Modern Vehicle Hazards in Parking Structures and Vehicle Carrier

Haavard Boehmer, P.E., Michael Klassen, PhD., P.E., and Stephen Olenick, P.E.

Combustion Science & Engineering, Inc.

International Conference on Fire in Vehicles (FIVE)Dec 15th, 2020

Haavard R. Boehmer, P.E., MSc. (FPE) is Senior Engineer at CSE with ten years of experience and has worked on a range of complex fire modeling problems both for commercial and for research purposes as well as conducted forensic investigations of residential, industrial, and vehicle fire cases.

Presenters

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Haavard Boehmer, P.E.

Michael S. Klassen, P.E., Ph.D. (Mechanical Engineering) is Principal Research Engineer with over 20 years of experimental fire and combustion research experience. He has been involved in numerous projects involving fire dynamics, experimentation, computer modeling, detection, and suppression.

Michael S. Klassen, P.E., Ph.D

■ New vehicle construction techniques and materials.

– Modern vehicles are larger, heavier

– Increased plastic use

■ Analyzing increased burning energy content of modern vehicles

– Existing vehicle fire tests

– Material data and properties

Project summary

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Project goals

■ Are current design standards/practices appropriate for the hazard?

– Should sprinklers be required?

– Requirements for open vs enclosed garages

– Do modern vehicles burn hotter/longer?

■ What are the knowledge gaps?

■ What further research is needed?

Columbus, OH, July 2015

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The vehicle fire problem2014 – 2018 average data for USA.

Annually;

■ 1,858 total parking garage fires

■ 20 civilian injuries

■ $22.8 million property damage

■ Liverpool: 1,300 vehicles damaged

■ Stavanger, Norway; building collapse

– 300+ vehicles totaled

Source: Ahrens, 2020, “Sprinklers in Commercial Garage Fires “

Liverpool, UK. 2017

Stavanger, Norway. 2020

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Existing codes

Common code requirements; open vs enclosed

■ Open parking structures

– Walls open, interior and exterior

– Sprinklers and fire alarms not required

■ Enclosed parking structures

– Underground, enclosed, or within other occupancy

– Sprinklers required

■ Stacker system require sprinklers

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Vehicle fire hazards

1. Vehicle fire tests

2. Plastic content in vehicles

3. Plastic fuel tanks

4. Alternative fuel vehicles

5. Marine vessels

Freemont, CA, 2017

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Plastic content and energy

■ 1970-2018 plastic energy:

– 2,298 MJ increase

– 91% increase

■ Heat of combustion: 30.3 kJ/g (Average)

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1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016

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rb W

eig

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stic

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y [M

J]

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Plastic Energy

Curb Weight

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Vehicle fire tests

Select HRR curves for each decade

■ No clear correlation for HRR and age. Depends on:

– Ignition source, location

– Ventilation

– Vehicle size

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HR

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kW]

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Fire spread

■ Building Research Establishment (BRE) UK found in 2009 testing:

– Spread to 2nd vehicle in 10 min (1 test) and 20 min (2 tests)

– Spread to 3rd vehicle (empty spot separating) <4 min later.

– 1000°C+ ceiling jet temperature pre-heats interior and aids spread

123

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Fire spreadEV fire. China, May 2020

Approximately 2 min of elapsed time

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Plastic fuel tanks

■ Currently 80%+ of fuel tanks are plastic

■ HDPE; HOC = 43.6 kJ/g

■ Average tank 8-10 kg > 349 MJ

■ 2 min fire resistance requirement

– ECE R34.01

■ Failure found at 1:50 – 4:36 min

[SwRI, 2003]

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Battery electric vehicles■ Comparison tests find:

– EV lower peak HRR than ICEV

– Growth rate similar

■ Ignition and fire dynamics main differences

– Thermal runaway

– Long reignition period possible

– Jet flame

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0.0

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EV 1

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EV 2

Evaluating design criteria

Enclosed parking garages:

■ Tests indicate sprinklers control fire

– Give time for fire department to arrive

■ Effectiveness of sprinklers

– Test less ideal configurations?

– Life safety concerns in nearby buildings?

■ Fire department access?

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Evaluating design criteria

Marine vehicle carrier vessels

▪ Strict fire safety requirements

▪ Worldwide code enforcement

▪ Notable incidents have been controlled when followed

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Evaluating design criteria

Open parking garages:

■ Open structures main area of concern

■ Faster vehicle fire spread

– Conflagrations increasingly likely?

■ No detection or extinguishment required

– Solely reliant on fire department

– BRE; spread to 2nd car in 10-20 min

■ NFPA 1710 response criteria; 5:20 min

– Survey found 34% exceeded

Sea-Tac airport, April, 2013

NFPA 1710: Standard for the Organization and Deployment of Fire Suppression Operations,

Emergency Medical Operations, and Special Operations to the Public by Career Fire Departments16

Knowledge gaps

1. Few tests of fire spread between cars

2. Limited testing of fuel tank failure

3. Can sprinklers control car fires?

– BRE test limited, but promising

– Less ideal configurations/conditions

4. Response time requirements?

5. What fire risk do stacker systems pose?

– Effect of different number of levels

6. Effect of openings on fire safety

– Evaluate current open garage definition

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Proposed future work

Main areas:

1. Fire spread mechanisms

‒ Configuration; garage and cars

‒ Fuel tanks and leakage

2. Sprinkler system effectiveness

‒ Shielded fires

‒ Wind effects

3. Detection and notification systems

4. ‘Open’ definition

‒ Percentage, placement

Conclusions

▪ Parking garage fires relatively rare

‒ Few deaths or injuries

‒ Potentially massive economic losses

▪ Enclosed garages:

‒ Alarms and sprinklers required

▪ Marine carriers well protected

▪ Open parking garages;

‒ Typically sprinklers and alarms not required

‒ Main area of concern

Newark airport, Jan. 2019

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Older vehicle tests should not be

used as basis for design or regulation

▪ Older than 2000s significantly different

‒ Curb weight, car width

‒ Plastic content

▪ Rapid vehicle to vehicle spread

▪ Within 10 min in BRE tests

▪ Cars from any decade yield 8 MW+

‒ HRR dependent on test configuration

Gothenburg, Sweden, March. 201120

Conclusions

Questions?For further questions please contact:

8940 Old Annapolis Rd, Suite L

Columbia, MD, 21045

410-884-3266

www.csefire.com

Haavard Boehmer, P.E.

hboehmer@csefire.com

Mike Klassen, Ph.D., P.E.

mklassen@csefire.com

Stephen Olenick, P.E., MBA

solenick@csefire.com

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