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39 The best way to learn is with actual tests. Commissioning values of 800C to 900C (1472F to 1652F). The tem- for fire life safety systems is done in other countries by burn- peratures during the HGV test reached 1300C (2372F). ing vehicles in the tunnel before the tunnel opens to the pub- Benelux Tunnel tests concluded that sprinklers reduced lic. Cold smoke tests or small fuel pan fire tests do not replace temperatures to safe levels upstream and downstream of a real vehicle fire. Such tests will allow the testing of the the fire and also reduced the probability of fire spreading design and all the systems, as well as the training of opera- between vehicles. tors, first responders, and design engineers. The Memorial Tunnel Fire Ventilation Test Program performed 91 tests with diesel oil pool fires in an aban- Some small-scale fire tests (physical modeling) are an im- doned 850-m-long road tunnel located in West Vir- portant scientific research tool that needs further development ginia, with fire sizes of 10, 20, 50, and 100 MW (34, 68, to allow better understanding of the physics involved and to 172, and 341 MBtu/hr). Diesel oil pool fire tests do not see the final results. Such tests allow for the installation of pre- allow making conclusions on among other issues the cise instrumentation and the ability to repeat the tests, while expected real tunnel fire size, growth rate, smoke gen- enabling easy changes of the parameters and systems res- eration rate, and real smoke stratification. Tests were ponses, as well as fine tuning the systems before the tunnel is performed with various ventilation systems including: built. It also allows for the checking of CFD models. Full-transverse ventilation Partial transverse Single-point extraction SUMMARY Oversized exhaust Natural ventilation Fire tests are of vital importance to the understanding of the Longitudinal ventilation with jet fans. physics of tunnel fires, understanding the impacts of fires, Tests concluded that a longitudinal ventilation system and verifying calculations, assumptions, computer models, employing jet fans is highly effective in managing the and tunnel design. They are also important for tunnel opera- direction of the spread of smoke for fire sizes up to tors and emergency responders to coordinate the efforts and 100 MW in a 3.2% grade tunnel, which allowed for its verify in practice the emergency response plans. application in the United States. The Runehamar Tunnel fire tests alarmed the industry Fire tests have been performed and can be classified as: with a 200 MW (682 MBtu/hr) HGV fire size and its fast growth. Tests before the design to develop design methodology. UPTUN Project tests indicated that there is a correlation between high HRR and high temperatures. The geo- Tests during the design to verify assumptions and com- metrical shape and size of the fire, the tunnel cross sec- puter models. tion (especially the height), and the ventilation rate are Tests during commissioning to verify the design and thought to be the principal parameters that determine equipment operation. the temperature level at the ceiling. Tests for training purposes. Most of these tests were performed in abandoned tunnels. Important conclusions and recommendations that were Each test was done differently and had its own purpose(s), determined from full tunnel fire tests included: often driven by the sponsors and vendors. The tests had dif- ferent methodologies and were performed in tunnels of dif- Ofenegg Tunnel Test results that raised doubts in ferent configurations. For a road application, extrapolations sprinkler systems for road tunnels. Important conclu- are often necessary because of the reduced cross section and sions on the danger of delayed sprinkler activation or its different shape. early deactivation of the sprinkler system were observed. Zwenberg Tunnel tests strongly supported the benefits The full-scale experiments generally provided interesting of a fully transverse system running in a full extraction qualitative observations. The relatively low number of exper- mode during a fire once the fire is quickly detected and iments does not lead to the creation of general laws. (An ventilation mode correctly activated. exception would be the Memorial Tunnel program, because PWRI experiments concluded that the stratification of of the large number of tests conducted.) It appears that the smoke was partially destroyed by longitudinal ventila- ideal full-scale test is one that can be done in a typical size tion at 1 m/s (197 fpm) and totally destroyed by longi- and shape road tunnel using actual cars and trucks for burning, tudinal ventilation at 2 m/s (394 fpm). They concluded can perform a large number of experiments, is well-prepared that the sprinklers had an adverse effect on the tunnel and equipped with the precise instrumentation suitable for the environment by causing a reduction in smoke density test conditions, and allows for the generalization of the test near the ceiling and an increase in smoke density in the results on both macro- and micro-levels. lower part of the tunnel. Repparfjord Tunnel fire tests registered that the tempera- The international practice of commissioning tunnel fire tures during most of the vehicle fires reached maximum life safety equipment and fire fighting procedures using hot

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40 TABLE 7 FIRE TESTS FOR RESEARCHES, DESIGNERS AND OPERATORS Means Use for Research Use for Design Use for Operation Full-scale Fire Test Advantages: Advantages: Advantages: Programs - Direct interpretation - Direct interpretation - Direct interpretation - Complete results - Possibility of using real Disadvantages: Disadvantages: road vehicles - Cost - Cost Disadvantages: - Limited number of tests - Limited number of tests - Cost Conclusions: Conclusions: - Limited number of tests - Unrealistic if not - Well suited - Geometry of the test associated with other facility objectives Conclusions: - This solution depends on the importance and specific problems of the project (e.g., Memorial Tunnel) Tunnel Fire Tests Before Advantages: Advantages: Advantages: or Under Operation - Partial results with full- - Accumulation of - Shows operators how the (aimed at optimizing scale facilities experience useful to ventilation reacts ventilation responses in - Numerous different choose a system - Fire departments are very fire event) situations - Test performed with real interested in expected Disadvantages: ventilation systems situation - Lack of information due to Disadvantages: Disadvantages: the limited number of - Limited number of tests - No operation possible sensors Conclusions: during the tests Conclusions: - Useful Conclusions: - Useful but partial results - Well suited Tunnel Fire Tests Before Advantages: Advantages: Advantages: or Under Operation - Visual observations - Test performed with real - Representative situation (aimed at operators possible ventilation systems Disadvantages: and fire department Disadvantages: Disadvantages: - No operation possible training) - Lack of information due to - Limited analysis due to during the tests the absence of sensors the lack of measurements Conclusions: Conclusions: Conclusions: - Well suited - Not suited - Not well suited Reduced-scale Models Advantages: Advantages: Advantages: - Many tests possible - Cost lower than full-scale - Cost - Possibility of studying tests. Disadvantages: global laws governing Disadvantages: - Linked to the limitations specific situations - Linked to the limitations induced by the similarity Disadvantages: induced by the similarity laws - Needs full-scale reference laws - No respect of time basis tests for transposition to Conclusions: Conclusions: real situations - Very difficult to conclude - Possibly unrealistic but Conclusions: that the results are demonstrative - Useful method for research representative of full-scale situations smoke tests and burning actual vehicles in the tunnels needs Technical conclusions are relative to the similarity law(s) to be evaluated for future national standards considerations. used. A fire is a complex phenomenon and its represen- tation cannot be limited to one or two global relations. Small-scale experiments can be designed to represent a HRR representation remains an unsolved problem. fire in a planned tunnel. This method is based on similarity laws, which are actually the link between the full-scale sit- Large-scale tests can be considered to be somewhere uation and the modeled one. Compared with full-scale between a full-scale road tunnel test and small-scale labora- tests, this method allows for some savings of time and money tory tests. Table 7 summarizes benefits for research, design and for analyzing the phenomena in detail. Such tests are and operation of tests and models, and their advantages and not affected by natural factors such as winds, elevations, disadvantages. and solar radiation, and can be repeated as many times as necessary. There have been no full-scale fire test programs with real cars, buses, and trucks in the United States. There is a need Using a small-scale model to design a tunnel ventilation for full-scale fire tests using real vehicles in real road tunnels system may be not be practical for two main reasons: to verify FHRRs with fewer corrections to local conditions.