In Sweden the responsibility for environmental damage when emergency responders are called to an incident is increasingly focussing on the responders. The problem is that most incident response personnel do not have the training and expertise to assess the environmental consequences of their suppression operations. The Fire Impact Tool was developed for training responders about how fire effluents and suppression media affect air, surface/groundwater and soil. The tool has three interdependent parts: fire models (for vehicles and enclosures), an environmental risk assessment (ERA) model for local impacts, and a life cycle assessment (LCA) model for global impacts. Users can create two scenarios that are compared with a reference case in which responders arrive at the incident and prevent the fire from spreading beyond the vehicle or enclosure but do not suppress the fire. The Fire Impact Tool is not intended for use during an actual fire incident. This work does not answer every question for every possible fire scenario, but it does provide a framework for deeper, broader, more comprehensive training and pre-planning. This is a necessary step toward a future in which responders are prepared to make informed decisions about firefighting strategies and tactics that include environmental consequences.

The increased use of electric vehicles has raised a concern about firefighting measures including water spray fire suppression systems (often denoted “drencher systems”) and tactics and equipment used for manual firefighting on ro-ro cargo and ro-ro passenger ships. A test series involving testing of two pairs of geometrically similar internal combustion engine vehicles (ICEV’s) and battery electric vehicles (BEV’s) under as equal test conditions as possible were conducted to investigate the performance efficiency of the drencher system. In addition, manual firefighting equipment and tactics was evaluated on three BEV fire tests. It is concluded that a fire in the two types of vehicles is different but share similarities. However, a fire in a BEV does not seem to be more challenging than a fire in an ICEV for the drencher system design given in current international recommendations. Similarly, there are common (e.g., handheld fire extinguishers and hoses) and new (e.g., fire blanket and water-cooling device) manual firefighting equipment that effectively can be used to control or limit a BEV fire.

Safe large scale hydrogen bunkering - Test and validation The project investigates the use of green hydrogen as a sustainable fuel for shipping. It focuses on developing and validating a new cylinder design with built-in cooling to handle temperature increases during bunkering. The project aims to validate and analyze this new cylinder design by manufacturing a prototype equipped with heat exchangers and conducting performance tests. The project has been carried out in three stages: prototype development, pressure and safety tests, and performance tests. The prototype tank passed both pressure and performance tests without leaking or visible damage. The cylinder design with built-in heat exchanger was found to be able to limit the temperature rise during hydrogen bunkering, enabling a higher fill rate and safe use. However, there are still open questions regarding a large-scale filling that should be investigated further in future projects to further optimize the process. Among other things, this applies to the influence of a plastic liner or a thinner metal liner, a larger tank volume, larger mass flows and realistic pipe/hose lengths and dimensions between the expansion valve and the tanks on board.

Society is changing ever faster, and tunnels are complex systems where performance is affected by many different stakeholders. These conditions suggest that safety management needs to be proactive and based on a systems perspective that acknowledges socio-technical theories. Although systems thinking principles are foundational in overarching European regulations and goals, system principles generally don’t affect tunnel fire safety design principles or engineering practice. In the countries investigated in this study, tunnel fire safety management (TFSM) builds on experience-based and risk management-based principles that are optimized independently system by system. This is usually done with limited consideration of how these systems are interconnected and affect the overall tunnel system. The purpose of this paper is to investigate how systems thinking could support existing engineering practice. The work presented in this article is the outcome of a collaboration between fire safety researchers and practitioners from five countries and three continents. Through three workshops, current TFSM principles have been compiled and discussed. It is suggested that tunnel safety regulations be redesigned to strengthen the ability of engineers to work in design teams using systems thinking principles.

The level of protection for personal protective equipment (PPE) in firefighting is important for Swedish shipowners; they want to be sure that the equipment they provide is sufficiently safe for the types of fires that can occur onboard. Shipowners also want to be updated on risks related to the carriage of alternative fuel vehicles (AFVs). Safety products and equipment used onboard ships with a European flag must be certified in accordance with the Marine Equipment Directive (MED) and follow the regulations in the International Convention for the Safety of Life at Sea (SOLAS). For fire suits, this means that they must be certified according to one of three standards listed in MED. Two of these standards cover suits used in special cases, with very intense radiant heat, and should only be worn for short periods. The third standard, EN 469, is the same standard that is referred to the PPE Regulation 2016/42, making EN 469-approved fire suits used among European firefighters ashore. However, EN 469 contains two different performance levels where the lower level is not suitable for protection against risks encountered when fighting fires in enclosures. Based on a user study and a risk assessment for AFVs, a set of suggested changes to MED and SOLAS were prepared, together with a set of recommendations for operators that were found important but not subject for regulations. A ready-to-use quick guide, containing the most important results, has been developed for operators.

 Safe Hydrogen Bunkering Compressed gaseous hydrogen (CGH2) storage and bunkering represent a viable alternative marine fuel with the potential to be entirely fossil-free. However, the adoption of CGH2 introduces unique challenges and risks that require rigorous assessment to ensure its safe and efficient use. CGH2 is favored for its sustainability potential and comparatively lower economic demands relative to liquid hydrogen. Nevertheless, its physical and chemical properties necessitate enhanced safety measures. CGH2 exhibits a broader flammability range, lower minimum ignition energy, and faster combustion rates compared to conventional fuels such as methane. Additionally, its storage under high pressures exceeding 250 bar implies that leaks may lead to hazardous phenomena, including jet flames or deflagrations (explosions). This report emphasizes the safety of personnel, including crew members, terminal workers, and passengers, while investigating the hazards associated with CGH2 bunkering. To this end, existing literature and regulations pertaining to LNG and hydrogen have been reviewed, stakeholder interviews have been conducted for a Visby case study, and a Hazard Identification (HAZID) analysis has been performed. Key hazards identified include loss of containment due to leaks, pipe, or tank ruptures. To effectively manage the risks of CGH2 bunkering, preventive and mitigative strategies must address multiple dimensions. These include operational limits, technical and physical measures, placement and design considerations, hazardous zones, safety distances, and maintenance protocols. Equally important are human factors such as access control, the establishment of clear safety protocols, well-defined roles and responsibilities, and procedural routines. The individual risk measure is used to ensure that no crew, terminal worker, or passenger is exposed to unacceptable risks. Input values for the individual risk calculation, such as limit values, failure frequencies, and consequences have been reviewed. For calculating the individual risk, uncertainty regarding modelling, input parameters and operational practices needs to be carefully managed. The high frequency of CGH2-bunkering drives the risk due to an increase in the number of transfer operations and the time for the system in operation.

The aim of this paper is to help a decision maker to decide whether a road tunnel is safe enough with respect to fire safety. Safety objectives as well as societal, ethical and political objectives are identified for the decision. It is argued that most uni-directional tunnels that comply with minimum EC requirements, with a longitudinal ventilation system along the traffic flow fails safely in the event of fire. Catastrophic fires should not be an issue, even for a risk averse decision maker. Considering the issue of fairness the tunnel is argued to be safe enough, and resources are either better used elsewhere or should be allocated so that the utility is maximized. For high-risk bi-directional tunnels, catastrophic fires could be an issue, in particular if there is no separate emergency pathway. Then a risk aversive decision maker may take extra safety measures against such fires. A risk neutral decision maker would allocate resources so that the utility is maximized. Road tunnel regulation should set minimum requirements rather than cautionary requirements and allow for a probabilistic approach.

Sweden and the EU today have high expectations and goals for a circular economy. In several areas, however, there is a large gap between these goals and how recycling decisions are handled in practice. A previous RE:Source project in 2019 identified several overarching principles and factors for recycling waste decisions (Gehandler & Millgård, 2020). This study is a continuation and argues that ambiguity is an important factor in reducing the gap between political goals and recycling in practice. Ambiguity is partly about the interpretation and application of laws and concepts such as what is waste or product, and about how risks and benefits should be valued.

RISE has previously studied alternative fuels, such as batteries and gaseous fuels including liquid and compressed hydrogen (GH2). Each fuel has its unique risks. Liquid hydrogen (LH2) is a cryogenic fluid and is thus stored in cooled liquid form, which entails specific risks. The purpose of this report is to, based on the current state of research, map the risks of hydrogen in underground facilities in relation to conventional fuels and investigate which technical measures can be taken to reduce the risks. Unlike diesel, hydrogen (and for instance methane or gasoline) has such a low flash point that an emission can be ignited at normal temperature by a small ignition source. Hydrogen is also very buoyant, with strong diffusion and dispersion characteristics, accordingly it accumulates at high points in a subsurface environment. Hydrogen requires very low energy to ignite at or near stoichiometric mixing with air at around 30%. The lower flammability limit is, compared to other flammable fuel/air mixtures high at around 4%, which means that many smaller releases in ventilated spaces will be too lean. Explosions would require a higher hydrogen concentration, above 8% or more. In subsurface environments, containment contributes to a higher increase in pressure, as well as an increased risk of explosion for both GH2 and LH2. The handling of hydrogen underground can therefore be seen as problematic. When it comes to hydrogen as a vehicle fuel, however, there are safety measures to achieve equivalent safety with conventional vehicles. For example, the shut-off valve (mandatory in regulation) on each tank that reduces the risk of leakage, and through the development of explosion-free composite tanks (not mandatory in regulation) in the event of fire that provide a less dangerous fire scenario than a diesel or gasoline tank in case of fire. When it finally comes to transporting hydrogen, pipelines are the long-term sustainable (and safe) alternative. Transport of compressed hydrogen gives a low amount of gas per trailer and entails relatively higher risks than CNG underground, for example in tunnels. The usage of liquid hydrogen, so far, has an impressive safety record, events like BLEVE or fireballs appear to be rare. The transport of liquid hydrogen provides a larger amount of hydrogen per trailer (than for compressed hydrogen) with a relatively lower risk than, for example, LNG in the open, but a slightly higher risk for explosion of accumulated gas compared to GH2 in enclosed spaces. The safety requirements for transport of compressed hydrogen are less stringent than for road vehicles, e.g., with regard to shut-off valves and melt-fuses and could be improved. Several risk mitigation measures for tunnels and other underground facilities have been identified.

This article aims to contribute to discussions and reflections upon the practice and theory of fire safety design. Are we reaching the results we want by the best available means? The theoretical framework of fire safety design is today restricted by a linear design process where mainly quantitative data and methods matters. A deterministic approach to safety ignores the decision-making context and considers each objective in isolation. Alternative methods for the fire safety design could view the design work as an iterative problem solving process between the designers and the stakeholders. Then decision making theory can be applied to solve the problem. In the iterative process key objectives are identified and the problem and its solutions are being reframed, creative inherently safer (cannot fail) and fail safe (forgiving to errors) alternatives are initially aimed at. Design should further embrace a function-centred view of the human-technology-structure system. A utilitarian evaluation that includes also qualitative factors can identify the best trade-offs between conflicting objectives. With a diversity of perspectives on fire safety design, the field of fire safety will be strengthened and be able to assist a rapidly changing world.

Despite the simple one-dimensional symmetry of a tunnel with a longitudinal ventilation flow, risk analysis often comprises resource intensive and complex calculations. The purpose of this article is to present a simple yet precise limit-based model for assessing the possibility for a safe tunnel evacuation. To estimate the model uncertainty, fire dynamics calculations were compared to experimental data. The calculations performed well compared to experimental test data, showing an average difference between 5 and 40% in predicting the time available for evacuation, when criteria for visibility, air temperature, CO, CO2 and O2 concentration and heat flux were calculated. For steadily growing fires, visibility showed a low sensitivity to variability in input parameters with a relative difference at 9% compared to experimental data. Due to several factors it was not possible to estimate the accuracy of HCN calculations. Visualizing the hazards in a time–distance diagram revealed visibility to be the key indicator for calculating ASET for a broad set of plausible input parameters. This resulted in a simple expression for calculating ASET and consequently a simple condition for evaluating life safety.

The report describes different underground systems including mines and tunnels during construction (tunneling). The key factors that affect fire development in underground systems are described. Proposal and recommendations for ventilation strategies in case of fire are given. The report covers both fuel- and ventilation-controlled fires. In general, a minimal ventilation limits the fire growth and may even inert the fire through ascended smoke. A minimal ventilation also contributes to improved conditions for a first fire extinguishing attempt and evacuation.

This paper contains a proposal of new Swedish framework for performance-based design of road tunnel fire safety derived from Swedish and European regulation. The overall purpose of the guideline is to protect life, health, property, environment, and key societal functions from fire. The guideline is structured into five key groups of requirements: #1 Proper management and organisation, #2 to limit the generation and spread of fire and smoke, #3 to provide means for safe self-evacuation, #4 to provide means and safety for the rescue service, and #5 to ensure load-bearing capacity of the construction. Each group contains a hybrid of prescriptive requirements, performance-based requirements, and acceptable solutions. Prescriptive requirements must be fulfilled, however, it is the choice of the design team to either adopt the proposed acceptable solutions, or to design alternative solutions by verifying that performance-based requirements are satisfied. For verification of performance-based requirements through risk analysis the operational, epistemic, and aleatory uncertainties are considerable. Therefore, a scenario-based risk analysis with several specified input variables and methods is recommended for verification of #3 and #5. Indispensable complements are scenario exercises, emergency exercises and similar methods that validate the design and highlight organisational aspects. The proposed design guide has been developed by the authors together with the advisory group established for the work.

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

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

Fuels with a high energy density have contributed to the development of modern communities. On the other hand, fuels contain energy that, during some conditions, can result in incidents, not least within transportation. CNG vehicles are designed according to safety standards of UNECE, including events such as fire. In case of a fire a thermally activated Pressure Relief Device (TPRD) should empty the container before a pressure vessel explosion potentially can occur. CNG tanks are according to UNECE regulation 110 tested against a 1.65 m long pan fire. However, local fires are not included in these tests. This report presents fire tests of CNG containers performed both with a UNECE compatible fire source and with a local fire source. Any pressure vessel explosion and jet flames were characterized for two different types of CNG containers, namely steel and composite. In five out of six tests the safety of the CNG containers prevailed also in the event of a local (0.24 m by 0.24 m) pan fire, meaning that no pressure vessel explosion occurred. In real vehicle fires, where the fire extends from its local characteristics to a more developed fire that expose the CNG containers to a larger extent, these tests support that TPRDs most likely will activate. The experience from running these test series call for that the fire source should be more accurately defined with regards to fuel and dimensions and a local fire should be included in the UNECE Regulation 110.

Vehicles that are powered by gaseous fuel, e.g., compressed natural gas (CNG) or hydrogen (H2), may, in the event of fire, result in a jet flame from a thermally activated pressure relief device (TPRD), or a pressure vessel explosion. There have been a few incidents for CNG vehicles where the TPRD was unsuccessful to prevent a pressure vessel explosion in the event of fire, both nationally in Sweden and internationally. If the pressure vessel explosion would occur inside an enclosure such as a road tunnel, the resulting consequences are even more problematic. In 2019 the authors investigated the fire safety of CNG cylinders exposed to localized fires. One purpose of the tests conducted in 2021 reported in this paper is to investigate whether extinguishment with water, e.g., from a tunnel deluge system, may compromise the safety of vehicle gas cylinders in the event of fire. Steel cylinders handles the situation with localizde fire and/or cooling with water well. Composite tanks can rupture if the fire exposure degrades the composite material strength, and the TPRD is not sufficiently heated to activate, e.g., if the fire is localized or if the TPRD is being cooled by water, which prevents its activation.

There can be situations, for example if gas containers have been damaged in a vehicle crash, when the fire and rescue service would like to depressurize the gas containers through shooting with a civilian rifle. Modern high-pressure hydrogen containers are designed for a working pressure of 700 bars. This means that they have a very thick and strong shell made of composite material. At the same time the fire and rescue service only have access to civilian rifles and ammunition that can be bought for hunting purposes. Thus, tactical and safe depressurization of hydrogen containers is a big challenge. RISE have, together with the Södra Älvsborgs Fire and Rescue Services (SÄRF), Swedish Civil Contingency Agency, and Lund University conducted shooting tests of gas tanks mounted on a hydrogen gas vehicle and three stand-alone hydrogen gas tanks. The shooting tests were conducted at Remmene shooting field in Sweden. Thirteen shooting tests with hydrogen tanks placed in favouarable positions were performed. Out of these, only four tests were succesful in puncturing the individual gas tank in a single shot. Furthermore, two unwanted events occurred; one rupture (after 7 shots) and two powerful jets (after 20 and one shot respectively). This shows that further development and research is required in order to develop a method to safely depressurize high pressure hydrogen tanks.

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.

Swedish recycling businesses argue that the Non-Toxic Environmental target gets too much weight and that resource efficiency gets too little focus, which results in decreased recycling. The purpose of this paper is to highlight different factors that recycling of waste decisions should consider, as well as contributing to a constructive discussion of the overall principles and policies for recycling. How recycling works in practice is explored based on nine interviews with stakeholders from the governmental agency level to recycling businesses. Theory with regards to ethics, risk, decision-making, governmental policy and laws is summarised. Finally, the discrepancy and connection between practice and theory is analysed. If recycling of waste is seen as a decision problem, the choice is between to recycle (in different ways) or not to recycle (i.e., energy recovery and/or landfill). Based on risk and decision theory, all relevant goals should be considered. This requires a broader problem framing when goals are in conflict. All parties agree that recycled and virgin material should be treated equally. From a higher policy perspective, it should then be demonstrated that any use of material (recycled and/or virgin) minimize environmental impact and promotes long-term sustainability. © 2020 by the authors.

Ingen ska skadas eller drabbas av sjukdom på grund av sitt arbete. Detta ställer krav på genomtänkt utformning av brandskyddet och utrymningssäkerhet under byggtiden för tunnel eller andra undermarksanläggningar. Ett syfte med denna handbok är att tydliggöra vilka krav som ställs på brandskydd under byggtiden, samt ge exempel på vanliga brandrisker och förslag på hur dessa kan hanteras.

Handboken vänder sig till aktörer, såsom byggherrar, projektörer, entreprenörer och byggarbetsmiljösamordnare, involverade i planering, projektering och byggnation av undermarksanläggningar. Med undermarksanläggning menas här väg-, järnväg-, vatten-, avlopps- kabel- och distributionstunnel, bergrum och slutförvar.  Handboken omfattar inte gruva, byggnader ovan mark, eller brandskydd i färdigställd anläggning.

Handboken är avsedd att användas som vägledning och inspiration vid planering, projektering, genomförande, samt utbildning och övning med fokus på brandsäkerhet. 

Klicka på länken ”TUSC Handbok” högst upp till höger för att öppna handboken. Strax under finns det en länk till en MS Power Point introduktion till handboken, ett övningsprotokoll och ett kommunikations material.

The purpose of this study has been to highlight different factors that waste recycling decisions can consider, as well as contributing to a constructive discussion of goals and overall principles for waste recycling. The background of the project is that it has been shown that the recycling of construction material has decreased with the application of the Swedish Environmental Protection Agency's handbook (2010:1). One view that emerged from an evaluation of the handbook is that the non-toxic environmental target (“Giftfri miljö”) gets too much weight and that resource management gets too little focus. As the climate crisis becomes more acute, and since recycling in many cases reduces the climate impact, this limitation can be questioned. However, it is currently unclear how a non-toxic environment and resource efficiency should be balanced.A literature study has been carried out in two parts: 1) decision and risk management theory, and 2) ethics. The first part was aimed at providing theory about risk decisions and basic steps that should be included in a decision-making process. The second part of the literature study, ethics, presents theory of ethical aspects linked to decisions. Ethics is central because it has long sought answers to the question of how we should act.Furthermore, nine interviews have also been conducted with various stakeholders, from the governmental agency level to recyclers, to capture how waste recycling works in practice. From the interview result, the theme "The goal Non-toxic environment and the difficulties that can arise in its practical application" crystallized. Which was discussed further in a workshop. Invited to the workshop were mainly those who had been interviewed and had relevant roles for the chosen theme.If waste recycling is seen as a decision problem, the choice is between to recycle (in different ways) or not to recycle (ie. landfill, incineration or energy recovery). Based on decision theory, all the relevant goals should be considered. This is likely to require a broader perspective for more difficult cases, which includes environmental risks linked to the different alternatives.With a broader perspective, it is recognized that no alternative is risk-free. A multi-criteria analysis can weigh the various factors against each other to see what weighs most, which from the perspective of the environmental code is most reasonable, ie. provides the most environmental benefit. A broader perspective favours long-term sustainability and, in the long run, all environmental goals. On a higher level, recycled and virgin material should be treated equally. Similarly, from a circular perspective, it should be demonstrated that the choice of material (recycled and virgin) promotes long-term sustainability.

The project BREND investigated risk with alternative fuel vehicles inside ro-ro spaces. BREND 2.0 is a continuation and has in particular investigated two of the major risks identified in BREND, namely the risk of toxic gases from electric vehicle fires and the risk of a pressure vessel explosion for fire exposed biogas or hydrogen vehicle tanks. Simulations of electric vehicle fires inside a ro-ro space based on real input fire data has been performed. Field experiments that investigate the conditions that can lead to pressure vessel explosion were made with fire exposed biogas and hydrogen tanks. Recommendations are given about how ro-ro space fires in alternative fuel vehicles, or indeed any vehicle fire, can be managed.

This qualitative risk analysis of dangerous goods transports with alternative propellants was ordered by the Swedish Civil Contingencies Agency (MSB). Scenario combinations consisted of five alternative fuels, six accident scenarios and five types of dangerous goods cargo. The alternative fuels were: methane, hydrogen, ethanol, methanol and dimethyl ether. The accident scenarios consisted of refuelling, fire in tire or engine, tunnel accident, road collision and sabotage of fuel tank. The dangerous goods were limited to: ammonium nitrate, petrol/diesel, methane, ethyl chloride, and EX/II cargo as defined in the ADR regulation. The main identified risks are due to the risk of pressure vessel explosion of gaseous fuels as it: 1) Threatens to detonate explosive load or ammonium nitrate. 2) Cause rescue service to take a defensive approach which will lead to larger consequences. Since there are sustainable liquid fuel alternatives such as bio diesel, this may be a better choice for dangerous goods transportation.

Reducing the environmental and climate impact of shipping propelled by liquefied natural gas (LNG) requires the introduction of alternative fuels such as liquid biogas/biomethane (LBG) (Jivén et al., 2022). Today, only a small part of the biomethane produced in Sweden is liquefied into LBG and an even smaller part is used as fuel for shipping. The price and availability of biogas is governed by supply and demand in an international market where shipping, industry and heavy trucks demand biogas. The biogas then needs to be processed into upgraded biogas (biomethane) or LBG quality in order to be transported and used in the respective sectors inside and outside of Sweden. The trend is for a larger proportion of biogas to be liquefied into LBG. The market has thus gone from a local market, where biogas was produced in the city's wastewater treatment plant and the city buses ran on biogas, to an international market where biogas often is transported in the same way as fossil gas and marketed using the fossil gas together with certificates. The project "Renewable liquid biogas (LBG) for shipping in practice" was carried out by IVL Swedish Environmental Research Institute and RISE in 2023 together with stakeholders from the shipping sector, ports and industry organizations for biogas. The project has studied the conditions required to make LBG available to shipping in practice at Swedish ports. The study shows that the major obstacles to an established use of LBG in the shipping sector in Sweden today are pricing/willingness to pay that is affected by international market prices, lack of suitable logistical solutions as well as the absence of the piece of the puzzle that is the business model and cooperation needed to make available the large volumes of biogas that shipping may demand. The stakeholders in the project estimate their total need of biogas to 3 TWh in a short term, and 10 TWh in a longer term. The project has identified a number of conclusions and recommendations for future work, including that the potential for biogas is large and untapped, but that new solutions for the distribution and logistics of LBG are needed. There is a clear interest from maritime actors as they see biogas as a strategic solution and the dialog between actors in the industry remains important. A change in the tax system could be needed so that more actors can use the green gas principle for LBG. In addition, a functioning "marketplace" is needed, which simplifies for sellers and buyers of LBG, and agreements/contracts are needed that are longterm and to a greater extent based on the costs of producing and providing LBG.

The results of a study carried out for the Swedish Transport Administration on fire detection in road tunnels is presented. Laboratory tests and numerous large-scale tests were carried out in order to verify a proposal for a test method for fire detection systems. The main aim was to investigate possible fire detector systems and to see if they could fulfil the requirement given by the Swedish Transport Administration to detect the fire within 90 seconds. The tests are presented as well as a recommendation for testing detection systems in Swedish road tunnels. In order to perform the fire test, pans of different sizes were tested in order to obtain a reasonable fire size. The method proposed requires the use of three 0.6 m diameter standard pans, each containing eight litres of 95 octane gasoline, and air flow velocities of 2 m/s and 6 m/s. It was found out that using only one 0.6 m pan is sufficient if early warning is required without identifying the position for the fire-fighting system.

Tunnel and rock lining systems are used for drainage and icing protection. These systems can consist of any combination of concrete, metal, plastic or textile. The report summaries the available methods, both for testing and for installation. The large variation in both systems and test methods often make it difficult for constructors or designer to understand the importance of different methods. The report gives indication of what type of linings exists and how to ensure the fire safety of such systems. Fire safety properties can be verified in three different ways: #1 Full systems can be tested in full scale fire tests, #2 a section of the system can be tested in standardized furnace tests, or #3 plastic and/or textile membrane can be tested with regards to requirements on fire spread. It is suggested to require that a fire should not be able to propagate in the system. This can be verified with #3 above requiring class B, C or D according to EN 13501-1. If the lining system offers structural fire protection, it can be verified suing #2 above.

This publication includes the Proceedings of the 10th International Symposium on Tunnel Safety and Security (ISTSS) held in Stavanger, Norway, April 26-28, 2023. The Proceedings include 45 papers and 16 posters. The papers were presented in 16 different sessions, i.e., Keynote sessions, Alternative Fuel Vehicle Safety, Risk Management & Explosion, Digitization, Explosion, Poster Corner, Ventilation 1&2, Fixed Fire Fighting Systems, Tenability and Evacuation, Emergency Management, Evacuation, Safety Management, Fire Dynamics and Resistance. Each day was opened by invited Keynote Speakers (in total five) addressing broad topics of pressing interest. The Keynote Speakers, selected as leaders in their field, consisted of Ove Njå (University of Stavanger, Norway), Vladimir Molkov (Ulster University, UK), Ulf Lundström (Swedish Transport Administration, Sweden), Mirjam Nelisse (TNO, The Netherlands), and Gunnar Jenssen (SINTEF, Norway). We are grateful that the keynote speakers were able to share their knowledge and expertise with the participants of the symposium.