Tabaddor compartmentfirepres

COPYRIGHT © 2013 UNDERWRITERS LABORATORIES INC. ALL RIGHTS RESERVED.

THIS DOCUMENT MAY NOT BE REPRODUCED OR DISTRIBUTED WITHOUT PERMISSION OF UNDERWRITERS LABORATORIES INC.

FIRE MODELING OF DIFFERENT

VENTILATION SCENARIOS IN A

COMPARTMENT FIRE

Mahmood Tabaddor, PhD

Majji T. Rao

Predictive Modeling and Risk Analysis

Corporate Research

The Seventh Triennial

International Fire &

Cabin Safety

Research Conference



OBJECTIVE

Assess and advance the use of CFD-based fire modeling tools (such as Fire Dynamics Simulator by NIST) to predict fire growth and spread within a compartment under different ventilation conditions.

2



EXTERIOR VIEW OF BASEMENT

3

Fro

nt L

eft

Ba

ck R

igh

t



INTERIOR OF BASEMENT

4

View towards back

View up the stairwell View of stair doorway

View towards front



I-JOIST BEAM CEILING

5



INSTRUMENTATION

Thermocouples Velocity Probes

6



FUEL LOAD DETAILS

7

Igniter



MODEL OF FULLY VENTILATED BASEMENT

8


THIS DOCUMENT MAY NOT BE REPRODUCED OR DISTRIBUTED WITHOUT PERMISSION OF UNDERWRITERS LABORATORIES INC. 9

EXPERIMENTAL HRR

0

1000

2000

3000

4000

5000

6000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Hea

t R

elea

se R

ate

(k

W)

Time (s)

Experiment 1

Experiment 2

Experiment 3

Average



MODELING OF FUEL LOAD

10

0

500

1000

1500

2000

2500

3000

0 50 100 150 200 250 300

HR

R

kW

Time Sec

average

FDS_HRR



BURNING BEHAVIOR OF PALLETS



FLAME BEHAVIOR OF FUEL LOAD

12



MESH DETAILS

• FDS v. 5.5

• 10 x 10 x 10 cm3 cubic cell

• 100 x 150 x 60 = 900,000 cells

• Typical computational time (serial processing) = 2-4 days

13



THERMAL PROPERTIES

• Non-combustible floor and walls

• Combustible wood ceiling

o Specific heat : 1.3 kJ/kg °C

o Thermal conductivity : 0.2 W/m °C

o Density : 570 kg/m3

o Ignition temperature : 250 °C

o HRRPUA : 150 kW/m2

Source: Eurocodes (EN:1995-1-2, 2006)

14



VENTILATION SCENARIOS

15

• Fully Ventilated Basement (Experimental Data)

• Sequentially Ventilated

o starting with one open window

• Sequentially Ventilated

o starting from fully closed basement

• Sudden Compartmentalization

o starting from fully open basement

• Closed Basement



FULLY VENTILATED BASEMENT



TEMPERATURE COMPARISON

17

Basement Corner TC_2 Basement Corner TC_1

Basement Center TC_1 Basement Center TC_2



-10

-5

0

5

10

15

20

25

0 50 100 150 200 250 300 350 400 450

Ve

loci

ty (

m/s

)

Time (s)

exp-ST

Exp-STM

Exp-SM

Exp-SBM

Exp-SB

Sim-ST

Sim-STM

Sim-SM

Sim-SBM

Sim-SB

VELOCITY AT STAIRWAY DOOR



HRR Fully Ventilated Scenario

19

0

5,000

10,000

15,000

20,000

25,000

30,000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

Hea

t R

ele

ase

Rat

e ,(

kw)

Time In Seconds,T

FDS_HRR_Open

FDS_HRR_Pallets

Wood Burning

(I Joist Beam )



COMPARISON OF FLAMING BEHAVIOR

20



FIRE PROPAGATION OVER TIME

21



CEILING JET

22



CEILING TEMPERATURE CONTOURS

23



I-JOIST BURN THROUGH

24



GAS TEMPERATURE CONTOUR

25



VISUALIZATION OF FLAMES ONLY

26



MESH REFINEMENT

27

0

100

200

300

400

500

600

700

800

900

1000

0 50 100 150 200 250 300

Tem

pe

ratu

re (

c)

Time (s)

Top of Basement Door

10 cm mesh

5 cm mesh



VARIABLE VENTILATION MODELS



MODELING SUDDEN CHANGES IN OPENINGS

29

Initially set to zero velocity

and ambient temperature



SEQUENTIALLY-VENTILATED WITH OPEN WINDOW

30



HEAT RELEASE RATE

31

0

5,000

10,000

15,000

20,000

25,000

30,000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

Hea

t R

elea

se R

ate

,(kw

)

Time In Seconds,T

FDS_HRR_Sequence

FDS_HRR_Pallets

Front door opened

at 180 Sec

Back Window

Opened at 210 Sec

Front window

Opened at 230 Sec

Top door opened

at 150Sec




32



GAS TEMPERATURE CONTOUR

33



TEMPERATURES

34

0

100

200

300

400

500

600

700

800

900

0 50 100 150 200 250 300Time In Second

Corner Temperature_TC_1

ThermoCouple_Corner_01

150 sec 180 sec

210 sec

230 sec

0

100

200

300

400

500

600

700

800

900

0 50 100 150 200 250 300

Tem

pe

ratu

re In

de

g C

els

ius

Time In Second

Corner Temperature_TC_4

ThermoCouple_Corner_04

0

100

200

300

400

500

600

700

800

900

0 50 100 150 200 250 300

Tem

pe

ratu

re In

de

g C

els

ius

Time In Second

Center Temperature_TC_1

ThermoCouple_Center_01

0

100

200

300

400

500

600

700

800

900

1,000

0 50 100 150 200 250 300

Tem

pe

ratu

re In

de

g C

els

ius

Time In Second

Center Temperature_TC_4

ThermoCouple_Center_04



SEQUENCE OF EVENTS

35



MODEL OF SEQUENTIALLY-VENTILATION IN INITIALLY

CLOSED BASEMENT

36



HEAT RELEASE RATE

37

0

5,000

10,000

15,000

20,000

25,000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

HR

R,(

kw/m

2)

Time In Seconds,T

FDS_HRR_Sequence

FDS_HRR_Pallets

Top Door Opened at

90 Sec.

Back Window

Opened at 60Sec. Front Door Opened at

120 Sec.

Right Window

Opened at 160 Sec.




38



SEQUENCE OF EVENTS

39



SEQUENTIALLY-VENTILATED IN CLOSED BASEMENT

40



SUDDEN COMPARTMENTALIZATION

41



HEAT RELEASE RATE

42

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

He

at R

ele

ase

Rat

e in

kw

Time In Seconds,T

FDS_HRR_Compartment

FDS_HRR_Pallets

All Doors and Windows are

Closed at 150-160sec.



OXYGEN CONCENTRATION

43

0.00

0.05

0.10

0.15

0.20

0.25

0 50 100 150 200 250 300

Oxy

gen

Co

nce

ntr

atio

n in

mo

l/m

ol

Time In Second, Sec

X_O2_Conc_Cent_Top

X_O2_Conc_Cent_Middle

X_O2_Conc_Cent_Bottom



FIRE PROPAGATION

44



SEQUENCE OF EVENTS

45



MODEL OF CLOSED BASEMENT

46



HEAT RELEASE RATE

47

-1,000

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

HR

R,(

kw/m

2)

Time In Seconds,T

FDS_HRR_Compartment

FDS_HRR_Pallets




48



OXYGEN CONCENTRATION

49

0.00

0.05

0.10

0.15

0.20

0.25

0 50 100 150 200 250 300

Oxy

gen

Co

nce

ntr

atio

n in

mo

l/m

ol

Time In Second, Sec

X_O2_Conc_Cent_Top

X_O2_Conc_Cent_Middle

X_O2_Conc_Cent_Bottom



HRR FOR VENTILATION SCENARIOS

50

0

5,000

10,000

15,000

20,000

25,000

30,000

0.00 50.00 100.00 150.00 200.00 250.00 300.00

HR

R,(

kw/m

2)

Time In Seconds,T

Fully_Ventilated_Basement

Sequentially_Ventilated_Open Window

Sequentially_Ventilated_Fully_Closed_Basement

Sudden Compartmentalisation

Closed_Compartmentalisation



REMARKS

• Modeling of changing ventilation conditions

o Do not place openings/closings on the boundary of computational

domain

o Simplified model in FDS is very good start

o Stability issues when configuration changes too much at once

• It is very important that fire tests consider the needs of model

validation when selecting an instrumentation scheme.

• Modeling tools are the key to advancing fire safety research and

engineering

o Data rich

o Efficient and economic

51

THANK YOU

Reports available at

www.ul.com/fireresearch

Technology

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