CFEI Exam (2024/2025) | Actual Questions and Answers Latest Updated 2024/2025 (Graded A+), Exams of Law

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CFEI Exam (2024/2025) | Actual Questions and Answers Latest Updated 2024/2025 (Graded A+) The scientific method - ✔✔Recognize the need, define the problem, collect data, analyze the data, develop hypothesis, test hypothesis, select final hypothesis Fire effects are the result of? - ✔✔Exposure to fire Fire effects are part of what portion of the scientific method - ✔✔Data collection What are the general categories of fire effects? - ✔✔Discoloration, deformation, deposition, mass loss Fire Effect - ✔✔The observable or measurable changes in or on a material as a result of a fire Fire Analysis - ✔✔The process of determining the origin, cause, development, responsibility, and when required, failure analysis of a fire or explosion Fire Dynamics - ✔✔The detailed study of how chemistry, Fire science, and the engineering disciplines of fluid mechanics and heat transfer interact to influence fire behavior Fire Investigation - ✔✔The process of determining the origin, cause, and development of a fire or explosion Job Performance Requirements - ✔✔A statement that describes a specific job task, list the items necessary to to complete the task, and defines measurable or observable outcomes and evaluation areas for the specific task What aspects are involved in finding a cause? - ✔✔Circumstances, conditions, or agencies that brought the ignition source, fuel, and oxidant together Empirical Data - ✔✔Observation or experience and is capable of being verified or known to be true Deductive reasoning - ✔✔The process by which conclusions are drawn by logical inference from given premises. Comparing hypothesis to collected data Inductive Reasoning - ✔✔Starts from a particular experience and proceeds to generalizations. Develops hypothesis based on facts, training, expertise, experience, and knowledge Expectation Bias - ✔✔The use of only the data that supports this previously formed conclusion and often results in the misinterpretation and/or the discarding of data that does not support the original opinion Confirmation bias - ✔✔Confirming data that supports your hypothesis What are the two levels of certainty for an expert - ✔✔Probable and possible What level of certainty does not qualify for an expert opinion - ✔✔Suspected Probable - ✔✔Greater than 50% certainty Possible - ✔✔Feasible but not, less than 50% sure. If two hypothesis are likely then certainty has to be possible Fire - ✔✔A rapid oxidation process, which is an exothermic reaction, resulting in the release of heat and light energy in varying intensities. Energy - ✔✔A property of matter that manifests as an ability to perform work, either by moving over a distance against a force or by transferring heat. Calorie - ✔✔The amount of energy required to raise the temperature of 1 g of water by 1 degree Celsius Nitrogen oxide or hydrogen cyanide is produced when... - ✔✔Materials containing nitrogen such as silk, wool, and polyurethane foam Woot and tarry products accumulate on... - ✔✔Surfaces that remain the coolest longest Temperature - ✔✔A measure that expresses the degree of molecular activity of a material compared to a reference point Heat - ✔✔The energy needed to change the temperature of an object k Heat transfer is accomplished by what three mechanisms - ✔✔Condition, convection, and radiation Thermal conductivity - ✔✔A measure of the amount of heat per unit of time that will flow across a unit area with a temp gradient of 1 degree per unit of length Steady State Thermal Condition - ✔✔When temps are all interior points have stopped increasing During steady state heat transfer what is the dominant heat transfer property - ✔✔Thermal conductivity Products used to determine thermal inertia - ✔✔Thermal conductivity, density, and heat capacity Thermal inertia - ✔✔A measure of how easily the surface temp of the material will increase when heat flows into the material High density, high conductivity, and high thermal inertia means what type of surface temp change? - ✔✔Slow surface temp increase Thermal inertia is most important during which stages of a fire - ✔✔Initiation and early stages of a fire Thermal inertia determines what - ✔✔How fast the surface temp will rise Low thermal inertia means - ✔✔Quick rise of surface temp I'm the early stages of a fire what type of heat transfer plays the most significant role - ✔✔Convection Convection heat transfer occurs by what two mechanisms - ✔✔Natural and forced convection Radiant heat transfer can only be transferred via - ✔✔Line of sight Thermometry - ✔✔The study of the science, methodology, and practice of temp measurement What are the two types of systems to measure degrees of temperatures - ✔✔Empirical and thermodynamic Empirical temperature scale - ✔✔F and C scales. Based on the relative temps at which water boils and freezes Fahrenheit - ✔✔Based on a 180-degree difference between the freezing and boiling temps of pure water Celcius - ✔✔Centigrade: based on the freezing point of pure water being 0 degrees Celsius and the boiling point 100 degrees celsius Thermodynamic Temperature Scale - ✔✔Based on the lowest possible temperature of absolute zero, and therefore are called absolute zero scale Rankine - ✔✔Begins at absolute zero Fuel load - ✔✔The amount of fuel present Fuel Load Density - ✔✔The potential combustion energy output per unit floor area or the mass of fuel per unit floor area Does fuel load have a bearing on the rate of growth of a given fire in preflashover? - ✔✔No: fuel load has no bearing on rate of growth during pre flashover phases Pre flashover rate of growth is determined by - ✔✔HRR of individual fuel areays Heat Release Rate - ✔✔Describes how the available energy in a given material or group of materials is released HRR during the growth phase generally increases as a result of what - ✔✔Increasing flame spread rates over the fuel package Peak or steady state period of heat release rates is characterized by... - ✔✔Full room involvement Individual fuel packages max HRR is determined by - ✔✔Rate of mass loss and heat of combustion The HRR of a liquid fuel fire is dependent on what factors - ✔✔The physical characteristics of the release and the combustion properties of the fuel How long does a typical fuel spill fire burn and why - ✔✔90 seconds or less due to the shallow depth How does unconfined liquid fuel fires on carpet respond - ✔✔The fire will behave like a confined fuel fire (deep fuel layer scenario) due to the porosity and complex structure of the carpet Is the color of the flame an accurate indicator of what is burning - ✔✔No, nor is it an indicator of the temperature of a flame A reduction in ambient air being entrained into the thermal plume does what - ✔✔Lessens the amount of mixing of cooler ambient air with the thermal plume resulting in less dilution and higher temp Self heating resulting in self ignition are common in what type of materials - ✔✔Organic materials (animal and vegetable fats and oils) Why are unsaturated fats more likely to self ignite than saturated fats? - ✔✔Because they contain carbon to carbon double bonds which are very reactive Do consumer quantities of motor oil or lubricating oil on rags general self heat or self ignite? - ✔✔No What steps are required for self heating - ✔✔1. The material must be able to self heat and conditions must support self heating 2. Self heating must proceed to thermal runaway 3. Thermal runaway must result in self-sustained smoldering What elements must a material have to move from self heating to ignition - ✔✔Porous, permeable, and oxidizable material What are the most common self heating substrates are what? - ✔✔Cotton fabrics, wood, and wood products, agricultural products, and coal In regards to self heating what does less surface area mean? - ✔✔Increased self heating The first few indications of self heating is what? - ✔✔A wet spot on the surface of the pile resulting from condensation of water or from products of the reactions. A musty odor when in an enclosed area Do surroundings or exposure temperatures necessary for self heating need to be at or above the ignition temperature of the material? - ✔✔No, often it is much lower Does the initial stages of self heating cause much smoke production? - ✔✔No, generally because it is quickly dispersed throughout the pile Do commercially available sizes of charcoal briquette generally self heat to ignition - ✔✔No Can biomass packages such as hay or compost self heat? - ✔✔Yes, they can begin self heating from biological activity What are the most commonly encountered forms of self heating and self ignition are? - ✔✔Polymerization of fatty acids Oxidation if carbonaceous materials Biologically induced oxidation Heat-induced oxidation of lignocellulose materials Polymerization reactions What are some common materials that ignite when exposed to air - ✔✔White phosphorus, sodium, potassium, zirconium when finely divided Pyrophoric - ✔✔Materials that undergo spontaneous combustion when exposed to air Once flaming combustion begins after self heating how does the development of the fire react? - ✔✔Development will be faster than a piloted ignition due to the pre heating Why are thin materials easier to ignite? - ✔✔Two-sided heating Wood autoignition temperatures - ✔✔400 C or 750 F at medium heat fluxes Flame spread - ✔✔The movement of flames on an individual fuel package Fire spread - ✔✔The ignition of more remote fuel packages What two methods can cause fire to spread - ✔✔Direct flame impingement or by remote ignition of adjacent fuel packages When a compartment has multiple openings what happens to the neutral plane? - ✔✔There is only one neutral plane regardless of how many openings. Some vents may be solely outflow or inflow Does glass generally fall out pre flashover - ✔✔No Ventilation factor - ✔✔The minimum size of a fire that can cause flashover What are the fire effect categories - ✔✔Discoloration, deformation, deposition, mass loss Pyrolysis - ✔✔A chemical decomposition that drives off gases, water vapor, and various pyrolysis products as smoke What is the most commonly observed fire effect? - ✔✔Smoke deposits Petroleum products and most plastics produce what type of fire effect? - ✔✔They are strong soot producers Bulbs below atmospheric pressure do what? - ✔✔Less than 25 Watts. Distort inward away from the fire. Bulbs whose internal pressure is above atmospheric pressure do what? - ✔✔Bulge towards the fire: greater than 25 Watts What are the effects of oxidation - ✔✔Color change and change of texture What does oxidation on stainless steel look like - ✔✔Severe oxidation will produce a dull gray color What does copper look like during oxidationi - ✔✔Dark red or black Rainbow effect - ✔✔Oily substances that do not mix with water, float and create interference patterns on the surface of water. In a low order explosion, the more windows, doors, or other available vents within the confined structure means what? - ✔✔Less structural damage Types of water based suppression systems - ✔✔Wet pipe sprinkler system, dry pipe sprinkler system, precaution sprinkler system, deluge sprinkler system, water spray, water mist system, foam water systems Types of piping for sprinklers - ✔✔Steel, copper, nonmetallic Area of coverage range for sprinkler system - ✔✔8.4m2 for high hazard areas, 21m2 for light hazard areas In regards to sprinkler systems, define design demsity - ✔✔A predetermined mount of water to discharge over the particular area that sprinkler protects Temperature ratings for activation of a sprinkler can be as low as? - ✔✔57C/135F Non-water based suppression systems protect what type of structures? - ✔✔Gaseous or chemical fires; commercial cooking, vessel engine room, heavy equipment engine compartments, telecommunications and data rooms, quench tanks, flammable liquid operations Dry chemical suppression is primarily used for what types of fir? - ✔✔Flammable liquid fire Wet chemical suppression agents are primarily used for what type of fires? - ✔✔Commercial cooking appliances What is the electrical unit for current? - ✔✔Amps Define current - ✔✔Flow rate of charge Apps are equal to? - ✔✔Coulombs per second Resistance is measured in? - ✔✔Ohms AWG - ✔✔American Wire Gauge Charge is measured in? - ✔✔Coulombs The amount of current in Amos can be measured with what? - ✔✔Ammeter Charge does what in an electrical system? - ✔✔Flows Volts can be related to what measurement in a hydraulic system - ✔✔PSI: pressure differential I'm the United States, utilities provide electricity at a frequency of what? - ✔✔60 hertz/60 cycles per second Electrical resistance leads to what? - ✔✔Voltage drop The amount of heat produced by an electrical current is based on what? - ✔✔The amount of resistance and the amount of current Common wire gauge for residential structures - ✔✔10, 12, 14 I'm regards to AWG smaller numbers mean what? - ✔✔Larger wires Ampacity - ✔✔The amapcity of the conductor is the current in amps a conductor can carry continuously under the conditions of use without exceeding its temperature rating Which generates more heat when current is passed through? Aluminum or Copper? - ✔✔Aluminum Better electrical conductors mean what, in regards to resistance? - ✔✔Better conductors mean less resistance Compare steel, aluminum, silver, and copper as conductors - ✔✔1. Silver 2. Copper 3 Aluminum 4. Steel Ohm's law - ✔✔Voltage is equal to current * resistance (E=IxR) Power - ✔✔The rate at which energy is used In regards to electricity energy is generally measured in what? - ✔✔Watt-seconds/ Watt-hours Transformer - ✔✔A device that lower or raises voltages to desired levels Electrical service drop - ✔✔Cables running to the building come from a transformer in a pole Electrical service lateral - ✔✔Underground feed from transformer in/on ground Ungrounded wire is more commonly called? - ✔✔Hot wire Grounded wire is more commonly called? - ✔✔Neutral wire Grounding wire is more commonly called? - ✔✔Ground wire