what is the probability of fire to spread in a car park? phd candidate: zahir tohir supervisors:...

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