The objective of the tests was to determine the water distribution characteristics using different water pressures and sprinkler spacing of two selected Extended Coverage sprinklers. The sprinklers may be used for the protection of the Muskö tunnel and the test set‑up simulated a freight truck trailer positioned inside the tunnel.

Adequate sprinkler coverage would require that sprinklers are positioned close to the peak of the ceiling. A relatively short vertical distance from the sprinklers and the ceiling is also essential for proper thermal activation. These requirements are best met by the use of upright sprinklers. Two extended coverage upright sprinklers with a K‑factor of 363 (metric) and 202 was selected for the tests.

For the extended coverage upright K363 sprinkler (Tyco model EC‑25), a sprinkler spacing of 4.0 m is recommended, in order to account for the fact that full coverage of the freight truck trailer was not achieved at the tested 4.2 m spacing. A density of 10 mm/min requires an operating pressure of around 0.7 bar at this particular spacing.

The tested extended coverage upright K202 sprinkler (Tyco model EC‑14) provided a wider water discharge pattern, with a proper water distribution on the top of a freight truck trailer positioned offset in the tunnel at sprinkler spacing up to 5.0 m. For an actual installation, a K202 sprinkler designed for a density of 10 mm/min require an operating pressure of around 3.6 bar at this particular spacing.

Due to environmental concern, policy goals for transportation aim at using renewable fuels. These include gaseous fuels such as motor gas, methane or hydrogen and electric vehicles. This research project focuses on a literature review to understand the emerging risks with alternative propellants in road tunnels and underground garages. Gaseous fuels and electric vehicles pose new risks compared to the liquid fuels that we are more used to. In particular this concerns gaseous fuels and the risk for pressure vessel explosion, and the release of toxic substances such as hydrogen fluoride from Li-ion batteries undergoing thermal runaway. Two workshops were organized to get feedback from stakeholders and to initiate discussions. Future research, risk reducing measures, rescue service guidance and changes of regulation and guidelines are discussed and proposed.

Due to environmental considerations, much current transportation policy development is aimed at increasing usage of renewable energy sources. These include gaseous fuels such as LPG, methane, and hydrogen, along with electricity. This research project focused on a literature review that was intended to research the risks involved in using alternative fuels in road tunnels and underground garages. Gaseous fuels and electric vehicles pose new risks that we, due to our greater familiarity with liquid fuels, are unused to. The greatest of these relate to gaseous fuels and pressure-vessel explosions, and the release of toxic gases such as hydrogen fluoride from Li-ion batteries undergoing thermal runaway. Two workshops were organised to obtain feedback from stakeholders and initiate discussion regarding the issue. Future research, risk-reducing measures, rescue service guidance, and changes to regulations and guidelines are discussed and proposed in this report.

Background. Swedish wildfires are handled by multipurpose municipal rescue services, raisingquestions about how non-specialist incident commanders (ICs) perceive and interpret wildfirebehaviour. Aims. Elucidating ICs’ interpretations of fire behaviour, fuel complexes, weather,landscape structure and the role of these in tactical decisions. Methods. We exposed SwedishICs to questionnaires and tabletop exercises for different standardised fire scenarios.Key results. Despite minimal formal wildfire training, ICs showed reasonable consensus in ratingof fuels, fire behaviour, hose-lay production rates, etc. Tactics were to access the fire from thenearest road with hose-line laid from the engine and water ferried on trucks. In a scenario whereinitial attack failed, they typically fell back to roads, without burning off. This indicates a fundamental flaw in tactics employed for high-intensity fires, which easily breach forestry roads, and inviteoutflanking. Conclusions. The IC wildfire knowledge is built on personal and group experiencerather than formal education. We found reasonable competence, despite the organisations beingdesigned primarily for other purposes. However, tactical understanding of complex, large incidentswas poor. IC training should emphasise potential hazards of such incidents to enhance groupcompetence despite their low frequency. Implications. Standardised tabletop exercises canprovide insight into decision-making of ICs that is otherwise hidden.

This report presents the results of the SafePos pre-study, in which different technologies for safety positioning to be used by first responders were identified, and techniques for ad hoc positioning were evaluated. The aim of the project, was to test various systems for localisation and communication and narrow- and wide-band radio transmission techniques, and to further investigate how the presence of such a system could support fire and rescue operations in complex underground environments. Tests have been carried out in real, pre-existing mining environments, and complex office corridors with similar conditions to those of a mine as regards curves and obstructions have been used for introductory tests. A computer application for digital simulation has been developed and adapted to the system, although this only operates on a relatively basic level, so as to support the testing of the positioning and communication systems; thus, more can be done to improve performance for real-life applications. The analysis was conducted by studying the results of the experiments and linking them to expected usage during a fire and rescue operation. Tests have also been carried out in cooperation with the fire and rescue services in order to identify equipment and wearable technologies that could support and make fire and rescue operations in mines and other complex underground constructions safer and more efficient. In order to transfer information to and from these wearable technologies and to improve the likelihood of a safe and efficient fire and rescue operation, positioning and connectivity are requirements.Keywords: Underground constructions, mine, fire safety, positioning, connectivity

The need for a successful fire and rescue operation in an underground facility, e.g., a tunnel, introduces challenges both in the planning phase and during the incident. This is because these types of facilities can be very complex, and thus, specific tactics are needed compared to the more common incidents, e.g. in residential premises. When planning a fire and rescue operation and developing the tactics many different aspects need to be considered: complexity of the facility, the expected number of people involved in the operation, information available about the incident, the purpose of operation, etc. This paper contains recommendations for firefighting in underground facilities. The recommendations are structured in accordance to the sequential time period during which some specific fire safety design measures are taken. These periods are the design phase, the construction phase and finally when the facility is in operation. The recommendations presented in this paper are based on the results of the Swedish TMU research project (Tactics and methodologies for firefighting in underground facilities), results from other research projects and experience from real fire and rescue operations.

This study explores how the Fire and Rescue Service can better prepare for solving complex problems in emergencies by using the concept of problems and problem-solving networks. Primary and secondary data from an extensive fire incident were analysed, including semi-structured interviews and incident assessment reports. Complex problems that arise during emergencies can be challenging to define, and solutions can be difficult to identify. However, this study demonstrates that breaking down complex problems into sub-problems can facilitate the identification of what kind of problem-solving network is needed to be able to solve problems in emergencies. Overall, this study contributes to a deeper understanding of the rationale behind problem-solving network in emergency situations and highlights the importance of relationships in problem-solving network to address complex problems during emergencies. 

Fire in alternative fuel vehicles in ro-ro spaces (BREND)

A literature study has been carried out that compiles the body of research regarding hazards related to fire in alternative fuel vehicles (AFV) in ro-ro spaces. Alternative fuels include liquefied gas (e.g. LNG), compressed gas (e.g. CNG) and batteries. Hazards related to a conventional vehicle on fire are heat, smoke and toxic gases. Another hazard is projectiles related to small explosions of e.g. tyres or airbags. AFVs also include hazards of large explosion, jet flames, more apparent re-ignition, etc.

The study also includes land based fire fighting tactics related to AFV fires. If the fuel storage on an AFV is affected, land-based firefighters often use a defensive tactic, which means securing the area around the vehicle and preventing fire propagation from a distance. This tactic has been evaluated in the context of a ro-ro space and the results are compiled in a test report (Vylund et al 2019). The project has resulted in guidelines on how to handle AFV fires in roro spaces (see appendix 1).

RISE Research Institutes of Sweden have carried out fire tests to evaluate fire fighting methods in case of a fire involving alternative fuel vehicles (AFV) in a ro-ro space. This report presents how selected fire fighting methods were practically evaluated for their possible to use in ro-ro spaces. The results can be applied for safer and more efficient manual fire fighting operations, which is increasingly important when carrying AFVs.

The fire tests were performed in a large fire test hall at RISE Fire Research in Borås and the fire load was represented by a steel mock-up of a personal vehicle with a propane test rig, creating a fire of 4 MW. Steel walls, representing adjacent vehicles, were fitted with thermocouples to measure the temperature 0.6 m from the mock-up vehicle. Extinguishing media were applied between the mock-up and the steel wall on the left-hand of the vehicle and the temperature reduction was measured. The results present the reduction coefficient achieved by different systems, i.e. the heat blockage effect achieved by the systems. A high reduction coefficient indicates that the system has a high capacity to reduce heat exposure and prevent fire spread to an adjacent vehicle.

For handheld system, the highest reduction coefficient was achieved by the Industrial system and the FRS system (but only with a high water flow rate), providing both a reduction coefficient of 0.64. Reduction coefficient on the opposite side of the vehicle, from where the water was applied, also varied between the different systems. The highest reduction coefficient on this side was achieved by the high pressure 60 system, providing a reduction coefficient of 0.34. For water curtain system the Hose provided the highest capacity to reduce heat exposure on both side of the vehicle.

How different tactical options could optimize the performance of the handheld systems was evaluated primarily by visual observations. After the first part of the test was conducted (measuring blockage effects) the operator was able to oscillate the water spray, both up and down and over the vehicle. The operator also approached the vehicle from the front, at an angel of 45°, in order to observe the effects with respect to cooling or suppression. By varying the technique, it was possible to optimize the cooling effect on both sides of the vehicle, but the operator must be able to adjust cone angle and water spray pattern to maximize the effect. During this part of the tests it was possible to observe that some systems had a limitation in capacity with respect to cooling or suppression, especially if the pressure was low or if it had a low water flow rate. The water curtain systems were not able to affect the other side of the vehicle, which indicates the need of positioning the nozzle or hose on at least two sides of the burning vehicle to be able to efficiently prevent fire spread.

A field test (outdoor) was also conducted to evaluate the practical usability of the tested systems. A simulated ro-ro space was built up on a fire rescue training field where relevant crew tried different tactical options with the different system. It was found that a semi-rigid hose with a small inner diameter is much easier to handle in most cases but must be compared with desired capacity of pressure, water flow rate and throw length. A hose with a larger inner diameter will have greater stiffness which proved to be useful when trying to position water curtain nozzles. The tests showed that it is possible to position water curtain nozzles to prevent fire spread, but the hose most be further developed to be able to use in ro-ro spaces.

Different extinguishment strategies for fires in cavities in tall timber buildings are presented together with their effectiveness and possibility to minimize water damages. In addition are exercises suggested to give training in how to extinguish fires in cavities in tall timber buildings.

Tall timber buildings are well fire protected today, but wood is a combustible material and the spread of fire to cavities sometimes occur. The first action when there is a hidden fire in a cavity is to identify the structure of the building. Infrared (IR) cameras are a good tool for identifying the building structure and indicate the location of the fire. However, it is important to have a good basic training of using the camera in order to correctly interpret the IR images.

The most important thing during the extinguishing work is to avoid opening up the cavities and thereby add oxygen to the fire before the fire is under control. Extinguishing media must therefore be applied through small openings. Tests have shown that, among water-based extinguishing media, the cutter extinguisher is the most efficient for fires in cavity with the least water supply. Potential other extinguishing agents are nitrogen or carbon dioxide, but techniques and tactics when using these extinguishing media must be further developed. The main drawback of these media is the limited cooling capabilities of the surfaces and gas volume.