Thermal runaway (TR) propagation is an essential characteristic of larger lithium-ion battery fires. Cell- and module-level battery abuse tests have been conducted using large-format NMC pouch cells. In both test campaigns, heating was used to trigger TR. An electrical heater was used for the cell-level tests, and heat exposure to an external flame was used to trigger a cell-to-cell propagating TR in the modules. Cell surface temperatures were measured during both test campaigns to evaluate thermal runaway properties, including TR onset temperatures, TR max temperatures, and TR heating rates, as a function of local heating rates. The TR propagation characteristics in the modules were analysed based on the module’s temperature distribution and heat release rate. A comparison between the conditions during single-cell and full-module tests was conducted to evaluate their effects on TR and, ultimately, to determine whether cell tests are representative of the conditions during a passive propagation test or a real Lithium-ion battery fire scenario

The integration of high-energy lithium-ion batteries (LIBs) as energy storage solutions is increasing in the building sector (e.g., residential, schools, offices, commercial and industrial buildings). This increases the fire load, raising fire safety concerns, including characteristic fire behaviour, increased fire intensity, faster fire growth, prolonged burning duration, fire spread and flashover risk. Full-scale fire experiments with NMC battery modules of nominal 6600 Wh were conducted in an ISO 9705 compartment. The emphasis of the work was to analyse the fire characteristics within the room from the beginning of thermal runaway in a set of individual cells and continuous cell-to-cell thermal propagation in a single module. The results revealed that simultaneous cells in thermal runaway within a module intensified heat release into the room. The fire development differed from fires in common technical rooms, exhibiting flash fire, ultra-fast fire growth, intense thermal feedback and multiple heat release rate peaks. The experimental findings provide critical data to support risk assessments of battery energy storage systems. Currently, the lack of guidelines on fire safety requirements for battery rooms limits the ability to design rooms with appropriate active and passive fire safety measures. Future research should further explore fire spread between modules and the effectiveness of active and passive fire protection measures in confined compartments

This study investigates the interaction between suppression, detection, ventilation, and explosion protection systems in a confined battery room to address the lack of fire safety data for building-integrated battery energy storage systems. Six large-scale fire suppression experiments were conducted in a mock-up battery room. Four suppression systems, high- and low-pressure water mist, sprinkler, and IG-541, were evaluated alongside a freeburn and gas venting scenario. Their performance was assessed based on thermal runaway propagation, temperature development, structural damage, gas accumulation, deflagration risk, and firewater contamination. IG-541 was the only system to extinguish external flames and prevent module-to-module propagation. However, explosion protection remains critical due to the accumulation of flammable gases. It is therefore essential to design inert-gas systems with a sufficient hold time and to establish a strategy for safely evacuating all flammable gases from the room once thermal runaway has fully ceased, without igniting the gas mixture. Achieving this can be challenging. The water-based systems were generally effective at cooling, but the low-pressure water mist experiment highlighted the need for optimised droplet distribution, as hot spots may lead to unit-to-unit propagation and structural damage. Ventilation prevented deflagration, but minimum airflow requirements need further study. Effective fire safety requires integrating suppression with detection, ventilation, and explosion protection, tailored to the thermal runaway characteristics

Fourteen thermal runaway propagation experiments were conducted on a 6.6 kWh Lithium-ion pouch-cell module to investigate the effects of four different trigger methods on thermal runaway propagation. The methods were Electrical heating with two 100 W heating pads, local heating with a small 2 kW flame, overcharging (1–2 C), and heating the module with a larger 50 kW burner. Studies of thermal runaway propagation typically employ only a single trigger method throughout the experimental campaign. However, from the literature on single Lithium-ion battery cells, it is known that the trigger method significantly affects many properties of a thermal runaway, such as the maximum temperature, mass loss, and gas production rate. The present research showed that the trigger method can significantly affect propagation, so that one method may lead to propagation throughout the entire module, while another may not. The total mass loss for the Local flame and Electrical heating, which resulted in slow cell-to-cell propagation, was independent of the trigger method. However, the change in the mass loss rate over time was different. A novel method for investigating individual thermal runaway events showed that thermal feedback from external flames did not affect cell-to-cell thermal runaway propagation.

School fires are a major problem in many countries, with more than 100 fires annually only in Norwegian schools. Many of these fires are caused by arson, typically in toilet rooms and locker rooms. Such fires are often small and do not spread but can create tremendous amounts of smoke, causing significant damage beyond the room of origin. One major consequence of these school fires is the costly restoration work of the building and its ventilation system. The two main ventilation strategies in Norwegian schools are the extraction strategy (the smoke is evacuated from the fire compartment through the comfort ventilation system) and the compartmentation strategy (using fire dampers to retain the smoke inside the fire compartment). As part of a larger research project that aims to develop and document a solution for pressure and smoke control of minor fires in school buildings using the existing comfort ventilation system (including VAV/DCV dampers), an engineering tool for fire safety engineers is under development. In this paper, we present the main points of advice from the engineering tool. The results from 14 fire tests of smoke spread in a large-scale test building and a review of existing ventilation solutions and previous fire incidents in school buildings in three municipalities in Norway, which have been conducted in an earlier stage of this project, form the basis. The test building contained a corridor, one larger classroom and a small office. The fire tests were conducted using different fuel types, like an electrical scooter, gas, and a foamed rubber mattress. The engineering tool includes advice for both new, existing, and preserved buildings

The amount of heat generated during thermal runaway in lithium-ion cells is dependent on the failure mechanism and abuse method. This study determines the heats generated inside and outside a 64 Ah lithium-ion pouch cell when it is forced into thermal runaway by nail penetration, heating, or overcharging. The generated heats were determined by battery calorimetry, jet flame calorimetry, and oxygen depletion calorimetry. The ratio between heat generated inside or outside the cell is found to be dependent on the abuse method. The overcharge experiment was most severe with respect to heat generated outside the cell, with 89% more thermal energy measured by the jet flame calorimeter compared to nail penetration. For heat generated inside the cell it was opposite, where nail penetration was the most severe with 53% more thermal heat generated compared to overcharge. We explain these differences from the cell mass losses during thermal runaway. When the cell mass loss increases, the heat generated outside the cell increases and simultaneously the internal heat generation decreases. For the safety of a battery module, these results imply that the possibility for propagation of a thermal runaway between cells is dependent on failure mechanism.

Hydrogen tanks used in transportation are equipped with thermal pressure relief devices to prevent a tank rapture in case of fire exposure. The opening of the pressure relief valve, in such a scenario, would likely result in an impinging and (semi-) confined hydrogen jet fire. Therefore, twelve large-scale experiments of hydrogen jet fires and one large-scale propane reference experiment have been conducted with various degrees of confinement, orientations of the jet, and distances from the nozzle to the impinging surface. Infrared and visible light videos, temperatures, heat fluxes, and mass flow rate of hydrogen or propane were recorded in each experiment. It was found that the hydrogen flame can be visible under certain conditions. The main difference between an open impinging jet and an enclosed impinging jet fire is the extent of the high-temperature region in the steel target. During the impinging jet fire test, 51% of the exposed target area exceeded 400 °C, while 80% of the comparable area exceeded 400 °C during the confined jet fire test. A comparison was also made to an enclosed propane jet fire. The temperature distribution during the propane fire was more uniform than during the hydrogen jet fire, and the localized hot spot in the impact region, as seen in the hydrogen jet fires, was not recorded. 

Modern heating, ventilation, and air conditioning (HVAC) systems have evolved from simple on-off, fan-driven systems to highly complex, energy-optimized systems involving sensors monitoring the building whose outputs result in dynamic changes to the HVAC system operation. In some buildings, the HVAC system is intended to aid in smoke and pressure control during the event of a fire. In such a case, the smoke, heat, and pressure from fire growth and spread interact with the HVAC system, while the control logic may react to the fire alarm and increase ventilation rates. A series of tests investigating the performance of modern damper-optimized demand control ventilation (DCV) systems during a fire and its effect on smoke and pressure control was recently performed. This paper examines the ability of Fire Dynamics Simulator (FDS) to model a DCV HVAC system undergoing a dynamic response change due to the presence of fire. Results show that the FDS HVAC model is capable of such simulations. However, there were challenges in the modelling process due to the limitations on the experimental data obtained from the real-world building management system software. A path forward for more complete simulations is identified. 

Modern heating, ventilation, and air conditioning (HVAC) systems are complex, interconnected systems optimised to be energy efficient. Damper-optimised demand-controlled ventilation systems (DCV) minimise energy consumption by using a dedicated control unit that calculates the optimal fan speed based on room sensors and the feedback from all DCV dampers, which each measures the airflow rate and adjusts its damper angle accordingly. In buildings that do not use a compartmentation strategy in the event of a fire, it is crucial that the ventilation system is pressurised and provides balanced ventilation in order to prevent smoke from spreading via the ventilation system and to avoid creating pressure imbalances, which may impair evacuation. In the present study, two full-scale fire tests from a series of 14 tests in a mock-up building equipped with a damper-optimised DCV system are presented, and the ventilation system’s performance during the fire is assessed. The tests revealed various failure mechanisms caused by heat exposure, leading to individual damper uncontrolled opening or closing or the building management system losing contact with all dampers. Furthermore, it was shown that the failure of individual dampers and the gradual clogging of the extraction filter can affect the pressure balance in other parts of the building outside the fire room and increase the risk of smoke spreading through the ventilation ducts.

RISE Fire Research sitt høst-webinar 2025 ble arrangert 28. november, kl 9-11. Her finner du opptak fra webinaret. Forskningen er finansiert av Direktoratet for samfunnsikkerhet og beredskap (DSB), Direktoratet for byggkvalitet (DiBK) og Statsbygg.