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  • 1.
    Aamodt, Edvard
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Säkerhetsforskning.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Säkerhetsforskning.
    Brandt, Are W
    RISE Research Institutes of Sweden, Säkerhet och transport, Säkerhetsforskning.
    Review of efficient manual fire extinguishing methods and equipment for the fire service2020Rapport (Annet vitenskapelig)
    Abstract [en]

    The late 90s and the early 2000s was a period with relative extensive research and innovation in the area of manual fire extinguishing methods and equipment for the fire service. New equipment such as the cutting extinguisher and extinguishing spears allowed to conduct offensive attacks from the exterior of a building, reducing the exposure of fire fighters to fire and smoke and their associated risks in general. This led to the development of new firefighting tactics, as for example the Quadrant Model of the Dutch fire service, which extends the “traditional” offensive interior attack and defensive exterior attack by the offensive exterior attack and defensive interior attack.Recently the research focus has furthermore increasingly shifted to environmental aspects, such as the water consumption and effect of additives (i.e., foam) on humans and the environment. Extinguishing with smaller amounts of water is beneficial for the environment, reduces water damage and lowers the burden on the water delivery system.ConclusionIn conclusion, the systems most relevant to be further tested in a fire situation in a small house or dwelling are the cutting extinguisher and the extinguishing spear.These systems are different in operation but have both shown to be promising with regard to fulfilling the different objectives of the overall project. Being relatively easy to utilize with the right training during internal extinguishing efforts executed from the outside of the building, and being only water based to minimize contamination, due to lower water consumption, of the surrounding areas give these systems advantages over conventional equipment.Especially if the systems are used in combination with an IR camera to locate the fire, the extinguishing efforts can be started early and effectively, and the water amount needed to control the fire may be reduced. The need for firefighters with breathing apparatus is reduced as well, hence reducing the smoke exposure to firefighters.The fact that the fire service also recognizes the potential of using these systems early in the extinguishing efforts, and is working on implementing them, prompts the need for scientific backup.

    Fulltekst (pdf)
    fulltext
  • 2.
    Fjellgaard Mikalsen, Ragni
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Anez, Nieves
    Western Norway University of Applied Sciences, Norway.
    Hagen, Bjarne C
    Western Norway University of Applied Sciences, Norway.
    Melia, Cristina S
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Holmvaag, Ole
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik. The Arctic University of Norway, Norway.
    Smouldering fires - scalability, simulation and application2021Annet (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 3.
    Fjellgaard Mikalsen, Ragni
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Hagen, Bjarne Christian
    HVL, Norway.
    FRIC webinar: Numerical simulation of smouldering fires2020Annet (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
    Fulltekst (mp4)
    fulltext
  • 4.
    Fjellgaard Mikalsen, Ragni
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Sæter Bøe, Andreas
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Stolen, Reidar
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Fra bensinstasjon til energistasjon: Endring av brann- og eksplosjonssikkerhet2020Rapport (Annet vitenskapelig)
    Abstract [en]

    From petrol station to multifuel energy station: Changes in fire and explosion safety

    A multifuel energy station is a publicly available station which offers refueling of traditional fossil fuels in combination with one or more alternative energy carriers, such as hydrogen or electric power to electric vehicles. The goal of this study is to survey how the transition from traditional petrol stations to multifuel energy stations affects the fire and explosion risk.

    Relevant research publications, regulations and guidelines have been studied. Four interviews with relevant stakeholders have been conducted, in addition to correspondence with other stakeholders. The collected information has been used to evaluate and provide a general overview of fire and explosion risk at multifuel energy stations. The scope of the project is limited, and some types of fueling facilities (in conjunction with supermarkets, bus- and industrial facilities), some types of safety challenges (intended acts of sabotage and/or terror), as well as transport of fuel to and from the station, are not included.

    Availability of different types of fuel in Norway was investigated and three types were selected to be in focus: power for electric vehicles, gaseous hydrogen, as well as hydrogen and methane in liquid form. The selection was based on expected future use, as well as compatibility with the goal of the National Transport Plan that all new vehicles sold from 2025 should be zero emission vehicles. Currently, the category zero emission vehicle includes only electric- and hydrogen vehicles.

    In facilities that handle flammable, self-reactive, pressurized and explosive substances there is a risk of unwanted incidents. When facilities with hazardous substances comply with current regulations, the risk associated with handling hazardous substances is considered not to be significant compared to other risks in society. When new energy carriers are added, it is central to understand how the transition from a traditional petrol station to a multifuel energy station will change the fire and explosion risk. Factors that will have an impact include: number and type of ignition sources, number of passenger vehicles and heavy transport vehicles at the station, amount of flammable substances, duration of stay for visitors, complexity of the facility, size of the safety distances, fire service’s extinguishing efforts, environmental impact, maintenance need etc. In addition, each energy carrier entails unique scenarios.

    By introducing charging stations at multifuel energy stations, additional ignition sources are introduced compared to a traditional petrol station, since the charger itself can be considered as a potential ignition source. The charger and connected car must be placed outside the Ex-zone in accordance with NEK400 (processed Norwegian edition of IEC 60364 series, the CENELEC HD 60364 series and some complementary national standards), in such a way that ignition of potential leaks from fossil fuels or other fuels under normal operation conditions is considered unlikely to occur. A potential danger in the use of rapid charging is electric arcing, which can arise due to poor connections and high electric effect. Electric arcs produce local hot spots, which in turn can contribute to fire ignition. The danger of electric arcs is reduced by, among others, communication between the vehicle and charger, which assures that no charging is taking place before establishing good contact between the two. The communication also assures that it is not possible to drive off with the charger still connected. There are requirements for weekly inspections of the charger and the charging cable, which will contribute to quick discovery and subsequent repair of faults and mechanical wear. Other safety measures to reduce risk include collision protection of the charger, and emergency stop switches that cut the power delivery to all chargers. There is a potential danger of personal injury by electric shock, but this is considered most relevant during installation of the charger and can be reduced to an acceptable level by utilizing certified personnel and limited access for unauthorized personnel. For risk assessments and risk evaluations of each individual facility with charging stations, it is important to take into account the added ignition sources, as well as the other mentioned factors, in addition to facility specific factors.

    Gaseous hydrogen has different characteristics than conventional fuels at a petrol station, which affect the risk (frequency and consequence). Gaseous hydrogen is flammable, burns quickly and may explode given the right conditions. Furthermore, the gas is stored in high pressure tanks, producing high mechanical rupture energy, and the transport capacity of gaseous hydrogen leads to an increased number of trucks delivering hydrogen, compared with fossil fuels. On the other hand, gaseous hydrogen is light weight and easily rises upwards and dilute. In the case of a fire the flame has low radiant heat and heating outside the flame itself is limited. Important safety measures are open facilities, safe connections for high pressure fueling, and facilitate for pressure relief in a safe direction by the use of valves and sectioning, so that the gas is led upwards in a safe direction in case of a leakage. For risk assessments and risk evaluations of each individual facility with gaseous hydrogen, it is important to take into account the explosion hazard, as well as the other mentioned factors, in addition to facility specific factors.

    Liquid hydrogen (LH2) and liquid methane (LNG, LBG) are stored at very low temperatures and at a relatively low pressure. Leakages may result in cryogenic (very cold) leakages which may lead to personal injuries and embrittlement of materials such as steels. Critical installations which may be exposed to cryogenic leakages must be able to withstand these temperatures. In addition, physical boundaries to limit uncontrolled spreading of leakages should be established. Evaporation from tanks must be ventilated through safety valves. During a fire, the safety valves must not be drenched in extinguishing water, as they may freeze and seal. Leakages of liquid methane and liquid hydrogen will evaporate and form flammable and explosive gas clouds. Liquid hydrogen is kept at such a low temperature that uninsulated surfaces may cause air to condense and form liquid oxygen, which may give an intense fire or explosion when reacting with organic material. For risk assessments and risk evaluations of each individual facility with liquid hydrogen and liquid methane, it is important to take into account the cryogenic temperatures during storage and that it must be possible to ventilate off any gas formed by evaporation from a liquid leakage, as well as the other mentioned factors, in addition to facility specific factors.

    For the combination of more than one alternative energy carrier combined with fuels of a conventional petrol station, two areas of challenges have been identified: area challenges and cascade effects. Area challenges are due to the fact that risks to the surroundings must be evaluated based on all activity in the facility. When increasing the number of fueling systems within an area, the frequency of unwanted incidents at a given point in the facility is summarized (simply put). If two energy carriers are placed in too close proximity to each other, the risk can be disproportionately high. During construction, the fueling systems must be placed with sufficient space between them. In densely populated areas, shortage of space may limit the development. Cascade effects is a chain of events which starts small and grows larger, here due to an incident involving one energy carrier spreading to another. This may occur due to ignited liquid leakages which may flow to below a gas tank, or by explosion- or fire related damages to nearby installations due to shock waves, flying debris or flames. Good technical and organizational measures are important, such as sufficient training of personnel, follow-up and facility inspections, especially during start-up after installing a new energy carrier. The transition from a traditional petrol station to a multifuel energy station could not only give negative cascade effects, since sectionalizing of energy carriers, with lower storage volume per energy carrier, as well as physical separation between these, may give a reduction in the potential extent of damage of each facility. Apart from area challenges and cascade effects no other combination challenges, such a chemical interaction challenges, have been identified to potentially affect the fire and explosion risk.

    For future work it will be important to keep an eye on the development, nationally and internationally, since it is still too early to predict which energy carriers that will be most utilized in the future. If electric heavy transport (larger batteries and the need for fast charging with higher effect) become more common, it will be necessary to develop a plan and evaluate the risks of charging these at multifuel energy stations. For hydrogen there is a need for more knowledge on how the heat of a jet fire (ignited, pressurized leakage) affects impinged objects. There is also a general need for experimental and numerical research on liquid hydrogen and methane due to many knowledge gaps on the topic. During operation of the facilities and through potential unwanted incidents, new knowledge will be gained, and this knowledge must be utilized in order to update recommendations linked to the risk of fire and explosion in multifuel energy stations.

    Fulltekst (pdf)
    fulltext
  • 5.
    Fjellgaard Mikalsen, Ragni
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Sæter Bøe, Andreas
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Stölen, Reidar
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    From petrol station to multifuel energy station: Changes in fire and explosion safety2021Rapport (Annet vitenskapelig)
    Abstract [en]

    A multifuel energy station is a publicly available station which offers refueling of traditional fossil fuels in combination with one or more alternative energy carriers, such as hydrogen or electric power to electric vehicles. The goal of this study is to survey how the transition from traditional petrol stations to multifuel energy stations affects the fire and explosion risk. Relevant research publications, regulations and guidelines have been studied. Four interviews with relevant stakeholders have been conducted, in addition to correspondence with other stakeholders. The collected information has been used to evaluate and provide a general overview of fire and explosion risk at multifuel energy stations. The scope of the project is limited, and some types of fueling facilities (in conjunction with supermarkets, bus- and industrial facilities), some types of safety challenges (intended acts of sabotage and/or terror), as well as transport of fuel to and from the station, are not included. Availability of different types of fuel in Norway was investigated and three types were selected to be in focus: power for electric vehicles, gaseous hydrogen, as well as hydrogen and methane in liquid form. The selection was based on expected future use, as well as compatibility with the goal of the National Transport Plan that all new vehicles sold from 2025 should be zero emission vehicles. Currently, the category zero emission vehicle includes only electric- and hydrogen vehicles. In facilities that handle flammable, self-reactive, pressurized and explosive substances there is a risk of unwanted incidents. When facilities with hazardous substances comply with current regulations, the risk associated with handling hazardous substances is considered not to be significant compared to other risks in society. When new energy carriers are added, it is central to understand how the transition from a traditional petrol station to a multifuel energy station will change the fire and explosion risk. Factors that will have an impact include: number and type of ignition sources, number of passenger vehicles and heavy transport vehicles at the station, amount of flammable substances, duration of stay for visitors, complexity of the facility, size of the safety distances, fire service’s extinguishing efforts, environmental impact, maintenance need etc. In addition, each energy carrier entails unique scenarios. By introducing charging stations at multifuel energy stations, additional ignition sources are introduced compared to a traditional petrol station, since the charger itself can be considered as a potential ignition source. The charger and connected car must be placed outside the Ex-zone in accordance with NEK400 (processed Norwegian edition of IEC 60364 series, the CENELEC HD 60364 series and some complementary national standards), in such a way that ignition of potential leaks from fossil fuels or other fuels under normal operation conditions is considered unlikely to occur. A potential danger in the use of rapid charging is electric arcing, which can arise due to poor connections and high electric effect. Electric arcs produce local hot spots, which in turn can contribute to fire ignition. The danger of electric arcs is reduced by, among others, communication between the vehicle and charger, which assures that no charging is taking place before establishing good contact between the two. The communication also assures that it is not possible to drive off with the charger still connected. There are requirements for weekly inspections of the charger and the charging cable, which will contribute to quick discovery and subsequent repair of faults and mechanical wear. Other safety measures to reduce risk include collision protection of the charger, and emergency stop switches that cut the power delivery to all chargers. There is a potential danger of personal injury by electric shock, but this is considered most relevant during installation of the charger and can be reduced to an acceptable level by utilizing certified personnel and limited access for unauthorized personnel. For risk assessments and risk evaluations of each individual facility with charging stations, it is important to take into account the added ignition sources, as well as the other mentioned factors, in addition to facility specific factors. Gaseous hydrogen has different characteristics than conventional fuels at a petrol station, which affect the risk (frequency and consequence). Gaseous hydrogen is flammable, burns quickly and may explode given the right conditions. Furthermore, the gas is stored in high pressure tanks, producing high mechanical rupture energy, and the transport capacity of gaseous hydrogen leads to an increased number of trucks delivering hydrogen, compared with fossil fuels. On the other hand, gaseous hydrogen is light weight and easily rises upwards and dilute. In the case of a fire the flame has low radiant heat and heating outside the flame itself is limited. Important safety measures are open facilities, safe connections for high pressure fueling, and facilitate for pressure relief in a safe direction by the use of valves and sectioning, so that the gas is led upwards in a safe direction in case of a leakage. For risk assessments and risk evaluations of each individual facility with gaseous hydrogen, it is important to take into account the explosion hazard, as well as the other mentioned factors, in addition to facility specific factors. Liquid hydrogen (LH2) and liquid methane (LNG, LBG) are stored at very low temperatures and at a relatively low pressure. Leakages may result in cryogenic (very cold) leakages which may lead to personal injuries and embrittlement of materials such as steels. Critical installations which may be exposed to cryogenic leakages must be able to withstand these temperatures. In addition, physical boundaries to limit uncontrolled spreading of leakages should be established. Evaporation from tanks must be ventilated through safety valves. During a fire, the safety valves must not be drenched in extinguishing water, as they may freeze and seal. Leakages of liquid methane and liquid hydrogen will evaporate and form flammable and explosive gas clouds. Liquid hydrogen is kept at such a low temperature that uninsulated surfaces may cause air to condense and form liquid oxygen, which may give an intense fire or explosion when reacting with organic material. For risk assessments and risk evaluations of each individual facility with liquid hydrogen and liquid methane, it is important to take into account the cryogenic temperatures during storage and that it must be possible to ventilate off any gas formed by evaporation from a liquid leakage, as well as the other mentioned factors, in addition to facility specific factors. For the combination of more than one alternative energy carrier combined with fuels of a conventional petrol station, two areas of challenges have been identified: area challenges and cascading effects. Area challenges are due to the fact that risks to the surroundings must be evaluated based on all activity in the facility. When increasing the number of fueling systems within an area, the frequency of unwanted incidents at a given point in the facility is summarized (simply put). If two energy carriers are placed in too close proximity to each other, the risk can be disproportionately high. During construction, the fueling systems must be placed with sufficient space between them. In densely populated areas, shortage of space may limit the development. Cascading effects is a chain of events which starts small and grows larger, here due to an incident involving one energy carrier spreading to another. This may occur due to ignited liquid leakages which may flow to below a gas tank, or by explosion- or fire related damages to nearby installations due to shock waves, flying debris or flames. Good technical and organizational measures are important, such as sufficient training of personnel, follow-up and facility inspections, especially during start-up after installing a new energy carrier. The transition from a traditional petrol station to a multifuel energy station could not only give negative cascading effects, since sectionalizing of energy carriers, with lower storage volume per energy carrier, as well as physical separation between these, may give a reduction in the potential extent of damage of each facility. Apart from area challenges and cascading effects no other combination challenges, such a chemical interaction challenges, have been identified to potentially affect the fire and explosion risk. For future work it will be important to keep an eye on the development, nationally and internationally, since it is still too early to predict which energy carriers that will be most utilized in the future. If electric heavy transport (larger batteries and the need for fast charging with higher effect) become more common, it will be necessary to develop a plan and evaluate the risks of charging these at multifuel energy stations. For hydrogen there is a need for more knowledge on how the heat of a jet fire (ignited, pressurized leakage) affects impinged objects. There is also a general need for experimental and numerical research on liquid hydrogen and methane due to many knowledge gaps on the topic. During operation of the facilities and through potential unwanted incidents, new knowledge will be gained, and this knowledge must be utilized in order to update recommendations linked to the risk of fire and explosion in multifuel energy stations.

    Fulltekst (pdf)
    fulltext
  • 6.
    Fjærestad, Janne Siren
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Fjellgaard Mikalsen, Ragni
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Rømning ved brann i litium-ion batteri i elsparkesykkel2023Rapport (Annet vitenskapelig)
    Abstract [en]

    Fire evacuation during lithium-ion battery fires in electric scooters

    This study deals with escape in the event of a lithium-ion battery fire. The study is funded by the Norwegian Directorate for Civil Protection (DSB) and the Norwegian Building Authority (DiBK). The main objective is to evaluate the consequences of a thermal runaway in an electric scooter in an enclosed space in terms of the spread of gas and smoke from the battery and the potential to prevent escape via escape routes. The scenarios examined are representative of public buildings, schools, office buildings, and other buildings that require many people to escape via large open spaces (e.g., classrooms, open-plan offices) and corridors (escape routes). In addition to the experimental study, information about incidents involving fires in electric scooters in Bergen in recent years has been collected, and the Bergen Fire Service’s experiences from these incidents are presented. A total of 6 large-scale experiments were carried out with a fire in an electric scooter, 3 of the experiments were carried out in a 55 m2 large room corresponding to a classroom, and 3 of the experiments were carried out in a 15 m long corridor (38 m2 ). The ceiling height in the building was around 3 m. The concentrations of the gases CO2, CO, O2, HCl, HF, HCN, SO2, CH2O, NO and NO2 were measured in the experiments. The measurements are used to establish an experimental basis for evaluating whether and when critical gas values (according to ISO 13571:2012 "Lifethreatening components of fire") are achieved and thus lead to reduced ability to escape. The temperature change caused by the fire was measured at different heights in the room. In addition, video documentation is used to assess how the spread of smoke affects escape in a situation where there is a fire in an electric scooter in an escape route. The study has shown that a thermal runaway in a lithium-ion battery leads to a rapid fire development where the battery essentially bursts into flames, with jet fires and potential ejections of burning battery cells far away from where the fire started. The duration of this fire behavior with jet fires and flying debris was between 3 and 7 minutes. In the fire experiments, the emitted energy was not high enough to raise the room temperature to a critical level. Near the fire, however, there is a hazard of fire spread to other combustible materials in the room due to the behavior of the fire and high temperature of the jet flame. Ejection of burning battery cells poses a hazard of fire spread even to areas far away from the start location. Fires in an electric scooter battery or similar lithium-ion batteries can cause a rapid spread of smoke to the entire room. In the conducted experiments, the fire room was no longer smoke-free at the height of 1.9 m already after 1-2 minutes. Due to this rapid spread of smoke, visibility in the room will be affected after a short time and make escape more difficult. In the corridor, the smoke spread was relatively evenly distributed in height, while the smoke in the large room ("classroom") spread in a layer under the roof. Both forms of dispersion are thus possible, depending on the room and ventilation configuration. The gas measurements in the fire experiments detected both asphyxiant and irritant gases. Due to the battery size, which affects how much gas is formed, in relation to room size and ventilation conditions, the calculated FEC, i.e., the critical concentration of irritant gases, was below the selected limit value of 0.1 in all experiments. Although the FEC value was below 0.1 in all the experiments, people in the fire room would have begun to feel an effect from some of the toxic gases. However, this effect would not have been disabling. The FED, that is, the critical dose for asphyxiant gases, was only obtained after 23 to 30 minutes. It is important to remember that the concentration of toxic gases in a room due to a fire in a lithium-ion battery depends on the ratio of battery size, room size, and ventilation conditions. This means the limit values could have been exceeded for a larger battery or in a smaller room. The most important recommendation from this study is: Avoid storing and charging electric scooters and similar in living areas and escape routes. Chapter 7 also presents 8 tips and recommendations for the population, as well as 1 for the building owner and 1 for the fire service.

    Fulltekst (mp4)
    Video Test 2
    Fulltekst (mp4)
    Video Test 4
    Fulltekst (pdf)
    fulltext
  • 7.
    Fjærestad, Janne Siren
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Jiang, Lei
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Stølen, Reidar
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Brannsikkerhet ved oppføring og rehabilitering av bygg2023Rapport (Annet vitenskapelig)
    Abstract [en]

    Fire safety during construction and rehabilitation of buildings. This study deals with how the covering of buildings during the construction or rehabilitation of buildings affects fire safety and to what extent the regulations take this into account. The main focus has been mapping relevant requirements, recommendations, and performances related to the covering of buildings, mapping available materials, investigating the material’s fire properties, and modelling the spread of smoke within the covering. A mapping of the relevant laws and regulations applied for constructing and rehabilitating buildings has been carried out. The mapping has shown that demands are placed on owners, users, project owners, builders, businesses, employers, planners and contractors through many different laws and regulations. The people involved can have several roles, and similar roles have different names in the various regulations. For buildings in use, fire safety must be ensured for both the users and workers. It also applies that both the owner and the users are responsible for ensuring fire safety. It requires good communication and cooperation between different actors to ensure that fire safety is maintained for all involved, during the construction and rehabilitation of buildings. When covered scaffolding is used, the Regulations concerning the performance of work, use of work equipment and related technical requirements [10] require that the covering satisfy the fire requirements for materials used in escape routes (§17-20). The guideline to the Norwegian Regulations on technical requirements for construction works, TEK10, (Veiledningen til TEK10) §11-9, provides pre-accepted performance levels. For escape routes, class B-s1,d0 (In 1) is specified for walls and ceilings. There is no requirement for fire classification of the walkways in the scaffolding under the applicable laws and regulations. We believe there should be requirements for fire classification of the walkways, in the same way as for the covering, i.e., B-s1,d0 (In 1) for surfaces on walls and ceilings and Dfl-s1 (G) for surfaces on floors. The simulations of the spread of smoke from a fire inside a building during construction or rehabilitation show that the spread of smoke is affected when the scaffolding around the building is covered. Covering around the sides leads to a greater horizontal spread of smoke in the scaffolding than without covering. When the cover also has a roof, the smoke first accumulates underneath the cover's roof before it eventually also fills up with smoke down the floors of the scaffolding. The simulations showed that establishing an open field in the upper part of the cover would ventilate the smoke gases effectively, and the spread of smoke was essentially the same as for a cover without a roof. In addition, the simulation indicated that the air flow through the walkways in the scaffold could be an important factor in reducing the covering's negative effect on the spread of smoke. Of the 64 different products used for covering found in the survey, 35% had full classification according to EN 13501-1 (such as B,s1-d0). About 6% stated that the product was not flame retardant. Of the remainder, it was evenly distributed between those who stated a fire classification according to other test methods, those who did not provide any information on the fire properties and those who stated that the product was flame retardant without further specification. The mapping also indicates that the products from market leaders used by large general contractors provide products with documented fire properties. Conversations with two of Norway’s largest fire and rescue services shed light on several challenges connected to covering scaffolding and construction during firefighting activities. They pointed out that the covering could cause challenges and delays throughout their efforts. The covering gives a reduced visual overview of the spread of smoke and the location of doors and windows. This information is important for planning both extinguishing and smoke diver efforts. In addition, the covering can be an obstacle to the actual extinguishing effort, the use of an extinguishing agent and smoke divers and rescue efforts.

    Fulltekst (pdf)
    fulltext
  • 8.
    Fjærestad, Janne Siren
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Yang, Aileen
    SINTEF, Norway.
    Dovran, Freddie
    Oslobygg KF, Norway.
    Olsen, Jørn
    GK Norge, Norway.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    BRAVENT – Storskala branntester (del 1): Brannytelse for ikke-brannklassifiserte ventilasjonskomponenter2024Rapport (Annet vitenskapelig)
    Abstract [en]

    BRAVENT – Large-scale fire tests (part 1): Fire performance for non-fire rated ventilation components In the overall BRAVENT project, the goal is to generate answers and documentation on current issues related to ventilation and fire by examining these with experimental fire tests. The present study aimed to evaluate the fire performance of key non-fire-rated components, mainly DCV dampers and exhaust filters, in a comfort ventilation system by testing the hypothesis that the ventilation components will not be damaged by fire within 30 or 60 minutes. To test the hypothesis, a total of 14 large-scale fire tests with different fuels were carried out. The tests were carried out in a test building with several rooms that are representative of classrooms, offices, and corridors. The fire tests were designed to investigate relevant fire scenarios for school buildings, but the findings from the tests can also be used for other purpose-built buildings. The building was equipped with a full-fledged damper-optimized ventilation system, sized to serve a total of 450 m2 and thus provide a realistic basis for the fire tests. Currently, there is no documentation on how non-fire-rated dampers are affected by high temperatures that occur during a fire. The temperature specifications given for non-fire rated DCV dampers are intended for normal operation. Two different types of DCV dampers were tested. In one type, the airflow was measured with a measuring cross, and for the other, the airflow was measured with sensors integrated into the damper blade itself. In several of the conducted tests the non-fire-rated dampers were not able to sustain their function for the required duration of 30 minutes or longer, and failed completely when the temperature inside or outside the dampers reached about 200 ºC. Misreporting of some temperature measurements in the building management system already occurred at lower temperatures, around 120˚C, without significantly affecting the delivered air flow rate. For the damper type with a measuring cross, the plastic hoses connecting the measuring cross and the measuring transducer for the damper melted when hot smoke was transported through the damper. This failure resulted in the DCV damper measuring too low or no airflow. In several tests, this measurement error meant that the DCV damper opened fully, trying to achieve a large enough airflow. In one of the tests where the supply air damper was placed inside the fire room, such a fault on the supply air damper caused it to close completely. In addition to the damage to the dampers, the power supply to the damper was destroyed, and a fuse for the power supply in the control cabinet was short-circuited. This resulted in the building management system losing contact with all the dampers. This shows that a local error can cause the entire system to fail. For the other damper type, where the sensors were located in the damper blade, the high temperatures caused the entire damper blade to melt. It was not observed that soot in the fire smoke led to problems with the dampers' measuring sensors for any of the damper types examined. This indicates that for the performed test series, high temperature and not soot was the greatest challenge for the dampers in the event of a fire. In addition to examining how dampers are affected by fire, there was also an investigation into how the filter performs during a fire. It was found that the filter could largely capture the soot particles in the smoke. This means that equipment located downstream of the filter is relatively well protected against soot, and the possibility of soot contamination to the supply air side via a rotating heat recovery unit can, therefore, be considered minimal as long as the filter is not damaged. However, when the filter collects so much soot, it shows that the potential for the filter to clog. How quickly this happens depends, among other things, on the materials that burn and the size of the fire in relation to the air handling unit's capacity. This also aligns with results from an earlier BRAVENT project [1]. The air temperature in the unit was in all tests carried out below 60˚C and thus lower than the filters' maximum operating temperature of 70˚C. The conclusion from the tests is that the extraction principle with non-fire-rated components cannot be considered a safe strategy for 30 or 60 minutes.

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  • 9.
    Haukø, Anne-Marit
    et al.
    SINTEF, Norway.
    Garberg Olsø, Brynhild
    SINTEF, Norway.
    Mysen, Mads
    GK Norge, Norway.
    Ingebrigtsen, Sturla
    Trox Auranor, Norway.
    Samuelsen, Per Henning
    Oslobygg KF, Norway.
    Byenstuen, Tommy
    Oslobygg KF, Norway.
    Dovran, Freddy
    Oslobygg KF, Norway.
    Øyen Knutsen, Peer
    Oslobygg KF, Norway.
    Haug, Hugo
    Oslobygg KF, Norway.
    Kausland, Åge
    Bergen kommune, Norway.
    Tvilde, Tor
    Bergen kommune, Norway.
    Fjærestad, Janne Siren
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Prosjektnotat : Kontrollplan – Ventilasjonsanleggets funksjon under brann2024Rapport (Annet vitenskapelig)
    Abstract [no]

    Dette notatet er en delleveranse i arbeidspakke WP3 i prosjektet BRAVENT – Effektiv ventilasjon av røyk fra små branner. Notatet med tilhørende vedlegg Kontrollplan gir en beskrivelse av hvordan periodisk kontroll og daglig/ukentlig internkontroll av ventilasjonsanleggets funksjon under brann i skolebygg kan utføres. Kontrollplanen kan også være nyttig for bruk i andre offentlige formålsbygg.

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  • 10.
    Haukø, Anne-Marit
    et al.
    SINTEF, Norway.
    Garberg Olsø, Brynhild
    SINTEF, Norway.
    Mysen, Mads
    GK Norge, Norway.
    Ingebrigtsen, Sturla
    Trox Auranor, Norway.
    Samuelsen, Per Henning
    Oslobygg KF, Norway.
    Byenstuen, Tommy
    Oslobygg KF, NorwayOslobygg KF, Norway.
    Dovran, Freddy
    Oslobygg KF, Norway.
    Øyen Knutsen, Peer
    Oslobygg KF, Norway.
    Kværner Hestetun, Johanne
    Oslobygg KF, Norway.
    Haug, Hugo
    Oslobygg KF, Norway.
    Kausland, Åge
    Bergen kommune, Norway.
    Tvilde, Tor
    Bergen kommune, Norway.
    Fjærestad, Janne Siren
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    BRAVENT – Veileder for brannteknisk prosjektering av ventilasjonsanlegg i skolebygg2024Rapport (Annet vitenskapelig)
    Abstract [no]

    Dette dokumentet er en veileder. Veilederen skal benyttes av rådgivende ingeniører i brannteknisk prosjektering av ventilasjonsanlegg i skolebygg. Det fokuseres på rømningssikkerhet og skadebegrensning ved små branner i en tidlig fase av brannforløpet. Veilederen beskriver forutsetninger for bruk, krav og preaksepterte ytelser i VTEK, samt ulike typer ventilasjonsanlegg med tilhørende komponenter. Dokumentet illustrerer typiske prinsippløsninger for ulike ventilasjonsstrategier i bygg, samt forskningsresultater fra brannforsøk og undersøkelser i tidligere faser av BRAVENT-prosjektet. Veilederen tar for seg nybygg, eksisterende bygg og verneverdige bygg hvor grensesnittet mellom rådgivende ingeniør brann (RIBr), ventilasjon (RIV), elektro (RIE) og automasjon (RIAut) defineres. En sjekkliste oppsummerer viktige punkter å hensynta ved prosjektering av ventilasjonsanlegg. Rutiner for drift og vedlikehold beskrives til slutt.

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  • 11.
    Haukø, Anne-Marit
    et al.
    SINTEF, Norway.
    Garberg Olsø, Brynhild
    SINTEF, Norway.
    Yang, Aileen
    SINTEF, Norway.
    Aamodt, Andreas
    SINTEF, Norway.
    Samuelsen, Per Henning
    Oslobygg KF, Norway.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Functional testing of ventilation systems in schools during activated fire alarm - Coherence with the fire safety strategy2022Inngår i: RISE rapport 2022:72. https://ri.diva-portal.org/smash/get/diva2:1657152/FULLTEXT01.pdf, 2022, s. 63-64Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The purpose of this paper is to present results from functional testing of ventilation systems in schools during activated fire alarm. It was investigated whether the results had coherence with the ventilation strategy in the fire safety concept and the function description for the ventilation system. Functional testing was performed at several schools in three different municipalities in Norway. Results from the preliminary mapping showed that some of the personnel responsible for maintenance of the ventilation systems lacked knowledge about the system's function during fire. Older schools often don't have a fire safety strategy at all, whereas newer schools and renovated schools normally have well documented fire safety strategies, including the ventilation system's function during fire. However, there is little or no information in the building's MOM-documentation (management, operation and maintenance) about how functional testing must be performed. The functional testing showed several incoherencies with the fire safety strategy of the school buildings.

  • 12.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Car Park Fires: A Review of Fire Incidents, Progress in Research and Future Challenges.2023Inngår i: Proceedings of Seventh International Conference on Fires in Vehicles, 2023, s. 7-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Fires in road vehicles are common, but a large part is associated with crashes. Of all vehicle fires registered in the USA between 2013 and 2017, 16% have occurred in a parking area and only a fraction of these involved vehicles parked in car parks. Furthermore, car park fires often involve few cars only and do not lead to fatalities. However, major car park fire incidents in the last years have shown that fires can lead to significant property and environmental damage if the fire can spread to a large enough number of adjacent vehicles. Large-scale experiments conducted in the 2000-10s have shown that it can take between 10 to 20 minutes before a car fire spreads to an adjacent car. Essential factors for the fire development are ventilation conditions within the car park, air supply to the burning car’s interior (i.e., breaking windows), and fuel involvement (i.e., breaking fuel tanks, a thermal runaway in lithium-ion batteries or gas releases from pressure release devices). Recent large-scale experiments involving a battery electric vehicle showed fire spreading 5 minutes after the first car was ignited. Thus, early detection and a quick response to the fire are essential to prevent a fire from spreading to multiple cars. Modern cars have become bigger, are thus parked closer to adjacent cars and contain more combustible material, especially plastics. A larger plastic content can increase the fire size of car fires, while an increased share of combustible material on the exterior and a decreased distance between cars may aid a faster fire spread. The increasing share of alternative fuel cars introduces new fire and explosion hazards and poses challenges for extinguishing efforts. However, early detection and quick response time still play an essential role in mitigating the associated risks

  • 13.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Aamodt, Edvard
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Storesund, Karolina
    RISE Research Institutes of Sweden.
    Wingdahl, Trond
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Holmvaag, Ole Anders
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Effektiv, skånsom og miljøvennlig slokking av brann i mindre bygningsenheter2021Rapport (Annet vitenskapelig)
    Abstract [en]

    This study evaluates efficient, low-exposure and environmentally friendly extinguishing of fires in small building units and is commissioned by the Norwegian Directorate for Civil Protection (DSB) and the Norwegian Building Authority (DiBK). The main objective is to increase the knowledge on how to extinguish fires in smaller building units efficiently in terms of time and water amount, with minimal exposure of the fire service to smoke, heat and direct contact with soot, as well as minimal environmental exposure in case of extinguishing water run-off. For a holistic evaluation of firefighting methods, the tactical assessments and priorities of the fire service were also studied. In total seven medium-scale fire tests were carried out in a 13.5 m2 compartment with a ceiling height of 2.4 m, a ventilation opening of 0.54 m2 and an adjacent corridor. The fuel in the experiments consisted mainly of a sofa with mattresses according to specifications given in the "open space" test specified in the standard IMO Resolution 265 (84) and walls clad with OSB boards. One experiment was carried out with real furniture. The study focuses on indirect extinguishing (i.e., cooling of the fire gases) with four different extinguishing methods, which are: • Coldcut cobra cutting extinguisher and water, • Spray nozzle and water, • Spray nozzle and foam, • Fognail extinguishing spear and water. The extinguishing was started based on a temperature criterion of 350°C, 80 cm below the ceiling. The water consumption during extinguishing, the fire compartment temperature, as well as the particle and the gas concentration (CO, CO2, etc.), were measured during the experiments. Measuring devices for temperature, polycyclic aromatic hydrocarbons (PAHs) in particulate phase and volatile organic compounds (VOCs) were attached to a firefighter’s jacket to measure exposure. The firefighters stayed, during all experiments, for at least 1.5 minutes in the fire compartment to ensure a measurable PAH and VOC exposure. The experiments were furthermore documented with video recordings from several angles and infrared video of the fire compartment. After four of the trials, interviews with the fire service were conducted to evaluate the tactical assessments made during the firefighting effort. In the experiments, all extinguishing methods caused the temperature in the smoke layer to drop below 150°C within 2.5 minutes and the flaming fire was extinguished. The fire re-ignited in all experiments approx. 6 minutes after the start of the experiment, except for experiment F4, extinguishing with foam, where there was re-ignition after approx. 4 minutes. The experiments showed that the cutting extinguisher and Fognail have a good effect, even under "artificial" limitations in the experiments (duration and direction of the extinguishment). Both of these extinguishing methods used approximately the same amount of water. As the purchase costs for a Fognail are significantly less than for a cutting extinguisher, the Fognail has been found to be not only an efficient extinguishing method but also beneficial from a cost/benefit perspective. Purchasing costs are important for the fire service, especially for smaller fire services. Foam had the poorest cooling effect in the experiments and led to the fastest re-ignition. It was therefore concluded that foam is at high temperatures the least suited extinguishing method to reduce the temperature in the fire compartment. However, it is important that the use of foam is considered depending on the given fire scenario since the present study did not evaluate all properties and possible benefits of foam (such as the ability to cover flammable liquid). Furthermore, it can be assumed that foam can have a better effect when the temperature in the fire compartment is first lowered by using an external extinguishing method. The combination of foam and external extinguishing methods was not investigated in the present study. It is therefore recommended to evaluate this combination in future studies. To use an external extinguishing method (cutting extinguisher or Fognail) as an immediate measure in advance of internal firefighting gives the following advantages compared with smoke diving without the use of an external extinguishing method: • less soot and less explosive/toxic fire gases in the fire compartment, • better effect of the secondary internal extinguishing agent, • faster reduction of the temperature in the fire compartment, • less sauna effect (high humidity can cause heat to penetrate the clothes of the firefighters, which in turn can lead to injuries and that the smoke divers must retreat). The measurements during the experiments show that the use of cutting extinguishers or extinguishing spears can reduce exposure to the fire brigade with regard to heat and contact with particles. It was not possible to identify a clear trend for exposure to the carcinogens (PAH and VOC) measured at the firefighter’s jacket, by comparing the different extinguishing methods in the experiments. The experiments and interviews with the fire service further showed that the firefighter underestimated the negative ejector effect that ventilation openings into the fire compartment have. That is, placing a nozzle near an opening can lead to more oxygen being supplied to the fire which aggravates the situation. The video recordings from the experiments are published together with this report and will be a good learning tool for the fire service.

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  • 14.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Aamodt, Edvard
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Storesund, Karolina
    RISE Research Institutes of Sweden.
    Wingdahl, Trond
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Holmvaag, Ole Anders
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Presentasjon: Effektiv, skånsom og miljøvennlig slokking av brann i mindre bygningsenheter2021Annet (Annet (populærvitenskap, debatt, mm))
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  • 15.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Fjellgaard Mikalsen, Ragni
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Frantzich, Håkan
    Lund University, Sweden.
    Fridolf, Karl
    WSP Sverige AB, Sweden.
    Brannsikkerhet i jernbanetunnel: Dimensjonerende brannscenario og forventninger til redningsinnsats2020Rapport (Annet vitenskapelig)
    Abstract [no]

    Denne studien belyser ulike aspekter ved personsikkerheten ved brann i tunnel og svarer ut konkrete spørsmål omkring temaet.

    Oppdragsgiver er Bane NOR. Prosjektet har fått innspill fra en arbeidsgruppe som er koordinert og ledet av hhv. KS Bedrift og Bane NOR – med fagressurser fra Vestfold Interkommunale Brannvesen IKS (VIB), Bergen brannvesen (BB), Oslo brann- og redningsetat (OBRE), Bane NOR, operatørselskaper (Vy og Flytoget), Direktoratet for samfunnssikkerhet og beredskap (DSB) og Statens havarikommisjon for transport (SHT).

    Rapporten er delt inn i to hoveddeler. Del 1 omhandler kartlegging av relevante forskningsprosjekt, dimensjonerende brannscenarier og røykkontroll, se sammendrag og forslag til veien videre i underkapittel 3.5. Del 2 omhandler kartlegging av kunnskap om menneskelig atferd i forbindelse med tunnelbrann, se sammendrag og forslag til veien videre i underkapittel 4.5. Denne delen er utarbeidet av Lunds Tekniska Högskola og WSP Sverige, og er følgelig på svensk.

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  • 16.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Fjærestad, Janne Siren
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    BRAVENT – Storskala branntester (del 2): Effekten av ventilasjonsstrategi på røykspredning og trykkontroll i en mock-up skolebygning2024Rapport (Annet vitenskapelig)
    Abstract [en]

    BRAVENT – Large-scale fire tests (part 2): The effect of the ventilation strategy on smoke dispersion and pressure control in a mock-up school building In the overall BRAVENT project, the goal is to generate answers and documentation on current issues related to ventilation and fire by examining these with experimental fire tests. The present study aimed to evaluate how different failure mechanisms identified in sub-report 1, "Fire performance for non-fire rated ventilation components" [5], affect the pressure conditions and possible smoke spread in the building. In order to investigate the ventilation system's ability to control pressure balance and smoke spread in the event of a fire, 14 large-scale fire tests with different fuel types were carried out. The tests were conducted in a test building with several rooms representing a classroom, an office and a corridor. The fire tests were designed to investigate relevant fire scenarios for school buildings, but the findings from the tests may also be relevant for other purpose-built buildings. The building was equipped with a full-fledged damper-optimized ventilation system which was sized to serve a total of 450 m2 and thus provide a realistic basis for the fire tests. In sub-report 1, a number of component failures were uncovered when the system was exposed to hot smoke. The failure mechanisms led to the system losing its status and control over the dampers, thus also losing the overview of which air volumes passed through the dampers. The failure of the dampers then led to an imbalance in the ventilation system, also in rooms other than the fire room. In the extreme, this can lead to challenges in connection with escape by making it difficult or impossible to open doors. Smoke spread via the supply air ducts can occur due to smoke backflow if the pressure in the fire compartment exceeds the pressure in the supply air duct. In the experiments, the ventilation system increased to the maximum design airflow rate (Vmax) upon fire detection, and no smoke spread due to backflow of fire smoke in the supply air ducts was observed. It was not tested whether a backflow of smoke could have also been prevented at lower airflow rates than Vmax. Whether the ventilation system maintains sufficiently high pressure in the supply air duct to prevent backflow depends on, among other things, the capacity of the supply air fans, the density of the fire compartment and how quickly the fire develops. The smoke from the fire caused the filter in the unit to gradually clog. In three tests, the filter was clogged so much that the air handling unit could not extract enough air, which created an imbalance in the ventilation system. The new BRAVENT tests show that the size of the fire in relation to the air handling unit's capacity plays an important role in how long the exhaust airflow can be maintained. An air handling unit serving several small fire cells with limited available fuel will be able to maintain the required exhaust air volume longer than an aggregate serving a few large fire cells as the ratio between smoke volume and total air volume changes. Other factors that affect how long the unit can compensate for filter clogging are: • whether the air handling unit is designed for 100% or less simultaneity, i.e. the proportion of rooms that can have the maximum amount of airflow at the same time, • the condition of the filter at the start of the fire, completely new filters were used in each of the fire tests, • whether the ventilation system operates with Vmax or less airflow when a fire alarm is triggered. No smoke spread between the rooms via the exhaust duct was observed. However, since the exhaust airflow rate in one of the tests was significantly reduced to around 50% of the maximum design airflow rate, it is concluded that gradual clogging of the exhaust filter will increase the risk of smoke spreading via the exhaust duct. Clogging of the filters can be avoided by establishing a bypass. Nevertheless, it must then still be documented that all other functions of the ventilation system are safeguarded in the event of a fire. The tests carried out showed that the failure mechanism of some components (measurement errors in dampers, short circuits and clogging of the exhaust filters) can lead to the whole system no longer being able to maintain its function.

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  • 17.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Sanfeliu Meliá, Cristina
    RISE Research Institutes of Sweden, Säkerhet och transport, Brandteknik.
    Avgassing fra litium-ion batterier i hjemmet2021Rapport (Annet vitenskapelig)
    Abstract [en]

    This study evaluates venting from lithium-ion batteries in homes and is commissioned by the Norwegian Directorate for Civil Protection (DSB) and the Norwegian Building Authority (DiBK). The main objective is to study the extent to which venting from a battery in a dwelling can pose a risk for people, focusing on the consequences associated with venting. The Norwegian fire statistics database BRIS was used to identify relevant scenarios. Based on these scenarios, a total of nine numerical simulations of gas dispersion in a generic dwelling were carried out. Boundary conditions, such as gas quantity and composition, were based on a literature study. The simulations were used to evaluate the potential for accumulation of an explosive gas mixture, exposure to toxicity-related gases (both asphyxiants and irritants) and the possibility of detection of carbon monoxide (CO). Electric car batteries, electric bikes, electric scooters, electric hoverboards and larger, stationary battery energy storage systems are found to be the lithium-ion batteries with the highest energy content, which are most common in homes. Other electrical appliances – consumer products make up a larger share in the fire statistics, but these have a lower energy content and thus less potential to pose a major risk for people. Electric cars that are charged in the garage and larger batteries used for energy storage contain the most energy and therefore have the potential for the most severe consequences. However, these batteries are not stored or charged/discharged in living areas, while electric bikes/ scooters/ balancing boards are often stored and charged in the living room, hallway and bedroom. Electric bikes and similar batteries are also subjected to more mechanical and thermal loads compared with battery energy storage systems. It is therefore assumed that the frequency of incidents involving these batteries will be larger than the frequency of incidents involving battery energy storage systems. Therefore, the simulations in this study focused on venting from an electric bike battery (from a single cell and from an entire pack) in the hallway to a generic dwelling. A quantitative risk analysis of the risk associated with electric bike batteries compared with the risk associated with battery energy storage systems was not carried out. Lithium-ion batteries undergoing a thermal event typically emits 1-3 litres of gas per ampere-hour (Ah) at 26 °C and 3.7 volts (V), depending on battery chemistry and state of charge (SOC). Venting from lithium-ion batteries contains carbon dioxide, flammable components such as carbon monoxide, various hydrocarbons, methanol and hydrogen, as well as toxic components such as hydrogen fluoride, hydrogen chloride and hydrogen cyanide. The relatively large proportion of flammable gases (e.g. around 30% hydrogen) makes venting from lithium-ion batteries an explosion hazard. Although batteries with a low state of charge emit less gas than batteries with a high state of charge, the risk of explosion of batteries with a low state of charge may be larger, since the likelihood of late ignition is larger. There are many different types of lithium-ion batteries on the market and several methods for battery safety tests. Today, there is no unified, public system or database with an overview of data for venting from thermal events in lithium-ion batteries. Such a system would be useful, to cover knowledge gaps and to provide data that can be used in risk evaluations. The results show that the largest amount of flammable gas mixture, 26 litres, was accumulated by venting from a 400 watt-hour (Wh) electric bike battery pack, which was placed on a shelf in a small hallway of 3.5 square meters. When the thermal event was limited to a single battery cell, 3.6 litres of flammable gas were formed. Moreover, the results show that the location of the battery plays an important role in the accumulation of flammable gas. When the battery is stored in a partially enclosed area, such as a shelf, the gas can accumulate. The results also show that, especially for venting from a battery pack, it is best to store the batteries in large and wellventilated rooms. No explosion risk analysis was performed related to the accumulated flammable gas clouds. Fire gases from lithium-ion battery fires are generally not significantly more toxic compared with comparable plastic fires, but have the potential for low concentrations of more harmful gases, such as hydrogen fluoride (HF), to be released. The results of the simulations carried out in this study show that the limits for health-hazardous or fatal gas concentrations are exceeded by a thermal event in a lithium-ion battery. Toxic gases can have an asphyxiating and an irritating effect on humans. The results show that the critical value of irritating gases obtained before the limit value of asphyxiating gases. Hydrogen chloride (HCl) and hydrogen fluoride (HF) reached most rapidly health-hazardous or fatal gas concentrations, and these gases also spread most in the room. Furthermore, the results show that risks for people associated with exposure to toxic gases are primarily relevant when the entire battery pack is involved in the thermal event. When the thermal event is limited to a single cell, the simulations show that critical gas concentrations are reached only nearby the battery. If, on the other hand, a thermal event spreads to the entire battery pack, it leads to critical levels of toxic gases throughout the room after about 1 minute for a small room (3.5 m2 ), and in the entire upper half of a large room (43.5 m2 ) after about 4 minutes. To reduce the risk of toxic gas venting, the same measures are recommended as for the reduction of the risk of accumulated flammable gas. Larger lithium-ion batteries should be charged and stored in well-ventilated rooms that are not living areas or part of the escape route, ideally in external buildings. This is consistent with NELFO's recommendations for battery energy storage systems in residential buildings. However, costs/ benefits must be considered, especially for electric bikes and smaller batteries containing less energy than battery energy storage systems. Furthermore, closed doors are good physical barriers to prevent or delay gas and smoke spread in the dwelling. Another important barrier recommended to reduce the risk associated with venting from or fire in a lithium-ion battery is early detection. It is especially important since a thermal runaway develops very quickly, compared with, for example, a fire that starts as a smouldering fire. In this study, only a coarse analysis of the possibility of early detection of increased concentration of carbon monoxide was carried out. The results suggest that combination detectors near the battery may be a good measure to ensure early detection. Recommendations for further work identified in this study are the validation of the simulations by conducting battery fire tests of relevant electric bike batteries and conducting large-scale experiments for validation of gas dispersion and detection. It is also recommended to evaluate the potential overpressure that a delayed ignition (explosion) of gas can generate. Furthermore, it should be considered conducting a similar study for battery energy storage systems or other scenarios with significantly higher energy content than electric bike batteries.

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  • 18.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Sarp Arsava, Kemal
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Brannsikkerhet i naturlig ventilerte parkeringshus2022Rapport (Annet vitenskapelig)
    Abstract [en]

    Fire safety in naturally ventilated car parks This study investigates fires in car parks, and is financed by the Norwegian Directorate for CivilProtection (DSB) and the Norwegian Building Authority (DiBK).The main objective of the study is to collect knowledge in order to evaluate whether it is safe to reducethe fire resistance of main load-bearing systems in car parks in fire classes 1 and 2 to R 15 A2-s1,d0[incombustible material], provided that more than 1/3 of the wall area is open and that the buildingdesign is such that good ventilation is ensured. Reduced fire resistance is indicated as a pre-acceptedsolution in the guideline to the Regulations on technical requirements for construction works(TEK17).The results of this study indicate that the fire resistance of the load-bearing structures shouldnot be reduced from R30 - R60 to R15, even if the wall surfaces have more than 1/3 open areafraction.Relevant regulations in Norway, Sweden, Denmark and Finland have been surveyed. The followingmain rules apply to load-bearing systems in car parks in these Nordic countries:• Car park with two floors : R 30 – R 60• Car park with three and four floors : R 60• Car park with more than four floors : R 60 – R 90 – R 120In Norway and Sweden, subject to different prerequisites, the fire resistance may be reduced to R 15.In Denmark and Finland, however, the use of R 15 for the load-bearing system in car parks is notallowed. Sweden and Finland require the installation of an automatic sprinkler system if the fireresistance is reduced. This requirement applies to car parks with two floors in Sweden (from R 30 toR 15 with sprinklers) and for car parks with a height above 28 m, which is around eight floors, (fromR 120 A2-s1,d0 to R 90 A2-s1,d0 with sprinklers). Of the four Nordic countries, only Norway uses theopen area fraction in wall surfaces as a basis for reducing the fire resistance.Under the pre-accepted solutions in the guideline to TEK17, car parks with open wall surfaces will inpractice often need to have sprinkler systems, either because each floor is defined as a separate firecell, or because the total gross area in a fire cell with open connection across several floors exceeds800 m2, or because the fire section size demands it. In these cases, the design will be morecommensurable with Sweden, i.e. a reduction in fire resistance, but with the installation of a sprinklersystem.In order to be able to assess the effect of wall surfaces with a different open area fraction, a total of tenfire simulations with different wind conditions (direction and force) were carried out. Two generic carparks, one with 21 % open area fraction and one with 41 % open area fraction, were examined. Thecar parks have one floor and a floor area of 1 797 m2, three «open» sides and one side closed by afirewall.It is emphasized that the CFD simulations and structural analysis involve a number of uncertaintiesand limitations. Absolute values for fire spread and collapse time therefore only provide some2© RISE Research Institutes of Swedenindications and no final answers. The focus is therefore on a comparison of car parks with a differentopen area fraction.In a car park with 41 % open area fraction, i.e. more than 1/3 open wall area, the main load-bearingsystem may under certain conditions be constructed with a fire resistance of minimum R 15 A2-s1,d0[incombustible material]. For a car park with 21 % open area fraction, the fire resistance must beminimum R 30 or R 60 depending on the number of floors.In this study, only one floor was simulated. The fire simulations are based on a simple spreadingmodel and are well suited for a comparative study. Owing to model uncertainty, spreading progresscannot be directly used for the analysis of other car parks.The fire simulations have shown that a larger open area fraction, and thus better ventilation, can limitthe extent of fire spread, i.e. the number of cars to which the fire spreads.The difference between a closed (less than 1/3 open area fraction) and an open (more than 1/3 openarea fraction) car park in terms of the number of cars that are burning, is most visible after 40 minutes– 60 minutes, when the fire has reached a certain size. This is because the difference in the time ittakes the fire to spread between cars is accumulated over time, and because the ventilation conditionsassume greater importance when the fire becomes so large as to make it ventilation controlled.For very high wind velocities (e.g. 11 m/s), the open area fraction plays a smaller role, since this leadsto good ventilation also when the open area fraction is lower (21 % in this study).Increased ventilation and thus increased wind velocity in car parks, leads to the fire spreading faster inthe wind direction, downstream of cars that are already burning. This is because the fire and smoke aredriven to one side, and thus closer to adjacent cars. In major fires, increased ventilation will also givethe fire increased access to oxygen.A faster spread of fire in the wind direction may result in more cars burning simultaneously, comparedwith a more closed car park, where the flow rate is lower. Several cars burning simultaneously maycause greater thermal stress on the support system, and potentially an earlier collapse of the structure.The extent of stress will depend significantly on the wind direction, layout of the car park, location ofthe fire start relative to the location of other cars, and so on.A simplified structural analysis showed that an increased open area fraction both entails a positive anda negative effect on the structure’s load-bearing ability in a fire, depending on whether windconditions are favorable or not.Regardless of wind conditions, the structural analysis showed that expanding the open area fractionfrom 21 % (i.e. less than 1/3) to 41 % (more than 1/3), has a smaller effect on the collapse time thanreducing the fire resistance from R 30 to R 15. The difference is even more pronounced in a reductionfrom R 60 to R 15. By using R 60 none of the beams collapsed. The results of this study indicatetherefore that the fire resistance for load-bearing structures should not be reduced even if the wallsurfaces have more than 1/3 open area fraction.For all the fire simulations visibility conditions were examined after 15 minutes. For very low or veryhigh wind velocities little difference in visibility conditions is expected, depending on the open areafraction. At moderate wind velocities, statistically the most common, it turned out

    In what way open wall surfaces impact a car park fire is highly dependent on the fire scenario andwind conditions. These two factors cannot be controlled. Dimensioning the fire resistance to the mainload-bearing system in a car park based on the open area fraction of wall surfaces (more than 1/3 ofthe area) is therefore considered unreliable. Open wall surfaces contribute in some cases to improvingvisibility conditions in car parks, which may extend the available escape time. For this reason, openwall constructions are nevertheless considered advantageous.This study did not examine the effect of sprinkler systems in combination with a reduction in fireresistance, such as is allowed in Sweden. Nevertheless, a sprinkler system, which is little affected bywind conditions, is generally considered better suited as a compensatory measure if the fire resistanceis reduced.It is, therefore, our recommendation that the possibility of reducing the fire resistance in open carparks in fire classes 1 and 2 be reconsidered. This option should be considered removed, or othercriteria could be employed to reduce the fire resistance, such as e.g. sprinkler systems (as in Sweden).Sprinkler systems are considered better suited as a compensatory measure if the fire resistance isreduced.As a basis for such reassessment experiments (fire tests) should be carried out. This is becauseCFD simulations have some limitations, especially regarding the interaction between sprinkler/dropsof water and solid fuel.In addition to the wall design, other factors may also impact the spread of fire, such as e.g. ceilingheight, the design of the floor slab, and the distance between cars. These factors were not examined inthis study. E.g., simulations show that a ribbed floor slab (floor slab with underlaying beams) mayhave a large impact on local flow conditions and thus the spread of fire. To examine these parametersit is recommended that the existing fire spreading model be used, and if relevant validated throughexperimental research.

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  • 19.
    Meraner, Christoph
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Sarp Arsava, Kemal
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Li, Tian
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    On the effect of ventilation conditions in naturally ventilated car parks on fire safety2023Inngår i: Proceedings of Seventh International Conference on Fires in Vehicles, RISE Research Institutes of Sweden , 2023, s. 240-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Ventilation conditions are an essential factor in the development of car park fires. This study investigates if larger open wall areas can affect fires in naturally ventilated car parks such that a reduction of the fire resistance of the main load-bearing system is warranted. A set of ten fire simulations with different wind conditions (direction and force) were carried out. Two generic car parks were examined, one with a 21 % open area fraction and one with a 41 % open area fraction. A simplified structural analysis for all scenarios was, furthermore, conducted to investigate the effect of different open area fractions on the collapse time of individual steel beams. The results of this study indicate that the fire resistance of the main load-bearing structure should not be reduced from R30 or R60 to R15, even if the wall surfaces have a larger open area fraction.

  • 20.
    Reitan, Nina Kristine
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Fjærestad, Janne Siren
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Fjellgaard Mikalsen, Ragni
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Skilbred, Ellen Synnøve
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Aamodt, Edvard
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    RISE Fire Research sitt høst-webinar [RISE Fire Research’s autumn webinar]: 17 november 20232023Annet (Annet vitenskapelig)
    Download (mp4)
    film
  • 21.
    Sarp Arsava, Kemal
    et al.
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Skilbred, Ellen Synnøve
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    FRIC webinar: High-Pressure Water Mist Applications for Façade Fires2023Annet (Annet vitenskapelig)
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  • 22.
    Sesseng, Christian
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Fire Research Norge.
    Storesund, Karolina
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Fire Research Norge.
    Meraner, Christoph
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Fire Research Norge.
    Sæter Bøe, Andreas
    RISE - Research Institutes of Sweden (2017-2019), Säkerhet och transport, Fire Research Norge.
    Utvendig brannbekjempelse i Midtbykvartalet – En mulighetsstudie2019Rapport (Annet vitenskapelig)
    Abstract [en]

    External fire-fighting in Midtbykvartalet – A feasibility study

    The property developer E. C. Dahls Eiendom (ECDE) plans a building complex in a quarter in the city centre in Trondheim, the "Midtbykvartalet". The building will be enclosed by existing building blocks which to varying degrees hinder the fire service's access and efforts. Also, since the new building is intended for residential purposes, it will be necessary to install windows in fire rated walls against adjacent building. These factors result in deviations from a number of performance requirements in the guidelines to the regulations on technical requirements for construction works and there is therefore a need to find alternative solutions. It must be documented that these alternative solutions have at least as good an effect on fire safety as pre-accepted solutions would have. A potential side-effect of new, alternative solutions is that these can also, to some extent, protect the existing wooden buildings in the quarter.

    The aim of this report has been to identify the state-of-the-art within active fire protection measures for external fire-fighting and to obtain an overview of existing solutions and manufacturers and to carry out an assessment of the potential of these solutions.

    Risk scenarios

    An overview of existing buildings in the Midtbykvartalet is presented as well as an overall description of the plans for development. Based on this, several scenarios have been identified to reveal the potential fire-spread hazard between the existing buildings and the planned building. Furthermore, a qualitative risk assessment has been carried out.

    A literature study describes the state-of-the-art in water-based extinguishing systems for outdoor use. It deals with fixed extinguishers (facade sprinklers, water curtains), dynamic extinguishers, foam extinguishers, fire gels, as well as with sprinkler systems' effect and reliability. Furthermore, existing solutions (e.g. facade sprinklers, water curtains, water cannons and water mist turbines) have been surveyed, existing documentation described and assessed regarding suitability for use in the Midtbykvartalet.

    From the identified scenarios, it appears that fires in existing buildings are more likely to spread to the new building than a fire from the new building to existing buildings. The greatest danger to the new building will be if a fire spreads in existing buildings, up through the roof, through windows or along the facade to the roof. In many cases, the fire service will have good access with their ladder trucks etc. to perform extinguishing efforts, at least in the early phase of the fire. But the risk of rapid internal fire spread, which may include several of the older buildings, can create a challenging situation for the fire service and a risk for the new building. In case of fire spread to the new building, the fire department will, due to the position and height of the building, have difficulty with aerial rescue and evacuation from the new building's higher floors.

    Concept for the Midtbykvartalet

    A combination of a static and a dynamic extinguishing system will provide the best balance between system robustness, extinguishing effect and flexibility for the Midtbykvartalet. Facade sprinklers are considered the most suitable static system solution. Facade sprinklers will primarily cool the facade of the new building and absorb heat radiation from a potential fire in the existing buildings, but will not be suitable for extinguishing or actively fighting a fire within the existing buildings. The design and planning of facade sprinklers shall take the design of windows, balconies and roof terraces into account, which have been identified as vulnerable points in the firewalls.

    Dynamic systems such as water cannons and water mist turbines can be used to cool facades and to actively fight a fire over relatively long distances. In addition, such systems can be established so that the fire service can take over control of the extinguishing system as needed. This property is important, because of the height of the new building and because of how it is surrounded by existing buildings.

    Both water cannons and water mist turbines can be combined with an automatic control that allows you to fight a fire at an early stage, even before the arrival of the fire service, as long as early detection is achieved. A fire that spreads within the existing buildings will not be possible to extinguish with permanently installed dynamic systems. Therefore, the cooling and extinguishing effect of such systems must be evaluated based on the scenario of a large fire in the neighbouring building, which has not been done before.

    The cooling and extinguishing effects for both systems are largely dependent on their control system. The control system must be capable of aiming the water cannon or the water mist turbine at the fire, if required compensating for wind effects and selecting an appropriate water jet mode. Therefore, in order to adapt the control system to the Midtbykvartalet, it is necessary to quantify the cooling and extinguishing effect of such a system in advance and with regard to a potentially large fire in the adjacent existing buildings.

    Selected water mist turbines have the option of operating in a full jet mode, like a water cannon. Therefore, such systems are considered more flexible than water cannons. However, water mist turbines set large amounts of air in motion and generate turbulence that can affect the fire. It is therefore important to investigate if and in which cases this can aggravate the fire and have a negative effect on other areas in the quarter.

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  • 23.
    Yang, A.
    et al.
    SINTEF, Norway.
    Aamodt, A.
    SINTEF, Norway.
    Samuelsen, P. H.
    Oslobygg KF, Norway.
    Olsø, B. G.
    SINTEF, Norway.
    Haukø, A. -M
    SINTEF, Norway.
    Meraner, Christoph
    RISE Research Institutes of Sweden, Säkerhet och transport, Brand och Säkerhet.
    Fire safety of ventilation systems and fire incidence reports in Norwegian schools2022Inngår i: ROOMVENT 2022, EDP Sciences , 2022Konferansepaper (Fagfellevurdert)
    Abstract [en]

    School fires are causes of concern in many countries. Although most of these fires are minor in terms of heat release rate, the amount of smoke produced can be substantial and cause significant damage beyond the room of origin. Currently, Norwegian schools have a wide spread of different ventilation strategies and systems, and building owners struggle with how to test, maintain and keep them fire safe. A systematic survey of fire incidences and ventilation strategies in schools for three municipalities in Norway was done to gain better insights into fire safety in schools. The results indicated that the place of origin is often in locker rooms/toilets, kitchen, or outdoors, and the fires were usually deliberately set. For non-arson fires, electrical failure was the most common cause. The majority of the fire incidences were small but would often result in smoke damage and spread of soot in the building, leading to high restoration costs for the local municipality. A lack of documentation of the fire safety and the function of the ventilation system was also identified, indicating a need for improved routines and systems for registering fire incidences and documentation of the technical systems. © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/)

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