Notes: The data presented in this table are raw data counts from the NFIRS data set. They do not represent National estimates of smoke alarms in large loss building fires. They are presented for informational 

purposes. 

Smoke Alarms in Occupied Buildings

One of the most important values of smoke alarms is 

detecting smoldering fires before they break into open 

flame or produce large volumes of smoke. Smoke alarms 

were reported as present in 41 percent of large loss fires 

in occupied buildings (Table 7). Smoke alarms are known 

to have operated in 28 percent of large loss fires in occupied buildings and were known to be absent in 20 percent. 

Firefighters were unable to determine if a smoke alarm was 

present in another 39 percent of these fires.

When operational status is considered for large loss fires 

in occupied buildings, the percentage of smoke alarms 

reported as present (41 percent) consists of:

•	 smoke alarms present and operated—28 percent;

•	 present, but did not operate—3 percent (fire too small, 

0.7 percent; alarm did not operate, 3 percent); and

•	 present, but operational status unknown—10 percent. 

When the subset of incidents where smoke alarms were 

reported as present is analyzed separately, smoke alarms 

were reported to have operated in 67 percent of the incidents. The alarms failed to operate, however, in 6 percent 

of the incidents, and in another 2 percent of incidents, the 

fire was too small to activate the alarm. The operational 

status of the alarm was undetermined in an additional 25 

percent of the incidents.

Table 7. NFIRS Smoke Alarm Data for Large Loss Building Fires 

(NFIRS, 2007-2009) Occupied Buildings

Presence of 

Smoke Alarms Smoke Alarm Operational Status Smoke Alarm Effectiveness Count Percent

Present

Fire too small to activate smoke alarm 10 0.7

Smoke alarm operated

Smoke alarm alerted occupants, occupants responded

Smoke alarm alerted occupants, occupants failed to respond

No occupants

243

18

101

15.9

1.2

6.6

Smoke alarm failed to alert occupants 9 0.6

Undetermined 50 3.3

Smoke alarm failed to operate 40 2.6

Undetermined 154 10.0

None present 307 20.0

Undetermined 601 39.2

Total Incidents 1533 100.0

Source: NFIRS 5.0.

Notes: The data presented in this table are raw data counts from the NFIRS data set. They do not represent National estimates of smoke alarms in occupied large loss building fires. They are presented for informational purposes. The total may not add to 100 percent due to rounding. “Fire too small to activate smoke alarm” category may be incorrectly coded as noted in the Data Issues section.
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 9

Automatic Extinguishment System Data

Overall, full or partial Automatic Extinguishing Systems 

(AES), mainly sprinklers, were present in just 14 percent 

of large loss fires (Table 8). Sprinklers are more likely to be 

present in nonresidential building large loss fires (16 percent) than in residential building large loss fires (8 percent).

The lack of suppression equipment (sprinklers) in large loss 

properties is not unexpected since almost half of all large 

loss fires occur in residential buildings. It has not been until 

recently that certain localities require the installation of 

sprinkler systems in all new home construction.15 Note that 

the data presented in Table 8 are the raw counts from the 

NFIRS data set and are not scaled to National estimates of 

AES in large loss fires.

Table 8. NFIRS Automatic Extinguishing System (AES) Presence in Large Loss Building Fires 

(2007-2009)

Presence of Automatic Extinguishing Systems Count Percent

AES present 214 11.7

Partial system present 33 1.8

AES not present 1,259 69.1

Unknown 316 17.3

Total Incidents 1,822 100.0

Source: NFIRS 5.0.

Notes: The data presented in this table are raw data counts from the NFIRS data set. They do not represent National estimates of AESs in large loss building fires. They are presented for informational purposes. Totals 

may not add to 100 percent due to rounding.

Data Issues

The high level of “undetermined” or “unknown” entries 

in the various data elements in the large loss incidents in 

NFIRS masks the true picture of large loss fires. For example, 50 percent of the large loss entries listed heat source as 

“undetermined,” 55 percent listed the item first ignited as 

“undetermined,” and insufficient information was provided 

to determine the fire cause in 40 percent of these large loss 

incidents. These large percentages of unknowns cause the 

credibility of the data to suffer. 

The issue of inconsistent data further clouded the analyses. 

A noteworthy number of incidents are coded as “confined 

to the object of origin” for fire spread. While some large 

loss fires may indeed be confined to highly valuable large 

machinery or an occasional piece of artwork, it is highly 

unlikely that fires resulting in $1 million or more stayed 

confined to the object of origin. To determine if these fires 

were in fact “confined to the object of origin,” an Internet 

search was undertaken on a random set of the incidents 

under the observation that fires resulting in such a large 

dollar loss would have likely been reported in the media. Of 

the dozen fires researched, none were reported as “confined 

to the object of origin” fires, since either the entire floor of 

a building or the entire building itself was consumed by 

flames. 

In addition, in a small (but troublesome) number of fires, 

smoke alarms did not operate as the “fire was too small.” 

Most of these particular fires (6 of 10) were noted as confined to the object of origin or to the room of origin.

When information is reported incorrectly or incompletely, 

the fire problem cannot be analyzed to its full extent. 

Examples

The following are some recent examples of large loss fires 

reported by the media:

•	 October 2010: A fire in a Franklin, TN, home resulted 

in $2.5 million worth of damage. The cause of the fire 

is still unknown, but the fire began in a patio fireplace. 

The family of four present in the house at the time of 

the fire was able to escape safely. Four firefighters were 

injured while fighting the fire; two of them were treated 

at the scene and two were sent to the hospital for minor 

injuries.16

•	 June 2010: A Palo Alto, CA, two-alarm house fire caused 

between $1 and $2 million worth of damage. The family of four living in the house was awoken by their son 

when he heard the smoke alarm. The fire is believed to 

have been started by an unattended candle or cigarette 

the son left in a second-story room. The fire was brought 

under control in about 45 minutes and no deaths or 

injuries were reported.17
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 10

•	 June 2010: A fire that started in a Carmel, IN, shopping mall is believed to have been caused by lightning. 

Investigators have determined that the fire started in a 

restaurant located at the north end of the mall. There 

were no deaths or injuries as a result of the fire, but 

investigators estimate that the fire caused over $5 million worth of damage.18

•	 May 2009: A fire that started in a Gallery Furniture 

storage warehouse located in Houston, TX, resulted in 

at least $15 million worth of damage. Investigators have 

determined that the fire was caused by arson. Thirty to 

40 employees were present when the fire broke out. The 

fire was determined to have been started in an area only 

accessible to employees. There were no injuries or deaths 

as a result of the fire.19

NFIRS Data Specifications for Large Loss 

Building Fires

Data for this report were extracted from the NFIRS annual 

Public Data Release (PDR) files for 2007, 2008, and 2009. 

Only version 5.0 data were extracted.

Large loss fires are defined as:

•	 Aid Types 3 (mutual aid given) and 4 (automatic 

aid given) are excluded to avoid double counting of 

incidents.

•	 Incident Types 111, 112, 120, 121, 122, and 123: 

Incident 

Type Description

111 Building fire

112 Fires in structure other than in a building

120 Fire in mobile property used as a fixed structure, other

121 Fire in mobile home used as fixed residence

122 Fire in motor home, camper, recreational vehicle

123 Fire in portable building, fixed location

Incident Type 112 is included prior to 2008 as previous 

analyses have shown that Incident Types 111 and 112 

were used interchangeably. As of 2008, Incident Type 

112 is excluded.

•	 Property use is used to differentiate residential and nonresidential buildings: 

– 400–499 are residential properties,

– Properties uses outside of 400–499 are considered to 

be “not residential” or nonresidential.

•	 Structure Type:

– For Incident Types 111, 112, and 120–123:

▪ 1—Enclosed building, and

▪ 2—Fixed portable or mobile structure.

•	 Fires resulting in total dollar loss of $1 million or more. 

The analyses contained in this report reflect the current 

methodologies used by the U.S. Fire Administration (USFA). 

The USFA is committed to providing the best and most current information on the United States fire problem, continually examining its data and methodology to fulfill this 

goal. Because of this commitment, data collection strategies 

and methodological changes are possible and do occur. As 

a result, analyses and estimates of the fire problem may 

change slightly over time. Previous analyses and estimates 

on specific issues (or similar issues) may have used different 

methodologies or data definitions and may not be directly 

comparable to the current ones.

To request additional information or to comment on 

this report, visit http://www.usfa.dhs.gov/applications/

feedback/index.jsp

Notes: 

1 National estimates are based on 2007–2009 native version 5.0 data from the National Fire Incident Reporting System 

(NFIRS) and structure fire loss estimates from the National Fire Protection Association’s (NFPA’s) annual surveys of fire loss. 

Fires are rounded to the nearest 100, deaths to the nearest 5, injuries to the nearest 25, and loss to the nearest $million.

2 In NFIRS, version 5.0, a structure is a constructed item of which a building is one type. In previous versions of NFIRS, the 

term “structure” commonly referred to buildings. To coincide with this concept, the definition of a building fire for NFIRS 

5.0 has, therefore, changed to include only those fires where the NFIRS 5.0 structure type is 1 or 2 (enclosed building and 

fixed portable or mobile structure). Such fires are referred to as “buildings” to distinguish these buildings from other structures that may include fences, sheds, and other uninhabitable structures. Confined fire incidents without a structure type 

specified are presumed to be buildings. Nonconfined fire incidents without a structure type specified are considered to be 

invalid incidents (structure type is a required field) and are not included.
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 11

3 Buildings include, but are not limited to, assembly buildings, eating and drinking establishments, educational buildings, 

institutional buildings, residential buildings, stores and office buildings, basic industry buildings, manufacturing buildings, 

storage buildings, detached garages, outside or special property buildings and other.

4 Total loss is comprised of the combined total of property loss and content loss.

5 James M. Dalton, Robert G. Backstrom, and Steve Kerber, “Structural Collapse: The Hidden Dangers of Residential Fires,” 

fireengineering.com, October 1, 2009. http://www.fireengineering.com/index/articles/display/9770307568/articles/

fire-engineering/volume-162/issue-10/features/structural-collapse.html (accessed November 2, 2010).

6 Gregory Havel, “Construction Concerns: Truss Failure,” fireengineering.com, December 29, 2008. http://www.

fireengineering.com/index/articles/display/348315/articles/fire-engineering/featured-content/2008/12/constructionconcerns-truss-failure.html (accessed November 2, 2010).

7 Gerard J. Naylis, “Storage Practices in Warehouses and Distribution Centers,” fireengineering.com, February 1, 1999. 

http://www.fireengineering.com/index/articles/display/60826/articles/fire-engineering/volume-152/issue-2/departments/

industrial-fire-safety/storage-practices-in-warehouses-and-distribution-centers.html (accessed December 1, 2010).

8 William R. Sager, “Gridlocked: Poor Circulation Hurts Emergency Response,” fireengineering.com, February 1, 2008. 

http://www.fireengineering.com/index/articles/display/320693/articles/fire-engineering/volume-161/issue-2/features/

gridlocked-poor-circulation-hurts-emergency-response.html (accessed November 10, 2010).

9 In NFIRS, confined fires are defined by Incident Type codes 113 to 118.

10 NFIRS distinguishes between “content” and “property” loss. Content loss includes loss to the contents of a structure due 

to damage by fire, smoke, water, and overhaul. Property loss includes losses to the structure itself or to the property itself. 

Total loss is the sum of the content loss and the property loss. For confined fires, the expectation is that the fire did not 

spread beyond the container (or rubbish for Incident Type 118) and hence, there was no property damage (damage to the 

structure itself) from the flames. There could be, however, property damage as a result of smoke, water, and overhaul.

11 There were 10 confined, large loss fires present in NFIRS. Confined fires are defined as small incident fires that are limited in extent and rarely result in serious injury or large content losses. They also are defined as having no significant accompanying property losses due to flame damage. Because of these definitional constraints, the large loss confined fires were not 

included in the analysis.

12 The average fire death and fire injury loss rates computed from the National estimates will not agree with average 

fire death and fire injury loss rates computed from NFIRS data alone. The fire death rate computed from National estimates would be (1,000*(35/900)) = 38.9 deaths per 1,000 large loss building fires and the fire injury rate would be 

(1,000*(100/900)) = 111.1 injuries per 1,000 large loss building fires. The fire death rate computed from National estimates would be (1,000*(2,690/470,300)) = 5.7 deaths per 1,000 nonlarge loss building fires and the fire injury rate would 

be (1,000*(14,325/470,300)) = 30.5 injuries per 1,000 nonlarge loss building fires. The fire death rate computed from 

National estimates would be (1,000*(2,725/471,200)) = 5.8 deaths per 1,000 building fires and the fire injury rate would be 

(1,000*(14,425/471,200)) = 30.6 injuries per 1,000 building fires.

13 For the purposes of this report, the time of the fire alarm is used as an approximation for the general time the fire 

started. However, in NFIRS, it is the time the fire was reported to the fire department.

14 The USFA cause hierarchy was used to determine the cause of large loss fire incidents: http://www.usfa.fema.gov/

fireservice/nfirs/tools/fire_cause_category_matrix.shtm.

15 “Maryland County Law Mandates Sprinkler Systems in Single-Family Homes,” firechief.com, October 15, 2003. http://

firechief.com/awareness/firefighting_maryland_county_law/ (accessed November 10, 2010).

16 Andy Humbles, “Damage for Franklin House fire is estimated at $2.5 million,” tennessean.com, October 4, 2010. http://

www.tennessean.com/article/20101004/NEWS01/101004042/Damage-from-Franklin-house-fire-is-estimated-at-2-5-million 

(accessed October 27, 2010).
TFRS Volume 12, Issue 4/Large Loss Building Fires Page 12

17 Jesse Dungan, “Family escapes injury in two-alarm Palo Alto house fire,” mercurynews.com, September 17, 2010. http://

www.mercurynews.com/peninsula/ci_16106549?nclick_check=1=5 (accessed October 27, 2010).

18 Chris Proffitt, “Fire destroys Carmel strip mall,” wthr.com, June 22, 2010. http://www.wthr.com/story/12686875/firedestroys-carmel-strip-mall (accessed October 26, 2010).

19 Taylor Timmins, “Gallery Furniture owner ‘shocked and stunned’ that fire was arson,” txcn.com, May 28, 2009. http://

www.txcn.com/sharedcontent/dws/txcn/houston/stories/khou090528_tnt_gallery-furniture-fire-arson.25986392.html 

(accessed October 25, 2010).