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.

The present research explores the influence of Bjørnis the Fire Bear on residential fire safety in Norway. Our survey, comprising 1275 participants, reveals that Bjørnis spurred the adoption of 5181 fire safety measures among the respondents, averaging 4.1 measures per household. The data suggests a positive association between exposure to Bjørnis and an increased number of safety measures implemented. These results highlight Bjørnis' efficiency in fostering awareness about fire safety, potentially serving as a model for introducing or sustaining similar mascots and initiatives on a global scale

BRAVENT – Large-scale fire tests (part 1): Fire performance for non-fire rated ventilation components In the overall BRAVENT project, the goal is to generate answers and documentation on current issues related to ventilation and fire by examining these with experimental fire tests. The present study aimed to evaluate the fire performance of key non-fire-rated components, mainly DCV dampers and exhaust filters, in a comfort ventilation system by testing the hypothesis that the ventilation components will not be damaged by fire within 30 or 60 minutes. To test the hypothesis, a total of 14 large-scale fire tests with different fuels were carried out. The tests were carried out in a test building with several rooms that are representative of classrooms, offices, and corridors. The fire tests were designed to investigate relevant fire scenarios for school buildings, but the findings from the tests can also be used for other purpose-built buildings. The building was equipped with a full-fledged damper-optimized ventilation system, sized to serve a total of 450 m2 and thus provide a realistic basis for the fire tests. Currently, there is no documentation on how non-fire-rated dampers are affected by high temperatures that occur during a fire. The temperature specifications given for non-fire rated DCV dampers are intended for normal operation. Two different types of DCV dampers were tested. In one type, the airflow was measured with a measuring cross, and for the other, the airflow was measured with sensors integrated into the damper blade itself. In several of the conducted tests the non-fire-rated dampers were not able to sustain their function for the required duration of 30 minutes or longer, and failed completely when the temperature inside or outside the dampers reached about 200 ºC. Misreporting of some temperature measurements in the building management system already occurred at lower temperatures, around 120˚C, without significantly affecting the delivered air flow rate. For the damper type with a measuring cross, the plastic hoses connecting the measuring cross and the measuring transducer for the damper melted when hot smoke was transported through the damper. This failure resulted in the DCV damper measuring too low or no airflow. In several tests, this measurement error meant that the DCV damper opened fully, trying to achieve a large enough airflow. In one of the tests where the supply air damper was placed inside the fire room, such a fault on the supply air damper caused it to close completely. In addition to the damage to the dampers, the power supply to the damper was destroyed, and a fuse for the power supply in the control cabinet was short-circuited. This resulted in the building management system losing contact with all the dampers. This shows that a local error can cause the entire system to fail. For the other damper type, where the sensors were located in the damper blade, the high temperatures caused the entire damper blade to melt. It was not observed that soot in the fire smoke led to problems with the dampers' measuring sensors for any of the damper types examined. This indicates that for the performed test series, high temperature and not soot was the greatest challenge for the dampers in the event of a fire. In addition to examining how dampers are affected by fire, there was also an investigation into how the filter performs during a fire. It was found that the filter could largely capture the soot particles in the smoke. This means that equipment located downstream of the filter is relatively well protected against soot, and the possibility of soot contamination to the supply air side via a rotating heat recovery unit can, therefore, be considered minimal as long as the filter is not damaged. However, when the filter collects so much soot, it shows that the potential for the filter to clog. How quickly this happens depends, among other things, on the materials that burn and the size of the fire in relation to the air handling unit's capacity. This also aligns with results from an earlier BRAVENT project [1]. The air temperature in the unit was in all tests carried out below 60˚C and thus lower than the filters' maximum operating temperature of 70˚C. The conclusion from the tests is that the extraction principle with non-fire-rated components cannot be considered a safe strategy for 30 or 60 minutes.

BRAVENT – Large-scale fire tests (part 2): The effect of the ventilation strategy on smoke dispersion and pressure control in a mock-up school building In the overall BRAVENT project, the goal is to generate answers and documentation on current issues related to ventilation and fire by examining these with experimental fire tests. The present study aimed to evaluate how different failure mechanisms identified in sub-report 1, "Fire performance for non-fire rated ventilation components" [5], affect the pressure conditions and possible smoke spread in the building. In order to investigate the ventilation system's ability to control pressure balance and smoke spread in the event of a fire, 14 large-scale fire tests with different fuel types were carried out. The tests were conducted in a test building with several rooms representing a classroom, an office and a corridor. The fire tests were designed to investigate relevant fire scenarios for school buildings, but the findings from the tests may also be relevant for other purpose-built buildings. The building was equipped with a full-fledged damper-optimized ventilation system which was sized to serve a total of 450 m2 and thus provide a realistic basis for the fire tests. In sub-report 1, a number of component failures were uncovered when the system was exposed to hot smoke. The failure mechanisms led to the system losing its status and control over the dampers, thus also losing the overview of which air volumes passed through the dampers. The failure of the dampers then led to an imbalance in the ventilation system, also in rooms other than the fire room. In the extreme, this can lead to challenges in connection with escape by making it difficult or impossible to open doors. Smoke spread via the supply air ducts can occur due to smoke backflow if the pressure in the fire compartment exceeds the pressure in the supply air duct. In the experiments, the ventilation system increased to the maximum design airflow rate (Vmax) upon fire detection, and no smoke spread due to backflow of fire smoke in the supply air ducts was observed. It was not tested whether a backflow of smoke could have also been prevented at lower airflow rates than Vmax. Whether the ventilation system maintains sufficiently high pressure in the supply air duct to prevent backflow depends on, among other things, the capacity of the supply air fans, the density of the fire compartment and how quickly the fire develops. The smoke from the fire caused the filter in the unit to gradually clog. In three tests, the filter was clogged so much that the air handling unit could not extract enough air, which created an imbalance in the ventilation system. The new BRAVENT tests show that the size of the fire in relation to the air handling unit's capacity plays an important role in how long the exhaust airflow can be maintained. An air handling unit serving several small fire cells with limited available fuel will be able to maintain the required exhaust air volume longer than an aggregate serving a few large fire cells as the ratio between smoke volume and total air volume changes. Other factors that affect how long the unit can compensate for filter clogging are: • whether the air handling unit is designed for 100% or less simultaneity, i.e. the proportion of rooms that can have the maximum amount of airflow at the same time, • the condition of the filter at the start of the fire, completely new filters were used in each of the fire tests, • whether the ventilation system operates with Vmax or less airflow when a fire alarm is triggered. No smoke spread between the rooms via the exhaust duct was observed. However, since the exhaust airflow rate in one of the tests was significantly reduced to around 50% of the maximum design airflow rate, it is concluded that gradual clogging of the exhaust filter will increase the risk of smoke spreading via the exhaust duct. Clogging of the filters can be avoided by establishing a bypass. Nevertheless, it must then still be documented that all other functions of the ventilation system are safeguarded in the event of a fire. The tests carried out showed that the failure mechanism of some components (measurement errors in dampers, short circuits and clogging of the exhaust filters) can lead to the whole system no longer being able to maintain its function.

Dette dokumentet er en veileder. Veilederen skal benyttes av rådgivende ingeniører i brannteknisk prosjektering av ventilasjonsanlegg i skolebygg. Det fokuseres på rømningssikkerhet og skadebegrensning ved små branner i en tidlig fase av brannforløpet. Veilederen beskriver forutsetninger for bruk, krav og preaksepterte ytelser i VTEK, samt ulike typer ventilasjonsanlegg med tilhørende komponenter. Dokumentet illustrerer typiske prinsippløsninger for ulike ventilasjonsstrategier i bygg, samt forskningsresultater fra brannforsøk og undersøkelser i tidligere faser av BRAVENT-prosjektet. Veilederen tar for seg nybygg, eksisterende bygg og verneverdige bygg hvor grensesnittet mellom rådgivende ingeniør brann (RIBr), ventilasjon (RIV), elektro (RIE) og automasjon (RIAut) defineres. En sjekkliste oppsummerer viktige punkter å hensynta ved prosjektering av ventilasjonsanlegg. Rutiner for drift og vedlikehold beskrives til slutt.

I denne FRIC studien er den forebyggende effekten av Bjørnis for brannsikkerheten i norske husstander studert. Hovedkonklusjonen er at Bjørnis har ført til en tydelig og dokumenterbar forbedring av brannsikkerheten i norske hjem. Studien er utført som en del av prosjekt 4.3 Brannsikkerhetstiltak for boliger i FRIC, i samarbeid med Stiftelsen Brannbamsen Bjørnis. Det er også et webinar på norsk og engelsk som presenterer studien, opptak av webinaret vil bli publisert her: https://fric.no/publikasjoner.

| In this FRIC study, the effect of the fire mascot Bjørnis on the fire safety in Norwegian households is studied. The main conclusion is that Bjørnis has led to a clear and documentable improvement of the fire safety in Norwegian homes. This study is a part of project 4.3 Fire safety measures for dwellings in FRIC, in collaboration with the Bjørnis Foundation. There is also a webinar in Norwegian and English presenting the study, the webinar recording will be published at: https://fric.no/en/publications.

Photovoltaic modules have been shown to influence how a fire propagates across a flat roof, but the circumstances for which building attached photovoltaic (BAPV) modules promote fire propagation on a sloped roof is not studied in detail. Therefore, a series of small-medium- and large-scale experiments on a sloped roof with a BROOF(t2)-rated bituminous roof membrane on a wood chipboard substrate has been performed. Steel plates mimicking non-combustible photovoltaic (PV) modules were placed at different distances above the roof. Different sized wood cribs placed in the gap between the roof and the PV module were used as the ignition source. Similarly to findings for flat roofs, the experiments showed that the gap distance and the size of the ignition source are key factors for how far the fire propagates from the starting point. This supports that BAPV installations affect the fire dynamics on roofs. As such, the complete system of roof composition and PV installation needs to be considered as a whole to ensure adequate fire safety levels.