NFPA 921 Certification Exam Questions And Answers Verified 100% Correct

NFPA 921 Certification Exam Questions And Answers Verified 100% Correct Unsaturated molecules contain? - ANSWER Carbon-to-carbon double bonds, which are reactive. Saturated hydrocarbons contain? - ANSWER carbon-to-carbon single bonds, which are far less reactive than unsaturated oils. Polyunsaturated fatty acids - ANSWER Animal and vegetable fats and oils. Saturated hydrocarbons - ANSWER Motor oil or lubricating oil Thermal Runaway - ANSWER Condition in which the heat generated exceeds the heat losses to the environment. Self-heating to ignition requires? - ANSWER Porous, permeable, and oxidizable material. The most common self-heating substrates? - ANSWER Organic solids derived from plant materials, such as cotton fabrics, wood and wood products, agricultural products, and coal. Pyrophoric - ANSWER Descriptive of any substance that ignites spontaneously when exposed to air. Transitions to flaming in upholstered furniture have been observed in time ranging from? - ANSWER 20 minutes to many hours. Range off ignition temperatures for solids? - ANSWER 270c to 450c (518F to 842F) Ignition temperatures for non-fire retardant plastics range from? - ANSWER 270C to 360C (518F to 680F) Ignition temperatures of wood based products range from? - ANSWER 330C to 375C (626F to 707F) Ignition temperature of fire retardant material? - ANSWER Above 400C (752F) For most materials, the critical radiant heat flux is in the range of? - ANSWER 10 to 15 kW/m2 Minimum heat flux for smoldering ignition? - ANSWER 7 to 8 kW/m2 Drysadale 1999 report AIT of wood by radiation? - ANSWER 600C (1112F) Drysdale 1999 report AIT of wood by convection? - ANSWER 490C (914F) Counterflow Flame Spread - ANSWER The flame spread direction is counter to or opposed to the gas flow. Horizontal or downward flame spread. Concurrent Flame Spread - ANSWER Wind aided flame spread. Flame spread direction is the same as the gas flow or wind direction. Most ramp or stair constructions in structures slope at? - ANSWER 30 degrees to 50 degrees from the horizontal. The "Inclined Trench" - ANSWER 1987 King's cross Underground subway station escalator fire in London. Sloped combustible surface that is laterally bounded by vertical side walls. PMMA - ANSWER Polymethylmethacrylate Fire spread - ANSWER Involves the ignition of more remote fuel packages. The dominant method of spreading fire from one remote location to another remote location is? - ANSWER Through Radiation. Flashover occurs at which temperature? - ANSWER 590C (1100F) A door opening 0.9m (3ft) wide and 2.1m (7ft) tall can support a heat release rate of about? - ANSWER 4000 kW or 4 MW. Glass cracks when the glass reaches? - ANSWER 60-100 deg C A heat flux from the hot gas layer of approximately how much at floor level is sufficient to cause flashover? - ANSWER 20 kW/m2 Heat flux at floor level in full room involvement have been recorded at what? - ANSWER 170 kW/m2 Ventilation Factor - ANSWER The minimum size of a fire that can cause a flashover in a given room is a function of the ventilation provided through an opening. The area of the opening (A) times the square root of the height of the opening (H). For a door opening 0.9m (3ft) wide and 2.1m (7ft) high, a heat release rate of what would be needed to cause flashover? - ANSWER 2000 kW or 2 MW. Flashover times of what are not unusual in residential room fire tests? - ANSWER 3-5 minutes. If the fuel package or the fire plume is against a wall (not in a corner), a given fire size will lead to a ________________ greater hot layer absolute temperature than the same fire size away from the wall. - ANSWER 30 percent. If the fuel package or the fire plume is placed in a corner, a given fire size will lead to a ________________ greater hot layer absolute temperature than the same fire size away from the walls and corners. - ANSWER 70 percent. The major objective of any fire scene examination is to? - ANSWER Collect data as required by the scientific method. Fire pattern - ANSWER The visible or measurable physical changes, or identifiable shapes, formed by a fire effect or group of fire effects. Fire effects - ANSWER The observable or measurable changes in or on a material as a result of exposure to a fire. Fire Pattern Analysis - ANSWER The process of identifying and interpreting fire patterns to determine how the patterns were created. Hydrocarbon Fuels - ANSWER Plastics and ignitable liquids Identifiable temperatures achieved in structural fires rarely remain above what temp for long periods of time? - ANSWER 1040 C (1900 F) Effective fire temperatures - ANSWER Identifiable temperatures that reflect physical effects that be defined by specific temperature ranges. Laboratory char rates from exposure to heat from one side vary? - ANSWER From 1 cm (0.4 in.) per hour to 25.4 cm (10 in.) per hour. The rate of charring of wood varies widely depending on variables, including: - ANSWER 1. Rate and duration of heating.