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157 APPENDIX E Fire Tests E-1 Full Scale Tests reduced the maximum ceiling arch temperatures from, but the steam apparently pushed burning gases and gasoline E-1.1 Ofenegg Tunnel Tests vapors into adjacent tunnel sections, where they continued to burn. The fire was apparently extinguished for 10 minutes, Ofenegg Tunnel (Switzerland 1965) (21) but the tunnel filled with fuel vapors, which exploded in the l9th minute. This caused extensive damage to the test facility These tests were carried out in order to study the ventila- injuring three technicians. tion capacities in the case of a fire under the large Swiss tun- nel projects of the sixties. All three incidents caused doubt on the effectiveness of sprinklers in containing a fire or in limiting the range and The total cross-sectional area of the Zwenberg and Ofenegg severity of damage tunnels was approximately 24 m2 (258 ft2), which is much smaller than the cross-sectional area of normal road tunnels with two lanes, which is between 45 m2 (485 ft2) and 60 m2 E-1.2 Zwenberg Tunnel Tests (650 ft2). Zwenberg Tunnel (Austria, 1975) (21). The ignited fuel areas The facility was a railway tunnel with a dead end located were 6.8 m2 (73.2 ft2) and 13.6 m2 (146.4 ft2). The performed 190 m (620 ft) from the portal. About 11 fires were performed measurements were: temperature, gas concentration (CO, using fuel pools from 6.6 m2 to 95 m2 (71 ft2 to 1,023 ft2). CO2, NOx, O2), opacity, and combustion rate. Gasoline was poured into a concrete tub and then ignited. The gasoline used was regular gasoline (86% carbon and Tests were commissioned by the Australian Ministry for 14% hydrogen) with a density of = 730 kg/m3 (at 15C) or Construction and Technical Affairs. They were carried out in 45.6 lb/ft3 (at 59C) and a lower calorific value of approxi- an abandoned rail tunnel equipped with a fully transverse mately 44 MJ/kg (18,917 Btu/lb). The rate of burning of gaso- ventilation system. The investigators attempted to answer the line in free air is a function of the fire area. It first increases as following questions: the fire site increases in size and then remains constant when the fire site reaches an area of approximately 1 m2 (11 ft2). How do conditions in the traffic space differ when apply- ing different patterns of ventilation? What improvements can be expected from selected The Ofenegg report details a number of tests performed in changes to the design, construction, and operation of an abandoned Swiss railway tunnel to investigate the CO con- exhaust air openings? centration, temperature distribution, visibility, response to ventilation, response to sprinklers, effect on tunnel systems The test program consisted of 23 tests of a "standard" fire and structures, and effect on vehicles and people of several using 200 liters (52.8 gal) of gasoline with a fire area of 6.8 m2 fire sizes as a function of time. Several animal carcasses and (73 ft2), three tests using 400 liters (106 gal) of gasoline with vehicles were exposed at various distances to deliberately a fire area of 13.6 m2 (146 ft2), and four other tests using ignited pans of fuel. other fuels. These tests investigated the effect of varying five parameters: During the 500 L (132 gal) fuel tests, the semi-transverse supply had no mitigating effects, while the longitudinal venti- Location of fresh air injection (high or low). lation "drove the flames torch-like" downwind. During the Quantity of smoke and fumes exhausted. 500 L (132 gal) sprinkler test, sprinkler droplets initially evap- Quantity of fresh air injected. orated into a high-temperature steam cloud, causing more Forced longitudinal ventilation in the traffic space. damage than the unsprinklered fires. The open fire was appar- Conditions in the traffic space (open or obstructed). ently soon extinguished, accompanied by a strong odor of fuel at the portal, but the fire reignited after 17 minutes (status of The investigators believe the size of the area affected by the sprinkler flow unstated) with significant but non-explosive fire and thus the possibilities of escape and rescue depend to a wave-front propagation. great extent on the pattern of ventilation, more so than on any other parameter. With longitudinal flows of at least 6.5 ft/s During the 1000 L (264 gal) fuel tests, calculated burning (4.4 mph or 7.1 km/h), a "burner effect" was created on the rates were lower than those observed for similarly sized fires exhaust air side of a fire. The smoke spread at approximately in the open. Started immediately after ignition, the sprinklers the same rate as the longitudinal flow (for the 200 L fires or

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158 52.8 gal), but even small fires filled long sections of the tunnel tunnel. Sixteen (16) experiments were performed in the gallery on the exhaust side of the fire point with smoke. and 8 in the tunnel. The fire sources were fuel pools (10 tests with 4 m2 or 43 ft2, 2 tests with 6 m2 or 64.6 ft2), passenger cars They suggest that it is not possible to rescue people on the (6 tests), and buses (6 tests). The physical conditions measured exhaust air side from the fresh air side. Contrary to the condi- in the tunnel during the fires were based on the emergency tions on the exhaust air side, however, a longitudinal flow cre- capabilities. The influence of the longitudinal airflow velocity ates very favorable conditions on the fresh air side of the fire. was tested. Other tests included oversized exhaust ports for If the longitudinal flow can be stopped or if none exists from smoke removal. the start, the danger area and the smoke area will be symmet- ric to the fire point. The tests confirmed that full extraction in The important results of this investigation were reported connection with throttled fresh air reduces the danger area as as follows: well as the smoke area. Best smoke removal was achieved by operating both Maximum exhaust air temperature reached during the full east and west fans for extraction regardless of the fire extraction tests was only 85C (185F) and decreased as the location, with the bulkhead damper fully open. fire point approached the fan location. With this dilution, the Under these conditions, air flowed toward the open investigators believe 250C (482F) is a sufficiently high tem- dampers by as much as 5 meters per second (11 mph or perature criteria for exhaust fans installed in a fully transverse 17.7 km/h). system. This does not agree with actual conditions experienced The space between the fire point and the open damper in the Holland Tunnel and Caldecott fires. or dampers is filled with smoke. The inertial effect of longitudinal air flow is lost within It was concluded that: three minutes after fire mode is activated. The fans allow for command from the control center to E-1.4 Repparfjord Tunnel Tests Near Hammerfest be executed within a very short period of time. (Norway, 19901992) (21) A fire alarm program for each tunnel specifies in detail the operating pattern of the ventilation system in relation These experiments were performed in an abandoned 2.3 km to the location of the fire and other marginal conditions. (1.4 mile) long mining gallery (rough wall surfaces and cross In cases where the control center is equipped with a com- section varying from 30 to 40 m2 or 323 to 430.6 ft2). They puter, the individual programs are stored and available to gathered nine European countries (these experiments were the be called off at any time. base of the EUREKA 499 "Firetun" project). A total of 21 tests were performed using rail and metro vehicles, passenger cars, Regarding the location of fresh air injection and exhaust heavy goods vehicles, and calibrated fires (heptane pools and openings: wood cribs). About 400 sensors were installed along the tun- nel and inside the fire loads. The measurements dealt with air The overriding recommendation derived from the tests and wall temperature, velocity, opacity, gases concentration, requires throttling of the fresh air supply (or change-over smoke motion (video network), and so forth. to extraction in case of a reversible semi-transverse sys- tem) in case of a fire. In these tests performed in Norway, special attention was When the fresh air supply is throttled, the injection "from paid to the smoke development and the smoke dispersal result- below" shows no decisive advantage compared with the ing from the combustion of vehicles (cars and trucks). The fire injection from "above." load was between 5,000 MJ (4.7 MBtu) for cars and 90,000 MJ The only conclusion gained during the tests is that the (85.3 MBtu) for heavy goods vehicles. enlargement of the exhaust openings near the fire point has no effect as long as a considerable (6.5 ft/s, 4.4 mile/h, One fire test was performed with n-heptane C7H16 (84% C or 7.1 km/h) longitudinal flow passes over the fire point. and 16% H). The density of n-heptane is about 680 kg/m3 (at In fully transverse systems, the immediate action must 15C) or 42.5 lb/ft3 (at 59F), the calorific value is approxi- be to get longitudinal flow under control before trying mately 44.4 MJ/kg (19,089 Btu/lb). Therefore, this fuel is very to make further improvements by enlarged exhaust similar to gasoline or diesel oil. The mean value of the tunnel openings. cross section was approximately 30 m2 to 35 m2 (323 to 377 ft2). As compared to fire tests performed with gasoline, diesel oil, and n-heptane, special attention must be paid to two E-1.3 PWRI Experiments factors that heavily influence the smoke development and the dispersal of smoke in fires involving real road vehicles: The Japanese full-scale test program (Japan, 1980) used a 700 m (2,300 ft) long gallery built by the Public Works The materials used for the vehicle construction (without Research Institute (PWRI) and a 3300 m (10,830 ft) long road load) are flame-retardant and hardly combustible.

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159 The natural initial temperatures at the tunnel wall in the centage, diesel oil mainly consists of carbon (86%) and hydro- test tunnel were relatively low. In addition, the tunnel gen (14%). The stoichiometric air consumption is 14.5 kg wall was roughly excavated and very rough, so that the (32 lb) of air per kilogram of diesel oil. Except for the fact heat released was rapidly conveyed to the rock. that diesel oil ignition qualities are not as good as those of gasoline, there are no major differences between diesel oil Both factors retard the heat release and thus the smoke and gasoline in terms of smoke development and in terms of development, and they reduce the fire temperatures compared smoke dispersal. to fuel fires. On the other hand, these fires last much longer than fuel fires. In addition, the smoke temperatures decreased rapidly with increasing distance from the fire site. This allowed E-1.6 Runehamar Tunnel Tests the smoke to become more quickly cooled down and then sink to the ground. The total tunnel cross section was filled with Runehamar Tunnel Tests (27) smoke. In contrast to other fire tests, where there is normally a ground zone without smoke, at least for a period of time, there In total, four tests were performed using a simulated was no such free zone during these fires (except in the case of HGV. In three tests, mixtures of different cellulose and plas- a wood fire). Therefore, the conditions in this test were signifi- tic materials were used. In one test, a "real" commodity, cantly worse than in the case of fuel fires. consisting of furniture and fixtures, was used. In all tests, the mass ratio was approximately 80% cellulose and 20% plas- tic. A polyester tarpaulin covered the cargo. The reason for E-1.5 Memorial Tunnel Tests: using furniture in one of the tests was to provide a compari- son to a past test (EUREKA 499), which was carried out Memorial Tunnel (United States, 19931995) (21, 25, 26) with similar materials and a very high ventilation rate of 6 m/s (1,180 fpm) at the start of the test. This provided a good Description of Facility point of reference between the data from Runehamar and the EUREKA tests. Length: 2,800 ft (853.4 m) Cross section: Former two-lane road alignment In the first two fire tests, Test 1 and Test 2, a pulsation of the fire was experienced during a time period when the fire was This facility is an abandoned two-lane tunnel near Stan- over 130 MW (444 MBtu/hr). This created a pulsating flow sit- dard, West Virginia. The tunnel was converted to a fire venti- uation at the measuring station. The measurements showed lation laboratory in 1993 to study the behavior of smoke and that the maximum velocity was pulsating in the range of 3 to heat under various ventilation systems (see Figure E1). Instru- 4 m/s (591 to 787 fpm) down to a minimum in the range of 1 mentation includes temperature sensors, video cameras, and to 1.5 m/s (197 to 295 fpm). The frequency of the maximum velocity probes. In contrast with the Zwenberg Tunnel and the velocities was about 45 seconds during this period. Since the Ofenegg Tunnel, the cross section in this tunnel was represen- air mass flow rate is dependent on the air velocity the HRR also tative of usual road tunnels (approx. 60.5 m2 or 651 ft2 without pulsate during this period. intermediate ceiling). Diesel oil was used as a fire source. The density of diesel oil is between 815 kg/m3 (50.9 lb/ft3) and 855 kg/m3 (53.4 lb/ft3) at 15C (59F). The lower calorific E-1.7 UPTUN Project Tunnel Tests (28) value is 42.5 MJ/kg (18,284 Btu/lb). In terms of weight per- This project was discussed earlier. The WP2 was devoted to the analysis of fire development in tunnels and potential mit- igation measures. Design fire scenarios and associated design fire curves were proposed by UPTUN WP2, and used as input to other work packages within UPTUN. These design fires can also be used in more general terms since they are based on current knowledge about fire scenarios as well as information created within the UPTUN project. All of the large vehicles have been burned in a tunnel, whereas passen- ger cars have either been burned under a calorimeter or in a tunnel. Small pool fires and small idle pallet fires, with a potential heat release rate of 1020 MW (3468 MBtu/hr), were also tested. FIGURE E1 Measuring equipment in the Memorial Tunnel; A characteristic of the UPTUN experiments is the use of velocity cabinet, data acquisition unit, and instrument tree (26). real road and rail vehicles as fire loads. The heat release rate

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160 of such fires was one of the unanswered fundamental ques- been burned in a tunnel, whereas passenger cars have either tions for fire life safety systems design. been burned under a calorimeter or in a tunnel. This project was discussed earlier. The WP2 was devoted Small pool fires and small idle pallet fires, with a potential to the analysis of fire development in tunnels and potential mit- heat release rate of 1020 MW (3468 MBtu/hr), were also igation measures. Design fire scenarios and associated design tested. fire curves were proposed by UPTUN WP2, and used as input to other work packages within UPTUN. These design fires can A characteristic of the UPTUN experiments is the use of also be used in more general terms since they are based on cur- real road and rail vehicles as fire loads. The heat release rate rent knowledge about fire scenarios as well as information cre- of such fires was one of the unanswered fundamental ques- ated within the UPTUN project. All of the large vehicles have tions for fire life safety systems design.