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51 "burn cars in the tunnel to demonstrate the smoke, heat and international responders is the need to develop computer- noise to our operators. This also enables the deluge and ven- based training tools for operators to manage fires using a tilation to be proven. All operators have to complete task tunnel fire systems simulator. Preparations and planning books on a regular basis." Tunnels and emergency response and emphasis on training are considered to be the most impor- equipment are inspected and tested every 6 months. The tant. This is one of the areas that require future studies and operational protocols for the use of the ventilation system development. Fire drills and having feedback from design during a fire event are "preprogrammed for a single fire, and construction are considered the strength of the agency's multiple fire and congested tunnel." fire management programs. Another lesson learned is that many agencies (55% of those FINDINGS AND FUTURE STUDIES responding worldwide) would consider protecting tunnels with the fixed fire suppression system (sprinkler system) if Responses were received from 15 agencies representing proven effective. Future studies are required to address this 319 tunnels worldwide. Nine U.S. agencies reported on a total area of technology for tunnels. of 32 tunnels, whereas 6 international agencies reported on a total of 287 tunnels worldwide (280 from Korea's average). Most of the agencies rely on CCTV for fire detection and incident detection. This technology needs to be further devel- The questionnaire proved that fires in road tunnels are rather rare events, with a greater number of fires occurring in oped for heat and smoke detection, as well as be tested and the busiest tunnels. In most of the U.S. tunnels, fires happen listed for tunnel fire-detection applications. one or two times a year; however, most of them are small and do not result in any significant issues. The most signifi- All responders rely on tunnel ventilation systems for heat cant fires occur with trucks (HGVs). In these cases, casualties and smoke control. There is a need to continue developing are likely. In 1948, the Holland Tunnel in New York and the such ventilation systems and ventilation response in conjunc- Lafontaine Tunnel in Canada experienced structural damage tion with other systems such as fixed fire suppression systems. after a fire and had to close for an extended period of time. Other tunnels have never experienced structural damages Specifications are needed for the devices that require fur- and/or lengthy closures. The maximum estimated fire HRR ther development. Reliable and maintainable devices could was reported at 57 MW (195 MBtu/hr). Typically, fire depart- become commercially available that are designed for the ments are involved in serious fire events and investigations tunnel environment, considering the typical tunnel cleaning/ follow most of the time. washing operations, chemicals and pollutants present, and dirt and debris build-up. One example is locating a commercially Based on the responses received to our survey, it takes available pull station system for a roadway tunnel that has about 30 min to extinguish a severe tunnel fire; however, the long-time reliability. longest reported event lasted for 120 min. Most of the tunnels are equipped with CCTV cameras and have videotapes of fire Although many U.S. agencies prohibit gasoline tankers incidents. Almost all of the tunnels have an emergency from entering tunnels freely (8 of 32 tunnels allow them), response plan. they are allowed freely in most of the international tunnels. Four U.S. tunnels allow gasoline tankers to travel through Most of the U.S. agencies and some international agencies while supervised and when the tunnel is closed to normal rely on NFPA 502 for tunnel safety design. International agen- traffic. Their experience may need further study. cies also use PIARC, the European Union, and other docu- ments for guidance. Several international agencies provide the Although most U.S. tunnels are uni-directional, many would designers with fire curves along with the fire size. All seven consider using them as bi-directional during construction or of the international agencies apply a risk assessment approach maintenance in the parallel tube. Thus, bi-directional mode is for fire engineering, whereas only 10 of the 30 U.S. tunnels considered for fire design for most uni-directional tunnels. reported applying a similar approach. Most of the national and international agencies responded that they would consider a COMPUTER-BASED TRAINING TOOLS fixed fire suppression system to meet the new NFPA 502 Max FOR OPERATORS TO MANAGE FIRE-- Fire HRR Requirements, if proven effective. Some stated that VIRTUAL TRAINING they are looking for real-world experience in the use of a deluge system. Survey results demonstrated the need for computer-based train- ing tools. The training of emergency service personnel and More than 60% of the tunnel agencies reporting world- tunnel operators is an important aspect in ensuring the safety wide expressed their interest in additional training tools for of tunnels. Often, such training is hampered by the limited operators to manage fires using a tunnel fire systems simulator. training opportunities. For the training of firefighters, tunnels One recommendation that came from most of national and either have to be temporarily closed or special underground

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52 facilities have to be used. Also, there is the additional environ- mat (AUTOCAD) and are used to generate the grid for the mental issue of making fires, which are generated by burning transient combustion calculation. cars or by pan fires. Finally, such exercises may damage or dirty the tunnel. Virtual training offers a user-friendly and clean The user may: alternative. In a virtual training tunnel, fire and smoke only exist in computer memory. Virtual exercises have many advan- Define a scenario and replay this scenario using the for- tages, including that they: ward/stop/rewind/start buttons on the graphic user interface. May be repeated as often as necessary, During a concurrent session, the user may switch on/off Do not require the closure of tunnels, and existing fans, fire extinguishers, and restart a session. Do not cause pollution. The following can be visualized: The VIRTUALFIRES simulator has been developed within a European project and allows the user to visualize the fire Smoke (using output from the CFD software) to check and smoke development and the transport of heat and toxic visibility. combustion products inside a tunnel and then move through Iso-surfaces of temperature to check survivability. the virtual space in the same way as through a real, physical Streamlines allowing for visualization of the efficiency tunnel (13). The simulator uses and accesses a database, of the ventilation system. which contains the results of 3D transient combustion (CFD) simulations for particular tunnel geometries with associated One of the goals of a project was to achieve real-time CFD safety installations, particular fire hazard scenarios, and so calculations so that users may immediately see the effects forth. The CFD results can be displayed using a personal from changes, such as from switching on/off fans and from computer and a head-mounted display. activating fire extinguishers. Two systems have been developed. The first where the The calculated dataset consists of different ventilation sce- CFD simulation is pre-calculated, stored in a database, and narios for the Mt. Blanc Tunnel in France and the Gleinalm then displayed. The other's calculations are carried out in Tunnel in Austria. Both tunnels were examined with their for- parallel to the visualization. In the first system, the user mer ventilation systems and also with the improved ventila- will be able to move through the data, but will not be able tion systems after reopening. to change the characteristics of the simulation such as the ventilation characteristics in real time. In the second sys- Another tunnel simulator was developed in Sweden and tem, the user may change the properties of the simulation has been in operation since the summer of 2004. It is an while the data are displayed and observe a real-time effect important instrument for creating realistic conditions to help of the changes. train operators to better handle fire situations. With this sim- ulator, the Swedish Road Administration can maintain a high The VIRTUALFIRES simulator can be used for assessing level of staff competence without causing disruptions in traf- the fire safety of tunnels, for the training of rescue personnel, fic that usually result from major exercises in tunnels. One of and for planning rescue scenarios, and will be able to supple- the major goals is to provide the training in a useful and cost- ment real fire tests. The end users of this system are rescue effective way. organizations such as fire departments, tunnel operators, and government organizations interested in tunnel safety. The sys- The simulator is also used to evaluate existing routines tem can be used for making an objective assessment of the fire and checklists for the Gteborg tunnels. Through the simula- safety of existing tunnels. It can also be used for educating tor, errors and weak spots in the routines can be found before drivers on how to behave in case of a fire emergency in a tun- they have an actual impact in the real world (see Figure 13). nel and what to expect. New tunnel simulators can also be developed and tested The VIRTUALFIRES system is able to handle tunnels of on the design stage before they are introduced into the traffic any cross section with a variety of installations, including: environment, so that operators will be well prepared when a new tunnel opens. In Sweden, all future tunnel projects will Fans; require a tunnel management application utilizing the simu- Ventilation inlets and outlets; lator. The simulated tunnel environment was in use for two Fire extinguishing nozzles; months before the opening of Gteborg's latest tunnel, the Escape compartments, exits, lights etc.; and Gta Tunnel. This gave the traffic managers ample time to Cars, trucks, or rolling stock. acquire experience with the new system before the opening. With periodic updates on various situations, they are better The data describing the shape of the tunnel cross section prepared when an incident occurs. Groups of operators from as well as the fixed installations are provided in a suitable for- various tunnels gather after training sessions to discuss the

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53 taught scenario. In this way they can learn from each other. The simulator is also used for training new operators; it helps to familiarize them with how the tunnel monitoring applica- tion works before they work on a real one. The simulator can also be extremely beneficial for existing tunnels. In the simulator, the tunnel and its vicinity are modeled using a 3D modeling tool, creating a virtual version of the tun- nel. The model is then filled with vehicles. Despite its com- plexity, the tunnel simulator can be run on a regular computer, without the need for upgraded hardware. The detailed graph- ics are created using normal graphic cards and an industry standard 3D graphics engine. The VIRTUAL FIRE project, discussed earlier, was devel- oped as a computer-based training tool. It is important to estab- lish a similar program for the United States and to incorporate FIGURE 13 New tunnel simulators. this tool into the U.S. standards.