Fire Investigation Exam with Complete Solutions

Fuel and an oxidizing agent - ANSWER-Each form of fire is a chemical reaction between when two things Endothermic - ANSWER-Reactions that absorb energy Exothermic - ANSWER-Reactions that give off energy Endothermic - ANSWER-Converting liquid to gas via heat is an example of what kind of reaction? Exothermic - ANSWER-Fire is and example of what type of chemical reaction? Oxidation - ANSWER-Chemical reaction between oxygen and other materials Smoldering/surface glow - ANSWER-Fire triangle is a reasonable explanation for what type of fires Self-sustained Chem reaction - ANSWER-Fire tetrahedron includes what vs fire triangle Flaming combustion - ANSWER-Fire tetrahedron explains Flaming combustion/ char. Of the fuel - ANSWER-If self sustained Chem reaction is inhibited, BLANK will cease but smoldering may continue depending on what? Fuel - ANSWER-Material or substance being oxidized or burned Reducing agent - ANSWER-Fuel in a combustion reaction is known as what? Inorganic fuel - ANSWER-Fuels with no carbon. Ex. Hydrogen, magnesium Organic fuel - ANSWER-Fuel that contains carbon; most common fuel; Hydrocarbon - ANSWER-This type of organic fuel contains gasoline,plastics Cellulose based - ANSWER-This type of organic fuel includes wood, paper Physical state of fuel & orientation - ANSWER-Two key factors affecting the combustion process Solid fuel - ANSWER-Fuel with a def size and shape Pyrolysis - ANSWER-Thermal/Chem decomposition via heat Plastics - ANSWER-What type of materials don't contain moisture that must be released before pyrolysis? Surface to mass ratio and distribution/orientation of fuel - ANSWER-Most common factors that can contribute to fires in Solid fuels Size and shape - ANSWER-Primary consideration with STM ratio is Quicker - ANSWER-In STM RATIO, as area increases, pyrolysis occurs Slower - ANSWER-Horizontal orientation burns Quicker - ANSWER-Vertical orientation burns Liquid fuel - ANSWER-Fuel with a mass and volume, but no def shape Specific gravity - ANSWER-Weight of a substance as compared to equal weight of water Floats - ANSWER-Liquid with Spec gravity less than one does what Gasoline - ANSWER-Example of a liquid with a SG less than one less than one - ANSWER-Most, but not all, Flammable liquids have a SG of what ? Epicholorhidrin - ANSWER-Example of a liquid with a SG greater than one Vaporization - ANSWER-Turning liquid to a vapor 14.7 PSI - ANSWER-In order to vaporize, liquids must over come the atomspheric pressure of? Vapor pressure and heat applied - ANSWER-Vaporization rate is determined by what 2 things Flash Point - ANSWER-Temp at which liquids release enough vapor to ignite but not sustain combustion Less than 100F - ANSWER-Flash point of flammable liquids is? Greater than 100 - ANSWER-Flash point of combustible liquids Flammable liquids - ANSWER-Liquids with a flash point less than 100 Combustible - ANSWER-Liquids with a flash greater than 100 solubility - ANSWER-Extent a fluid will mix with water No - ANSWER-Do hydrocarbons mix with water? Yes - ANSWER-Do polar solvents mix with water? miscible - ANSWER-When Liquids will mix in any proportion they are considered what? Gaseous - ANSWER-Fuel that has mass but no def shape or volume Gaseous; its already in a state required for ignition - ANSWER-Type of Fuel that can be the most dangerous & why? Vapor density - ANSWER-Weight of gases in relation to Air Rise - ANSWER-VD less than one will do what? Methane - ANSWER-Example of a gas with a VD less than 1 sink - ANSWER-Gases with a VD greater than one will do what propane (LPG) - ANSWER-Example of a gas with a VD greater than one 68F - ANSWER-VD assumes that the air and gas are at what ambient temp Expand and become less dense - ANSWER-Heated gases do what contract and become more dense - ANSWER-Cooled gases do what Oxygen - ANSWER-What is the primary oxdizing agent in most fires 21% - ANSWER-Air contains about how much Oxygen? No, but will support combustion - ANSWER-Are oxidizers combustible? 70F / 14% - ANSWER-At an ambient temp of BLANK, materials can ignite with O levels as low as BLANK... Surface - ANSWER-BLANK combustion can continue at extremely low O levels even @ relatively low temperatures More intesely and ignite more readily - ANSWER-At higher levels of O, materials that burn at normal O levels will burn how? calcium hypochlorite - ANSWER-Common oxidzer used in pools chlorine - ANSWER-common oxydizer use in water purification ammonium nitrate - ANSWER-common oxidizer used in fertilizers hydrogen peroxide - ANSWER-common oxydizer used in Industrial bleaching/paper/pulp/disenfectant uses MEKP - ANSWER-common oxidizer used in plastics Flammable (explosive) range - ANSWER-range of concentration to support combustion 5-15% - ANSWER-flammable/explosive range of methane 2.1-9.5% - ANSWER-flammable/explosive range of propane 12-75% - ANSWER-flammable/explosive range of CO 1.4-7.4% - ANSWER-flammable/explosive range of Gasoline 1.3-6% - ANSWER-flammable/explosive range of Diesel 3.3-19% - ANSWER-flammable/explosive range of ethanol 6-35.5% - ANSWER-flammable/explosive range of methanol potential and kinetic - ANSWER-What are the 2 states of energy potential - ANSWER-energy that may be released in the future kinetic - ANSWER-energy possessed by moving object Heat - ANSWER-This is the kinetic energy associated with the movement of atoms/molecules that comprise matter Temperature - ANSWER-This is a measure of kinetic energy Piloted - ANSWER-The most common type of ignitiion Piloted Ignition - ANSWER-type of ignition when fuel and O meet an external heat source Auto-Ignition - ANSWER-Ignition when temp is sufficient to ignite Chemical, Mechanical, Electrical, Light and Nucleur - ANSWER-What are the 5 types of heat energy Chem, Mech and Elec - ANSWER-What are 3 of the most COMMON types of heat energuy Chemical - ANSWER-What is the MOST COMMON type of heat energy overcurrent/overload - ANSWER-Unintended resistance heating Arcing - ANSWER-high temp luminous charge across a gap or through a medium Sparking - ANSWER-Spattering of particles away from arcing compression and friction - ANSWER-Mechanical energy is generated by what 2 things? 18F - ANSWER-In Spontaneous igntion, the rate @ which most chem reactions occur doubles with each BLANK degree increase in reacting materials Temp must increase faster than disapation; temp must increase to ig temp, must be a adequate air supply - ANSWER-Self heating must have what 3 things? conduction - ANSWER-Heat flow through or between solids 7x - ANSWER-copper is X times more heat conductive to heat than steel 40x - ANSWER-Steel is X times more heat conductive than Concrete LEAST - ANSWER-Wood is one of the BLANK heat conductive materials Convection - ANSWER-Transfer of heat energy from a liquid/gas to a solid surface; Heat energy that explains movement of hot air/gases Radiation - ANSWER-Transmission of heat energy via electromagnetic waves without an intervening medium; This type of heat become the most dominant mode of heat transfer in exposure fires 4th power / 16 - ANSWER-Q - As temperature of a heat source increases, the radiant energy increases by a factor to the X power? Thus a doubling of the temp increase the energy by a factor of X. Passive agents - ANSWER-Materials that absorb heat but do not actively contribute to the burning process Conduction - ANSWER-This type of heat transfer results from increased molecular motion Conduction & Radiation - ANSWER-Direct Flame contact is a combo of what 2 type of heat energy transfers Smoke - ANSWER-aeresol comprised of fire gases and solid particulates CO, HCN and Co2 - ANSWER-3 most common products of combusiton? CO - ANSWER-This comes for the incomplete combustion of organic materials; probably the most common product of combustion HCN - ANSWER-Comes from combustion of materials containing nitrogen; polyurethane foams CO2 - ANSWER-Comes from complete combustion of organic materials; causes increase resp rate and displaces oxygen; simple asphyxiant A - ANSWER-Class of fire - ordinary solids B - ANSWER-Class of fire - flammable/combustible fluids/gases C - ANSWER-Class of fire - Electical D - ANSWER-Class of fire - combustible metals K - ANSWER-Class of fire -Oils/Grease/Kitchens Cooling - ANSWER-Best method to extinguish Class A Foam/Dry Chem/shut off gas supply - ANSWER-Best method to extinguish Class B Denergize and cool - ANSWER-Best method to extinguish Class c Differing agents - No best agent for all metals - ANSWER-Best method to extinguish Class D Saponification Agents - ANSWER-Best method to extinguish Class K Fats and oils; used in class K fires - ANSWER-Saponification describes reaction between agent and ? Chemical flame inhibition - ANSWER-Surface combustion cannot be extingushed by what? Free Radical - ANSWER-Atom or grp of atoms that has at least one unpaired electron; unstable; highly reactive Incipient - ANSWER-The stage of fire that starts with ignition Fuel controlled - ANSWER-Incipient fires are X controlled fires Incipient, growth, fully developed, decay - ANSWER-What are the 4 stages of fire Forming a ceiling jet - ANSWER-Mushrooming is also called Growth - ANSWER-Mushrooming occurs in what stage Drawing of air into the plume - ANSWER-The first effect caused by the transition into the growth stage is the ? The location of the fuel package in relation to the compartment walls - ANSWER-What determines the amount of air that is entraining and thus the amount of cooling that takes place thermal layering, isolated flames, rollover, flashover - ANSWER-Fire can exert what traits during the growth stage? thermal layering - ANSWER-the tendency of gases to seperate into layers accoring to temperature heat stratification and thermal balance - ANSWER-other words used for thermal layering isolated flames - ANSWER-Q - pockets of flame moving through the hot gas layer ghosting - ANSWER-isolated flames can also be called rollover - ANSWER-Q - where the unburned gases at the top of the compartment ignite and flame propgate across the ceiling flashover - ANSWER-Rollover usually, but not always, precedes ? Flashover - ANSWER-Q - rapid transition between growth and fully developed stages, but is not a specific event like ignition Flashover - ANSWER-Q - when the temp in a compartment results in the simultaneous ignition of all combustible contents 900-1200F - ANSWER-Temp range of flashover; correlates with autoginition temp of CO. rapid temp increase; additional fuel is becoming involved, fuel releasing gases due to pyrolysis - ANSWER-Most notable 3 events that occur prior to flashover fuel must have sufficient heat energy & developing fire must have sufficient oxygen. - ANSWER-what 2 related factor determine IF flashover will occur ventilation - ANSWER-Most fires that extend beyond the incipient stages become BLANK controlled fully developed - ANSWER-Stage when all combustible materials are burning fully developed - ANSWER-stage when fuels are releasing max amount of heat possible for available fuel/ventilation heat release rate - ANSWER-measurement of amount of heat released; expressed in BTU or kilowatts decay - ANSWER-stage where the O levels falls to a point where flaming combustion can no longer be supported backdraft - ANSWER-explosion occuring from rapid burning of superheated gases when O is introduced decay - ANSWER-Q - backdraft occurs in what stage of a fire horizontal - ANSWER-What type of opening should you NOT make if backdraft conditions exist Mass and Surface area - ANSWER-What are the Two most fundamental fuel characteristics that affect fire development fuel type, availablity/config of additional fuels, volume and ceiling height, ventilation, thermal properties, ambient conditions, effects of changing conditions - ANSWER-7 factors that influence fire development Large - ANSWER-All things being equal, a fire in a X size compartment will develop more slowly insulation, heat reflection, heat retention, and conductivity - ANSWER-Thermal properties of a compartment include impede/slow down - ANSWER-High humidity and cold temp can do what to the natural movement of smoke? vertical ventilation - ANSWER-High humidty can reduce the effect of ?, acting to hold smoke in the building 212F - ANSWER-water is converted to steam (boils) at what temp 1,700x - ANSWER-When water is converted to steam, it expands how many times? fuel removal - ANSWER-Q - What extingushment method extingushies any fires reducing temp, fuel removal, seperating fire from fuel, changing O levels, interruping self-sustained chem chain reactions - ANSWER-Fire is controlled by removing one piece of the fire tetrahedron; FF do this by doing at least one of 5 things including? allow fire to burn until all fuel is consumed - ANSWER-Q - simplest method of fire control/fuel removal? close valve or remove all solid fuels in the path of fire - ANSWER-Extinguishment method preferred with pressurized gases removing O - ANSWER-dry chem range hoods act extinguish fires by some dry chem agents, halons and halon replacement agents - ANSWER-What extinguishing agents interupt chem chain reaction gases and liquid fuels; because they must flame to burn - ANSWER-chem change reaction inhibition is effective on burning of 5 - ANSWER-IBC and NFPA recognized how many types of construction? struc frame, ext and interior load bearing walls, int and exterior non bearing walls/partitions, floor and roof - ANSWER-Every structure is composed of what 7 elements Type I construction - ANSWER-Type of construction comprised of only non combustible materials and provides the highest level of safety The fire resistance of the members - ANSWER-Q- type I construction can be expected to remain structurally stable for the duration of? Type I - ANSWER-Reinforced concrete and precast concrete along with protected steel frame meet the criteria for what type of construction ? Type II - ANSWER-Type of construction composed of bldg mats that will not contrib to fire development or spread. Consists of non combustible mats that do not meet the stricter req of type I construction Type II - ANSWER-Structure with metal framing members, metal cladding,or concrete block walls with metal deck roofs supported by unprotected open web joists are most common in what type construction? Type II - ANSWER-Type of construction used when fire risk is expected to be low or when fire suppression and detection systems are designed to meet the hazard load Fireproof - ANSWER-Type I is often Incorrectly referred to as ? The amt of combustibles the owner places in a structure - ANSWER-Fire resistance/structural integ of type I structure may be compromised by? Occupancy loads - ANSWER-NFPA divides assembly occupancies into 3 groups based on what? Over 1,000 - ANSWER-Q+ - Class A assembly occupancy has occ load of 301-1000 - ANSWER-Q+ - Class b assembly has occ load of 50-300 - ANSWER-Q+ - Class c assembly has occ load of Specific use - ANSWER-The ICC USES 5 class groups of assembly use based on Business use - ANSWER-Types of occupancies that provide working place for large numbers of occupants in an office environment Business - ANSWER-doctors,air traffic control towers, city halls, courthouses,college instructional buildings, dry cleaning laundry facilities and barber shops are included in what occupancy type Business - ANSWER-ICC also includes buildings that house outpatient clinics where patients are ambulatory and not incapacitated by anesthetic in what occ type Ambulatory health care facilities - ANSWER-NFPA considers outpatient clinics as? 6 or more/ preschool - 12th grade - ANSWER-Education occ is any building or portion of used for X persons from what grades? Low to moderate - ANSWER-Risk of fire in education occupancies are usually rated how? High occupant loads and variety of uses - ANSWER-Ed facilities pose hazard due to what 2 factors Type III - ANSWER-Type of construction most common in churches, schools, apartment buildings, and mercantile structures? type III - ANSWER-Construction type where ext walls constructed of non combustible mats and interior elements of any mat allowed by code Type III - ANSWER-Const. Type with ext and int non bearing walls of brick, concrete and reinforced concrete. Floors, roofs and int non bearing framing/partitions of small dimensional wood or metal stud systems Type III - ANSWER-Unprotected steel and alum non bearing wall framing members, as well as wood or steel trusses, while new bldgs tend to have more wood truss/floor joist systems are in what type? Void spaces of roof/truss systems, renovations created large voids above ceilings/floors, reduced load capacity caused by reno'd, change in use requiring higher load capacity - ANSWER-What are some dangers of type III construction? Heavy Timber - ANSWER-Type IV is also called? Type IV - ANSWER-Type of construction characterized by large dimensional wood 4in - ANSWER-Type IV requires large dimensional lumber of greater than X for all structural members Columns, beams joists girders, and ROOF SHEATHING/planks. - ANSWER-Structural members include what in type IV construction 1 hour - ANSWER-Any materials used in type IV not composed of wood must have a min fire resistance rating of? Type IV - ANSWER-These types of structures are extremely stable and more resistant to collapse due to fire that other types that are not protected by fire suppression systems Type IV - ANSWER-Const type with noncombustible ext walls and int walls of solid or lam wood with NO CONCEALED SPACES Type IV; churches, auditoriums and other large vaulted facilities. - ANSWER-Laminated beams are extremely strong and have same or improved fire performance. They are often used in Use of steel columns or other non compliant material to support glued or laminated beams - ANSWER-What is a common violation of type IV construction Type V - ANSWER-Const type most often referred to as wood frame or frame Single family dwelling/residence - ANSWER-What is the most common example of type V construction Type V - ANSWER-Framing including 2x4 wood studs, steel or alum studs and wood sill plates are in what type of const 2x4's, creating the top and bottom of the truss. - ANSWER-When wood Ibeams are used, they are usually thin plywood attached to Void spaces - ANSWER-Wood truss systems used in type V create ?, not found in closed channel systems 50 or more persons. - ANSWER-Q+ - An assembly occupancy is any building, structure or compartment used for gathering of how many people? Daycare and residential board & care - ANSWER-NFPA 101 separates these two occupancies into their own categories 6 or more - ANSWER-In FIC, educational facitities are used for education of X or more persons from preschool through the 12th grade high occupant load and variety of uses - ANSWER-Hazards in educational facilites are primarily what 2 things 6 or more students from preschool through grade 12 that meet for 4 or more hours per day or more than 12 hours per week - ANSWER-Q+ - NFPA 101 and 5000 describe ed facilites as those used by X number of student from X to X grade that meet X or more hours per day or more than X hours per week 20 SF - ANSWER-Q+ - Codes allow for 1 student per X SF of classroom space 50 SF - ANSWER-Q+ - Codes allow for 1 student per X SF of lab/voke shops space Follow the rules for assembly space - ANSWER-Q+ - Codes allow for 1 student per X SF of gym, lecture or dining hall space? general purpose, special purpose, High hazard - ANSWER-NFPA classifies factory/industrial into what 3 groups? hazard materials type - ANSWER-ICC does not include what group in factory/industrial Institutional - ANSWER-Health Care, Ambulatory health care, detention, residential board and care and day care are examples of what types of occupancy via NFPA 1 and 101?