Thisreport summarizes the work conducted within the project ”Analysis of physicaldeterminants and technical measures in support of the zero vision” financed bythe Civil Contingency Authority (MSB) in Sweden. The work aims to find measuresto prevent and reduce the number of fatalities in fires in residentialbuildings in a Sweden, a list of such measures is provided in the end of thereport. The list is based on work conducted in several small sub-projects, ashort summary of these is also provided in the report.

The shipping industry is facing increasing pressure to cut emissions. Diesel-electric hybrid or fully electrical propulsion systems can offer significant savings in fuel consumption and reduce emissions. However, the use of energy storage battery systems on board vessels is introducing new fire hazards and advice on suitable fire extinguishing systems and agents is desired. In a series of tests, both total compartment application water spray and water mist systems and direct injection (using several different agents) into the module were evaluated in fire tests conducted to compare different fire extinguishing approaches for a fire in a battery cell. A test compartment was constructed to simulate a battery room and a commercially available lithium-ion (Li-ion) battery cell was positioned inside a cubic box that mimicked a battery module. By heating the battery cell, combustible gases were generated, and these gases were ignited by a pilot flame inside the simulated battery module. The tests indicated that fire extinguishment of a battery cell fire inside a battery module is unlikely when using total compartment water spray or water mist fire protection systems. The water droplets are simply not able to penetrate the battery module and reach to the seat of the fire. Direct injection of the fire extinguishing agent inside the battery module is necessary. The tests also showed that agents such as water and low-expansion foam, with a high heat capacity, provide rapid cooling and fire extinguishment. The reduced water surface tension associated with low-expansion foam may improve the possibilities for water penetration whilst agents with a high viscosity may not be able to spread to the seat of the fire. Agents with less heat capacity, such as high-expansion foam and nitrogen gas, provide less cooling but fire extinguishment can still be achieved if designed correctly.

Electric propulsion using batteries as energy storage has the potential to significantly reduce emissions from shipping and thus the environmental impact. The battery type that is currently on the top of the agenda to be used for ship propulsion applications is Li-ion batteries. Li-ion batteries pose different safety issues than e.g. other propulsion technologies and other batteries such as lead-acid batteries. It is essential that the safety level on board, including fire safety, is maintained, when introducing electric propulsion with energy storage in batteries. This report discusses the different regulations and guidelines available today for fire safety of batteries on board in relation to current knowledge about Li-ion batteries. Also fire safety measures available on board ships today and their applicability for Li-ion batteries is discussed, as well as the different test methods available and their applicability. A workshop gathering different stakeholders from Sweden, Norway and Finland identified fire safety as the main challenge for the introduction of battery propulsion at sea. The workshop concluded that future work is desired in order to increase knowledge and to develop publicly available strategies, training and designs.

Traditionally, the only parameter used to measure the performance of total compartment (i.e. total flooding) water mist or water spray systems during fire testing has been the time to extinguishment. However, the use of a single parameter has been criticized since it can result in poor system designs. This study evaluates additional parameters in order to improve the characterization of system performance. Two series of fire tests were conducted with a number of water mist and water spray fire protection systems: the former in a 500 m3 test compartment using three different systems; the latter in a 250 m3 compartment using four different systems. The heat release rate of the fire and the gas temperatures inside the test compartment were measured. Based on these measurements, the fire suppression capability of the systems, their temperature reduction capability and their ability to mix water vapor, water droplets and combustion gases within the compartment were determined. The tests revealed that the time to extinguishment varies several tens of percent under identical conditions. It was also observed that the relative performance of the systems was influenced by the size of the fire. The results obtained with the additional parameters were much more repeatable and consistent than using time to extinguishment alone. It is concluded that fairly simple and inexpensive measurements can improve current fire test procedures.

Commercial residential sprinklers are usually fitted with 3 mm glass bulbs having a nominal operating temperature of 68°C or a high-sensitivity solder link, usually with a nominal temperature rating of 74°C. Previous work show that there is a significant potential for improving sprinkler response times in a residential room fire scenario by using glass bulbs with a lower Response Time Index (RTI) and lower operating temperature than commonly used. The objective of this study was to investigate any improved performance due to earlier activation of residential sprinklers. A series of fire tests was conducted inside a test compartment sized 3.66 m by 3.66 m. The fire test source consisted of either a simulated or authentic upholstered chair. For the majority of the tests, the flow rate of the residential sprinkler was 30.3 liter/min (corresponding to the minimum design density 2.05 mm/min as per the recommendations in NFPA 13D and 13R). Additional tests were conducted at 60.6 liter/min (the minimum design density 4.1 mm/min as per NFPA 13). Tests were also conducted with commercial low- and high-pressure water mist nozzles and a stand-alone high-pressure water mist system.

The results show that earlier activation of residential sprinklers had a small effect on its performance, especially for the authentic upholstered chair scenario, when flowing 30.3 liter/min. The rather small effect is probably due to that the discharge density was too low to provide fire suppression. When the flow rate was increased to 60.6 liter/min, the performance was considerably improved as compared to the flow of 30.3 liter/min. Any improvement in performance of earlier activation was, however, not investigated for the 60.6 liter/min flow rate.

The flow rates of the commercial low- and high-pressure water mist water mist nozzles ranged from 17.2 liter/min to 36.7 liter/min. Roughly, it could be concluded that the performance of the water mist nozzles were comparable or better than the residential sprinkler at approximately half the water flow rate for the tested fire scenarios.

The stand-alone high-pressure water mist system had a flow rate of 8.2 liter/min. The performance was comparable to that of the other water mist nozzles in the study The performance was comparable to that of the other water mist nozzles in the study, despite a considerably earlier activation. However, the results indicate that the performance was relatively much influenced whether the simulated upholstered chair was orientated with its front towards the test compartment or with its front towards the back wall (poorer performance). This would suggest that the position of the fire test relative to the position of the unit is a crucial factor and underlines the importance of a thoughtful positioning in practical applications.