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Ir Steven LAI

28 April 2017

HKIE FIRE DIVISION9TH ANNUAL SYMPOSIUM

FROM VISION TO PRACTICE

SPECIAL CONSIDERATIONS FORTUNNEL VENTILATION DESIGN

TUNNELSMetro / Rail TunnelsRoad TunnelsCable TunnelsSewage TunnelsWater Supply TunnelsGas / Fuel Supply TunnelsNuclear Waste Tunnels

Train Fire in Hong KongTrain Fire in Japan Train Fire in Korea

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ROLLING STOCK PROVISIONConstruction of train bodyis non-combustibleA fire will not stop the trainreaching the next station30 mins FRP train floorSmoke detection to close-off fresh air intake damperFire-fighting equipment ineach carriage……

EXAMPLE: METRO ACCIDENTDate Location Remark

10 February 2017 Hong Kong 0 killed, 18 injured7 July 2016 Taipei, Taiwan 0 killed, 25 injured

22 March 2016 Brussels, Belgium 32 killed, over 300 injured30 June 2015 Odawara, Japan 2 killed, 11 injured

13 February 2013 Singapore 0 killed, 0 injured10 January 2011 Guangzhou, China 0 killed, 2 injured29 March 2010 Moscow, Russia At least 40 killed, over 100 injured

14 February 2007 Hong Kong 0 killed, 11 injured18 February 2003 Daegu, Korea 192 killed, 151 injured

Train Fire in Japan Train Fire in Korea

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METRO ACCIDENT IN HONG KONG (14 FEB 2007)

External train fire in Tai Lam Tunnel14 February 2007(Wednesday, 9:15a.m.)0 Dead, 11 injuredPassengers to walk for ~2km.

Tunnel VentilationSystem controlledthe smokeeffectively

Source of reference: Metro – 15 Feb 2017

RECENT METRO ACCIDENT IN HONG KONG

Arson in the Hong Kong MTR10 February 2017 (Friday, around7p.m.)0 Dead, 18 injured

Source of Reference: http://www.scmp.com/news/hong-kong/article/2069900/five-injured-fire-breaks-out-hong-kong-mtr-train

Tunnel Ventilation System(TVS) was designed tohandle external train fireTVS was not designed tocontrol smoke inside thetrain car

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CONTENT

Train Fire Heat Release RateCritical VelocityActivation of TVSSmoke Control at CrossoverSmoke Controlwith Open Cross-passagesOne Train vs Two Trainsinside a TunnelMid-Tunnel VentilationComputational Simulation ToolsOther ChallengesConclusion

1. TRAIN FIRE HEAT RELEASE RATE (HRR)

Train with DC Power Supply

Train length: 70m to 200mHeadway: 90~150sSpeed: 80kphTrain Cross-section Area: 10~12m2

Typical Tunnel Cross-section Area: 24~32m2

Train Fire Heat Release Rate: 5~15MW

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1. TRAIN FIRE HEAT RELEASE RATE (HRR)

Train with AC Power SupplyTrain length: 120m to 240mHeadway: 90~125sSpeed: 80~130kphTrain Cross-section Area: 10~14m2

Typical Tunnel Cross-section Area: 24~30m2

Train Fire Heat Release Rate: 10~20MW

Train of High Speed Railway SystemTrain length: 210m to 430mHeadway: ~240sSpeed: 200~350kphTrain Cross-section Area: 11~14m2

Typical Tunnel Cross-section Area: 43~100m2

Train Fire Heat Release Rate: 7.5~22MW

1. TRAIN FIRE HEAT RELEASE RATE (HRR)

Freight Train (Diesel Train Fire)Train length: 1,800mFire heat release rate: 200MWSmoke temperature over 400oC at firesite

IssueFan may be damaged by hot smoke

Possible solutionTo protect tunnel structure, fans andassociated equipment

Sprinkler systemDeluge systemWater mist system…..

Freight Train Fire in State of Maryland, America

Tunnel Deluge System

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2. CRITICAL VELOCITY

Previous Critical Velocity calculationas per NFPA 502-2014

Froude number factor (K1) is 0.606

NFPA502-2017

Latest Critical Velocity calculationas per NFPA 502-2017

Froude number factor (K1) asper Table D.1

NFPA502-2014

2. CRITICAL VELOCITY

Tunnel ventilation capacity: Increase by ~50% for 5~20MW fire?

Critical Velocity %Increase against HRR

5MW ~48%

10MW ~50%

20MW ~40%

50MW ~16%

100MW ~0%

200MW ~0%

Grade 5%

Grade 3%

Grade 0%

1.5

2

2.5

3

3.5

4

4.5

0 50 100 150 200

Criti

calV

eloc

ity(m

/s)

HRR (kW)

Typical Critical VelocityNFPA 502 - 2014 & NFPA 502 - 2017

NFPA 2017

NFPA 2014

Metro System

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3. ACTIVATION OF TVS

Detection Inside Tunnel?Aspirating Smoke Detection SystemLinear Heat Detection SystemInfra-red Camera…..

ManualActivation

of TVSOperator

Passenger/ Driver /

Equipmenton Train

3. ACTIVATION OF TVS

Considerations:Staff / passengersFire developmentTrain speedResponse time of the systemMaintenance

Early warming systemNOT for automatic activation of thetunnel ventilation system

ManualActivation

of TVSOperator

Passenger/ Driver /

Equipmenton Train

TTMS Cable

AspiratingSmoke Detection System

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4. SMOKE CONTROL AT CROSSOVER

Issues:Insufficient airflow in incident tunnelSpread of smoke

Possible Solutions:Crossover doorIncrease fan capacityTunnel jet fans / Tunnel impulse fans

“Push”Ventilation

Non-incidentTunnel

“Pull”Ventilation

4. SMOKE CONTROL AT CROSSOVER

Smoke Control Strategy

“Push”Ventilation

Air ThrustDirection

(Direct Flow)

“Pull”Ventilation

Concept A: Direct Thrust

“Push”Ventilation

Air ThrustDirection

(AerodynamicResistance)

IMF

“Pull”Ventilation

Concept B: Resistive Thrust

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5. SMOKE CONTROL WITH OPEN CROSS-PASSAGES

Issues:Insufficient airflow in incident tunnelSpread of smoke

Possible Solutions:Increase fan capacityTunnel jet fans / Tunnel impulse fansFan serving cross-passage aditSelf-closing door

NumberRelative position to the fire

6. ONE TRAIN VS TWO TRAINS INSIDE A TUNNEL

One Train RuleMaximum 1 trainoperating in each tunnelsectionSmoke control(either direction)

Train Travelling Direction Airflow Direction

Two Trains RuleMaximum 2 trainsoperating in each tunnelsectionFire Resistance Periodfor train floor to avoidfront/ rear train fire

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6. ONE TRAIN VS TWO TRAINS INSIDE A TUNNEL

Application of Two Trains Rule to

New System: Possibility of reducing the number of ventilation plants

VentShaft

VentShaft

VentShaft

VentShaft

VentShaft

6. ONE TRAIN VS TWO TRAINS INSIDE A TUNNEL

Application of Two Trains Rule to

Existing System: Can implement headway reduction

VentShaft

VentShaft

VentShaft

VentShaft

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7. MID-TUNNEL VENTILATION SYSTEM

ProsReduce no. of fan plantsReduce station footprintVent buildings can be integrated with MOE & MOA

ConsVentilation system capacity depends on station arrangementNot applicable for full height PSD systemNeed lands to locate mid-tunnel ventilation buildingsOnly ONE direction smoke control

Station A Station B

Station A Station B

Station A Station B

Station A Station B

Station A Station B

Airflow direction

Incident Train

Incident Train

Incident Train

Incident Train

Incident Train

Incident Train

Airflow direction

Airflow direction

Airflow direction

Station A Station BVB VB VB VB

VB VB VB VB

VB VB VB VB

VB VB

VB VB

VB VB

8. COMPUTATIONAL SIMULATION TOOLS

Before 2016: Subway Environmental Simulation (SES)

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8. COMPUTATIONAL SIMULATION TOOLS

Before 2016: Subway Environmental Simulation (SES)

Major Features:

One-dimensional simulation program

Simulate multiple train operation

Simulate tunnel deep sink effect

Provide result for air velocity, temperature, humidity throughoutstations, tunnels and vent shafts

…..

8. COMPUTATIONAL SIMULATION TOOLS

After 2016: Subway Ventilation Simulation (SVS)

Major New Features:

Modeling of tunnel cooling pipes

Air curtain model

Platform screen door model

Saccardo nozzle model

De-rating of jet fan, etc.

…...SVS Manual Cover

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8. COMPUTATIONAL SIMULATION TOOLSComputational Fluid Dynamics (CFD)

Step 1: SVS To provide Boundary Condition for CFD simulation

CFD model

SVS model

8. COMPUTATIONAL SIMULATION TOOLS

Computational Fluid Dynamics (CFD) – critical velocity analysis

Step 2: Use CFD result to determine if Critical Velocity can be achieved

Plan views from top of train in TBM tunnel

Air Temperature Profile

Velocity ProfileFire Under Train

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Computational Fluid Dynamics (CFD) – max velocity along evacuation path

Step 2: CFD to verify maximum air velocity at evacuation level shall notgreater than international practice (e.g. NFPA 130 – 11m/s)

Contour of tunnel air velocity profile (m/s)at 1.5m above the Evacuation Walkway Level

Tenable environmentnear the fire site

Air velocity alongevacuation route

8. COMPUTATIONAL SIMULATION TOOLS

9. OTHER CHALLENGESHigher Requirement on Equipment

Standby Fans

150oC,1 Hour

250oC,1 Hour

250oC,2 Hours

400oC,2 Hours

Nostandby

1 fan permode

operation1 fan perstation

1 fan perfan group

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9. OTHER CHALLENGESExtreme Outdoor Air Temperature (e.g. 43 deg. C)

Impact on normal operation and evacuation

Evaporative cooling system

Tunnel cooling system

10. CONCLUSION

Technology advancement:

Rolling stock Reduce HRR Reduce TVSFire suppression system Reduce HRR Reduce TVS

Fan & motor materials Operate at higher temperatureHigher efficiency

Signalling system More accurate, fast responseDetection system More accurate, fast responseControl & monitoring system More accurate, fast responseAutomatic control of TVS

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10. CONCLUSIONTechnology advancement:

More considerations (Fire engineering + human behavior)Simulation tools Reduce design risk

10. CONCLUSION

Public education + Trainings to operators

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10. CONCLUSION

Upcoming Challenges

Signalling system Shorter headwayRolling stock FastMore than 2 trains in tunnel

Fuel cell HRR

Cyber security protection Resilient Control Systems

…..

Ir Steven LAIDirector, Infrastructure, China Regionlai.steven@pbworld.com(852) 9126 5638(86) 1592 075 1996(65) 8184 3168