The RISE report 2019:04 «Charcoal and wood burning ovens in restaurants – Fire safety and documentation requirements» [1] investigated regulations and documental demands tied to charcoal and wood burning ovens in restaurants in Norway. A part of the conclusion in this report emphasized the need for, through physical testing, mapping whether existing test standards covers the safety requirements of charcoal ovens in restaurants. NS-EN 13240:2001 «Roomheaters fired with solid fuel. Requirements and test methods» [2] was chosen as a relevant test standard. Three test ovens (a closed test oven, a dummy oven and an open test oven) was produced at RISE Fire Research. Their construction with regard to insulation capabilities, materials and dimensions was based on existing charcoal ovens placed on the Norwegian marked. This was done to achieve an objective depiction of the issue, without the need for a specific brand of ovens. Restaurant oven charcoal was utilized to achieve as real heat development as possible in the test ovens. The test layout is based on NS-EN 12340:2001, with a test rigg constructed of two «safety walls», ceiling and floor attached with thermocouples. Temperatures from the test oven are registered in the safety walls at several positions according to a standardised grid, and in the ceiling and the floor each have one single measurement position measuring warmest point. Thermocouples in the chimney and exhaust duct measured the flue gas temperatures transported to the exhaust system. Four different tests were conducted, where the first one was a standardized safety test including the closed oven model. The second test was the same safety test setup with the dummy oven besides the closed oven. The dummy contained a built-in propane burner to simulate the heat load from a real oven. The purpose was to simulate two ovens placed next to each other. The third test was an overload test on the closed test oven with 150 % fuel load and higher refuelling frequency. The last test was a test of the open test oven. The safety test method described in NS-EN 13240:2001 is suitable to test the level of stable maximal temperature in the surrounding combustible materials, in the same way as for roomheaters, which the method is designed for. The method addresses safety aspects such as surface temperatures and handles on the oven. Tests show that the temperatures developed in the ovens have the potential to breech the temperature criterion given by the test standard, and therefore contribute to the ignition of surrounding combustible materials. Such situations pose a fire risk and safety measures regarding this aspect must be documented by the producer. NS-EN13240:2001 does not cover temperatures for exhaust duct and the production of sparks and their possible spread to combustible materials. These are important safety aspects which must be addressed when documenting the fire safety of restaurant grills. Tests show that sparks are created in the oven, including from restaurant charcoal fuel, and are transported into the exhaust duct, and out through the opening of the grill door. Together with high flue gas temperatures in the exhaust duct and deposits of soot and cooking oil this pose a fire risk. Documentation must therefore be presented, showing that the oven is equipped with measures (for instance spark screen) which guards the exhaust duct from sparks to a satisfactory degree. Operators of the oven must receive adequate training and must operate the closed oven with caution, as to avoid incidents with sparks being released though the door. The placement of ovens next to each other does not seem to increase the heat load on surrounding walls but may lead to increased temperatures in between the ovens. The consequences of temperature increases must be documented. Tests show that overloading with fuel and intensifying the refuelling intervals can lead to increased temperatures in the oven, which can affect materials and welding seams. Overloading can also affect the temperatures towards surrounding walls and exhaust ducts and therefore may affect fire safety negatively. NS-EN 13240:2001 requires the producer to documents how the oven is constructed and of what materials, and that the welding seams are dimensioned for the materials used. It is recommended that the producer documents the safety level of the oven materials with an overload test. It must also be documented that the exhaust ducts in which the flue gas are transported are constructed to handle the potential temperatures that can arise, including erroneous use.

In the frame of the European RFCS (Research Fund for Coal and Steel) TRAFIR (Characterization of TRAvelling FIRes in large compartments) project, three natural fire tests in a large compartment were conducted at Ulster University. The aim of this investigation was to understand the conditions in which the travelling fires develop and to study the impact of such fires on the surrounding steel structure. This paper provides details of the second fire test where the size of the openings was reduced to induce different ventilation conditions in comparison to the first fire test. During the test, behaviour of the travelling fire was observed and the gas temperatures at different levels and locations were recorded. The influence of travelling fires on the surrounding structure is studied in terms of the temperatures recorded in the selected steel columns and beams. The influence of change in the ventilation conditions is presented and highlighted through the comparison of results of the second fire test with those recorded earlier during the first fire test. It was found that the travelling fires produce non-uniform temperatures in the compartment irrespective of the ventilation conditions although the magnitude of this non-uniformity is related with the opening sizes. This non-uniformity exists along the length as well as along the height of the test compartment. It was found that for reduced opening sizes, more heat is retained within the compartment which induces higher temperatures in the surrounding steel structure. The transient heating of the surrounding structure caused by travelling fires should be considered while performing the structural fire design of large compartments. The results obtained during the test are state-of-the-art and will help in understating the behaviour of travelling fires and their influence on the surrounding structure which will help to devise fire design methods for future use.

This work explores the challenges of using life cycle assessment (LCA) and life cycle cost (LCC) analysis to provide easily accessible decision support for early product development in cases where intellectual property (IP) and privacy issues require special consideration. Innovation research projects with partners representing different links along the value chain are potential examples of such cases. A case study in which spreadsheet-based cradle to compounder's gate LCA and LCC screening tools were created for candidate flame retarded polymer formulations exemplifies the need for better solutions to overcome problems associated with lack of transparency due to IP/privacy concerns. These problems affect data quality, scaling up processes, and uncertainty of the results. The consortium in this case study had a common overall goal, although each of the partners had a unique perspective on the polymer development process and different IP/privacy needs. The measures used to overcome the challenges include aggregation, normalisation, and omission of costs and impacts common to all candidate compounds. The resulting LCA and LCC screening tools represent a compromise between providing the requested information at the level of detail required by the partners and reporting results that are as accurate and useful as possible. The findings are: in cases where absolute secrecy must be maintained, no one can learn which materials and processes provide the optimal results; appointing a trusted third party to handle sensitive inventory data can cause increased uncertainty of the results due to lack of peer review; the results of the work cannot be built upon by subsequent research.

Several attempts have been made in the past to develop a European harmonized testing and assessment method for façades before the European commission decided to publish a call for tender on the topic. A project consortium from five countries (Sweden, UK, France, Germany and Hungary) applied to the call for tender and was contracted to develop a European approach to assess the fire performance of façades. 24 sub-contractors and 14 stakeholder entities were part of the project. The objective of the European project was to address a request from the Standing Committee of Construction (SCC) to provide EC Member States regulators with a means to regulate the fire performance of façade systems based on a European approach agreed by SCC. The initial stages of this project were focused on establishing a register of the regulatory requirements in all Member States in relation to the fire performance of façade systems, and to identify those Member States who have regulatory requirements for the fire performance façade systems which go beyond the current EN 13501 (reaction to fire and fire resistance) classification systems and to collate the details of these additional requirements. After having confirmed the regulatory needs a testing and classification methodology based on BS 8414 and DIN 4102-20 was developed to address the identified key performance and classification characteristics. This paper is a short overview of results the two-year development work, which Final Report published by the European Commission in 2018. © 2020 The Authors. Fire and Materials published by John Wiley & Sons Ltd.

In this work, a review of current literature on artificial intelligence (AI) and more specifically machine learning (ML) is presented. ML is illustrated by two case studies where artificial neural networks are used for regression analysis of 110 spalling experiments and 81 Fire Dynamics Simulator (FDS) models of tunnel fires. Tunnel fires are often assessed by fire safety engineers using time-consuming simulation tools where a trained model has the potential to significantly reduce time and cost of these assessments.

A regression model based on a neural net is used to study small scale spalling experiments and similar accuracy compared to least-square fits are obtained. The result is a function based on 14 determining experimental parameters of spalling and result in, spalling times and depths. It is a relatively small effort to get started and set up models, comparably to regular curve fitting. In this first case study the training times are short, it is thus possible to establish how the model performs on average.

The 81 tunnel fire simulations are trained using a similar neural net however it takes considerable time to organize data, creating input, target data of the desired format and training. Here, it is also crucial to normalize the data in order to have it in a suitable format when training. 

It should be noted that ML is often an iterative process in such a way that it may be difficult to know what settings will work before starting the process. It is equally important to illustrate and get to know the data, e.g., if there are large differences or orders of magnitude differences in the data. A normalization procedure is most often practical and will give better predictions.

The present paper investigates a travelling fire scenario in an elongated structure (Length 18 m × width 6 m × height 3 m) with a controlled fire source of six trays filled with diesel (width 4 m × length 0.5 m). The fire spread is controlled manually by initiating fires consecutively in the pools. Fire dynamics simulator (FDS) is used to a-priori investigate variations in geometry, material data and fire load, whereas simulations using the final design and measured heat release rates (HRR) were performed after the test. The input to the model beside fire source and geometry are thermal material data. The FDS simulations were used to determine the appropriate size of the downstands (2 m from the ceiling in the final design) on the side to create a sufficiently one-dimensional fire spread. The post-test simulations indicate that although there are a lot of variations not included in the model similar results were obtained as in the test.

An experimental evaluation was conducted on the bench-scale test methods most commonly applied for generating data for fire toxicity assessments. The test methods evaluated were ISO/TS 19700, ISO 5660-1 with the controlled atmosphere box, and ISO 5659-2. Toxic gases were quantitatively analyzed using Fourier transfer infrared spectroscopy. Tests were made with 11 different insulation materials and polymethylmethacrylate as a reference material. The evaluation made was on the combustion conditions in the test apparatus, not generally on the precise yields measured. The evaluation focused on the ventilation conditions created in flaming combustion tests. It was seen that ISO/TS 19700 currently offers the best means among the three test methods evaluated for conducting tests at pre-determined and controlled equivalence ratios. The controlled-atmosphere cone calorimeter does not give a prolonged steady flaming combustion period for most materials and the influence of vitiation was difficult to predict and limiting in achieving higher equivalence ratios, with the test settings applied. ISO 5659-2 generally accumulates a mixture of gases from periods of both flaming and nonflaming combustion in a test, and the yields measured do not, in those cases, represent any specific combustion stage. For materials not showing flaming combustion, for example, mineral fiber products, the influence on the test conditions regarding oxygen consumption and heat generation from the material itself is limited compared to burning materials. However, there were specific properties and limitations of the different test methods observed that are important to consider. 

This report describes three case studies that each involved an analysis of a fire test of an external wall that included a timber structure or part of a timber structure. These external walls all had wooden façade panels, were ventilated behind the façade panels and had glass wool or stone wool insulation. The three case studies aim to assess the contribution of structural timber to the fire development and the fire spread. In addition, the potential of façade systems with combustible materials to limit the fire spread through and along the external wall was assessed. The fire tests were performed for commercial purposes and their results were made available for this study. Not all details of the façade systems details are included in this report.

The analysis discussed in this report indicates that the timber structures did not contribute to the fire development and the fire spread in two of the three tests. The structural members in the external wall remained unaffected during the test. Visual inspection of the third test showed locally some superficial coloring and charring. However, the temperature measurements of the remaining test did not indicate any contribution of the structural timber to the fire development and fire spread. The energy contribution corresponding to the local and superficial coloring and charring is considered negligible.

Two of the three tests analyzed in this study were performed in accordance with the Swedish façade fire testing standard SP Fire 105. Both tests were assessed by the accredited testing institute to meet the requirements set by the Swedish Building regulations that: (1) the fire spread inside the external wall shall be limited; (2) the risk for fire spread along the façade surface shall be limited and; (3) the risk for injuries as a consequence of falling parts from the external wall shall be limited.

There has been a huge increase in the number of electric cars over the last few years, as of the 1st of September 2019 a total of 247,565 electric cars were registered in Norway. There is a clear political incentive to facilitate the charging of electric cars in parking garages in Norway. This has resulted in a public inquiry regarding a proposed amendment to the Norwegian Planning and Building Act (Planning and Building Act, the Norwegian Act relating to owner-tenant sections and the Norwegian Housing Cooperatives Act). The inquiry proposes that housing cooperative owners be given the right to install chargers for electric cars. The inquiry has resulted in a consultation paper in which the uncertainties regarding fire safety during electric car charging in confined spaces were highlighted.

The study examined whether the charging of electric cars in parking garages results in unacceptable risk of fire and, if so, what sort of measures would be required to ensure acceptable risk levels.

One of the objectives of the study was to identify the required measures to ensure acceptable safety levels when parking and charging electric cars in parking garages.

This was done through the use of a comprehensive evaluation of the risk of fire in electric cars while charging, the risk of fire in electrical installations in parking garages during charging and also the layout of the parking garage and the possibility for active firefighting or extinguishing using sprinklers and water mist systems.

It also investigated the relevant measures that could be taken to prevent increased fire risk arising from the installation of charging points for electric cars.

Conclusions

Based on the findings from statistics and a literature review, there were no indications that charging of electric cars in parking garages would result in an increased probability of fire. The regulations regarding charging points for electric cars seem to be adequate for ensuring that the risk of fire arising due to the charging of electric cars in parking garages is acceptable. This requires that the charging points are in accordance with the regulations and that the recommendations from the car manufacturers and the producers of the charging points are followed. It is important to avoid the use of power sockets not intended for the charging of vehicles and also to avoid the use of extension leads. Based on this, the need for fixed water-based firefighting systems in parking garages is no higher for parking garages with the possibility of charging of electric cars than in other parking garages.

There are still unknown factors with regard to both the development of fire in parking garages in general and also regarding potential fire propagation to the battery pack specifically. More knowledge is needed in order to increase the accuracy of evaluations and recommendations.

Charging of electric cars in parking garages

There has been a huge increase in the number of electric cars over the last few years, as of the 1st of September 2019 a total of 247,565 electric cars were registered in Norway. There is a clear political incentive to facilitate the charging of electric cars in parking garages in Norway. This has resulted in a public inquiry regarding a proposed amendment to the Norwegian Planning and Building Act (Planning and Building Act, the Norwegian Act relating to owner-tenant sections and the Norwegian Housing Cooperatives Act). The inquiry proposes that housing cooperative owners be given the right to install chargers for electric cars. The inquiry has resulted in a consultation paper in which the uncertainties regarding fire safety during electric car charging in confined spaces were highlighted.

The study examined whether the charging of electric cars in parking garages results in unacceptable risk of fire and, if so, what sort of measures would be required to ensure acceptable risk levels.

One of the objectives of the study was to identify the required measures to ensure acceptable safety levels when parking and charging electric cars in parking garages.

This was done through the use of a comprehensive evaluation of the risk of fire in electric cars while charging, the risk of fire in electrical installations in parking garages during charging and also the layout of the parking garage and the possibility for active firefighting or extinguishing using sprinklers and water mist systems.

It also investigated the relevant measures that could be taken to prevent increased fire risk arising from the installation of charging points for electric cars.

Conclusions

Based on the findings from statistics and a literature review, there were no indications that charging of electric cars in parking garages would result in an increased probability of fire. The regulations regarding charging points for electric cars seem to be adequate for ensuring that the risk of fire arising due to the charging of electric cars in parking garages is acceptable. This requires that the charging points are in accordance with the regulations and that the recommendations from the car manufacturers and the producers of the charging points are followed. It is important to avoid the use of power sockets not intended for the charging of vehicles and also to avoid the use of extension leads. Based on this, the need for fixed water-based firefighting systems in parking garages is no higher for parking garages with the possibility of charging of electric cars than in other parking garages.

There are still unknown factors with regard to both the development of fire in parking garages in general and also regarding potential fire propagation to the battery pack specifically. More knowledge is needed in order to increase the accuracy of evaluations and recommendations.

Purpose: The purpose of this paper is to propose a simplified representation of the fire load in computational fluid dynamics (CFD) to represent the effect of large-scale travelling fire and to highlight the relevance of such an approach whilst coupling the CFD results with finite element method (FEM) to evaluate related steel temperatures, comparing the numerical outcomes with experimental measurements. Design/methodology/approach: This paper presents the setup of the CFD simulations (FDS software), its corresponding assumptions and the calibration via two natural fire tests whilst focusing on gas temperatures and on steel temperatures measured on a central column. For the latter, two methods are presented: one based on EN 1993-1-2 and another linking CFD and FEM (SAFIR® software). Findings: This paper suggests that such an approach can allow for an acceptable representation of the travelling fire both in terms of fire spread and steel temperatures. The inevitable limitations inherent to the simplifications made during the CFD simulations are also discussed. Regarding steel temperatures, the two methods lead to quite similar results, but with the ones obtained via CFD–FEM coupling are closer to those measured. Originality/value: This work has revealed that the proposed simplified representation of the fire load appears to be appropriate to evaluate the temperature of steel structural elements within reasonable limits on computational time, making it potentially desirable for practical applications. This paper also presents the first comparisons of FDS–SAFIR® coupling with experimental results, highlighting promising outcomes. 

Biomass pyrolysis in the thermally thick regime is an important thermochemical phenomenon encountered in many different types of reactors. In this paper, a particle-resolved algorithm for thermally thick biomass particle during high-temperature pyrolysis is established by using reactive molecular dynamics (MD) and computational fluid dynamics (CFD) methods. The temperature gradient inside the particle is computed with a heat transfer equation, and a multiphase flow algorithm is used to simulate the advection/diffusion both inside and outside the particle. Besides, to simulate the influence of intraparticle temperature gradient on the primary pyrolysis yields, a multistep kinetic scheme is used. Moreover, a new tar decomposition model is developed by reactive molecular dynamic simulations where every primary tar species in the multistep kinetic scheme cracks under high temperature. The integrated pyrolysis model is evaluated against a pyrolysis experiment of a centimeter-sized beech wood particle at 800–1050 °C. The simulation results show a remarkable improvement in both light gas and tar yields compared with a simplified tar cracking model. Meanwhile, the MD tar cracking model also gives a more reasonable prediction of the species yield history, which avoids the appearance of unrealistically high peak values at the initial stage of pyrolysis. Based on the new results, the different roles of secondary tar cracking inside and outside the particle are studied. Finally, the model is also used to assess the influence of tar residence time and several other factors impacting the pyrolysis.

Soot generation is an important problem in high-temperature biomass gasification, which results in both air pollution and the contamination of gasification equipment. Due to the complex nature of biomass materials and the soot formation process, it is still a challenge to fully understand and describe the mechanisms of tar evolution and soot generation at the reactor scale. This knowledge gap thus motivates the development of a comprehensive computational fluid dynamics (CFD) soot formation algorithm for biomass gasification, where the soot precursor is modeled using a component-based pyrolysis framework to distinguish cellulose, hemicellulose and lignin. The model is first validated with pyrolysis experiments from different research groups, after which the soot generation during biomass steam gasification in a drop-tube furnace is studied under different operating temperatures (900–1200 °C) and steam/biomass ratios. Compared with the predictions based on a detailed tar conversion model, the current algorithm captures the soot generation more reasonably although a simplified tar model is used. Besides, the influence of biomass lignin content and the impact of tar and soot consumptions on the soot yield is quantitatively studied. Moreover, the impact of surface growth on soot formation is also discussed. The current work demonstrates the feasibility of the coupled multiphase flow algorithm in the prediction of soot formation during biomass gasification with strong heat/mass transfer effects. In conclusion, the model is thus a useful tool for the analysis and optimization of industrial-scaled biomass gasification. © 2021 The Author(s)

Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence. © The Author(s) 2021.

This review article analyzes factors affecting emergency response to hazardous events on highways and their bridges, with focus on man-made and natural scenarios: heavy vehicle collision with a bridge, earthquake, heavy snowfall, and flooding. For each disaster scenario, selected historical events were compiled to determine influential factors and success criteria for efficient emergency response, both related to organizational and technical measures. This study constituted a part of a resilience management process, recently developed and demonstrated within the European Union (EU)-funded H2020 project IMPROVER and can be a useful approach in aiding operators of transportation infrastructure to improve their resilience to emergency incidents.

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

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.

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.

Programmet ”IMI-verktyget” (se länk till höger) är utvecklat för att ge räddningstjänst, studenter och forskare ett verktyg för att öka kunskapen angående konsekvenserna av taktiska val vid respons till en brand, exemplifierad av några fordons- och rumsbränder.

I rapporten till höger (”fulltext”) beskriver hur verktyget fungerar och innehåller också exempel på datorlabbar som skulle kunna genomföras inom en brandingenjörsutbildning eller räddningsledarutbildning.

The EURAMET EMPIR project “16NRM05 - Ion gauge” aims to develop an ionisation vacuum gauge suitable as a reference vacuum standard. In such a gauge the electron trajectories and their kinetic energy inside the ionisation volume should be well defined and stable. In the search for a suitable design, a series of simulations on different ionisation gauge concepts that have the potential to meet stringent stability requirements have been carried out. Different software packages were used for this purpose. This paper focuses on the design aspects and the performance of the different ionisation gauge concepts that have been investigated by simulation. Parameters such as ionisation gauge sensitivity, ion collection efficiency and electron transmission efficiency, have been determined as a function of emission current, pressure and electron source alignment.

Nine participants, representing eight different Swedish fire consultancy firms participated in a Round Robin study where two different cases were simulated with the Fire Dynamics Simulator. The first case included a large open warehouse where the activation of a sprinkler system was to be studied. In the second case time to critical conditions in a theatre was to be calculated. The participants were given clear instructions on the building layout and heat release rate for the two cases. Still, the results demonstrate a significant variation in time to sprinkler system activation (range of 110 seconds) and available safe escape time (range of 60 seconds), between the participants. It is important to emphasise that some degree of variation is unavoidable, as engineers can model things differently without the modelling solution necessarily being incorrect. Even though it is hard to isolate and specific cause of the variation, some of the variation seen in this study is related to modelling choices that are questionable and consequently problematic for the reliability of the fire safety design. © 2020 The Authors. 

RISE Fire Technology has replaced the use of the desiccant DRIERITE for drying smoke gases with Peltier and high compression cooling for the Servomex ServoPro 4100 O2 and CO2 analyser used for the medium-scale cable testing according to EN 50399. The replacement is made mainly for work environment improvement purposes. A prerequisite for measuring correctly is that the concentration of water vapor prior to the analysers is low, and most important, has a low variation. An increasing amount of water vapor due to a change in drying efficiency, will proportionally dilute the species concentration in the gases introduced into the analyser, thus giving a measurements error of the HRR (Heat Release Rate). Prior to the change of drying method, tests were made to ensure that the measurements using the new drying unit were correct and according to standard. The following tests were performed: 1. Sampling ambient air to evaluate the drift in humidity, O2 and CO2 over time. 2. Sampling ambient air during changes between the two Peltier units of the new drying unit, evaluating instantaneous humidity changes. 3. Sampling the effluents from a 20.5 kW propane burner directed against a wet wooden chip board to evaluate the new drying unit’s ability to dry out high concentrations of water vapour. 4. Sampling ambient air during different seasons where the RH in the surrounding air differs, evaluating the drifts at different moisture levels. 5. Conducting all calibrations according to EN 50399 which affect O2 and CO2 and HRR. Performed with DRIERITE as well as with the new drying unit, comparing them and assuring that the calibration criteria are passed. The evaluation of the Peltier and high compression drying unit gave the following results: 1. A small negative drift was seen in the H2O level reaching the O2 and CO2 analysers over time. There is a reverse linear correlation with the O2 reading which rises when the H2O level drops. By calculating the influence on HRR and using RMS over 30 minutes, a drift in HRR of 0.36 kW can be seen. The corresponding THR during a test can be calculated to 0.2 MJ. These levels of drifts in HRR and THR can be regarded as acceptable compared to other uncertainties in the HRR and THR measurements. 2. It was found that there are instantaneous humidity changes that have an impact on the analysers when changing between the two Peltier coolers. The corresponding HRR changes are calculated to 1.5 kW, which cannot be regarded as acceptable. Thus, a change of Peltier coolers should not be accepted during a test, nor within 10 minutes prior to or after a test. 3. The results of the fire test with the chip board confirm the ability of the new cooling unit’s technique to dehumidify combustion gases to an extent that can be regarded as a worst case. The levels were also smooth with a low drift. 4. Tests that were performed during different seasons showed that the absolute drift may be higher during seasons with a higher RH. However, still at acceptable levels. 5. All calibrations were approved with a margin, both for the DRIERITE as well as for the new drying unit. The conclusion is that the new drying unit solution works well from a measurement uncertainty point of view. However, good routines are needed to ensure that testing does not take place when this drying solution changes the Peltier element cooler.

This investigation studied the utilization of intumescent thermal resistive mats to provide surface protection to the core natural fibre-reinforced Elium® composite structural integrity. The intumescent mats contained flame retardant (FR) i.e. expandable graphite (EG) with four different expansion ratios and alumina trihydrate (ATH). All natural fibre thermoplastic composites were fabricated using a resin infusion technique. The impact of char thickness and chemical compositions on the flammability and smoke properties was investigated. It was found that surface protection significantly reduced the peak heat release rate, total smoke release, smoke extinction area and CO2 yield, and substantially enhanced UL-94 rating, time to ignition and residual char network, depending on the EG exfoliation ratio, ATH and mineral wool fibre. The glass transition temperature increased for the FR composites containing EG with lower expansion ratio. Inclusion of intumescent mats increased the strength of the composites while it had a negative effect on the modulus. 

This paper reports on two experiments conducted in a fire resistance furnace to study the differences in the boundary conditions, the fire dynamics and the fuel required to run the furnace when a combustible timber specimen as opposed to a non-combustible concrete specimen is tested. In both experiments measurements were taken in the furnace to evaluate the difference in the environments of the furnace and the response of the elements being tested. These include non-control plate thermometers distributed throughout the furnace; O2, CO2 and CO gas measurements taken at different distances from the specimen surface and in the furnace exhaust; instrumentation of one of the bricks comprising the furnace lining with thermocouples at different depths from the exposed surface; and mass loss of the combustible timber specimen. Thermal exposure of elements in a furnace is discussed, as well as the impact of the different materials on the similarity of thermal exposure. This is done through analysis and discussion of the different measurements taken and the apparent influence of the specimen being tested on the boundary condition of the heat diffusion equation. We conclude that; (1) the fire dynamics in a furnace are dependent on the specimen being tested; (2) that the test with the combustible specimen requires less fuel flow to the burners such that the control plate thermometers follow the ISO 834 temperature–time curve compared to the non-combustible specimen, however that this is not only a result of the combustibility of the specimen but is also a consequence of the different thermal inertia of the two materials; (3) that the boundary condition for heat transfer to a test object in furnace tests is dependent on the properties of the specimen being tested; and (4) that the timber when placed on the furnace experiences smouldering combustion after the char layer has formed. A fire resistance test of combustible construction of a given period represents a significantly less onerous test in terms of energy absorbed or fuel made available than one of a non-combustible construction, implying that the existing fire resistance framework may not be appropriate for timber structures and that an alternative approach may be required.

A commonly known problem with storage of biomass pellets is the risk for self-heating. The propensity for self-heating depends on several parameters e.g. type of pellets, humidity, ventilation, temperature, type of storage and handling prior to storage.

Within the framework of the research project SafePellets (Safety and quality assurance measures along the pellets supply chain) a medium-scale methodology to assess the propensity for self-heating has been developed. In addition, methods to study carbon monoxide (CO), carbon dioxide (CO2) and oxygen (O2) concentrations as well as different aldehydes have been tested and evaluated in this study.

Biomass pellets from three different sources, i.e. 100 % pine; a mixture of spruce and pine and a mixture of straw, seed residue and spruce, were tested in a 1 m3 test container. The test container and the pellets were pre-heated and kept at the nominal test temperature until self-heating occurred, or the test was terminated. Temperatures were measured at more than 40 different positions and gas samples were extracted from the test container and analysed.

Differences were observed as a function of pellet type, but also as a function of nominal test temperature and ventilation. Significant levels of CO and CO2 and a reduced level of O2 were observed direct after the pre-heating, indicating oxidation of the pellets. Ten different tests were made; ignition occurred in four of them. The higher the nominal test temperature, the higher propensity for self-heating. When ignition occurred, the concentrations of CO and CO2 increased rapidly. It was found that the ventilation conditions were important. In some of the tests, natural convection caused the pellet bulk to cool. In other tests, when the test container was closed, the oxygen concentration dropped, and self-heating was reduced.

Measurements of CO, CO2 and O2 contributed with information about the tests. However, the results from aldehyde measurements were unconcise and the values have only been used as indicative. Identified aldehydes were hexanal, butyraldehyde, valeraldehyde, formaldehyde, propionaldehyde, acetaldehyde and acrolein.

Our earlier study showed significant differences in average particle velocity between simulation and experimental results for devolatilizing biomass particles in an idealised entrained flow reactor [N. Guo et al., Fuel, 2020]. This indicates that the simulations do not accurately describe the physicochemical transformations and fluid dynamic processes during devolatilization. This article investigates the reasons for these discrepancies using time-resolved analyses of the experimental data and complementary modelling work. The experiments were conducted in a downdraft drop-tube furnace with optical access, which uses a fuel-rich flat flame (CH4[sbnd]O2[sbnd]CO2) to heat the particles. Gas flow was characterized using particle image velocimetry, equilibrium calculations and thermocouple measurements. High-speed images of devolatilizing Norway spruce (Picea Abies) particles were captured and analysed using time-resolved particle tracking velocimetry methods. The data were used to estimate the balance of forces and fuel conversion. Thrust and “rocket-like” motions were frequently observed, followed by quick entrainment in the gas flow. Rocketing particles were, on average, smaller, more spherical and converted faster than their non-rocketing counterparts. These differences in conversion behaviour could be captured by a particle-size dependent, 0-D devolatilization model, corrected for non-isothermal effects. The results from this investigation can provide a basis for future modelling and simulation work relevant for pulverized firing technologies. © 2021 The Author(s)

The addition of polypropylene (PP) fibres has been shown to reduce the fire spalling propensity of concrete. When including this type of fibres in the concrete, the concrete mix becomes less robust, and small deviations in the constitutes change the workability and properties of the concrete. So, from a manufacturing perspective as small dosages as possible of PP fibres are desirable. Very few large-scale fire resistance tests of concrete loaded in compression exist showing the function of PP fibres at low dosages on concrete mixes sensitive to spalling if no fibres are added. In this paper, results from 26 fire tests are presented and analysed. The test results are from four different experimental campaigns, but all the mixes have in common that the water-to-cement ratio is 0.40. The results show that an amount of only 0.6 kg/m3 PP fibres has a significant effect on the spalling propensity and that even lower amounts reduce the spalling although they do not eliminate it entirely. During one of the fire tests on large slabs loaded in compression, unloaded small cubes of the same mixes were also included in the furnace. None of the small specimens spalled, whereas some of the corresponding large slabs spalled beyond the layer of reinforcement. This illustrates that tests on small, unloaded specimens are not relevant when assessing fire spalling of larger cross-sections loaded in compression.

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.

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.

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.

The International Maritime Organization, through its correspondence group on fire safety of ro-pax ships, has underlined the need for more scientific studies regarding the performance of boundaries in case of a ro-ro space fire, especially to prevent fire and smoke spread to accommodation spaces. Following these discussions, Swedish Flag State has underlined the issue of the smoke tightness of doors in A class divisions. While smoke tightness is a requirement for A class divisions, the fire resistance test method in the FTP Code is not designed to evaluate hazards associated with smoke spread.RISE has carried out the RoBound project to meet this need.To increase the understanding of this weakness in the FTP Code, RISE has performed experimental tests of two almost identical doors. The only difference between the two doors was the presence or not of an intumescent joint between the leaf and the frame of the door, intended to prevent the passage of smoke. The doors were exposed to the test for fire boundaries in Part 3 of the FTP Code, which exposes specimens to a simulated fire by a temperature increase according to the standard fire curve ISO 834.A modification of the standard experimental rig was added and consisted of the addition of a canopy above the tested doors to gather and measure the rate of carbon dioxide to quantify the amount of smoke leaking from the doors. This set up of canopy and measurement rig was taken from the standard EN 81-58 which is applied for elevator doors acting as fire barriers.The results of the tests showed that both doors marginally failed the A-60 integrity criteria since there was presence of a sustained flame at the unexposed side before 60 minutes of test. However, both doors satisfied to the insulation criteria by maintaining a rise of temperature lower than 140 °C in average at the unexposed side. The main difference between the doors was that the door with the intumescent joints presented a rate of smoke leakage which was almost half of that of the fire door without intumescent joints.This result clearly shows the importance of evaluating the smoke tightness of A class doors during testing and the need

Concrete spalling is an important phenomenon to consider when evaluating the fire behavior of concrete, as this can sometimes have an impact on the structural capacity of the studied element. Spalling can be assessed experimentally using screening tests although it is influenced by the size, geometry, and boundary conditions of the tested element, among other factors. No standardized and systematic methods are yet available to assess concrete spalling sensitivity by testing. Plus, comparative results between screenings tests (small and medium scale) and full-scale tests to evaluate their representativity remain scarce in the literature. In this study, five different spalling tests—with different geometries and boundary conditions—that are used as screening tests were investigated. A concrete mix known to be sensitive to spalling was used to evaluate the representativity of two types of screening tests (material screening tests and intermediate-scale screening tests). The representativity of these test setups was evaluated by comparing the measured spalling depths to the spalling measured on a full-scale slab test using the same concrete mix. This comparative study confirmed that the presence of load and/or restraint was essential for a good representativity for a screening test but should always be implemented in large enough specimens.

FIRENWOOD is an Era-NET cofund Forest Value project (2019-2022) dealing with the fire resistance testing and design methods of engineered wood products at elevated temperatures and fire. As one part of the project, various adhesives, allowed for load bearing timber structures, are tested in finger joints in small scale and medium scale fire tests. The paper will provide a description of these tests and an overview and analysis of the results. Based on the test data of both types, a good agreement regarding the adhesive performance between the tests can be shown. The design model for wooden I-joists is described and values for the depth of the zero-strength layer are proposed for different adhesive performance levels in finger joints.

Biomass devolatilization and incineration in grate-fired plants are characterized by heterogeneous fuel mixtures, often incompletely mixed, dynamical processes in the fuel bed and on the particle scale, as well as heterogeneous and homogeneous chemistry. This makes modeling using detailed kinetics favorable but computationally expensive. Therefore, a computationally efficient model based on zero-dimensional stochastic reactors and reduced chemistry schemes, consisting of 83 gas-phase species and 18 species for surface reactions, is developed. Each reactor is enabled to account for the three phases: the solid phase, pore gas surrounding the solid, and the bulk gas. The stochastic reactors are connected to build a reactor network that represents the fuel bed in grate-fired furnaces. The use of stochastic reactors allows us to account for incompletely mixed fuel feeds, distributions of local temperature and local equivalence ratio within each reactor and the fuel bed. This allows us to predict the released gases and emission precursors more accurately than if a homogeneous reactor network approach was employed. The model approach is demonstrated by predicting pyrolysis conditions and two fuel beds of grate-fired plants from the literature. The developed approach can predict global operating parameters, such as the fuel bed length, species release to the freeboard, and species distributions within the fuel bed to a high degree of accuracy when compared to experiments. © 2020 American Chemical Society

While maintaining a minimum level of service and rapidly restoring services to normal are key components of critical infrastructure (CI) resilience, who should and how to define these parameters remains under debate. Rarely solicited in the debate, yet integral actors in CI resilience, is the general public. In response to this, this paper presents a questionnaire-based methodology for determining public tolerance levels for service reduction and recovery rapidity. This paper explores this under-researched area using a case-study of the Barreiro Municipal Water Network. It draws on key themes that emerged from the literature as well as interviews with the CI operators in order to develop a tolerance questionnaire, implements said questionnaire (N = 1005), and analysizes the results. Results demonstrate that the methodology works for collecting tolerance levels, that when taking into account vulnerable groups, public tolerance levels appear higher than CI operator capability and that communication expectations are high. 

This FRIC report presents a popular scientific overview of 13 facts about smouldering fires. Theaim is that the reader will get an insight into why these fires fascinate, their challenges andconsequences, and how to extinguish them. The 13 facts are on the following topics:

1. Fragmented knowledge2. Nicknames3. Peat and coal areas - a worldwide challenge4. Peat fires in Indonesia5. Burning Mountain of Australia6. Wood pellets silo fires7. Fire deaths caused by smouldering fires8. Coal fires in China9. World Trade Center10. Smouldering in space11. Zombie Fires12. Titanic13. Fighting flameless fires

The report is complemented with an interactive, online presentation which may be found here:https://prezi.com/view/yVFHODruMbxK3e9yMLkF/

Dry wood pellets (diameter 8 mm) of mixed Norwegian spruce and pine were tested in samples of 1.25 kg (1.7 l) in configurations with and without air draft from below. The pellets were placed in a vertical 15 cm diameter cylinder on top of a hot plate. Air draft inlet, when allowed, came through narrow openings in the cylinder bottom periphery. The bulk void of 36% formed channels for gas flows within the pellets bed. Initially, the samples were heated externally from below for 6 h. Time series of distributed temperatures were recorded, together with values of the mass. Smouldering with air draft was observed with two distinct behaviours: Type 1, where the sample after the period of external heating cooled down for several hours, and then increased in temperature to intense smouldering, and Type 2, where the sample went into intense smouldering before the end of external heating. Without draft airflow from below, the sample cooled down after external heating, before developing into intense smouldering about 20 h later. In all cases, the intense period lasted for 2 h. Typical temperatures were in the range 300–450 °C, while higher temperatures occurred in the intense period. Draft flow caused fast oxidation spreading, while slow without draft. Indications of oxidation spreading as a distriäbuted reaction were seen. Circulating air motions in the irregular void between individual pellets is discussed as an explanation for the behaviour. Uneven access to oxygen, with possibilities of locally excess air, can explain the peak temperatures observed. © 2019 The Author(s)

When materials are tested and classified before entering the market, they are mainly tested as newly produced. However, it is known that material properties change with time and when exposed to temperature, humidity, wind and light. As a result, it is important to have knowledge of how material age and which parameters are affected in order to retain safety. Studies show how the mechanical properties change when the materials age. But not much can be found in literature about the ageing effect on fire properties. In the present study, accelerated ageing testing was made with a composite material of phenolic resin and basalt fibres. Selected ageing methods applied were thermal ageing at 90 C and moisture ageing at 40 C and 90 % Relative Humidity. Samples were collected from ageing chambers after one, two and four weeks. To investigate the ageing effect on the fire properties of the composite, fire testing was conducted using cone calorimetry according to ISO 5660-1. The test results showed that ageing does matter. There was an impact on the material and the fire properties were affected. The ignition time decreased for the aged samples and the heat release rate slightly increased. Also, the smoke production increased with ageing. © Published under licence by IOP Publishing Ltd.

The market for lightweight fibre reinforced polymer (FRP) composites is growing. This is seen within advanced applications for e.g. aeronautics, modern ship vessels and railway vehicles. FRPs are often used to save weight, but the downside is that they are ignitable, which implies a potential higher fire risk. It is thus important to thoroughly characterise the material properties of FRPs, including the fire performance, in order to ensure a high safety level. Fire performance testing is made with newly produced materials to show the conformance to required standard test. However, the impact of ageing on the fire performance of materials and products is not mandatory information and hardly ever known. This is still an overlooked matter that is important to address for combustible materials in transport applications, where the requirements of personal safety are especially high. Accelerated ageing is a method to expose materials and products to various environmental parameters for a simulation of long-term usage. Within a few days, weeks or months the damage and degradation of the materials can occur, which normally would be after years in normal climate and after normal usage. Fire performance testing of test samples subjected to accelerated ageing would potentially give important information on the long-term safety of the end-use application of FRPs. The objective of this paper is twofold. One is to find out if the industry, society and research need to deal with the effect of ageing on materials in relation to fire safety as this is not dealt with in fire regulations. And further to identify the state-of-the-art of accelerated ageing methods relevant for Fibre Reinforced Polymer (FRP) materials. In summary, the findings in the literature were limited of reported ageing effects of FRPs, with respect to the fire behaviour. An important conclusion is that there is a major lack of knowledge regarding material aging and fire behaviour, especially for FRPs. However, the identified ageing studies showed that both fire and mechanical properties were affected by ageing. The accelerated ageing methods described in literature was not consequently applied. The ageing methods were special designed for each study and application of material. All methods need a proper validation applying real time ageing. 

ISO 5660-1 specifies the cone calorimeter method for characterizing the ignition and surface burning behavior of materials. The specimen is irradiated through a square opening in the frame of the specimen holder. The frame is intended to protect the edges of the specimen from irradiation but covers the edges with only a few mm. In tests with products such as composite laminates and sandwich wall panels, the production of pyrolysis gases from the edges and, in many cases, burning have been observed. Early contribution from the edges in the test is not representative for surface burning. A modified specimen holder was developed with a larger specimen size to allow better protection of the edges. The opening for exposure to irradiance of the retainer frame is circular and of the same area as that of the original frame. The distance between the exposed surface and the specimen edges is larger in order to prevent early exposure of edges. Tests using the standard specimen holder resulted in pyrolysis and burning from edges that took place outside of the specimen holder. Comparative tests using the modified specimen holder showed that it prevented the exposure and pyrolysis from edges for an extended time. However, the influence on ignition time and peak heat release due to the increased size of the modified specimen holder has not been characterized fully, and test results should not be used for direct comparison with those of the standard holder.

As material age, the durability, strength, and other mechanical properties are impacted. The lifespan of a material generally decreases when exposed to weathering conditions such as wind, temperature, humidity, and light. It is important to have knowledge of how materials age and how the material properties are affected. Regarding materials´ fire behaviour and the effect of ageing on these properties, the knowledge is limited. The research questions of the current work are: Are the fire properties of composite materials affected by ageing? And if so, how is it affected? The study is on material at Technology Readiness Level 9 (TRL). In this study, three composite fibre laminates developed for marine applications were exposed to accelerated ageing. Two different ageing conditions were selected, thermal ageing with an increased temperature of 90°C and moisture ageing in a moderately increased temperature of 40°C and a relative humidity of 90%. Samples were collected after one, two and four weeks of ageing. The reaction-to-fire properties after ageing was evaluated using the ISO 5660–1 cone calorimeter and the EN ISO 5659–2 smoke chamber with FTIR gas analysis. The test results showed that the fire behaviour was affected. Two of the composite laminates, both phenolic/basalt composites, showed a deteriorated fire behaviour from the thermal ageing and the third composite laminate, a PFA/glass fibre composite, showed an improved fire behaviour both for thermal and moisture ageing. The smoke toxicity was affected by the accelerated ageing, especially for the PFA/glass fibre composite that showed a higher production of CO and HCN, both for the thermal aged and the moisture aged samples. © 2021, The Author(s).

Modern buildings are being built with increasingly complex technical installations and energy systems. The introduction of renewable energy production, like photovoltaic (PV) panels on building roofs and facades and an increasing number of connected electric appliances, changes the way the electric power is distributed from production to end-user. The difference in production and demand for energy over time also gives incentives for installing energy storage systems. Electric energy can be stored in batteries, transferred into hydrogen gas via electrolysis or stored as thermal energy for use later. The current work presents an overview of an ongoing study in the Fire Research and Innovation Centre (FRIC), on fire safety implications related to implementing new technology for energy storage and production. The focus is on the built environment such as dwellings and office buildings situated in the Nordic countries. This study builds on previous studies of related topics

Fires in wood waste storages cause financial losses, are difficult to extinguish, and emit large amounts of fire effluents. The mechanisms related to fires in wood chip piles are not well elucidated. To find suitable preventive measures for handling such fires in wood waste, a better understanding of the physical properties of wood waste is needed. The present study investigates how granularity affects mechanisms of smoldering fire and transition to flaming in wood chip piles. Eighteen experiments with samples inside a top-ventilated, vertical cylinder were conducted. Heating from underneath the cylinder induced auto-ignition and smoldering fire, and temperatures and mass loss of the sample were measured. The results showed that granularity significantly affects the smoldering fire dynamics. Material containing larger wood chips (length 4-100 mm) demonstrated more irregular temperature development, higher temperatures, faster combustion, and higher mass losses than material of smaller wood chips (length <4 mm). The larger wood chips also underwent transition to flaming fires. Flaming fires were not observed for small wood chips, which instead demonstrated prolonged and steady smoldering propagation. The differences are assumed to be partly due to the different bulk densities of the samples of large and small wood chips affecting the ventilation conditions. Increased knowledge about these combustion processes and transition to flaming is vital to develop risk-reducing measures when storing wood chips made from wood waste in piles.

This report describes a series of tests of the new proposed method for assessing the performance of façades when exposed to flashover fires. The tests consider the large fire exposure and consists of the 8.5 meter high incombustible walls placed in a 90° angle towards each other. The report assesses reproducibility and the effect of moisture content, stick size, wind and depth of the combustion chamber.The data from the report will be publicly available at the project website for further use and scrutiny. https://www.ri.se/en/what-we-do/projects/finalisation-of-the-european-approach-to-assess-the-fire-performance-of-facades