12th North American/US Mine Ventilation Symposium

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Fires in Vehicular TunnelsFires in Vehicular Tunnels

Ian J. Duckworth, Ph.D., P.E.Ian J. Duckworth, Ph.D., P.E.

Senior Project Manager, Freeport McMoRan Copper & GoldSenior Project Manager, Freeport McMoRan Copper & Gold(formerly Senior Program Director, Earth Tech)(formerly Senior Program Director, Earth Tech)

An OverviewAn Overview

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BackgroundBackgroundBackgroundBackground

Thousands of road and rail tunnels are in service worldwideThousands of road and rail tunnels are in service worldwide Some meet modern safety standardsSome meet modern safety standards Majority do notMajority do not

Major fire is one of the primary risks recognized by operatorsMajor fire is one of the primary risks recognized by operators Many modern tunnels safer, per kilometer, than above groundMany modern tunnels safer, per kilometer, than above ground Public perception and reaction to major tunnel firePublic perception and reaction to major tunnel fire General public neither trained nor equipped to fight fires or evacuate General public neither trained nor equipped to fight fires or evacuate

under smoke conditionsunder smoke conditions Loss of life unacceptableLoss of life unacceptable

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Transportation Transportation TunnelsTunnelsTransportation Transportation TunnelsTunnels

Road TunnelsRoad Tunnels Particular safety focus during last decadeParticular safety focus during last decade Tunnels in service that do not meet modern standards Tunnels in service that do not meet modern standards Large road tunnels may have +50 accidents/yr and +3 fires/yr - Large road tunnels may have +50 accidents/yr and +3 fires/yr -

majority minormajority minor

SubwaysSubways Complex networks of tunnels and stationsComplex networks of tunnels and stations

New York: +1,000km track, 468 stations, 4.8 million ppdNew York: +1,000km track, 468 stations, 4.8 million ppd London: +400km line, 274 stations, 2.7 million ppdLondon: +400km line, 274 stations, 2.7 million ppd

Original design for control of environment not fire / PassiveOriginal design for control of environment not fire / Passive Heavily urbanized areas / Deep mined stationsHeavily urbanized areas / Deep mined stations Large transit systems may have +30 fires/yr – majority minorLarge transit systems may have +30 fires/yr – majority minor

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Road Tunnel FiresRoad Tunnel FiresRoad Tunnel FiresRoad Tunnel FiresDate Name Country Length Cause of Fire Fire Duration Fatalities/Injuries

Mar 2007 Burnley Tunnel Australia 3,400m Truck / car collision 1 hr 3 dead / 2 injuries

Sep 2006 Viamala A-13 Switzerland 742m Car & bus collision 4 hrs 6 dead / 6 injured

Jun 2005 Fréjus T2 France-Italy 12,895m Truck fire – mechanical 6 hrs 2 dead / 21 injured

Oct 2001 St. Gotthard A-2 Switzerland 16,918m 2 truck collision 48 hrs 11 dead

Aug 2001 Gleinalm A-9 Austria 8,320m 2 car collision - 5 dead / 4 injured

May 1999 Tauern A-10 Austria 6,401m 2 trucks/4 cars collide 16 hrs 12 dead/49 injured

Mar 1999 Mont Blanc France-Italy 11,600m Truck fire – mech 56 hrs 39 dead

Mar 1996 Is. De. Femmine Italy 148m Tanker & bus collision - 5 dead / 20 injured

Apr 1995 Pfänder Austria 6,719m Car/truck/van collision 1 hr 3 dead / 4 injured

1994 Huguenot South Africa 3,914m Bus electrical 1 hr 1 dead / 28 injured

1993 Serra Ripoli Italy 442m Truck & car collision 2 hrs 4 dead / 4 injured

1987 Gumefens Switzerland 343m Truck & van collision 2 hr 2 dead

1986 L'Arme France 1,105m Truck mechanical - 3 dead / 5 injured

1983 Pecorila Galleria Italy 662m Truck & car collision - 9 dead / 22 injured

1982 Salang Afghanistan 2,700m Military collision - >150 dead

1982 Caldecott United States 1,028m Tanker/bus/car collision 3 hrs 7 dead / 2 injured

1980 Kajiwara Japan 740m Truck collision - 1 dead

1979 Nihonzaka Japan 2045m 4 Truck/2 car collision 6.5 days 7 dead / 2 injured

1978 Velsen Netherlands 770m 2 trucks/4 car collision 1 hr 5 dead / 5 injured

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1999 Mont Blanc Road 1999 Mont Blanc Road Tunnel FireTunnel Fire1999 Mont Blanc Road 1999 Mont Blanc Road Tunnel FireTunnel Fire

Major trans-Alpine road tunnelMajor trans-Alpine road tunnel 11.6 km long, 8.6 m wide, 4.35 m high11.6 km long, 8.6 m wide, 4.35 m high consists of single cross section with a two-lane dual-consists of single cross section with a two-lane dual-

direction roadwaydirection roadway Managed by French and Italian public companiesManaged by French and Italian public companies

1999 fire resulted in 1999 fire resulted in 39 people losing their life39 people losing their life Initiated by refrigerated truck carrying 9t flour, 12t Initiated by refrigerated truck carrying 9t flour, 12t

margarine & 550 l dieselmargarine & 550 l diesel Fire burned for 56 hours, +1,000 °C, and spread to 40 Fire burned for 56 hours, +1,000 °C, and spread to 40

vehiclesvehicles

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Rail Tunnel FiresRail Tunnel FiresRail Tunnel FiresRail Tunnel Fires

Date Name Country Cause of Fire Fatalities/Injuries

Feb 2003 Taegu Subway Korea Arson. 2 cars engulfed. 192 dead / 148 injured

Nov 2000 Kaprun AustriaCable car fire from heater system.Steeply inclined tunnel.

155 dead

May 1999 Salerno ItalyArson suspected.Tunnel may not have been a factor.

4 dead / 9 injured

Oct 1995 Baku Metro Azerbaijan Electrical fault on train. 289 dead / 265 injured

1987 Kings Cross England Escalator fire 31 dead

1984 San Benedetto ItalyBomb detonated in 18.5 km tunnel.2 cars destroyed. Small fire.

17 dead / 120 injured

1981 Moscow Russia Electrical fault / 2 cars on fire 7 dead

1980 LUL London, England Trash fire in cross-passage 1 dead

1979 BART San Francisco, US Electrical short-circuit 1 dead / 58 injured

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2003 Taegu Subway Fire2003 Taegu Subway Fire2003 Taegu Subway Fire2003 Taegu Subway Fire

Occurred February 18, 2003Occurred February 18, 2003 Initiated by an arsonist with gasolineInitiated by an arsonist with gasoline Fire destroyed two trains and caused Fire destroyed two trains and caused

many additional casualties at many additional casualties at Jungangno StationJungangno Station

Duration of the fire ~ 3 hrsDuration of the fire ~ 3 hrs 192 fatalities192 fatalities

Such fires have led to changes to the Such fires have led to changes to the components of transit vehiclescomponents of transit vehicles More fire hardenedMore fire hardened Smoke is less toxicSmoke is less toxic

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What are Conditions Really Like?What are Conditions Really Like?What are Conditions Really Like?What are Conditions Really Like?

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Typical Transportation Tunnel Typical Transportation Tunnel Safety SystemsSafety SystemsTypical Transportation Tunnel Typical Transportation Tunnel Safety SystemsSafety Systems

Fire & smoke detection systemsFire & smoke detection systems Manual, opacimeters, temperature (linear, spot, array), air sampling, Manual, opacimeters, temperature (linear, spot, array), air sampling,

infra-red, UV, image recognitioninfra-red, UV, image recognition Ventilation systemsVentilation systems

Natural, vehicle-induced, mechanicalNatural, vehicle-induced, mechanical Traffic operation & information provisionTraffic operation & information provision

Monitoring, tracking, CCTV, radio, phonesMonitoring, tracking, CCTV, radio, phones Escape and refuge facilitiesEscape and refuge facilities

Walkways, stairs, dedicated tunnel/plenum/adit, refuge bays, cross Walkways, stairs, dedicated tunnel/plenum/adit, refuge bays, cross passagewayspassageways

Fire suppression & rescueFire suppression & rescue Passive resistance, standpipe, sprinklers, hydrants, deluge, mist, Passive resistance, standpipe, sprinklers, hydrants, deluge, mist,

screens, etc.screens, etc. Other – power, lighting, tunnel management, etc.Other – power, lighting, tunnel management, etc.

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Some Design Some Design ConsiderationsConsiderationsSome Design Some Design ConsiderationsConsiderations

Legislation & StandardsLegislation & Standards NFPA 130 & 502NFPA 130 & 502

Performance vs. prescriptive designPerformance vs. prescriptive design Strict interpretation of design criteria and standards vs. application of Strict interpretation of design criteria and standards vs. application of

engineered approach to demonstrate systems are safeengineered approach to demonstrate systems are safe

Practical yet sufficientPractical yet sufficient MaintainableMaintainable

“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at and repair.” Douglas Adams: Mostly Harmless

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More Design More Design ConsiderationsConsiderationsMore Design More Design ConsiderationsConsiderations

Challenge of retrofitChallenge of retrofit Innovative solutions often requiredInnovative solutions often required Risk of delay – Acceptable?Risk of delay – Acceptable? Compromise – Acceptable?Compromise – Acceptable?

Keep it simple – if possibleKeep it simple – if possible

Source of funding – Federal, state, private, combinationSource of funding – Federal, state, private, combination

“Engineers like to solve problems. If there are no problems handily available, they will create their own problems.” Scott Adams

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Common ConceptsCommon ConceptsCommon ConceptsCommon Concepts

TenabilityTenability Visibility (30m for lit sign)Visibility (30m for lit sign) Heat (temperature and duration)Heat (temperature and duration) Toxicity (combination vs. single gas)Toxicity (combination vs. single gas) CFD coupled with evacuation modelingCFD coupled with evacuation modeling

Fire Heat Release RateFire Heat Release Rate Rate of fire development, number of Rate of fire development, number of

vehicles, flammable liquid spills, etc.vehicles, flammable liquid spills, etc.

Urban Vent Shaft Bangkok

Type of Vehicle Peak Fire Heat Release Rate (MW)

Passenger Car Multiple Passenger Cars (2-4) Light Rail Vehicle Large Passenger Rail Car Bus Heavy Goods Truck Diesel Locomotive Gasoline Tanker

5-10 10-20

9-17 20-30 20-30

70-200 100+

200-300

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Simulation SoftwareSimulation SoftwareSimulation SoftwareSimulation Software

One DimensionalOne Dimensional Integrated modeling of aerodynamic, Integrated modeling of aerodynamic,

thermodynamic and fire scenariosthermodynamic and fire scenarios Transient & dynamic requirementTransient & dynamic requirement

Computation Fluid DynamicsComputation Fluid Dynamics Prediction of hot smoke and gases from first Prediction of hot smoke and gases from first

principalsprincipals Requirement on most subsurface transit Requirement on most subsurface transit

projectsprojects Evacuation ModelingEvacuation Modeling

Three dimensional modeling of peopleThree dimensional modeling of people Behavioral aspectsBehavioral aspects Coupling with CFDCoupling with CFD

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ConclusionsConclusionsConclusionsConclusions

Fires will continue to occur in transportation tunnelsFires will continue to occur in transportation tunnels Responsibility of operators to ensure safety systems and Responsibility of operators to ensure safety systems and

procedures are adequate to cope with major firesprocedures are adequate to cope with major fires

Design of fire-life safety systems for public subsurface facilities Design of fire-life safety systems for public subsurface facilities is a complex processis a complex process Standards – Compliance requirementsStandards – Compliance requirements Constructability considerations Constructability considerations Retrofit for existing tunnels presents unique challengesRetrofit for existing tunnels presents unique challenges

Consider the futureConsider the future Tunnels, once built, are around for a long timeTunnels, once built, are around for a long time Facility upgrades will continue to be requiredFacility upgrades will continue to be required

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Support MaterialSupport MaterialSupport MaterialSupport Material

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Visibility & Smoke ConcentrationVisibility & Smoke ConcentrationVisibility & Smoke ConcentrationVisibility & Smoke Concentration

NFPA 130 Annex B.2.1.3 requires that smoke obscuration levels are continuously maintained below the point at which a sign illuminated at 80 lux (7.5 foot-candles) is discernible at 30 meters (100 feet), and doors and walls are discernible at 10 meters (33 feet).

NFPA 130 Annex B2.2 proposes these criteria to be applied at 2.5 m (8.2 ft) height above the walkway for visibility, to allow a margin of simulation error above head height.

A combined visibility calculation methodology will be used.

The extinction coefficient (K [m-1]) for a lit sign at a distance S (m) is defined as:

)(m S

8 K 1-

Where 8 is a constant (ref. Klote & Milke). The maximum allowed extinction coefficient, relating to a minimum 30 m distance is therefore:

1-m 0.267 m 30

8 K

The allowable smoke concentration (Csmoke) is calculated from:

S 7.6

8

7.6

K Csmoke (1)

The smoke obscuration levels, or visibility is derived from the equation:

)1 AF (

C Y C prods

smoke (2)

AF represents the combustion ratio of air mass to fuel mass, which is assumed to be 14. Ys represents the smoke yield (0.129 gsmoke/gfuel) as a mass ratio. Therefore, from substituting (2) into (1), the visibility S (m) is evaluated from CFD by:

prodprods C

122.4

C Y7.6

AF 1 8 S

CFD results will report both contours of visibility (distance) and smoke concentration.

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CFD NotesCFD NotesCFD NotesCFD Notes

CFD analysis conducted by creating three-dimensional mesh models. The mesh consists of thousands of small cells or elements. The software solves the partial differential equations for the conservation of mass, momentum, species, turbulence scalars (k and epsilon), and energy in each cell.

The simulation results provide air velocities, temperatures, pressures, and concentration of products of combustion. A time sequence of these results portrays the spread of smoke, the rise of temperatures, and the airflow patterns as they relate to evacuation routes.

Time-squared fires are described in NFPA 92B as having slow, medium, fast and ultra-fast growth rates. Typical medium for transit and fast for road vehicles.

Smoke production often based on 75% efficiency. Fire growth modeled by expanding the volume to which heat is added in steps.

Transient and steady state simulation used.