what is the probability of fire to spread in a car park? phd candidate: zahir tohir supervisors:...
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What is the probability of fire to spread in a car park?
PhD candidate : Zahir Tohir
Supervisors : Michael Spearpoint Charles
Fleischmann
• Place: Westfield Westcity Henderson
• Time: Around 11.30 AM• Fire fighters attended
the fire and carried out full evacuation of the mall
Auckland van fire – 27 Feb 2015
Van fire – 27 Feb 2015
Should there be a vehicle parked next to the van, will the fire be
able to spread?
Question?
Should there be a vehicle parked a space away to the van, will
the fire be able to spread?
Question?
• To quantitatively assess the probability of fire spread from a burning vehicle to another vehicle within vicinity using probabilistic analysis.
Objective
Research overview
Risk-based research
Car park scenarios
Fire spread between vehicles
Vehicle characteristics
Vehicle design fire
Application
• What is the typical parking space dimension in a car park?
Parking space dimension
Width
Length
Source Parking space dimensions Reference
Width (m) Length (m)
Parking structures: planning, design, construction, maintenance and repair
2.2 – 2.7 N/A Chrest et al. (2000)
Car park designers’ handbook 2.3 – 2.5 4.8 Hill (2005)
County of San Diego Parking Design Manual 2.7 5.5 Department of Planning and Land Use (2013)
Asphalt paving design guide 2.7 – 2.8 5.6 Asphalt Paving Association of Iowa (1990)
Information bulletin / Public-zoning code: Parking design
2.3 – 2.6 4.5 – 5.4 Department of Building and Safety (2002)
USAF Landscape Design Guide 2.75 6.0 US Air Force (1998)
Parking Design Standards 2.5 – 3.2 N/A Fife Council (2006)
Parking Standards Design and Good Practice Supplementary Planning Document
2.5 – 2.9 5.0 – 5.5 Rochford District Council (2010)
Parking Structures: Recommended Practice for Design and Construction
2.3 – 2.7 N/A Precast Concrete Institute (1997)
Parking space dimension
Probability of fire spread scenarios
• Scenario 1 –
• Scenario 2 –
• a – vehicle width, b – distance between vehicle to the border of the parking space, c – parking width
• EFFECTIVE DISTANCE = a + b (+ c)
Approach
• Use probabilistic simulation approach
• Statistical distributions of:– Vehicle fleet distribution– Design fire of a single vehicle distribution
Vehicle classification by curb weight
Classification Curb weight
Passenger car: Mini 1500 – 1999 lbs (680 – 906 kg)
Passenger car: Light 2000 – 2499 lbs (907 – 1134 kg)
Passenger car: Compact 2500 – 2999 lbs (1135 – 1360 kg)
Passenger car: Medium 3000 – 3499 lbs (1361 – 1587 kg)
Passenger car: Heavy ≥ 3500 lbs ( ≥ 1588 kg)
Van / MPV Not defined
SUV Not defined
Based on American National Standards Classification
Statistical distribution – Vehicle fleet
Mini Light Compact Medium Heavy0
5
10
15
20
25
30
35
Vehicle classification
Perc
enta
ge o
f veh
icle
s on
the
roa
d
International dataNZ data
Statistical distribution – Design fire of a single vehicle
Peak heat release rate(kW)
Fire growth coefficient(kW/min²)
Fire decay coefficient
(min-1)
Distribution shape Weibull Gamma Weibull
Distribution parameters α β α β α β
Class
Mini 5.19 3809 1.39 11.86 0.93 0.17
Light 1.66 5078 1.23 14.78 1.21 0.11
Compact 2.40 5879 1.18 5.14 3.93 0.08
Medium 3.18 7688 2.24 2.75 1.38 0.11
Heavy 3.11* 8723* 1.51* 1.82* 1.86* 0.11*
Statistical distribution - Example
0 10 20 30 40 50 60 70 800
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Mini classification
Time, min
Hea
t re
leas
e ra
te, k
W
Ignition prediction characteristics – flame radiation model
• = heat flux received by the target• = heat output from the burning item• λr = radiative fraction• R = radial distance from the center of the burning item to the nearest
point of secondary item
• 0.3 – radiative fraction selected
Secondary item
Q
R
Ignition prediction characteristics – ignition criterion
FTP = 21862 and heat flux = 3.1 kW/m2𝑘𝑊 ∙𝑠𝑛
𝑚2
2.2 2.8 3.4 4 4.6 5.2 5.8 6.40
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1f(x) = 0.0449237140075021 x² − 0.621078622192884 x + 2.1085309821756R² = 0.992166868449486
Effective distance, m
Prob
abili
ty o
f fire
spr
ead
𝑦=0.045 𝑥2−0.62𝑥+2.11𝑎𝑡 𝑦≤1𝑎𝑛𝑑 𝑦≥0
Estimation of probability
Scenario 1
Scenario 2
Where y is the probability of fire spread and x is the effective distance
Sensitivity analysis
• Varying vehicle fleet distribution datasets
2.2 2.4 2.6 2.8 3.0 3.200.10.20.30.40.50.60.70.80.91
Effective distance, m
Pro
babi
lity
of
fire
spr
ead
New Zealand dataInternational data
• Equation of is obtained to estimate the probability of fire spread for both scenarios and different effective distances
• Different vehicle distributions datasets produces different sets of results.
• For more specific study, a different dataset of vehicle distribution fleet can be adopted in future analysis.
• Future work: How about if there are two vehicles initially burning, will it be able to spread to a vehicle across an empty space?
Conclusion & Recommendations