Interaction of Heat Release Rate, Flame Tilt Angle and Flame Length of a Compartment Fire Under Stack Effect

Many factors have an influence on the development of compartment fire notably on its heat release rate as well as on its capability to propagate and become a flashover situation. The main element which rapidly conveys fire from a compartment to another is hot smoke flowing out through openings of the compartment source of fire. The present work aims to experiment the impact of the variation of heat release rate of the source on the behaviour of fire. So, five fire tests with different heat release rates were thus carried out in a reduced scale room. Temperature of burned gases inside the room, were measured during tests by sensors connected to a data acquisition system. Results revealed that temperature of burned gases as well as its content in carbon monoxide, evolves differently according to two ranges of the incoming air/outgoing gases ratio. The first range of which the ratio is lower than 2, corresponds to the case where both parameters decrease rapidly. The second range of which the ratio is higher than 2, corresponds to the case where both parameters decrease moderately. The transition from the first to the second range, points out the passing from the ventilation-controlled fire to the fuel-controlled fire. A relation expressing the variation of the mass flow rate of outgoing burned gases according to the heat release rate of the fire source has been given.

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Corrigendum to: Estimating the amount of water required to extinguish wildfires under different conditions and in various fuel types

International Journal of Wildland Fire ◽

10.1071/wf11022_co ◽

2012 ◽

Vol 21 (6) ◽

pp. 778

Author(s):

Rickard Hansen

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Combustion Zone ◽

Unit Length ◽

Water Flow Rate ◽

Flame Length ◽

Low Intensity ◽

Surface Fires ◽

Fire Front

In wildland fires where water is used as the primary extinguishing agent, one of the issues of wildfire suppression is estimating how much water is required to extinguish a certain section of the fire. In order to use easily distinguished and available indicators, the flame length and the area of the active combustion zone were chosen as suitable for the modelling of extinguishing requirements. Using Byram's and Thomas' equations, the heat release rate per unit length of fire front was calculated for low-intensity surface fires, fires with higher wind conditions, fires in steep terrain and high-intensity crown fires. Based on the heat release rate per unit length of fire front, the critical water flow rate was calculated for the various cases. Further, the required amount of water for a specific active combustion zone area was calculated for various fuel models. Finally, the results for low-intensity surface fires were validated against fire experiments. The calculated volumes of water can be used both during the preparatory planning for incidents as well as during firefighting operations.

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EXPERIMENTAL STUDY ON INFLUENCE OF STACK EFFECT ON FIRE IN THE COMPARTMENT ADJACENT TO STAIRWELL OF HIGH RISE BUILDING

Journal of Civil Engineering and Management ◽

10.3846/13923730.2013.802729 ◽

2014 ◽

Vol 20 (1) ◽

pp. 121-131 ◽

Cited By ~ 23

Author(s):

Wen Xi Shi ◽

Jie Ji ◽

Jin Hua Sun ◽

S. M. Lo ◽

Lin Jie Li ◽

...

Keyword(s):

Experimental Study ◽

Mass Loss ◽

Heat Release ◽

Release Rate ◽

Tilt Angle ◽

Loss Rate ◽

Mass Loss Rate ◽

Air Flow ◽

Stack Effect ◽

High Rise

In this paper, to study the influence of stack effect on fire in the compartment adjacent to a stairwell, a set of experiments were conducted by varying the pool size, top vent state and bottom vent size in a 1/3 scaled 12-layer-stairwell configuration. The phenomenon of methanol flame tilting in the fire room was observed and studied. Results showed that the flame tilt angle increases with an increase of Ri-1. The temperatures of hot gases in the fire room decrease due to the cooling effect of fresh air induced by stack effect. The mass loss rate of methanol fuel is influenced by fresh air flow sucked into fire room due to stack effect. On the basis of the experimental results, we conclude that the velocity of air flow into fire room is proportional to 1/3 power of the heat release rate in the stairwell.

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EFFECT OF DISTRIBUTION PROPERTIES OF COMBUSTIBLES ON HEAT RELEASE RATE OF COMPARTMENT FIRE AT CROWTH STAGE

Journal of Environmental Engineering (Transactions of AIJ) ◽

10.3130/aije.69.9_4 ◽

2004 ◽

Vol 69 (580) ◽

pp. 9-14 ◽

Cited By ~ 3

Author(s):

Yoshikazu DEGUCHI ◽

Makoto TSUJIMOTO ◽

Mamoru KOHNO

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Compartment Fire

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Estimating the amount of water required to extinguish wildfires under different conditions and in various fuel types

International Journal of Wildland Fire ◽

10.1071/wf11022 ◽

2012 ◽

Vol 21 (5) ◽

pp. 525 ◽

Cited By ~ 9

Author(s):

Rickard Hansen

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Combustion Zone ◽

Unit Length ◽

Water Flow Rate ◽

Flame Length ◽

Low Intensity ◽

Surface Fires ◽

Fire Front

In wildland fires where water is used as the primary extinguishing agent, one of the issues of wildfire suppression is estimating how much water is required to extinguish a certain section of the fire. In order to use easily distinguished and available indicators, the flame length and the area of the active combustion zone were chosen as suitable for the modelling of extinguishing requirements. Using Byram’s and Thomas’ equations, the heat release rate per unit length of fire front was calculated for low-intensity surface fires, fires with higher wind conditions, fires in steep terrain and high-intensity crown fires. Based on the heat release rate per unit length of fire front, the critical water flow rate was calculated for the various cases. Further, the required amount of water for a specific active combustion zone area was calculated for various fuel models. Finally, the results for low-intensity surface fires were validated against fire experiments. The calculated volumes of water can be used both during the preparatory planning for incidents as well as during firefighting operations.

Download Full-text