| 1. |
- Ingason, Haukur, et al.
(författare)
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Taktik och Metodik vid brand i Undermarksanläggningar (TMU) - Sammanfattningsrapport
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The report compiles the results from the TMU-project. The focus is on fire-fighting performance, capability and organization in underground constructions. The emphasis was on large-scale testing with authentic fire conditions and fire-fighting equipment, development of tools for prediction of hazardous conditions and capabilities of fire-fighting during different conditions, organizational management and tactics, education and development of recommendations. The project was divided into different work packages and these are presented in this final summary report. The test fires performed in the project created severe conditions for fire-fighters who moved in smoke for over 180 m before fighting fully developed fires in a range of 18 to 33 MW. The fires consisted of wood pallets placed in a semi-open steel container, simulating a train wagon fire. The walking speed and connection time for hoses and connections were registered and documented by infra-red cameras. The most important results from these tests is that the time taken to approach the fire depends on parameters as type of equipment, preparation, possibilities for use of infra-red (IR) cameras and the capacity of the extinguishing media. The heat radiation from the fire was found to be important to overcome in order to get close enough to fight the fire. Recommendations and tactics for fighting fires in underground constructions are given.
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| 2. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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CFD-simulation of under-ventilated fires - Comparison to experimental results
- 2009
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- To investigate how different configurations in a large room affect the smoke spread andtemperature during a fire, eleven tests were performed. The tests scenario was built in scale1:2 and can be described as a large room with small ventilation openings near the floor. Thefire tests were simulated using the CFD (computational fluid dynamics) code FDS (FireDynamics Simulator). To see how well FDS simulates under-ventilated fires, both wellventilated and under-ventilated cases were selected for the validation. Gas temperaturesand oxygen concentrations for the experiments and the simulations, respectively, arecompared. The results of the validation show that the combustion model (mixture fractioncombustion model), with empirical amendments for when the fire is allowed to burn, is verysensitive to changes in the oxygen level.
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| 3. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Rekommendationer för räddningsinsatser i undermarksanläggningar
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The report contains recommendations for firefighting in underground facilities. This implies results from a research project and the recommendations are based on case studies, interviews, experiments and discussion with different fire departments. The recommendations are structured in accordance to the time period of the actual incident occurrence or the time period during which some specific measures are taken. These periods are project period, construction phase and finally when the facility is in operation. The recommendations are based on the work in the TMU project (Tactics and methodologies for firefighting in underground facilities), results from other research projects and experience from real fire and rescue operations.
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| 4. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Smoke Spread and Gas Temperatures during Fires in Retail Premises - Experiments and CFD Simulations
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In analytical solutions, e.g. for evacuation design, the use of computer programs for simulating the smoke spread is common. In recent years a group of computer codes named CFD (Computational Fluid Dynamics) codes has emerged as an engineering tool for describing smoke spread. The CFD codes need to be compared against experimental data so that they can be fully validated. To investigate how different configurations in a retail premises affect the smoke spread and temperatures during a fire, 11 tests were performed. The tests scenario was built in scale 1:2 and can be described as a large room with small ventilation openings near the floor. The configuration parameters were: different fire sizes, different fire positions and different shelf configurations. Heptane pools were used to represent the fires. Three different fire sizes were used and during the test with the largest fire size, 650 mm × 650 mm, the test conditions became under-ventilated, i.e., there was insufficient oxygen available to allow stoichiometric combustion of all evaporated fuel. For the simulations conducted as part of this work, the focus was on under-ventilated fires. However, the experimental results for all of the tests are presented and discussed. The fire tests were simulated using the CFD code FDS (Fire Dynamics Simulator). To see how well FDS simulates under-ventilated fires, both well ventilated and under-ventilated cases were selected for the validation. Gas temperatures and oxygen concentration for the experiments and the simulations, respectively, are compared. Different types of meshes for the simulations and different ways of modelling the fire were used. The results of the validation show that the combustion model (mixture fraction combustion model) with empirical amendments for when the fire is allowed to burn, is very sensitive to changes in the oxygen level. The comparison between the experimental data and the simulation indicates that FDS easily can underestimate the oxygen level and thereby the heat release rate which, in turn, creates an underestimation of the temperatures. The validation has shown that the simple empirical expression used for when the fire is allowed to burn is very sensitive and if used without proper understanding it may produce large differences between the experiments and the simulations. It is also clear that the temperatures for well ventilated cases may be overestimated and that the use of visibility and toxicity (soot and carbon monoxide yields) are related to uncertainties. It should also be noted that there are cases where the temperature from the simulations and the temperature measurements correspond relatively well with each other and yet other cases when the simulated temperature is higher than the measured temperature. This depends on the simulation case, the position in the set-up and the time period compared.
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| 5. |
- Palm, Anders, et al.
(författare)
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Breathing air consumption during different firefighting methods in underground mining environment
- 2022
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Ingår i: Fire safety journal. - : Elsevier Ltd. - 0379-7112 .- 1873-7226. ; 133
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Tidskriftsartikel (refereegranskat)abstract
- The paper analyses the breathing air consumption among participating firefighters during full-scale tests performed in the Tistbrottet mine in Sweden 2013. The availability of breathing air during firefighting has in earlier work been identified as a critical tactical factor in underground firefighting. Results from the tests show that there are differences in the breathing air consumption and that this depends on the methods used, equipment and the workload. The use of BA-teams, i.e. firefighters equipped with breathing apparatuses, is a complex group activity where the largest breathing air consumer will set the limits for the whole team. Light equipment and a structured command and control during the activities will enhance the endurance and the firefighting performance. Equipment and methods affect both firefighting performance and the durability of the firefighting activities. Examples of tested methods and equipment during the test series are: different variations of conventional hose lay-out; CAFS; cutting extinguisher; and trolley for equipment and complementary air. The aid of additional air supply and the use of trolleys will support the activities but is dependent on a large degree of preparation and training to function properly. Based on the tests, it is concluded that the larger model of air bottles should be considered for distances longer than 75 m. © 2022 The Authors
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| 6. |
- Andersson, Jonas, et al.
(författare)
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External conditions have a significant impact on the air flow in tunnels using transverse ventilation for smoke extraction
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In 2008 the City of Stockholm Traffic Administration conducted a series of full scale tests, with heat and smoke generation equivalent to that from a fire in a small car, in one of their urban tunnels with transverse ventilation. The primary goal of the tests was to verify how the ventilation system worked and also to provide an opportunity for the local fire brigade and consultants in this field to see what one could expect in a similar situation. A total of four different tests were carried out at two different locations in the tunnel. Methanol was chosen as fuel and the smoke was produced from smoke machines. The ventilation conditions were set according to a pre-set function to simulate both low and high traffic conditions and the fire ventilation was activated 10 minutes after ignition of the simulated car fire. The result of the tests illustrated a variety of phenomena where the external conditions and the general design of the tunnel had a significant impact on the air flow. These aspects determined the direction of airflow in the tunnel regardless of the pre-set ventilation settings. The ventilation settings for the different traffic cases had a significant impact on the stratification of smoke in the event of a fire.
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| 7. |
- Blomqvist, Per, et al.
(författare)
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Polycyclic Aromatic Hydrocarbons (PAHs) Quantified in Large-Scale Fire Experiments
- 2012
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Ingår i: Fire technology. - : Springer Science and Business Media LLC. - 0015-2684 .- 1572-8099. ; 48:2, s. 513-528
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Tidskriftsartikel (refereegranskat)abstract
- A number of large-scale fire experiments with detailed quantitative analysisof polycyclic aromatic hydrocarbon (PAH) including PAH congener distributionhave been conducted by SP. This data is reviewed here and is further assessed withregard to toxicity applying a Toxic Equivalency Factor (TEF) model for estimationof cancer potential. The PAH yield data from the large-scale fire experiments is alsocompared to emission factors from other combustion sources. The study shows thatfull-scale fire experiments with different products exhibit a large variation in totalPAH yields. Fires with products containing flame retardants were shown to producethe highest yields and generally a more toxic mixture of PAHs than fires with nonflameretarded products. The distribution of individual PAH congeners is generallyquantitatively dominated by low molecular weight PAHs, whereas a small number ofmedium to high molecular weight PAHs are most important in determining the toxicityof the PAH mixture. The large-scale fire experiments indicate that fires normallyproduce orders of magnitudes higher yields compared to, e.g. modern residentialcombustion devices. The relative distribution of individual PAHs, which determinesthe toxicity of the PAH mix, is similar for the fires and open burning data studied, inthat benzo(a)pyrene and dibenz(a,h)anthracene dominate the toxicity of the mix as awhole.
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| 8. |
- Claesson, Alexander, et al.
(författare)
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Laboratory fire experiments with a 1/3 train carriage mockup
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A total of six fire tests were conducted in a mock-up of a subway carriage that is about 1/3 of a full wagon length. They were carried out under a large scale calorimeter in a laboratory environment. The aim of the tests was to investigate the initial fire growth in a corner scenario using different types of ignition sources that could lead to a flashover situation. The ignition sources used were either a wood crib placed on a corner seat or one liter of petrol poured on the corner seat and the neighboring floor together with a backpack. The amount of luggage and wood cribs in the neighborhood of the ignition source was continuously increased in order to identify the limits for flashover in the test-setup. The tests showed that the combustible boards on parts of the walls had a significant effect on the fire spread. In the cases where the initial fire did not exceed a range of 400 – 600 kW no flashover was observed. If the initial fire grew up to 700 – 900 kW a flashover was observed. The maximum heat release rate during a short flashover period for this test set-up was about 3.5 MW. The time to reach flashover was highly dependent on the ignition type, wood cribs or backpack and petrol.
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| 9. |
- Dahlbom, Sixten, et al.
(författare)
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A theoretical evaluation of the impact of the type of reaction on heat production and material losses in biomass piles
- 2023
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Ingår i: Fire and Materials. - : John Wiley & Sons, Ltd. - 0308-0501 .- 1099-1018. ; 11:12, s. 2693-
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Tidskriftsartikel (refereegranskat)abstract
- Self-heating during storage of biomass in piles causes material losses, leads to emissions to air, and poses a risk of fire. There are different techniques to assess a biomass material's propensity for self-heating, some of these are briefly reviewed. One of these techniques is isothermal calorimetry, which measures thermal power from materials and produces time-resolved curves. A recently developed and published test standard, ISO 20049-1:2020, describes how the self-heating of pelletized biofuels can be determined by means of isothermal calorimetry and how thermal power and the total heat produced during the test should be measured by isothermal calorimetry. This paper supports interpretation of the result obtained by isothermal calorimetry; the mentioned standard provides examples of peak thermal power and total heat but does not provide any assistance on how the result from isothermal measurements should be interpreted or how the result from measurements on different samples could be compared. This paper addresses the impact of different types of reactions, peak thermal power, total heat released (heat of reaction), activation energy, heat conductivity, and pile size on the temperature development in a generic pile of biomass. This paper addresses important parameters when the result from isothermal calorimetry is evaluated. The most important parameter, with respect to temperature development in large piles, was found to be the total heat released. It was also proposed that safe storage times, that is, the time until a run-away of the temperature in the pile, could be ranked based on the time to the peak thermal power.
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| 10. |
- Fjellgaard Mikalsen, Ragni, et al.
(författare)
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Fires in waste facilities : Challenges and solutions from a Scandinavian perspective
- 2021
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Ingår i: Fire safety journal. - : Elsevier Ltd. - 0379-7112 .- 1873-7226. ; 120
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Tidskriftsartikel (refereegranskat)abstract
- Fires in waste facilities represent significant potential social, economic and environmental challenges. Although the awareness of fires in waste facilities and their consequences has increased in recent years, significant fire safety challenges remain. Fires in waste facilities in Norway and Sweden have been studied to make an overall fire safety assessment and propose measures for increased fire safety. Common ignition causes include self-heating, thermal runaway in batteries, friction, human activity, technical or electrical error and unfavourable combined storage. High-risk wastes include general, residual waste, batteries, electrical and electronics waste, and paper and cardboard. Frequent fires in outdoor storage, increasing indoor storage and new types of waste appear to result in an increased reluctance by insurance companies to work with waste facilities. Measures are suggested for fire safe facility design, operations, waste handling and storage, as well as actions to limit the consequences for the environment and the facility during and after a fire. These actions may prevent fires and minimise the impact of fires that do occur. Increased fire safety at waste facilities may foster a better dialogue between the industry and insurance providers by reducing the potential economic impacts, and limit potential social costs and environmental impacts. © 2020 The Authors
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