NIST Technical Note 1600 

Residential Structure Separation Fire 

Experiments 

Alexander Maranghides 

Erik L. Johnsson 

NIST Technical Note 1600 

Residential Structure Separation Fire 

Experiments 

Alexander Maranghides 

Erik L. Johnsson 

U.S. Department of Commerce 

Technology Administration 

Building and Fire Research Laboratory 

National Institute of Standards 

And Technology 

Gaithersburg, MD 20899 

August 2008 

U.S. Department of Commerce 

Carlos M. Gutierrez, Secretary 

National Institute of Standards and Technology 

James M. Turner, Deputy Director
ii 

Certain commercial entities, equipment, or materials may be identified in this 

 document in order to describe an experimental procedure or concept adequately. Such 

identification is not intended to imply recommendation or endorsement by the 

National Institute of Standards and Technology, nor is it intended to imply that the 

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Technical Note 1600 

Natl. Inst. Stand. Technol. Tech. Note 1600, 42 pages (August 2008) 

CODEN: NSPUE2
iii 

Table of Contents

List of Figures................................................................................................................................ iv

List of Tables .................................................................................................................................. v

Abstract.......................................................................................................................................... vi

1.0 Background............................................................................................................................... 1

2.0 Introduction............................................................................................................................... 2

3.0 Technical Approach and Experimental Design ........................................................................ 3

3.1 Technical Approach.............................................................................................................. 3

3.2 Design and Fabrication of Realistic Residential Structure Separation Fixture..................... 3

3.3 Unrestricted Construction Experiment ................................................................................. 3

3.4 Fire Resistant Construction Experiment ............................................................................... 3

3.5 Structure of Fire Origin Contents ......................................................................................... 8

4.0 Experimental Measurements and Procedures ........................................................................... 9

4.1 9 m x 12 m Hood Description.............................................................................................. 9

4.2 Heat Release Rate Calorimeter ............................................................................................. 9

4.3 Temperature ........................................................................................................................ 11

4.4 Heat Flux............................................................................................................................. 11

4.5 Data Acquisition ................................................................................................................. 11

4.6 Experimental Procedure...................................................................................................... 12

5.0 Experimental Results .............................................................................................................. 13

5.1 Experiment 1 - Unrestricted Construction .......................................................................... 13

5.2 Experiment 2 - Fire Resistant Construction........................................................................ 15

6.0 Discussion of Results.............................................................................................................. 20

6.1 Unrestricted Construction ................................................................................................... 20

6.2 Fire Resistant Construction................................................................................................. 21

7.0 Summary................................................................................................................................. 22

8.0 Acknowledgements................................................................................................................. 23

9.0 References............................................................................................................................... 24

APPENDIX A. – Uncertainty Analysis........................................................................................ 26

A.1 General............................................................................................................................... 26

A.2 Heat Release Rate .............................................................................................................. 26

A.3 Temperature ....................................................................................................................... 27

A.4 Heat Flux............................................................................................................................ 27

APPENDIX B. – Data (only in electronic form, available upon request) .................................... 29

APPENDIX D. – NFIRS Data...................................................................................................... 33
iv 

List of Figures 

Figure 1. Photograph of the side of the structure of origin facing the adjacent target wall........... 4

Figure 2. Plan and cross section views of the two structures (not to scale)................................... 5

Figure 3. Cross section B-B (above) and C-C (below) of the two structures (not to scale). ......... 6

Figure 4. Schematic showing structural differences between unrestricted and fire resistant 

construction.................................................................................................................... 7

Figure 5. Photograph showing structural differences between unrestricted (left) and fire resistant 

(right) construction......................................................................................................... 7

Figure 6. Photograph showing interior of room of origin including wall, window, curtain, some 

furniture, and a thermocouple tree. ................................................................................ 9

Figure 7. Large Fire Laboratory 9 m x 12 m exhaust hood and duct system .............................. 10

Figure 8: Photograph of flux gauge (FG3) in target wall window looking at structure of fire 

origin. ........................................................................................................................... 12

Figure 9. Experiment 1 (unrestricted construction) heat release rate versus time. Uncertainty is 

16.4 %. ......................................................................................................................... 14

Figure 10: Sample of burned OSB from Target Wall - Experiment 1......................................... 14

Figure 11: Sample of unburned OSB from Target Wall - Experiment 2..................................... 15

Figure 12. Experiment 2 (fire resistant construction) heat release rate versus time. Uncertainty 

is 16.4 %....................................................................................................................... 16

Figure 13. Experiment 2 (fire resistant construction) temperatures versus time. Data have been 

smoothed (5 s window). Uncertainty before 380 s is about +0/-200 °C for the two 

thermocouples at the lowest height and +100/-0 °C for the others. After 380 s, the 

uncertainty for all temperatures is about +50/-0 °C..................................................... 17

Figure 14. Experiment 2 (fire resistant construction) heat fluxes versus time. Data have been 

smoothed (5 s window). Uncertainty is ±3 %............................................................. 18

Figure 15. Unrestricted Construction Experiment: Target Wall OSB Ignited 1 min 20 s after 

Window Failure............................................................................................................ 19

Figure 16. Fire Resistant Construction Experiment: 9 min after Window Failure – Target Wall 

OSB Not Ignited........................................................................................................... 19

Figure 17. Fire Service Response Times to Structural Fires ....................................................... 20
v 

List of Tables 

Table 1 Contents’ descriptions and weights ................................................................................... 8

Table 2 Location and orientation of heat flux gauges................................................................... 11

Table 3 Times of events during each experiment. ........................................................................ 13
vi 

Residential Structure Separation Experiments 

by 

Alexander Maranghides, Erik L. Johnsson 

Abstract 

Building codes often allow structures with window openings and combustible exteriors to be 

built with as little as 1.8 m (6 ft) of separation between them. In a recent full-scale laboratory 

experiment at the National Institute of Standards and Technology (NIST), it took less than 80 s 

for flames from a simulated house with combustible exterior walls to ignite a similar “house” 1.8 

m (6 ft) away. In another experiment, involving the same type of structures, the flames from one 

simulated house again reached the second, but this time a gypsum barrier protected the simulated 

home from sustained ignition. The experiments showed that an adjacent structure can be ignited 

if flames from a fire inside a house exit through window openings. The experiments illustrated 

how a fire resistant barrier can, in the scenario tested, slow down flame spread between two 

structures separated by 1.8 m (6 ft). The scenarios tested were not the worst case. Flame spread 

between structures is a complex process primarily affected by structure construction type, 

structure separation distance, placement and size of windows and weather conditions. 

KEY WORDS: residential structures, structure separation distance, community fire spread, 

multi-structure fires
1 

1.0 Background 

According to the National Fire Incident Reporting System (NFIRS) [National Fire Data Center, 

Feb 2006], the following summarizes the statistics related to recent U.S. occurrences of fire 

spread between structures. In 2003, fires spreading beyond the building of origin accounted for 

5.4 % of all structure fires. Between 2001 and 2003, fires that spread beyond the building of 

origin were responsible, on average, for 100 deaths per year, or about 11 % of all structural fire 

related fatalities. The costs from these fires are estimated at over $0.25 billion per year or 12 % 

of the total dollar loss from structure fires. See Appendix D for detailed tabulation of these 

statistics. Even though NFIRS does not include all fire incidents, the above data illustrates the 

magnitude of the problem. Fire spread between structures (when not prevented by suppression) 

is governed by four parameters: construction type, placement and size of windows, proximity of 

structures or structure separation distance, and weather conditions, specifically wind. Recent 

building code changes permit structures built of unrestricted construction (no enhanced fire 

resistance) to be separated by only 1.8 m (6 ft). As the preponderance of high density housing 

increases, so does the risk of fire incidents involving multiple structures. 
2 

2.0 Introduction 

Fire spread between adjacent homes has always been a concern of the firefighting community, 

yet the effect of more dense construction and more closely built homes on fire spread has not 

been extensively characterized. In a recent full-scale laboratory experiment at the National 

Institute of Standards and Technology (NIST), it took less than 80 s for flames from a simulated 

house with combustible exterior walls to ignite a similar “house” 1.8 m (6 ft) away. In another 

experiment, involving the same type of structures, the flames from one simulated house again 

reached the second, but this time a gypsum barrier protected the simulated home from sustained 

ignition. This helps to illustrate the significance of the problem. Solving this problem would 

address the $0.25 billion fire losses associated with multiple structure fires. 

The two experiments described above were part of a NIST Building and Fire Research 

Laboratory (BFRL) project to develop computer models that better predict the spread of fire in 

communities. The computer fire modeling and visualization programs, developed by NIST, are 

the Fire Dynamic Simulator (FDS) [McGrattan et al, 2007] and Smokeview [Forney, 2004]. 

FDS numerically models the movement of smoke and hot gases from a fire, predicting gas 

temperatures, heat fluxes, gas velocities and sprinkler activation times. The Smokeview program 

graphically depicts this information. FDS and Smokeview are beginning to be used by both fire 

investigators looking into why fires behave in specific ways and by builders or architects who 

want to know how fire detection equipment will react to fires. Data from the house-to-house 

fires, once incorporated into the FDS program and portrayed with the Smokeview software, will 

allow fire protection engineers, fire code officials and firefighters to better understand fire spread 

potential in dense housing communities. Fire departments are particularly interested in estimates 

of the time required for fire spread from one house to another. Such data would allow them to 

plan an appropriate and effective response. 

The NIST house-to-house fire spread experiments may be of considerable interest to building 

code authorities and community planners due to the possible implications on public safety. In 

recent years, building codes often allow structures with window openings and combustible 

exteriors to be built with as little as 1.8 m (6 ft) separation between them. The NIST experiments 

duplicated the 1.8 m (6 ft) distance between structures. The experiments showed that an adjacent 

structure can be ignited if flames from a fire inside a house exit through window openings. The 

second experiment, however, demonstrated that the inclusion of a fire-resistant barrier on 

exterior walls can significantly delay fire spread. 

The scenarios tested were not the worst case, and the experiments conducted address several but 

not all fire spread scenarios. Fire spread between structures is a complex process primarily 

affected by construction type, separation distance, placement and size of windows and effects of 

weather. All of these factors influence ignition and flame spread between structures. 

The data collected from these experiments has been used to evaluate the NIST FDS model so it 

can be used to predict fire spread in residential communities with particular structures and 

separation distances. The findings of the two experiments will be used to determine what 

additional experiments and research are needed to better estimate the potential for fire spread as 

a function of separation distance. 
3 

3.0 Technical Approach and Experimental Design 

3.1 Technical Approach 

The technical approach included two indoor/laboratory experiments. The four step process is 

listed below: 

• Design of realistic residential structure separation fixture 

• Fabrication and instrumentation of laboratory experiments 

• Execution of laboratory experiments 

• Interpretation of experimental results 

3.2 Design and Fabrication of Realistic Residential Structure Separation Fixture 

For both the unrestricted and fire resistant structure experiments, the structure of fire origin, 

shown in Fig. 1, consisted of a 3.7 m (12 ft) by 4.3 m (14 ft) room with a 2.4 m (8 ft) high 

ceiling. A single 0.6 m (2 ft) by 0.9 m (3 ft) window in the center (horizontally) of the wall 

facing the second structure was closed and locked. This window is shown in the Fig. 1 

photograph and the schematics of Figs. 2 and 3. An access door was closed, but below the door 

was a 0.3 m (1 ft) by 1.8 m (6 ft) vent that was continuously open. For the fire resistant structure 

test, two 15 cm by 20 cm floodlights were placed in the vent for visibility, decreasing the area by 

about 1/9. The room was furnished as described in Sec. 3.5. The schematics show the relative 

spacing of the furnishings. 

The target wall window was offset from the structure of fire origin window to prevent flames 

from the fire room window from entering the target wall through its window. The target wall 

window was necessary for locating a heat flux gauge without breaching the structure in a way 

that could affect the durability of the wall. 

3.3 Unrestricted Construction Experiment 

Figures 4 and 5 are schematics and photographs, respectively, of the two construction techniques 

used in these experiments. The structure of fire origin and the target wall were both assembled 

using unrestricted construction, typical of many current buildings. The order of the structural 

layers from inside to the outside was: drywall, wood studding, oriented strand board (OSB), 

weather wrap, and vinyl siding. The area between wood studs was filled with fiberglass 

insulation. 

3.4 Fire Resistant Construction Experiment 

The main difference between the first and the second experiment was the introduction of a fire 

resistant barrier between the OSB and the weather wrap. The fire resistant barrier used on both 

structures was 1.3 cm (1/2 inch) drywall. Placing gypsum board on an exterior wall is not a 

typical construction practice for many reasons. It is, however, a simple means to demonstrate the 

value of a fire resistance level at least equal to what a gypsum board would provide. 
4 

Figure 1. Photograph of the side of the structure of origin facing the adjacent target wall. 
5 

Figure 2. Plan and cross section views of the two structures (not to scale). 

A 

1.2 m 

(4 ft) 

0.6 m 

(2 ft) 

Target 

Wall 

Structure of Fire Origin 

3.7 m 

(12 ft)

4.9 m 

(16 ft) 

1.8 m 

(6 ft) 

4.3 m 

(14 ft) 

0.9 m 

(3 ft) 

1.5 m 

(5 ft) 

 A 

0.9 m 

(3 ft) 

 B 

 B 

1.8 m 

(6 ft)

Plan View

North

 C 

 C 

Thermocouple Tree X 

1.0 m 

(3.3 ft) 

1.1 m 

(3.7 ft) 

Elevation View 

A-A Cross Section

Second Story Facade 

“Back Side” 

4.9 m 

(16 ft) 

Target 

Wall 

2.4 m 

(8 ft)

0.3 m 

(1 ft)

1.5 m 

(5 ft) 

Access Door 

(Closed) 

Supply 

Vent 

(Always 

Open) 

1.8 m 

(6 ft)

3.7 m 

(12 ft)

Thermocouple

Tree 
6 

Figure 3. Cross section B-B (above) and C-C (below) of the two structures (not to scale). 

4.9 m 

(16 ft) 

Target Wall

4.9 m (16 ft)

4.3 m (14 ft)

1.2 m 

(4 ft) 

1.2 m 

(4 ft) 

0.9 m 

(3 ft) 

0.6 m 

(2 ft) 

Flux Gauges on 

Target Wall 

Facing Structure 

of Fire Origin 

FG2 FG1 

FG3 2.4 m 

(8 ft)

Large Fire Lab 

North Wall 

North 

Second Story Facade 

“Back Side” 

2.4 m 

(8 ft)

0.3 m 

(1 ft)

1.8 m 

(6 ft) 

4.9 m 

(16 ft) 

0.9 m 

(3 ft)

Access Door 

(Closed) 

Target Wall 

4.9 m (16 ft) 

4.3 m (14 ft) 

Supply Vent (Continuously Open) 

1.8 m (6 ft)

FG1 FG2 

Flux Gauges on 

Target Wall 

Facing Structure 

of Fire Origin 

Large Fire Lab

North Wall 

North
7 

Figure 4. Schematic showing structural differences between unrestricted and fire resistant 

construction. 

Figure 5. Photograph showing structural differences between unrestricted (left) and fire 

resistant (right) construction. 

Weather 

Wrap 

Vinyl 

Siding 

Exterior Interior 

(5 x 10) cm wood stud 

Insulation 

1.3 cm Drywall 

Fire Resistant 

Barrier 

1.3 cm Drywall 

Fire Resistant Construction

Exterior 

Unrestricted Construction

OSB 
8 

3.5 Structure of Fire Origin Contents 

The structure of fire origin was furnished with the identical furnishings for both experiments. 

The “living room” type of arrangement contained a sofa, an arm char, a coffee table, an end table 

with a lamp and a bookcase. The interior walls were covered with wood paneling and the floor 

was carpeted. Table 1 contains the particulars of room contents. Figure 7 is a photograph of the 

interior of the structure of fire origin which shows a wall, window, curtain, some furniture, and a 

thermocouple tree. Figure 2 shows the locations of the major furnishings. 

Table 1 Contents’ descriptions and weights 

Item Dimensions 

Width, Height, Length 

(m, m, m) 

(±1 %)1

Quantity Combustible 

Material 

Total Mass 

(kg) 

(±2 %)1

Sofa 0.91, 0.74, 2.16 1 Plastics/ wood 50.6 

Arm chair 0.91, 0.74, 1.00 1 Plastics 30.0 

Coffee table 0.66, 0.40, 1.28 1 Wood 17.2 

End Table 0.59, 0.48, 0.63 1 Wood 9.5 

Bookcase 0.92, 1.82, 0.31 1 Particle board 39.7 

Wall Trim 0.011, 0.087, 25.6 - Plastic 10.0 

Window Trim 0.0055, 0.0235, 3.2 - Plastic 0.1 

Wood paneling2 0.004, 1.22, 2.44 13 Wood 115.7 

Curtain 1.0, 2.0, 0.002 1 Plastic 0.4 

Carpet 3.62, 0.02, 4.24 1 Plastic 39.3 

Total 312.5 

Fuel Loading (19.7 ± 0.5) kg/m2 [(4.0 ± 0.1) lbs/ft2]

1

1

 Uncertainties are combined and expanded (k=2) 

2 0.004 m thick (5/32 inch) medium density fiberboard (MDF) 

Flame Spread 200 or less ASTME-84 
9 

Figure 6. Photograph showing interior of room of origin including wall, window, curtain, 

some furniture, and a thermocouple tree. 

4.0 Experimental Measurements and Procedures 

The primary objective of the experiments was to assess the impact of construction differences on 

the ignition of one structure by a burning adjacent structure. Two structure separation 

experiments (SSE) were conducted in the NIST Large Fire Laboratory (LFL). The uncertainties 

for the measurements described here are detailed in Appendix A. Throughout this report, 

uncertainties are combined with coverage factor k=2 unless otherwise stated. 

4.1 9 m x 12 m Hood Description 

The LFL High Bay test area is nominally 9 m (30 ft) wide and 37 m (120 ft) long. The SSE 

experiments were conducted under the 9 m by 12 m (30 ft by 39 ft) hood which is permanently 

installed in the facility. Top and side view diagrams of the hood and duct system are shown in 

Fig. 7. The test area beneath the hood is open on three sides, and the fourth side is near the north 

wall of the laboratory. The base of the hood is located 6.4 m (21 ft) above the laboratory floor. 

The constructed room was centered between the north and south sides of the hood. 

4.2 Heat Release Rate Calorimeter 

The heat release rate (HRR) was measured using oxygen consumption calorimetry in the 9 m by 

12 m (30 ft by 39 ft) exhaust hood in the NIST Large Fire Laboratory. The products of 

Thermocouple 

Tree 
10 

combustion from the fire filled the upper layer of the room and then flowed out of the window 

where they were completely captured by the exhaust hood. Measurements of the duct mass flow 

rate and the concentrations of various gas species were used to infer the HRR of the fire. This 

form of fire calorimetry was first suggested by Huggett [1980], who exploited the finding that 

the amount of heat released from most organic materials per unit mass of oxygen consumed in 

their complete combustion is nearly constant. Thus, the oxygen decrease in the duct flow 

(relative to ambient air) is a measure of the HRR in the flow. Huggett showed that for most 

common materials containing C, H, O, N, the heat release per unit mass of oxygen consumed is 

constant to within ±5 %. This sets a fundamental accuracy limit in this method for materials that 

are not chemically characterized. For fuels that are well-characterized, this parameter can be 

estimated with greater accuracy. 

Figure 7. Large Fire Laboratory 9 m x 12 m exhaust hood and duct system 

Bryant et al. [2003] describe the heat release measurement facility, instrumentation, calibration, 

measurement uncertainty and experimental procedures in detail. The calorimetry determination 

required about 40 measurements. These included temperature and pressure in the exhaust duct to 

quantify the total mass flow of exhaust gases and gas species sampled in the exhaust duct, 

transported to the instruments in a control room, and analyzed for oxygen, carbon dioxide, and 

carbon monoxide. Water vapor in the exhaust stream was trapped and not measured. The 

ambient temperature, pressure, and relative humidity in the test bay were measured and used in 

the HRR calculation. The computation of HRR was made following Bryant et al. [2003; 2004]. 

Appendix A.2 details the inputs resulting in 16.4 % HRR uncertainty for these experiments. 

0.91 m

Gas Sampling Plane

Velocity Measurement Plane

Flow

Straightener

D1.98 m

D1.98 m DN Th

Top View

Above Roof

Access Hatch

9.00 m x 12.00 m 

6.40 m

1.83 m

D1.98 m

MOD

Side View Top View 

Above Roof 

D 1.98 m Down 

Motor Through Roof 

Operated 

Damper
11 

4.3 Temperature 

The thermocouple tree for measuring temperatures in the fire room (shown in Fig. 6.) was 

located approximately 1.8 m (6 ft) from the south wall and 1.2 m (4 ft) from the east wall. The 

tree consisted of six 24 gauge type K bare-bead thermocouples. The beads were located on 

individual horizontal “branches” approximately 6 cm from the vertical centerline of the tree. 

The locations of the thermocouples relative to the ceiling were: 2.5 cm (1 in), 30.5 cm (1 ft), 61.0 

cm (2 ft), 91.4 cm (3 ft), 152.4 cm (5 ft) and 213.4 cm (7 ft). The tree was suspended from the 

ceiling and attached to the floor with a screw to provide tension for maintaining vertical 

alignment. Appendix A.3 describes asymmetrical uncertainties for temperature measurements in 

these experiments which depend on fire condition and thermocouple location. 

4.4 Heat Flux 

Heat fluxes were measured only during Experiment 2. The objective of these measurements was 

to provide information on the incident heat flux experienced by the adjacent structure from the 

burning structure. Three Schmidt-Boelter total heat flux gauges were used to measure the heat 

fluxes generated on the target wall: two at the top of the wall and one at the target wall window. 

The target wall window gauge is shown in the Fig. 8 photograph. Table 2 summarizes the 

location, orientation, and designation of the total heat flux gauges used in these experiments. 

Table 2 Location and orientation of heat flux gauges 

Heat Flux Gauge Height above 

Ground (m) 

(±1 %) 

Distance from 

South End of 

Target Wall (m)

(±1 %) 

Location Orientation 

(Horizontal 

Axes) 

Gauge 1 SN#120295 4.9 2.3 Top of target wall Pointing East 

Gauge 2 SN#120294 4.9 3.5 Top of target wall Pointing East 

Gauge 3 SN#120297 1.4 3.5 Target wall window Pointing East 

A Schmidt-Boelter flux gauge uses a water-cooled thermopile as a sensor whose surface 

temperature is uniform and close to that of the cooling water used. The gauge was used to 

measure the combined convective and radiative heat fluxes to the sensor surface. The gauges 

(Medtherm Model GTW-15SB-6-60-40-484K) had a field of view of 180°. They were rated at 

150 kW/m2

, and had a time response of approximately 0.1 s to 0.2 s. Signal and thermocouple 

wires from the gauges and cooling water supply and return lines were thermally protected using 

a thermal ceramic blanket and then wrapped with aluminum foil. Uncertainties were ±3 %.

4.5 Data Acquisition 

The NIST Large Fire Laboratory Data Acquisition system (DAQ) was utilized to monitor HRR, 

heat fluxes and temperatures at a sampling rate of 1 Hz. The following description of the data 

acquisition system is modified from a more detailed description in Bryant et al [2004]. 

The signals from the various measurement devices used for oxygen-depletion calorimetry 

determination of heat release rate were collected using the NIST Large Fire Laboratory data 

acquisition system (DAQ) programmed with LabView. The DAQ was configured to collect data 
12 

both from instruments for calorimetry calculations and from other instruments or sensors being 

utilized for the experiment. All channels were scanned at a rate of 200 Hz and the signals were 

multiplexed to a single channel on the primary DAQ board. Each channel was electronically 

averaged for 1 s and the digital value was stored to the computer. Some signal conditioning 

features included an electronic filter (200 Hz low pass), gains of 100 for temperature and heat 

flux millivolt signals, and cold-junction compensation for thermocouples. 

Figure 8: Photograph of flux gauge (FG3) in target wall window looking at structure of 

fire origin. 

4.6 Experimental Procedure 

The two experiments were conducted using similar experimental procedures. Once the 

structures were constructed and furnished, the instrumentation was installed. The compartment 

was evacuated and the compartment door was set partially open at a 30° angle. A remotely 

ignited book of matches was used to set fire to a newspaper on a sofa cushion. Ignition was 

noted and once the window broke (it was always closed), the door was closed. The first 

experiment was terminated when the target structure was ignited and the HRR exceeded 15 MW, 

the safety threshold for sustained fires in the LFL. The second experiment was allowed to burn to 

completion. 
13 

5.0 Experimental Results 

Results and timelines for the two experiments are listed below. For this discussion, combined 

expanded uncertainties related to time are ±2 s. 

5.1 Experiment 1 - Unrestricted Construction 

At ignition, the window was closed and the access door was set partially open. The fire was 

initiated on one side of the sofa, and 3 min and 40 s after ignition, the window broke. The door 

was then secured in the closed position while the supply vent remained open providing air to the 

fire. The flames exiting the window impinged on the target structure within seconds. On the 

structure of origin, the oriented strand board located above the window was ignited shortly after 

the flames exited the window. On the target wall and second story facade, the vinyl siding and 

weather wrap melted away with minimal contribution to the total energy release since no flames 

were visible from them. The oriented strand board of the target wall was ignited 5 min after 

ignition, or 80 s after the fire exited the structure of origin. The experiment was terminated at the 

point that the peak heat release rate nominally reached (15.0 ± 2.5) MW. Table 3 summarizes 

the event times for each experiment. 

Table 3 Times of events during each experiment. 

Unrestricted Construction 

Experiment 1 

Fire Resistant Construction

Experiment 2 

Time (2σ uncertainty ±2 s) Event 

(min:s) (s) (min:s) (s) 

Ignition 00:00 0 00:00 0 

Window breakage 03:42 222 03:38 218 

Flames begin target wall 

impingement 03:51 231 03:53 233 

Smoke exiting structure (no 

flames) Not Applicable 04:09 to 

05:42 249 to 342 

Flames resume Not Applicable 05:43 343 

Fire extinguished 04:57 297 14:45 885 

Flame impingement duration on 

target wall 01:09 69 09:18 558 

OSB ignited on target wall 05:00 300 OSB did not ignite 

Figure 9 shows the HRR versus time for Experiment 1. The peak HRR of (14.1 ± 2.3) MW 

occurred at 297 s. The structure of origin flashed over at approximately (2.5 ± 0.4) MW. The 

fire was extinguished 5 min after ignition; therefore the period of time that the fire HRR 

exceeded 2.5 MW was limited to about 99 s. The measured peak heat release rate includes 

contributions from the building contents and the oriented strand boards burning on the outside of 

both structures. Figure 10 shows a section of burned OSB from the wall of the target structure. 
14 

0

2000

4000

6000

8000

10000

12000

14000

16000

0 200 400 600 800 1000

Heat Release Rate, kW

Time, s

Figure 9. Experiment 1 (unrestricted construction) heat release rate versus time. 

Expanded uncertainty is 16.4 %. 

Figure 10: Sample of burned OSB from Target Wall - Experiment 1 

Fire Suppressed (t=297 sec) 
15 

5.2 Experiment 2 - Fire Resistant Construction 

The window failed approximately 3 min and 40 s after ignition, which was the same time as 

during the previous experiment. Within 15 s the flames were impinging on the target wall. The 

fire went through a transition period of 1 min 45 s where only hot gases (no flames) were exiting 

the structure. At approximately 6 min after ignition, flames resumed. At 14 min and 25 s, the 

fire was extinguished. In this experiment, the fire resistant barrier prevented ignition of the OSB 

even after approximately 9 min of direct flame impingement on the target structure. Figure 11 

shows a section of unburned OSB from the wall of the target structure. 

Figure 12 shows the HRR versus time for Experiment 2. The peak HRR of (10.0 ± 1.6) MW 

occurred at 398 s. The period of the fire that the HRR exceeded 2.5 MW totaled about 536 s. 

Figure 13 shows the temperatures versus time from the thermocouple tree in the room and in the 

window. The temperature in the window increased to 560 °C +10/-0 °C before it broke at 3:38. 

The indicated window temperature dropped when the thermocouple fell with the glass, but 

peaked again at 613 °C +50/-0 °C when the room flashed-over. After that time, all of the 

thermocouples in the room measured similar temperatures with the ones near the ceiling 

decreasing somewhat over time. 

Figure 14 shows the heat fluxes versus time. Gauges 1 and 2 were at the same height, 4.9 m 

(16 ft). Gauge 3 was located at the height of the window. Gauge 2 saw the flames escaping 

from the window and therefore experienced the largest heat flux which peaked at nearly 

140 kW/m2

 and was over 50 kW/m2 for much of the fire. Gauge 1 measured fluxes mostly in the 

range from 20 kW/m2

 to 70 kW/m2. Gauge 3 measured fluxes less than 30 kW/m2. 

Figure 11: Sample of unburned OSB from Target Wall - Experiment 2 
16 

0

2000

4000

6000

8000

10000

12000

0 200 400 600 800 1000

Heat Release Rate, kW

Time, s

Figure 12. Experiment 2 (fire resistant construction) heat release rate versus time. 

Expanded uncertainty is 16.4 %. 

Fire Suppressed (t=885 sec) 
17 

0

200

400

600

800

0 200 400 600 800 1000

2.5 cm (1 in) from ceiling

30.5 cm (1 ft) from ceiling

61.0 cm (2 ft) from ceiling

91.4 cm (3 ft) from ceiling

152.4 cm (5 ft) from ceiling

213.4 cm (7 ft) from ceiling

Window, structure of origin

Temperature, 

o

C

Time, s

Figure 13. Experiment 2 (fire resistant construction) temperatures versus time. Data have 

been smoothed (5 s window). Expanded uncertainty before 380 s is about +0/-

200 °C for the two thermocouples at the lowest height and +100/-0 °C for the 

others. After 380 s, the uncertainty for all temperatures is about +50/-0 °C. 

Fire Suppressed (t=885 sec) 
18 

0

20

40

60

80

100

120

0 200 400 600 800 1000

HF1 at top of target wall

HF2 at top of target wall

HF3 in target wall window

Total Heat Flux, kW/m2

Time, s

Figure 14. Experiment 2 (fire resistant construction) heat fluxes versus time. Data have 

been smoothed (5 s window). Relative expanded uncertainty is ±3 %. 

Fire Suppressed (t=885 sec) 
19 

Figure 15. Unrestricted Construction Experiment: Target Wall OSB Ignited 1 min 20 s 

after Window Failure 

Figure 16. Fire Resistant Construction Experiment: 9 min after Window Failure – Target 

Wall OSB Not Ignited 
20 

6.0 Discussion of Results 

It is revealing to relate the results of these experiments with the time required for the fire service 

to respond to a structure fire incident. In NFIRS, [National Fire Data Center, Aug 2006] 

response times are measured from alarm time to arrival on scene, but there is uncertainty in the 

data. NFIRS 5.0 defines alarm time as “when the alarm was received by the fire department.” 

This definition is vague and subjective. Some departments may read this definition to mean 

when the notification comes into the 911 communications center (911 activation), while others 

may interpret it as when the notification comes into the station (dispatch time).Thus, depending 

on the interpretation by the department, response times reported to NFIRS may or may not 

include call processing and dispatch time, which could typically take between 30 s and 120 s. 

In 2001 and 2002, as shown in Fig. 17, the highest percentage (16 %) of structure fires had a 

fire service response time in the 4 min range. The percent of structure fires with response 

times of 3 min and 5 min were not far behind at 15 % and 14 %, respectively. Overall, 61 % of 

structure fires in 2001 and 2002 had a response time of less than 6 min. 

Figure 17. Fire Service Response Times to Structural Fires 

The two NIST experiments provide limited information and do not represent a worst case 

scenario. The limited data from the two experiments illustrate the benefits of fire resistant 

construction in providing significant time for fire department response based on the NFIRS 

provided data. 

6.1 Unrestricted Construction 

The unrestricted construction experiment resulted in window failure at 3 min and 

42 s after ignition and involvement of the adjacent structure another 1 min and 18 s later. If the 

fire department was notified as soon as the fire exited the structure of origin, for the unrestricted 

construction scenario, less than 10 % of the fire departments would be able to arrive on the scene 

in 80 s, before the second structure was on fire. Alternatively, in the most extreme case, if the 

Response Time (min) Response Time (min) 

Percent of Fires 

Cumulative Percent of Fires 
21 

fire department was notified immediately upon ignition, approximately 55 % of fire departments 

would be able to get on the scene in 5 min, before fire spread to an adjacent structure. 

6.2 Fire Resistant Construction 

The fire resistant construction experiment resulted in window failure at 3 min and 42 s after 

ignition. The fire did not spread to the adjacent structure even after 9 min of flame impingement. 

During that experiment the fuel load of the structure of origin only provided enough energy for 9 

min of flame impingement on the adjacent structure. In a real world scenario, it is likely that the 

exposure duration would have been longer. The additional protection provided by the fire 

resistant construction would provide critical time for fire department response. If adjacent 

structure ignition was assumed after 9 min of flame exposure, a conservative assumption, and if 

the fire department was notified after window failure, over 85 % of fire departments would be on 

the scene by that time. 
22 

7.0 Summary 

The primary objective of the NIST Community Fire Spread Project is to develop tools that assess 

and predict the risk of communities and structures to Wildland-Urban Interface (WUI) fires. 

These tools will be based on computer models of fire spread and smoke transport as well as data 

sets derived from experiments conducted in NIST’s Large Fire Laboratory and in the field. 

Two experiments were conducted at NIST to investigate fire spread between adjacent structures. 

In both experiments, the structures were separated by 1.8 m (6 ft). The first experiment with 

unrestricted construction resulted in ignition of the adjacent structure in 5 min after ignition, or 

80 s after the structure of fire origin was breached. The second experiment was conducted with 

fire resistant construction that prevented ignition of the adjacent structure. There are a number of 

options with respect to fire resistant material selection, and no attempt has been made to provide 

any materials recommendations at this time. The two experiments have demonstrated that fire 

resistant construction can significantly reduce the overall flame spread risk in communities 

where structures are placed in close proximity to each other. Even though NFIRS does not 

contain information on all fire incidents, the available fire department response data suggests that 

the delayed flame spread between adjacent structures associated with fire resistant construction 

can provide significant valuable time for fire department response. 

The NIST Community Scale Fire Spread project [Rehm et al] will continue investigating fire 

propagation in communities. Additional model input and validation experiments are being 

planned to further develop the community scale prediction capabilities of the NIST FDS fire 

model. 
23 

8.0 Acknowledgements 

The authors would like to acknowledge Matt Bundy of NIST for conducting the calorimeter 

calibration, Bradley S. Pabody of the United States Fire Administration for the NFIRS data. 

Laurean DeLauter, Ed Hnetkovsky, Jack Lee and Gale Miller of NIST were instrumental in the 

construction of the experimental enclosures and Robert Anleitner of Geo-Centers Inc. provided 

data acquisition support. Dr. Dave Evans of the Society of Fire Protection Engineers (and 

formerly of NIST) deserves credit for initiating these experiments. 
24 

9.0 References 

Bryant, R., Ohlemiller, T., Johnsson, E., Hamins, A., Grove, B., Guthrie, W.F., Maringhides, 

A.and Mulholland, G., The NIST 3 Megawatt Quantitative Heat Release Rate Facility, NIST 

Special Publication 1007, National Institute of Standards and Technology. Gaithersburg, 

MD, December 2003. 

Bryant, R., Ohlemiller, T., Johnsson, E., Hamins, A., Grove, B., Guthrie, W.F., Maringhides, 

A.and Mulholland, G., The NIST 3 Megawatt Quantitative Heat Release Rate Facility –

Description and Procedures, NISTIR 7052, National Institute of Standards and Technology, 

Gaithersburg, MD, September 2004.

Bundy, M., personal communication, National Institute of Standards and Technology, 

Gaithersburg, MD, April 2008. 

Forney, G.P. and McGrattan, K.B. User's Guide for Smokeview Version 4: A Tool for 

Visualizing Fire Dynamics Simulation Data, NIST Special Publication 1017, National 

Institute of Standards and Technology, Gaithersburg, MD, 2004, 

http://fire.nist.gov/bfrlpubs/

Hamins, A.; Maranghides, A.; McGrattan, K. B.; Johnsson, E. L.; Ohlemiller, T. J.; Donnelly, M. 

K.; Yang, J. C.; Mulholland, G. W.; Prasad, K. R.; Kukuck, S. R.; Anleitner, R. L.; 

McAllister, T. P., Experiments and Modeling of Multiple Workstations Burning in a 

Compartment. Federal Building and Fire Safety Investigation of the World Trade Center 

Disaster, NIST NCSTAR 1-5B; National Institute of Standards and Technology, 

Gaithersburg, MD, 352 p, Sept 2005. 

Huggett, C., “Estimation of the Rate of Heat Release by Means of Oxygen Consumption,” 

Journal of Fire and Materials, 12: 61-65 (1980).

Janssens M.;Parker, W. J., “Oxygen Consumption Calorimetry,” Heat Release in Fires, 

Babrauskas, V., Grayson, S. J., Eds. (E & FN Spon.), pp. 31-59 London, UK, 1995.

McGrattan, K. B.;Hostikka, S.;Floyd, J. E.; Baum, H. R.; Rehm, R. G. Fire Dynamics Simulator 

(Version 5), “Technical Reference Guide”, NIST Special Publication 1018-5, National 

Institute of Standards and Technology, Gaithersburg, MD, Oct 2007. 

McGrattan, K. B.; Klein, B.; Hostikka, S.; Floyd, J. E. Fire Dynamics Simulator (Version 5), 

“Users Guide”, NIST Special Publication 1019-5, National Institute of Standards and 

Technology, Gaithersburg, MD, Oct 2007, http://fire.nist.gov/bfrlpubs/

Mulholland, G. “The emission and optical properties of smoke”, Recent Advances in Flame 

Retardancy of Polymeric Materials, Vol. 3, pp. 22-29 (1992) 

National Fire Data Center, National Fire Incident Reporting System (NFIRS) Database, U.S. Fire 

Administration, Feb 2006, http://www.usfa.dhs.gov/fireservice/nfirs/index.shtm.
25 

National Fire Data Center, Structure Fire Response Times Topical Fire Research Series, Volume 

5 – Issue 7, U.S. Fire Administration, January 2006 / Revised August 2006.

Parker, W. J., “Calculations of the Heat Release Rate by Oxygen Consumption for Various 

Applications,” Internal report NBSIR 81-2427, National Bureau of Standards (NBS), 

Gaithersburg, MD, 1982.

Rehm, R. G.; Hamins, A.; Baum, H. R.; McGrattan, K. B.; Evans, D. D., Community-Scale Fire 

Spread, NIST IR 6891, National Institute of Standards and Technology, Gaithersburg, MD; 

July 2002. 

Taylor, B. N.; C. E. Kuyatt, Guidelines For Evaluating and Expressing the Uncertainty of NIST 

Measurement Results. NIST-TN 1297, National Institute of Standards and Technology, 

Gaithersburg, MD; September 1994. 

Walton, W.D., McElroy, J., Twilley, W.H., Hiltabrand, R.R. (1994) Smoke Measurements 

Using a Helicopter Transported Sampling Package, Proceedings of the 17th Artic and 

Marine Oil Spill Program (AMOP) Technical Seminar, Vol. 1, June 8-10, 1994, Vancouver, 

British Columbia. 
26 

APPENDIX A. – Uncertainty Analysis 

A.1 General 

There are different components of uncertainty in the data for each of the measurement types 

reported here. Uncertainties are grouped into two categories according to the method used to 

estimate them. Type A uncertainties are evaluated by statistical methods, and Type B are 

evaluated by other means [Taylor and Kuyatt, 1994]. Type B analysis of systematic 

uncertainties involves estimating the upper ( + a) and lower ( - a) limits for the quantity in 

question such that the probability that the value would be in the interval ( ± a) is essentially 

100 %. After estimating uncertainties by either Type A or B analysis, the uncertainties are 

combined in quadrature to yield the combined standard uncertainty. Multiplying the combined 

standard uncertainty by a coverage factor of two results in the total expanded uncertainty that 

corresponds to a 95 % confidence interval (2σ). Portions of the uncertainty analyses are taken 

from Bryant [2003, 2004]. 

A.2 Heat Release Rate 

Bryant et al. [2003; 2004] discuss the analytical equations, the calibration procedures, and the 

methods used to determine the HRR and its uncertainty for calorimetry in the NIST 6 m by 6 m 

(20 ft by 20 ft) exhaust hood. The instrumentation and uncertainty analysis is analogous to 

Bryant et al. [2003; 2004] for calorimetry in the 9 m by 12 m hood (29 ft by 39 ft), which was 

used for these experiments. The largest contribution to the measurement uncertainty is due to the 

determination of the mass flow in the exhaust duct [Bryant et al., 2004]. Parker [1982] and 

Janssens and Parker [1995] discuss the details of the HRR calculation based on the extent to 

which the duct gas flow is characterized. 

Calibration burns using natural gas were conducted in the time frame surrounding the series of 

experiments to assess the accuracy of the HRR measurement and to characterize its repeatability. 

Burning a substance such as a gaseous fuel at a controlled rate provides an independent 

measurement of HRR to compare to the measurement by oxygen consumption calorimetry. A 

natural gas burner with active flow control was employed [Bryant et al., 2003]. Calibration 

experiments were performed 12 weeks before the experiments. The burner was placed directly 

under the 9 m by 12 m (29 ft by 39 ft) exhaust hood. During the calibration, the heat output of 

the burner was held constant for 2 min to 5 min at each setting. For this calibration, the 

expanded uncertainty of the natural gas HRR using oxygen depletion calorimetry was estimated 

as 15.6 %. This uncertainty resulted from combining, in quadrature, the general uncertainty of 

the LFL calorimetry method (11 %), the variation in the calibration factor (10.8 %), and the 

uncertainty in the calorific value of the natural gas (2.5 %). The calorific value variation was 

over a six-month period, as determined by examination of gas chromatographic concentration 

measurements provided by the natural gas supplier, the Washington Gas Company. 

For the SSE experiments, an additional 5 % expanded uncertainty was added in quadrature to 

reflect the unknown oxygen depletion characteristics of the fuels burned in the structures. 

Huggett [1980] determined that the 5 % variation captured the burning characteristics of most 

fuels. The resulting expanded 2σ uncertainty for HRR measured in the SSE experiments was 

16.4 %. 
27 

The calorimetric HRR measurements were corrected for baseline drift which was likely due to 

the instability of the oxygen analyzer. For Experiment 1, this baseline drift correction ranged 

from about 8 kW to 9 kW. For Experiment 2, the correction ranged from 17 kW to 84 kW. The 

corrections were performed by calculating a linear equation for the drift using the HRR recorded 

with no fire before and well after the part of the experiment experiencing combustion. These 

corrections did not have a significant impact on the HRR uncertainty. 

It should be noted that more recent experimentation has shown some sensitivity of the 9 m x 

12 m hood calorimetry to the location of the fire plume under the hood. [Bundy, 2008] This has 

not been characterized or quantified sufficiently to include it in these uncertainty estimates. 

Finally, there is an additional uncertainty in the HRR measurement related to the time response 

of the system to brief events. The system time response is about 10 s so any HRR peaks or 

valleys that are shorter in duration than 10 s will have a measured amplitude (relative to the base 

or background average) somewhat less than the true amplitude. 

A.3 Temperature 

Type K thermocouples was used with an inherent standard uncertainty of 2 °C (4 °F) based on 

the manufacturer’s specification. The expanded uncertainty (95 % confidence interval) with a 

coverage factor of two is 4 °C (8 °F). The uncertainty due to A/D conversion is an order of 

magnitude less than this and is thus neglected. 

Additional uncertainties in measured temperature are primarily due to radiative heating and 

cooling of the thermocouple bead that causes it to respond to phenomena other than the 

surrounding gas temperature. Generally, thermocouples located in a hot upper layer will 

measure temperatures cooler than the actual gas temperature due to some radiative losses at the 

bead. Thermocouples in cooler locations that receive radiation from the fire or hot upper layer 

will read higher than the actual gas temperature. The error caused by the radiative environment 

is generally much greater for thermocouples located in cool locations than for those in hot 

locations. 

The thermal environment surrounding a given thermocouple is very difficult to characterize. 

Generally, temperatures measured in the hot upper layer were estimated to be less than 100 °C 

lower than the real temperatures. Before the room flashed over, the temperatures in the lower 

layer were estimated to be less than 200 °C too high. After flashover, all temperatures were 

likely within 50 °C of the true gas temperatures because the environment surrounding the 

thermocouples became much more uniform which decreased radiative gains and losses. These 

uncertainties overwhelm the inherent uncertainties in the thermocouple described earlier. 

A.4 Heat Flux 

The main sources of uncertainty pertaining to the total heat flux are: (1) the uncertainty of the 

A/D conversion, (2) uncertainty in the calibration, and (3) uncertainty due to soot deposition on 

the sensing surface of the gauge. The uncertainty in A/D conversion is inherent to the data 

acquisition system. It is system specific and is associated with the digitization of the analog 
28 

signals from the gauge. This type of uncertainty was taken as negligible. The calibration from 

the heat flux gauge manufacturer was obtained using water at 23 oC ± 3 oC. The relative 

expanded uncertainty reported by the manufacturer is ± 3 % of the gauge sensitivity (the slope of 

the calibration curve) with a coverage factor of 2. This would result in an uncertainty of about 4 

kW/m2

 for a nominal reading of 140 kW/m2. 

Initial background heat fluxes in the absence of fire were subtracted from the gross heat fluxes 

measured by the DAQ. These background levels were (0.73, 0.75, and 0.87) kW/m2

 for gauges 1, 

2, and 3, respectively. These offsets could be due to using cooling water of a different 

temperature than at calibration. Since the offsets were constant and correctible, they don’t result 

in additional uncertainty in the measurement. 

The uncertainty due to soot deposition is more difficult to quantify. The amount of soot 

deposition depends on many parameters, such as the location of the gauge, the flow field and 

temperature fields near the gauge, the duration of an experiment, and the soot volume fraction. 

No attempt was made to quantify this soot effect for these experiments. Since flame 

impingement on the gauges was, at most, intermittent and brief, the additional uncertainty is 

considered negligible. 
29 

APPENDIX B. – Data (only in electronic form, available upon request) 

Heat Release Rate, Heat Flux, Temperature
30 

APPENDIX C. – Calorimeter Calibration Report

Filename(s): (1) 042804_9mCalVer(1) 

(2) 042804_9mCalVer(2) 

Lab: NIST LFL 

Date: 4/28/2004 

Start Time: (1) 8:42 AM; (2) 1:24 PM 

Operator: JL 

Hood Size (m): 9 x 12 

Hood Calibration Factor (Ave, Std Dev): (1) 0.914, 0.059; (2) 0.887, 0.038; 

(combined) 0.900, 0.049 

Heat Release Rate Range Used to Determine 

Calibration Factor (MW) 

0.6 to 10 

Exhaust Volume Flow Rate (m3/s): (1) 40.6; (2) 41.4 

Exhaust Mass Flow Rate (kg/s): (1) 50.1; (2) 50.6 

HRR Correction Due to Ambient Oxygen Drift: (1) HRRcorr(kW)=0.01728(t-7620)+25.4 

(2) HRRcorr(kW)=0.03594(t-3033)+8.4 

Fuel Net HOC per unit Oxygen (MJ/kg O2): 12.52 

0.7

0.8

0.9

1.0

1.1

1.2

0 2000 4000 6000 8000 10000

CF(1)

CF(2)

Calibration Factor, Cf (HRRburner/HRRcal)

Burner Heat Release Rate (NG+Heptanes), kW

Uncertainty represents

a coverage factor of

2 standard deviations 

Cf ± 2stdev = 0.900 ± 0.098
31 

0

2000

4000

6000

8000

10000

8000 9000 10000 11000 12000

Burner HRR (1)

Calorimeter HRR (1)

Heat Release Rate, kW

Time, s

Calibration #1

04/28/04
32 

0

2000

4000

6000

8000

10000

12000

3000 4000 5000 6000 7000

Burner HRR (2)

Calorimeter HRR (2)

Heat Release Rate, kW

Time, s

Calibration #2

04/28/04
33 

APPENDIX D. – NFIRS Data 

NFIRS Fire Tally Report 

BY: FIRE SPREAD 

February 28, 2006

12:56 PM

2002 NFIRS Data 

United States Fire Administration 

National Fire Data Center

WHERE: struc_type BETWEEN '1' AND '2' AND (aid != '3' AND aid != '4') 

Descriptor FIRE_SPRD Frequency % Deaths % Injuries % Dollar Loss % 

FIRE SPREAD 20,269 24.6% 55 7.7% 599 15.8% $143,530,632 7.6%

Confined to object of origin 1 6,321 7.7% 10 1.4% 114 3% $21,220,589 1.1%

Confined to room of origin 2 22,591 27.4% 100 14% 1,360 35.9% $205,436,127 10.8%

Confined to floor of origin 3 5,546 6.7% 86 12.1% 365 9.6% $152,439,160 8%

Confined to building of origin 4 23,187 28.1% 379 53.2% 1,143 30.2% $1,147,688,704 60.4%

Beyond building of origin 5 4,554 5.5% 82 11.5% 207 5.5% $228,898,294 12.1%

Category Totals FIRE_SPRD 82,476 100% 712 100% 3,788 100% $1,899,216,106 100%

NFIRS Fire Tally Report 

BY: FIRE SPREAD 

February 28, 2006

12:54 PM

2003 NFIRS Data 

United States Fire Administration 

National Fire Data Center

WHERE: struc_type BETWEEN '1' AND '2' AND (aid != '3' AND aid != '4') 

Descriptor FIRE_SPRD Frequency % Deaths % Injuries % Dollar Loss % 

FIRE SPREAD 76 0.1% 0 0% 0 0% $287,110 0%

Confined to object of origin 1 37,225 31.7% 71 7% 901 17.6% $220,392,624 9%

Confined to room of origin 2 32,632 27.8% 138 13.5% 1,876 36.7% $271,727,439 11.1%

Confined to floor of origin 3 8,254 7% 103 10.1% 557 10.9% $216,124,079 8.8%

Confined to building of origin 4 32,710 27.9% 580 56.9% 1,453 28.5% $1,399,343,256 57%

Beyond building of origin 5 6,351 5.4% 127 12.5% 319 6.2% $346,691,842 14.1%

Category Totals FIRE_SPRD 117,248 100% 1,019 100% 5,106 100% $2,454,566,350 100%
34 

NFIRS Fire Tally Report 

BY: FIRE SPREAD 

February 28, 2006

12:58 PM

2001 NFIRS Data 

United States Fire Administration 

National Fire Data Center

WHERE: struc_type BETWEEN '1' AND '2' AND (aid != '3' AND aid != '4') 

Descriptor FIRE_SPRD Frequency % Deaths % Injuries % Dollar Loss % 

FIRE SPREAD 16,476 27.1% 35 6% 467 17.7% $116,142,116 8.6%

Confined to object of origin 1 5,024 8.3% 14 2.4% 79 3% $27,382,932 2%

Confined to room of origin 2 14,952 24.6% 76 13.1% 856 32.5% $126,517,714 9.4%

Confined to floor of origin 3 3,751 6.2% 46 7.9% 263 10% $110,988,097 8.2%

Confined to building of origin 4 16,929 27.9% 327 56.5% 777 29.5% $805,798,247 59.7%

Beyond building of origin 5 3,587 5.9% 81 14% 192 7.3% $163,667,011 12.1%

Category Totals FIRE_SPRD 60,728 100% 579 100% 2,634 100% $1,350,514,317 100%