Report 1 and report 2 from the BRAVENT project are now published. The project topic is spread of heat and smoke in ventilation ducts. Based on the results of the theoretical calculations and experiments, our opinion is that the use of fire insulation on ducts should in general be avoided. It is possible to develop a fire safe ventilation concept without the use of fire insulation.
Background: 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. 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.
The BRAVENT project: 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.
Sub-report 1 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.
Sub-report 2 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.
The project is
funded by Omsorgsbygg Oslo KF, Hordaland county council, Stavanger municipality, Sykehusbygg HF, Trondheim municipality, Undervisningsbygg Oslo KF and the Norwegian building authority (DiBK).
More information is available in the reports (in Norwegian, summary in English), which may be
downloaded here:
Report 1: theory and state-of-the-art
Report 2: Spread of heat and smoke in ventilation ducts