Fire Star conclusive symposium: Marseille March 18th 2005 1

FIRE STAR, Conclusive Symposium

Session 2

WP4 : To assess the hazardous consequences of the wildland fire for the target

– Point des travaux en mars 2005, Michel Curtat, CSTB

– Analysis of results from wildfire simulations, Tuomas Paloposki, VTT

– Démonstrateur CSTB, Présentation et exemples en 2-D et 3-D, Philippe Fromy, CSTB

Fire Star conclusive symposium: Marseille March 18th 2005 2

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Requirements for the analysis:–The criteria must be simple and easy to understand.– It must be possible to evaluate the situation quickly.–There must be a sufficient safety margin.

• However, the wildfire simulations produce an enormous amount of very detailed results.

• Compromises must be made!

Fire Star conclusive symposium: Marseille March 18th 2005 3

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Criteria for assessment are based on Deliverable D4-02 (June 2003).

• Some additions and changes are proposed to create a more systematic approach.

Fire Star conclusive symposium: Marseille March 18th 2005 4

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Examples of proposed criteria:–To prevent ignition of wooden materials:

Air temperature must be less than 200 ºC.

–To prevent death of people: Air temperature must be less than 80 ºC.

The effects of increased concentrations of CO and CO2 and the effect of oxygen vitiation are to be computed using the fractional effective dose (FED) approach.

Fire Star conclusive symposium: Marseille March 18th 2005 5

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Points chosen for detailed analysis of simulation results are shown in the drawing (not in scale).

Fire Star conclusive symposium: Marseille March 18th 2005 6

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Example of analysis of results from wildfire simulations for French Garrigue.

• Photograph taken from Fire Star Gallery (Quercus Coccifera garrigue in Aramon, France).

Fire Star conclusive symposium: Marseille March 18th 2005 7

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Conditions at Point 7.

• Effect of treatment.

• No slope.

Point 7 (x = 225 m / z = 1.5 m)

0

200

400

600

0 120 240 360 480 600 720 840

Time [s]

Tem

pera

ture

[°

C]

0

20

40

60

Hea

t flu

x [k

W/m

2 ]

Temperature

Heat flux

Case 10 (FGS00T0)

Point 7 (x = 225 m / z = 1.5 m)

0

5

10

15

20

25

0 120 240 360 480 600 720 840

Time [s]

Mol

e fr

actio

n of

O2

and

CO

2 [%

]

0

2000

4000

6000

8000

10000

Mol

e fr

actio

n of

CO

[pp

m]

Oxygen

Carbon dioxide

Carbon monoxide

Case 10 (FGS00T0)

Point 7 (x = 225 m / z = 1.5 m)

0

200

400

600

0 120 240 360 480 600 720 840

Time [s]

Tem

pera

ture

[°

C]

0

20

40

60

Hea

t flu

x [

kW/m

2 ]

Temperature

Heat flux

Case 13 (FGS00T1)

Point 7 (x = 225 m / z = 1.5 m)

0

5

10

15

20

25

0 120 240 360 480 600 720 840

Time [s]

Mol

e fr

actio

n of

O2

and

CO

2 [%

]

0

2000

4000

6000

8000

10000

Mol

e fr

actio

n of

CO

[pp

m]

Oxygen

Carbon dioxide

Carbon monoxide

Case 13 (FGS00T1)

Fire Star conclusive symposium: Marseille March 18th 2005 8

The hazardous consequences of the wildland fire for the target Analysis of results from wildfire simulations

• Conclusions:–For the French Garrigue case, treatment of the stand

improves conditions near the targets.• Air temperatures are lower.• Radiative heat fluxes are lower.

• Changes in CO2 and O2 concentrations are more moderate.

– In this case, the changes are not very significant.–More results shall be analyzed when the results from

wildfire simulations become available.