- Author
- Yii, E. H.
- Title
- Modelling the Effects of Fuel Types and Ventilation Openings on Post-Flashover Compartment Fires.
- Coporate
- University of Canterbury, Christchurch, New Zealand Building Research Association of New Zealand, Judgeford
- Report
- Fire Engineering Research Report 03/1, March 2003, 336 p.
- Distribution
- FOR MORE INFORMATION CONTACT: School of Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. Telephone: 643-364-2250, Fax: 643-364-2758, Website: http://www.civil.canterbury.ac.nz
- Keywords
- compartment fires | flashover | fuels | ventilation | zone models | fire models | vents | heat of combustion | pool fires | furniture | wood | roof vents | doors | experiments | fire simulation
- Identifiers
- post-flashover fire computer code CFIRE
- Abstract
- This thesis describes the details used to model a post-flashover fire compartment as a well-stirred reactor. In particular, it examines the two foremost important variables that dictate post-flashover fire behaviour inside the fire compartment. These two variables are: (l) the mass flow rate of air into the compartment via the vent opening and (2) the fuel mass loss rate inside the compartment. The vent flow analysis shows that the orifice analogy typically used to describe compartment vent flow is restricted to small wall opening applications. For large wall openings, such as a window occupying one whole wall, the flow rate is dictated by the plume entrainment with a flow rate -60% of the flow rate estimated from the orifice theory. A series of fire experiments using a reduced-scale compartment were conducted to study the vent flow behaviour in a compartment with a horizontal roof opening and a vertical wall opening. Based on the analytical and experimental studies, it is shown that in the case where the roof vent opening is not excessively large and a wall opening having a small downstand, the neutral-plane exists below the soffit of the wall opening giving outflow and inflow through the wall opening and outflow through the roof opening. In such a case, the flows through these openings can be adequately described using an extended form of the vent flow formulation that includes the roof vent opening. The area of the roof vent and the depth of the downstand between the ceiling and the soffit of the wall opening are found to be significant in determining the extra air inflow induced due to the existence of the roof vent opening.