COMPENSATORY EFFECTS OF FIXED FIRE FIGHTING SYSTEMS IN TUNNELS. Stefan Kratzmeir Managing Director.

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1 COMPENSATORY EFFECTS OF FIXED FIRE FIGHTING SYSTEMS IN TUNNELS Stefan Kratzmeir Managing Director

2 FFFS in Tunnels State of the Art FFFS in Tunnels are an accepted measure to increase the safety level of tunnels In most cases FFFS are only add-on Technologies: Water Mist (Europe) Deluge (US + AUS + JP) Foam Most full scale fire tests are carried out with water mist systems. Some other results might be published in future.

3 Effects of FFFS in Tunnels FFFS in Tunnels reduce temperatures significantly FFFS can reduce the radiant heat FFFS enables fire brigades to approach very close to the fire FFFS limit the fire spread FFFS reduce the fire growth rate and limit the maximum HRR The theoretic value HRR gives no information on conditions inside the tunnel in case of an activated FFFS

4 Design of Tunnel Safety Systems Protection targets: Life safety Stability of infrastructure Possibility of fire fighters operation No interruption Criterias (e.g. Temperatures) + Accepted safety level: By rules / guidelines (e.g. RABT) (prescriptive based design) Accepted detriment factor Accepted risk by society / other defining parties Values for Criterias (e.g. Limit of 300 C reinforcement) Measures (e.g. Ventilation Concept, Emergency Exits, Passive Protection, etc..

5 Compensation Why? New Requirements for Tunnel Safety: New knowlege (e.g fire sizes, effects of tunnel fires) New rules Change of risk (other traffic, more traffic) Change in social acceptance Safety Level Increasing Safety Level same costs Same Safety Level less costs Required Safety Level Increasing Safety Level higher costs Costs Safety System

6 Compensation What is it? Option 1 Option 2 Measure to be compensated Safety Level Aim: Life Safety for 30 Minutes with a 100 MW design fire Measure according to guidline: Extraction system with XYZ m³/s power New measure: Extraction with only 30% power FFFS Better emergency guidance

7 The SOLIT² Research Project Runtime: Full Scale Fire Test Program in 2011 Working Program: State of the Art Compensation / CFD FFFS / RAMS LCC Comparison of safety levels

8 Compensation of Life Safety Measures Fire tests have shown: 30 MW free burning fire 100 MW fire + FFFS (water mist) -> same effect: smoke free area of 2 m / no backlayering Less ventilation power needed for extraction / jet fans Possibilty of only using longitudinal ventilation Possibilty of extending escape ways In the area of activation (~100 m): slightliy reduced visibilty, but emergency signs can be seen without problem

9 Compensation for Life Safety Reduction of Ventilation Systems Reducing longitudinal air speed up (~50%) Reducing the power of smoke extraction (~30%) More time avaiable for self-rescuing procedures Fire growth rate is slower Conditions (Temperatures, etc.) in the tunnel are improved Additional aspects that should be taken into account Visibility Safety for escaping people

10 Compensation for the Infrastructure FFFS reduce the maximum temperature (e.g. 800 C (directly above the fire) instead of 1350 C RWS FFFS reduce the duriation of temperature exposure (e.g. 10 Minutes instead of 120 Minutes) Infrasturcture protection / passive fire protection can be designed according modified time-temperature-curves

11 Further Effects Reduction of Damages by high temperatures Higher temperatures (> 300 C) are limited only to the area directly above the fire Maximum temperatures are lower than with free burning fires Impact of higher temperatures is much shorter (< 15 min) Less down time due to less repair works Longer (Realistic) time for fire brigade approach avaiable

12 Design Process 1. Risk analysis (evaluation) 2. Definition of the aims of protection 3. Design of various technical alternatives and evaluation of the efficiency 4. Evaluation: - LCC - Technical - RAMS 5. Proof of same level of safety 6. Supervision/Check

13 Summary FFFS may be used to optimize a tunnel saftey system FFFS may (partly) compensate measures for life safety and building protection Reduction of ventilation power Modified self-rescuing concepts FFFS may (partly) compensate measures for building proetction Modified time-temperature curve to assess the impact on the structure Decision can be made individually based on LCC analysis Effeciency (incl. time to 100 % efficiency) and Avaiablitly of all systems should be taken into account

14 Outlook SOLIT² Conference in Berlin (Scandic Hotel) 27.6 / SOLIT² Engineering Guidance will be published 07/2012 SOLIT² report will be published 07/2012

15 Thank you for your attention! Questions?