Report: What Led To The Flashover Occurring?
What Led To the Flashover Occurring?
A flashover is probably the most significant thing to occur during a structure fire. As the fire burns, combustible gases are produced by the early stages of the fire growth process and the particles are not completely consumed. The gases rise, as discussed below, and form a superheated gas layer at the ceiling. In a typical structure fire the gas layer at the ceiling can reach temperatures near the 1,500 degree Fahrenheit mark. If enough oxygen is present in the fire compartment, flashover will occur causing everything in the room to combust almost simultaneously. The flashover is a critical part of the fire growth for two reasons. First, any living thing in the flashover room whether protected or not …show more content…
During a fire in a building a fire plume will be generated and begin to impinge on the ceiling, unless the ceiling is very high or the fire itself is very small in nature. As the fire plume rises, the hot gases hit the ceiling surface and make a 90 degree turn, spreading horizontally across the ceiling forming a ceiling jet. This is what allows sprinklers and smoke detectors to recognize the presence of fire. If the walls are too far away, then the temperature and the velocity of the ceiling jet will decay before it has a chance to reach the nearest wall and begin to bank down (Gann & Friedman, 2016).
Is there filling of the compartment by smoke? When a fire is present in a compartment without any openings for ventilation, two things will happen. First the ideal gas law comes into play because of the release of heat causes an increase in the pressure and gases inside the fire compartment. Second thing is if no opening is created by the pressure rupture, then the oxygen in the room will become oxygen depleted and the combustion process will cease. But in either case, as long as an opening does not exist, a hot layer of gas will form at the ceiling and begin to bank down filling the compartment with …show more content…
Well as the ceiling jet (hot gases moving horizontal across the ceiling) approached a wall, it began to bank downwards towards the floor. Continued burning within the structure increases the thickness of the smoke until it banks down and reaches the neutral plane. This smoke pressure is equalized throughout the room, causing it to bank to the less pressurized area below (Jones & Forney, 1992). This area is where the inside pressure equalized with the outside pressure entering the structure. A two-way flow begins to occur from the opening to the room. The inward flow is due to the air entrainment being sucked into the flames while the outward flow through the upper part of the opening is due to the added mass of combustible materials. This would only occur if the flame source were away from the opening, otherwise it would have just vented out the opening instead of traveling across the ceiling. Once the neutral plane is reached the smoke will travel into the next opening and fire spread will
A flashover is probably the most significant thing to occur during a structure fire. As the fire burns, combustible gases are produced by the early stages of the fire growth process and the particles are not completely consumed. The gases rise, as discussed below, and form a superheated gas layer at the ceiling. In a typical structure fire the gas layer at the ceiling can reach temperatures near the 1,500 degree Fahrenheit mark. If enough oxygen is present in the fire compartment, flashover will occur causing everything in the room to combust almost simultaneously. The flashover is a critical part of the fire growth for two reasons. First, any living thing in the flashover room whether protected or not …show more content…
During a fire in a building a fire plume will be generated and begin to impinge on the ceiling, unless the ceiling is very high or the fire itself is very small in nature. As the fire plume rises, the hot gases hit the ceiling surface and make a 90 degree turn, spreading horizontally across the ceiling forming a ceiling jet. This is what allows sprinklers and smoke detectors to recognize the presence of fire. If the walls are too far away, then the temperature and the velocity of the ceiling jet will decay before it has a chance to reach the nearest wall and begin to bank down (Gann & Friedman, 2016).
Is there filling of the compartment by smoke? When a fire is present in a compartment without any openings for ventilation, two things will happen. First the ideal gas law comes into play because of the release of heat causes an increase in the pressure and gases inside the fire compartment. Second thing is if no opening is created by the pressure rupture, then the oxygen in the room will become oxygen depleted and the combustion process will cease. But in either case, as long as an opening does not exist, a hot layer of gas will form at the ceiling and begin to bank down filling the compartment with …show more content…
Well as the ceiling jet (hot gases moving horizontal across the ceiling) approached a wall, it began to bank downwards towards the floor. Continued burning within the structure increases the thickness of the smoke until it banks down and reaches the neutral plane. This smoke pressure is equalized throughout the room, causing it to bank to the less pressurized area below (Jones & Forney, 1992). This area is where the inside pressure equalized with the outside pressure entering the structure. A two-way flow begins to occur from the opening to the room. The inward flow is due to the air entrainment being sucked into the flames while the outward flow through the upper part of the opening is due to the added mass of combustible materials. This would only occur if the flame source were away from the opening, otherwise it would have just vented out the opening instead of traveling across the ceiling. Once the neutral plane is reached the smoke will travel into the next opening and fire spread will