Essentials of Fire Fighting 7th Edition Chapter 4, Fire Dynamics questions and answers

Which element is included in the fire tetrahedron that is not part of the fire triangle model? Chemical chain reaction In order to burn, fuel must be in a _____ state. Gaseous Which statement about smoke is accurate? Smoke has the potential to burn. Which is a measure of heat energy transfer rate? Heat Flux Heat transfers from one body to another by three mechanisms: conduction, radiation, and: Convection A fuel's _____ is the total amount of thermal energy released when a specific amount of that fuel burns. heat of combustion Which type of fuel is difficult to extinguish using water as the only extinguishing agent? Liquids that are less dense (lighter) than water What is the primary consideration affecting how easily solid fuels ignite? Surface to mass ratio What is the primary oxidizing agent in most fires? Oxygen in the air The range of concentrations of fuel vapor and air within which combustion can occur is the: flammable (explosive) range. Which is an example of a self-sustaining chemical reaction? Flaming combustion The four stages of fire development are: incipient, growth, fully developed, decay Which stage of fire occurs when all combustible materials in the compartment are burning at their peak heat release rate based on the available oxygen? Fully developed Development of a fire in the incipient stage depends largely upon the: characteristics and configuration of the fuel involved. If there are no openings for lateral movement during the growth stage of a fire, the hot gases released during combustion will fill the compartment: starting at the ceiling and filling down. Most residential fires that develop beyond the incipient state become: ventilation limited. When a compartment fire is in ventilation-limited decay, _____ can trigger flashover quickly. introduction of new oxygen Which statement about flow paths and ventilation in a structure is accurate? When firefighters make entry into a building, they establish new flow paths between the fire compartment and exterior vents of the building. The total quantity of combustible contents of a building, space, or fire area is referred to as the: Fuel Load Slower fire development in large compartments is due to the _____ and the increased distance that radiated heat must travel from the fire to the contents that must be heated. greater volume of air Fires involve a heat producing chemical reaction between fuel and: An Oxidizer When a substance changes from one type of matter into another, such as two or more substances combining to form compounds, the substance undergoes a: chemical reaction. Which statement about energy and combustion is accurate? Which statement about energy and combustion is accurate? Which element of the fire tetrahedron is included to explain flaming (gas-phase) combustion? Chemical Chain Reaction What occurs when a mixture of fuel and oxygen encounters an external heat source with sufficient heat or thermal energy to start the combustion reaction? Piloted Ignition The minimum temperature at which a fuel in the air must be heated in order to start self-sustained combustion is known as the: Autoignition Temperature What causes flaming combustion to occur? A gaseous fuel mixes with an adequate amount of oxygen and heats to ignition temperature. What is the cause of most fire deaths? Exposure to toxic gases found in smoke and/or lack of oxygen Which statement about the dangers of products of combustion is accurate? Low oxygen concentrations alone can result in hypoxia or death. Which product of combustion acts as a chemical asphyxiant by excluding oxygen from the blood, leading to hypoxia of the brain and tissues? Carbon monoxide (CO) Hydrogen cyanide (HCN) is a product of combustion that: targets the brain after being inhaled, ingested, or absorbed into the body. How does a compartment fire affect pressure in and around gases in the compartment? Heat from a fire increases the pressure of the surrounding gases. What is the measurement of the average kinetic energy in the particles of a sample of matter? Temperature Which measurement is often used to measure how long PPE will protect a firefighter in an interior fire environment? Heat flux to the PPE What is the MOST common source of heat in combustion reactions? Chemical Energy What may occur in an oxidation reaction when the heat generated exceeds the heat being lost? Spontaneous Ignition Which type of electrical heating occurs when the current flowing through a conductor exceeds its design limits? Overcurrent or overload What occurs when a gas is compressed? Heat is generated The transfer of heat through and between solids is known as: Conduction In the fire environment, convection usually involves the transfer of heat through: the movement of hot smoke and fire gases. Which heat transfer mechanism is dependent on several factors including the turbulence and velocity of moving gases? Convection By which mechanism of heat transfer does heat travel in a straight line at the speed of light, allowing heat to travel through vacuums and air spaces? Radiation Heat that is radiated to the insulating air layer between PPE and your body: can cause heat stress and failure of the PPE. A fuel's chemical content influences its heat release rate and its: heat of combustion. Gaseous fuels can be the most dangerous of all fuel types because they: are already in the physical state required for ignition. What will a liquid with a specific gravity of less than one do when combined with water? Float The minimum temperature at which a liquid gives off sufficient vapors to ignite, but not sustain combustion, is its: flash point. What may occur if water is added to a burning liquid that is less dense than water? The water may disperse the burning liquid instead of extinguishing it. When solid fuels are heated, they begin to _____ and release fuel gases and vapors. pyrolize Sawdust ignites more easily than a log because the sawdust has a higher: surface-to-mass ratio. In most compartment fires, the energy release in fire is directly proportional to the: In most compartment fires, the energy release in fire is directly proportional to the: Materials that burn at normal oxygen levels will burn more intensely in _____ atmospheres. oxygen-enriched Combustion can occur within a range of concentration of fuel vapor and air; this range is referred to as the: flammable (explosive) range. How does the self-sustained chemical reaction influence the oxidation reaction in flaming combustion? Increases the speed of the oxidation reaction An extinguishing agent, such as dry chemical or Halon-replacement agent, terminates the combustion reaction by: interfering with the chemical chain reaction. Which statement describes the factor that MOST influences compartment fire development? Whether the fire is fuel-limited or ventilation-limited Fires develop through four stages: incipient, growth, _____, and decay. fully-developed During the _____ stage of fire development, the three elements of the fire triangle come together and the combustion process begins. incipient Which statement describes a fire in the incipient stage? The temperature is only slightly above ambient in areas that the fire, plume, and ceiling jet directly affect.