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This is sub-report 2 of the BRAVENT project (Fire and smoke distribution in ventilation ducts) which presents results from experiments where the risk of spreading fire and heat in ventilation ducts has been investigated. In the experiments, the effect of fire insulation on the duct, and mixing hot smoke with air at room temperature in the duct (as from adjacent rooms) has been investigated. The ventilation duct was connected to a furnace at one end and a fan at the other end. The furnace was heated to the desired temperature, and hot smoke was drawn through the duct at a certain velocity. Thermocouples measured the temperature both inside the duct (smoke gas temperatures) and on the duct’s external surface at different distances from the furnace.

Recently questions about whether spread of heat and smoke in ventilation ducts during a fire represent an increased risk for personal safety and loss of properties have been raised. The technical solutions currently used to fulfill the pre-accepted performance given in the guidelines to the building regulations with regard to fire protection of ventilation ducts are largely based on descriptions in SINTEF's Building Design Sheet 520.352 on fire- and smoke protection of ventilation systems, and in BV Netts Guide for fireproof ventilation, also known as the BVNett Guide. This topic was once again raised in connection with the revision of the 2017 edition of the building regulations, when it was pointed out in inquiry statements that the pre-accepted performances are insufficiently defined and that the solutions outlined in the Building Design Sheet and the BVNett Guide are not sufficiently documented. In order to elucidate this topic and provide scientific documentation on the extent to which the spread of heat and smoke in ventilation ducts represents a risk to persons and properties, the BRAVENT project (Fire and smoke spread in ventilation ducts) was initiated. The project investigates issues related to heat dissipation in ventilation ducts, clogging of filters in ventilation systems due to smoke, the effect of the seal-up strategy with respect to pressure build-up in the fire room and smoke spread through leakages in the construction. The objective of the sub-task presented in this report was to: Compile a theoretical basis for the experiments and analyzes to be carried out. 1. Map relevant regulations for fire protection of ventilation systems. 2. Map standards that are the basis for determining the fire resistance of components included in a ventilation system. 3. Map the state-of-the-art regarding a. the need to fire insulate ventilation ducts. b. the need to install bypass channels to prevent the filter systems from being clogged by smoke particles. c. the effect of installing fire dampers in all fire-partitions with respect to smoke spread. d. how smoke can be spread via ventilation ducts and leaks in the building structure. e. the pros and cons of seal-up and extraction strategies. © RISE Research Institutes of Sweden This is sub-report 1, which summarizes the relevant, fire-related theory and state-of-the-art in the focus area. The report serves as the theoretical basis for planning of experiments and for the other activities in the BRAVENT project.

External fire-fighting in Midtbykvartalet – A feasibility study The property developer E. C. Dahls Eiendom (ECDE) plans a building complex in a quarter in the city centre in Trondheim, the "Midtbykvartalet". The building will be enclosed by existing building blocks which to varying degrees hinder the fire service's access and efforts. Also, since the new building is intended for residential purposes, it will be necessary to install windows in fire rated walls against adjacent building. These factors result in deviations from a number of performance requirements in the guidelines to the regulations on technical requirements for construction works and there is therefore a need to find alternative solutions. It must be documented that these alternative solutions have at least as good an effect on fire safety as pre-accepted solutions would have. A potential side-effect of new, alternative solutions is that these can also, to some extent, protect the existing wooden buildings in the quarter. The aim of this report has been to identify the state-of-the-art within active fire protection measures for external fire-fighting and to obtain an overview of existing solutions and manufacturers and to carry out an assessment of the potential of these solutions. Risk scenarios An overview of existing buildings in the Midtbykvartalet is presented as well as an overall description of the plans for development. Based on this, several scenarios have been identified to reveal the potential fire-spread hazard between the existing buildings and the planned building. Furthermore, a qualitative risk assessment has been carried out. A literature study describes the state-of-the-art in water-based extinguishing systems for outdoor use. It deals with fixed extinguishers (facade sprinklers, water curtains), dynamic extinguishers, foam extinguishers, fire gels, as well as with sprinkler systems' effect and reliability. Furthermore, existing solutions (e.g. facade sprinklers, water curtains, water cannons and water mist turbines) have been surveyed, existing documentation described and assessed regarding suitability for use in the Midtbykvartalet. From the identified scenarios, it appears that fires in existing buildings are more likely to spread to the new building than a fire from the new building to existing buildings. The greatest danger to the new building will be if a fire spreads in existing buildings, up through the roof, through windows or along the facade to the roof. In many cases, the fire service will have good access with their ladder trucks etc. to perform extinguishing efforts, at least in the early phase of the fire. But the risk of rapid internal fire spread, which may include several of the older buildings, can create a challenging situation for the fire service and a risk for the new building. In case of fire spread to the new building, the fire department will, due to the position and height of the building, have difficulty with aerial rescue and evacuation from the new building's higher floors. Concept for the Midtbykvartalet A combination of a static and a dynamic extinguishing system will provide the best balance between system robustness, extinguishing effect and flexibility for the Midtbykvartalet. Facade sprinklers are considered the most suitable static system solution. Facade sprinklers will primarily cool the facade of the new building and absorb heat radiation from a potential fire in the existing buildings, but will not be suitable for extinguishing or actively fighting a fire within the existing buildings. The design and planning of facade sprinklers shall take the design of windows, balconies and roof terraces into account, which have been identified as vulnerable points in the firewalls. Dynamic systems such as water cannons and water mist turbines can be used to cool facades and to actively fight a fire over relatively long distances. In addition, such systems can be established so that the fire service can take over control of the extinguishing system as needed. This property is important, because of the height of the new building and because of how it is surrounded by existing buildings. Both water cannons and water mist turbines can be combined with an automatic control that allows you to fight a fire at an early stage, even before the arrival of the fire service, as long as early detection is achieved. A fire that spreads within the existing buildings will not be possible to extinguish with permanently installed dynamic systems. Therefore, the cooling and extinguishing effect of such systems must be evaluated based on the scenario of a large fire in the neighbouring building, which has not been done before. The cooling and extinguishing effects for both systems are largely dependent on their control system. The control system must be capable of aiming the water cannon or the water mist turbine at the fire, if required compensating for wind effects and selecting an appropriate water jet mode. Therefore, in order to adapt the control system to the Midtbykvartalet, it is necessary to quantify the cooling and extinguishing effect of such a system in advance and with regard to a potentially large fire in the adjacent existing buildings. Selected water mist turbines have the option of operating in a full jet mode, like a water cannon. Therefore, such systems are considered more flexible than water cannons. However, water mist turbines set large amounts of air in motion and generate turbulence that can affect the fire. It is therefore important to investigate if and in which cases this can aggravate the fire and have a negative effect on other areas in the quarter.

Eight out of ten fire-related fatalities occur in dwellings. It is a fact that smoke detectors save lives, which emphasizes the importance of every home having a functioning smoke detector. In Norway, smoke detectors in dwellings are mandatory, and recommendations on which detector technology to use and the position of the detectors are given. Smoke detectors should be installed on the ceiling, outside of dead-air space (close to walls). In this study, ten smouldering fire experiments have been conducted to: • investigate if smoke detectors with CO sensing can alert residents at an earlier stage than photoelectric smoke detectors, consequently increasing chances of egress and survival for a sleeping person. • measure concentrations of toxic gases in a room where a smouldering fire occurs and investigate if tenability limits are exceeded when n photoelectric smoke detector is activated. • investigate if smoke detectors placed within dead-air space are activated at a later stage than smoke detectors placed according to the recommendations.