Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
Any fuel or oxidizer, often an ignitable liquid, used to *INITIATE* a fire or increase the rate
of growth or speed the spread of fire === ______ - ansAccelerant
Fires for which the proven cause does not involve an intentional *HUMAN* act to ignite or
spread fire into an area where the fire should not be === ______ fires - ansAccidental
A system that uses moving *MECHANICAL* or electrical parts to achieve a fire protection
goal ===______ ____ protection system - ansActive Fire
Fire alarm and detection systems in which devices and system components are assigned a
*DATA ADDRESS*, are capable of two-way communication, and can perform certain
activities based on signal input ===______ _____ - ansAddressable Technology
ages 14 to______years, who are often responsible for fires that occur at places other than
their homes ===_______ firesetters - ans16
Adolescent
Loose, not on moorings or towline ===_______ - ansAdrift
All green or dead materials located in the forest canopy === _______ fuels - ansAerial
A voluntary written statement of fact or opinion *MADE UNDER OATH* and signed by the
author ===____ - ansAffidavit
Floating in water; not sinking ===______ - ansAfloat
The aerial *APPLICATION*of water, foam, or retardant mixture directly onto the fire or
threatened area or along a strategic position ahead of the fire ===Air_____ - ansDrop
The process of air or gases being drawn into a fire, plume, or jet ===______ _____ - ansAir
Entrainment
A method of smoke detection designed to draw air from the *PROTECTED* area into a
detection chamber for analysis ===______ _____ _____ detection - ansAir Sampling Smoke
A type of *INITIATING DEVICE installed on all types of WET-BASED* fire suppression
systems; the device initiates a fire alarm signal once a water pressure threshold is met
===______ _____ switch - ansAlarm Pressure
A warning signal that *ALERTS* occupants of a fire emergency ===_______ signal -
ansAlarm
The mixture of *TWO* or more metals in which one or more of the metals is in a liquefied
state ===______ - ansAlloying
An electric current that changed its direction very frequently at *REGULAR* intervals
===______ current - ansAlternating (AC)
Air temperature of the surrounding environment ===______ temperature - ansAmbient
The current, in amperes, that a conductor can carry continuously under the conditions of use
*WITHOUT* exceeding its temperature rating ===_____ - ansAmpacity
The strength of an electric current, measured in amperes ===_____ - ansAmperage
,Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
A device that uses indicating lamps, alphanumeric displays, or other means to *provide first
responders with status, condition*, and location information concerning fire alarm system
components and devices ===_____panel - ansAnnunciation
The *SYSTEMATIC EVALUATION of the electrical circuit configuration*, spatial
relationship of the circuit components, and identification of electrical arc sites to assist in the
identification of the area of origin and analysis of the fires spread ===arc ______ -
ansMapping
*Locations of electrical arcing are identified and plotted on a diagram of the affected area of
the structure*. The spatial relationship of the arc sites can create a pattern and help establish
the sequence of damage. This analysis can be used on building circuits and electrical devices
within a compartment to help identify or narrow the area of origin === arc ______ diagram -
ansSurvey
A cylinder of fused silica/quartz with electrodes at either end that is used in most
*MERCURY* and metal halide lamps ===______ ____ - ansArc Tube
A high-temperature luminous electric discharge across a gap where the conductor is missing
or through a medium such as charred insulation ===______ - ansArc
Result of an arcing event where the conductors sever due to the arc - ansArced and Severed
Designed to protect against fires caused by arcing faults in_____ electrical wiring. The
circuitry continuously monitors current flow ===____ ____ ____ interrupter - anshome
Arc-Fault Circuit (AFCI)
A structure, part of a structure or *GENERAL GEOGRAPHIC* location within a fire scene
in which the "point of origin" of a fire or explosion is reasonably believed to be locates
===____ of _____ - ansArea of Origin
The crime of *MALICIOUSLY AND INTENTIONALLY*, or recklessly, starting a fire or
causing an explosion. Legal definitions of "arson" are defined by statues and judicial
decisions that vary among jurisdictions ===______ - ansArson
The direction the slope faces (N, E, S, W) ===______ - ansAspect
Manufactured parts put together to make a completed product ===________ - ansAssemblies
The lowest temperature at which a combustible material ignites in air without a spark or
flame === ______ temperature ( __ __ __) - ansAutoignition (AIT)
A valve that prevents *GAS* from reentering a container or distribution system ===_______
valve - ansBackflow
A proportioner that uses an *ATMOSPHERIC TANK and PUMP* to introduce the foam
concentrate into the system with the water supply === ____ _____ proportioner -
ansBalanced Pressure
A construction type in which the exterior wall studs go from the foundation wall to the
roofline. The floor joists are attached to the walls by the use of a ribbon board, which creates
,Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
an open stud channel between floors, including the basement and attic. - ansBalloon Frame
Construction
Holes driven into the surface of the ground or pavement with either weighted metal bars or
drills. Gas detectors are then inserted into the holes in order to detect the location of a gas
leak. - ansBar Holes
Events that are particularly valuable as a *FOUNDATION* for the timeline or may have
*SIGNIFICANT RELATION* to the cause, spread, detection, or extinguishment of a fire
===______ events - ansBenchmark
A fire pattern that indicate fire direction on wood wall studs. The_____ leans toward the
direction of travel ===_______ - ansBevel
beveling
beveling, along with the tendency of wall studs to point toward the heat source when viewed
from above, is also known as "____ __ ____" patterns - ans"pointer and arrow"
The lowest, interior part of a vessel's hull; the area where spilled water and oil can collect. -
ansBilges
Large quantities of *GAS* being produced by the explosion of the material === blast ______
- ansOverpressure
A _______ is the most frequent type of mechanical explosion you will encounter -
ansBLEVE
Visible holes in the conduit or metal panels of branch circuits caused by an arcing event -
ansBlow Holes
( or blowouts )
Any vessel that can be placed or stored on another vessel. - ansBoat
The individual circuits that feed lighting, receptacles, and various *FIXED* appliances ===
______ circuits - ansf
Branch
The vertical separations in a vessel that form compartments and that correspond to walls in a
building. The term does not refer to the vertical sections of a vessel's hull. - ansBulkheads
The rate of flame propagation relative to the *VELOCITY* of the unburned gas ahead of it
=== burning _______ - ansVelocity
A fire effect realized in gypsum products, including wallboard, as a result of exposure to heat
that drives off free and chemically bound water. - ansCalcination
The carbon monoxide saturation in the blood. - ansCarboxyhemoglobin (COHb)
A device in the exhaust system that exposes exhaust gases to a catalyst metal to promote
oxidation of hydrocarbon materials in the exhaust gas. - ansCatalytic Converter
, Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
A relatively thin layer of flowing hot gases that develops under a *HORIZONTAL* surface
(e.g., ceiling) as a result of plume impingement and the flowing gas being forced to move
horizontally ====______ jet - ansCeiling
A facility that *RECEIVES* fire alarm signals from properties that is staffed with trained,
qualified, and proficient personnel who take the appropriate action to process, record,
respond, and maintain monitored fire alarm systems ===____ ____ service - ansCentral
Station
The trail of accountability that *DOCUMENT* the possession of evidence in an investigation
=== _____ of _____ - ansChain of Custody
Carbonaceous material that has been burned or pyrolyzed and has a blackened appearance
===_____ - ansChar
Explosion in which a chemical reaction is the source of the high-pressure fuel gas. The
fundamental nature of the fuel is changed ===_____ _____ - ansChemical Explosion
The most common chemical explosions are those caused by the burning of combustible
_________ fuels - ansHydrocarbon
A ______ explosion is characterized by the presence of a fuel with air as an oxidizer -
ansCombustion
The minimum *PREDETERMINED* amount of water that must flow from the fire sprinkler
heads in the most hydraulically demanding part of the fire sprinkler system (remote area) to
control or extinguish a fire ===______ ______ - ansDesign Density
A transition phase in the development of a compartment fire in which surfaces exposed to
thermal radiation reach ignition temperature more or less simultaneously and fire spreads
rapidly throughout the space, resulting in full room involvement or total involvement of the
compartment or enclosed space ===______ - ansFlashover
ages ____to 6 years, who are often responsible for fires in their homes or in the immediate
area ===_____ fire setters - ans2
Child
*Proof of a fact indirectly based on LOGICAL* inference rather than personal knowledge
===______ evidence - ansCircumstantial
A *mechanically generated aggregation of bubbles that have a lower DENSITY* than water
===___ ___ foam - ansClass A
A fire effect that appears on noncombustible surfaces after any combustible layers (such as
soot, paint, and paper) have been burned away. The effect may also appear where soot was
not deposited due to high surface temperatures. - ansClean Burn
A signal that *generates a predetermined VISUAL* or *AUDIBLE pattern to identify the
location* of the initiating device that is operating ===______ signal - ansCoded
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
Any fuel or oxidizer, often an ignitable liquid, used to *INITIATE* a fire or increase the rate
of growth or speed the spread of fire === ______ - ansAccelerant
Fires for which the proven cause does not involve an intentional *HUMAN* act to ignite or
spread fire into an area where the fire should not be === ______ fires - ansAccidental
A system that uses moving *MECHANICAL* or electrical parts to achieve a fire protection
goal ===______ ____ protection system - ansActive Fire
Fire alarm and detection systems in which devices and system components are assigned a
*DATA ADDRESS*, are capable of two-way communication, and can perform certain
activities based on signal input ===______ _____ - ansAddressable Technology
ages 14 to______years, who are often responsible for fires that occur at places other than
their homes ===_______ firesetters - ans16
Adolescent
Loose, not on moorings or towline ===_______ - ansAdrift
All green or dead materials located in the forest canopy === _______ fuels - ansAerial
A voluntary written statement of fact or opinion *MADE UNDER OATH* and signed by the
author ===____ - ansAffidavit
Floating in water; not sinking ===______ - ansAfloat
The aerial *APPLICATION*of water, foam, or retardant mixture directly onto the fire or
threatened area or along a strategic position ahead of the fire ===Air_____ - ansDrop
The process of air or gases being drawn into a fire, plume, or jet ===______ _____ - ansAir
Entrainment
A method of smoke detection designed to draw air from the *PROTECTED* area into a
detection chamber for analysis ===______ _____ _____ detection - ansAir Sampling Smoke
A type of *INITIATING DEVICE installed on all types of WET-BASED* fire suppression
systems; the device initiates a fire alarm signal once a water pressure threshold is met
===______ _____ switch - ansAlarm Pressure
A warning signal that *ALERTS* occupants of a fire emergency ===_______ signal -
ansAlarm
The mixture of *TWO* or more metals in which one or more of the metals is in a liquefied
state ===______ - ansAlloying
An electric current that changed its direction very frequently at *REGULAR* intervals
===______ current - ansAlternating (AC)
Air temperature of the surrounding environment ===______ temperature - ansAmbient
The current, in amperes, that a conductor can carry continuously under the conditions of use
*WITHOUT* exceeding its temperature rating ===_____ - ansAmpacity
The strength of an electric current, measured in amperes ===_____ - ansAmperage
,Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
A device that uses indicating lamps, alphanumeric displays, or other means to *provide first
responders with status, condition*, and location information concerning fire alarm system
components and devices ===_____panel - ansAnnunciation
The *SYSTEMATIC EVALUATION of the electrical circuit configuration*, spatial
relationship of the circuit components, and identification of electrical arc sites to assist in the
identification of the area of origin and analysis of the fires spread ===arc ______ -
ansMapping
*Locations of electrical arcing are identified and plotted on a diagram of the affected area of
the structure*. The spatial relationship of the arc sites can create a pattern and help establish
the sequence of damage. This analysis can be used on building circuits and electrical devices
within a compartment to help identify or narrow the area of origin === arc ______ diagram -
ansSurvey
A cylinder of fused silica/quartz with electrodes at either end that is used in most
*MERCURY* and metal halide lamps ===______ ____ - ansArc Tube
A high-temperature luminous electric discharge across a gap where the conductor is missing
or through a medium such as charred insulation ===______ - ansArc
Result of an arcing event where the conductors sever due to the arc - ansArced and Severed
Designed to protect against fires caused by arcing faults in_____ electrical wiring. The
circuitry continuously monitors current flow ===____ ____ ____ interrupter - anshome
Arc-Fault Circuit (AFCI)
A structure, part of a structure or *GENERAL GEOGRAPHIC* location within a fire scene
in which the "point of origin" of a fire or explosion is reasonably believed to be locates
===____ of _____ - ansArea of Origin
The crime of *MALICIOUSLY AND INTENTIONALLY*, or recklessly, starting a fire or
causing an explosion. Legal definitions of "arson" are defined by statues and judicial
decisions that vary among jurisdictions ===______ - ansArson
The direction the slope faces (N, E, S, W) ===______ - ansAspect
Manufactured parts put together to make a completed product ===________ - ansAssemblies
The lowest temperature at which a combustible material ignites in air without a spark or
flame === ______ temperature ( __ __ __) - ansAutoignition (AIT)
A valve that prevents *GAS* from reentering a container or distribution system ===_______
valve - ansBackflow
A proportioner that uses an *ATMOSPHERIC TANK and PUMP* to introduce the foam
concentrate into the system with the water supply === ____ _____ proportioner -
ansBalanced Pressure
A construction type in which the exterior wall studs go from the foundation wall to the
roofline. The floor joists are attached to the walls by the use of a ribbon board, which creates
,Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
an open stud channel between floors, including the basement and attic. - ansBalloon Frame
Construction
Holes driven into the surface of the ground or pavement with either weighted metal bars or
drills. Gas detectors are then inserted into the holes in order to detect the location of a gas
leak. - ansBar Holes
Events that are particularly valuable as a *FOUNDATION* for the timeline or may have
*SIGNIFICANT RELATION* to the cause, spread, detection, or extinguishment of a fire
===______ events - ansBenchmark
A fire pattern that indicate fire direction on wood wall studs. The_____ leans toward the
direction of travel ===_______ - ansBevel
beveling
beveling, along with the tendency of wall studs to point toward the heat source when viewed
from above, is also known as "____ __ ____" patterns - ans"pointer and arrow"
The lowest, interior part of a vessel's hull; the area where spilled water and oil can collect. -
ansBilges
Large quantities of *GAS* being produced by the explosion of the material === blast ______
- ansOverpressure
A _______ is the most frequent type of mechanical explosion you will encounter -
ansBLEVE
Visible holes in the conduit or metal panels of branch circuits caused by an arcing event -
ansBlow Holes
( or blowouts )
Any vessel that can be placed or stored on another vessel. - ansBoat
The individual circuits that feed lighting, receptacles, and various *FIXED* appliances ===
______ circuits - ansf
Branch
The vertical separations in a vessel that form compartments and that correspond to walls in a
building. The term does not refer to the vertical sections of a vessel's hull. - ansBulkheads
The rate of flame propagation relative to the *VELOCITY* of the unburned gas ahead of it
=== burning _______ - ansVelocity
A fire effect realized in gypsum products, including wallboard, as a result of exposure to heat
that drives off free and chemically bound water. - ansCalcination
The carbon monoxide saturation in the blood. - ansCarboxyhemoglobin (COHb)
A device in the exhaust system that exposes exhaust gases to a catalyst metal to promote
oxidation of hydrocarbon materials in the exhaust gas. - ansCatalytic Converter
, Comprehensive Fire Investigator:
Principles and Practice to NFPA
921 and 1033, Fourth
Edition.Guide with Verified
Answers. Latest Updated
2026/2027.
A relatively thin layer of flowing hot gases that develops under a *HORIZONTAL* surface
(e.g., ceiling) as a result of plume impingement and the flowing gas being forced to move
horizontally ====______ jet - ansCeiling
A facility that *RECEIVES* fire alarm signals from properties that is staffed with trained,
qualified, and proficient personnel who take the appropriate action to process, record,
respond, and maintain monitored fire alarm systems ===____ ____ service - ansCentral
Station
The trail of accountability that *DOCUMENT* the possession of evidence in an investigation
=== _____ of _____ - ansChain of Custody
Carbonaceous material that has been burned or pyrolyzed and has a blackened appearance
===_____ - ansChar
Explosion in which a chemical reaction is the source of the high-pressure fuel gas. The
fundamental nature of the fuel is changed ===_____ _____ - ansChemical Explosion
The most common chemical explosions are those caused by the burning of combustible
_________ fuels - ansHydrocarbon
A ______ explosion is characterized by the presence of a fuel with air as an oxidizer -
ansCombustion
The minimum *PREDETERMINED* amount of water that must flow from the fire sprinkler
heads in the most hydraulically demanding part of the fire sprinkler system (remote area) to
control or extinguish a fire ===______ ______ - ansDesign Density
A transition phase in the development of a compartment fire in which surfaces exposed to
thermal radiation reach ignition temperature more or less simultaneously and fire spreads
rapidly throughout the space, resulting in full room involvement or total involvement of the
compartment or enclosed space ===______ - ansFlashover
ages ____to 6 years, who are often responsible for fires in their homes or in the immediate
area ===_____ fire setters - ans2
Child
*Proof of a fact indirectly based on LOGICAL* inference rather than personal knowledge
===______ evidence - ansCircumstantial
A *mechanically generated aggregation of bubbles that have a lower DENSITY* than water
===___ ___ foam - ansClass A
A fire effect that appears on noncombustible surfaces after any combustible layers (such as
soot, paint, and paper) have been burned away. The effect may also appear where soot was
not deposited due to high surface temperatures. - ansClean Burn
A signal that *generates a predetermined VISUAL* or *AUDIBLE pattern to identify the
location* of the initiating device that is operating ===______ signal - ansCoded
