Fire Protection and Safety in Tunnels Conference Opening Remarks Dr Fathi Tarada Secretary, PIARC Tunnel Operations Committee
Agenda Background to the conference Key themes Recent tunnel fires Major infrastructure projects Questions and challenges
Background to the Conference Spending on new infrastructure projects worldwide Maintenance and refurbishment of existing tunnel stock Recurring fires and incidents in tunnels Investment decisions on how to balance safety and cost-efficiency
Key Conference Themes Development and harmonisation of national, European and global standards RABT, TSIs, PIARC Information from full-scale fire tests METRO project New technologies automation, fire suppression, passive fire protection
Recent Tunnel Fires
Brynglas Tunnel Fire, South Wales 26 th July 2011 Lorry fire in westbound tunnel tube Severe traffic disruption for 4 days Extensive clean-up and repairs required
Simplon Rail Tunnel Fire 9 th June 2011 Fire on goods train, 3 km from Italian portal Fire spread to 10 other goods carriages Damage to tunnel and rail infrastructure Severe traffic disruption
Østfold - Hurum Fjord Tunnel, Oslo 24 th June 2011 Truck fire Fire brigade needed to evacuate tunnel Five persons treated for smoke inhalation
Key Issues from Real Tunnel Fires Life safety for tunnel users and emergency responders Traffic disruption impact on local, regional and national economy Tunnel damage structure and installations Secondary impacts toll collection, diversion routes, reputation
Major Infrastructure Projects
Crossrail Project, UK Largest construction project in Europe Will connect 37 stations linking Maidenhead and Heathrow in the west, to Shenfield and Abbey Wood in the east 21 km of new twinbore tunnels under central London.
Crossrail Tunnel Ventilation 8 underground stations Ventilation shafts at each end of station Two additional intervention/ventilation shafts Smoke control in case of train fire Cooling in case of train breakdown
Jack Lynch Tunnel, Ireland 610m long immersed tube tunnel Joints particularly vulnerable Passive fire protection being installed to protect against 100MW fire scenario
Qatar Integrated Railways Project 107 stations and more than 130 km of tunnels (Doha Metro with Red, Green, Golden and Blue Line; Long Distance Line for passenger and freight service) Tunnel ventilation for cooling, air quality and smoke control Station-based ventilation shafts
Questions and challenges
Challenge the speakers Is this safety system really necessary? What design basis has been used? Where is the cost/benefit evidence? What is the track record? Is this safety system feasible for my application? How can I apply the technology to my project/infrastructure/tunnel?
Evolving Standards and Practices in Tunnel Fire Safety Dr Fathi Tarada Managing Director, Mosen Ltd Chief Executive, HBI Haerter Ltd
Agenda Design Fires for Tunnels Key factors Latest PIARC guidance Air Quality in Tunnels Changes in vehicular emissions Latest PIARC guidance
Design Fires for Tunnels
Fires in Tunnels Key Factors Trigger events: accidents, mechanical failures Combustibles: vehicles and contents Hydrocarbons (petrol, diesel, fat,...) Dangerous goods Fire spread from vehicle to vehicle Tauern Tunnel: fire jumped over 130m Tunnel airflow Higher airflow can cause more intense fire Tunnel geometry Smaller cross-sections can lead to radiative feedback
Fire Heat Release Rates Research projects such as UPTUN have suggested much higher fire heat release rates are possible
UPTUN Fire Heat Release Rates T1 = wood and plastic pallets T2 = wood pallets and mattresses T3 = furniture T4 = plastic (PS) cups in cardboard cartons Temperatures up to 1300 C
But Small tunnel cross-section High radiative feedback Tarpaulin covers High airflow velocities Is this representative of tunnels?
Latest PIARC Guidance Previous: prescriptive approach, specific fire size depending on type of vehicle Performance-based approach now possible Design fire is not largest possible fire Conscious choice of design fire and residual risk required
START 1 TRAFFIC TUNNEL GEOMETRY TUNNEL LOCATION Estimation of fire hazard Normal / congested Bi / unidirectional Dangerous goods HGVs Traffic Density Cross-section Height Slope Length Intersections DESIGN FIRE CHARACTERISTICS Q/t curve HRR peak value T/ t curve Urban / rural Climate Altitude 2 Fire safety level requirement DESIGN OBJECTIVES Evacuation Fire fighting Asset protection
Longitudinal vs. Transverse Ventilation
Typical Design Fires Longitudinal ventilation: 100 MW Transverse ventilation: 30 MW Is this difference justifiable?
Fire Heat Release Rates Fire heat release rates increased from last PIARC report
Longitudinal vs. Transverse Ventilation Lower capital costs for longitudinal ventilation - higher fire heat release rates can be designed for Better smoke confinement in transverse ventilation systems Different residual risks may be acceptable
Design Fires in Tunnels PIARC s latest guidance: Substantial increase in design fire heat release rates Designers and authorities have responsibility for selections Residual risk is always present choice of tolerable risk required
Tunnel Air Quality
Key air quality measures CO traditional measure Visibility NOx becoming increasingly critical
New PIARC Air Quality Report New vehicle emission standards EU5 and EU6 Two vehicle emissions calculation schemes: Simple methodology with 2010 base year, with country-specific factors Detailed emissions calculations based on vehicle-specific factors
Fleet Segmentation Passenger cars gasoline & diesel Light-duty vehicle Heavy-goods vehicles and buses Vehicles using alternative fuels (alcohol, compressed natural gas)
Country-Specific Factors Obtained from questionnaires of various countries Emission factors specified for: Euro standards Australia Algeria China
NOx NO 2 can affect both healthy and sensitive individuals For healthy people, effects have been noted for peak levels higher than 4000 μg/m³ observed Impacts motorists within tunnels and external air quality PIARC proposes an in-tunnel air quality limit of 1 ppm for NO 2
Emission Factors Emission factors dependent on: Vehicle type Speed Gradient Correction factors for: Altitude Year (if different from base year) Technology standard Vehicle gross mass Non-exhaust particulate emissions
Tips for the Unwary Ventilation equipment may be oversized if congested or stopped traffic is assumed over the entire tunnel length Percentage of HGVs quoted as an average; this may be too high for peak traffic flow Large uncertainties in non-exhaust particulate matter emissions due to resuspension and abrasion
New PIARC Air Quality Report Key Points: Reducing trend of vehicular emissions captured Increasing importance of NO 2 as air quality issue Alternative calculation schemes proposed
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