Trial Prep - General questions Flashcards
What is a rapid oxidation process, which is an exothermic chemical reaction resulting in the evolution of light and heat in varying intensities
Fire
Define “fire”
A rapid oxidation process, which is an exothermic chemical reaction, resulting in the evolution of light and heat in varying intensities
Four sides of the fire tetrahedron
heat
fuel
oxidizing agent
uninhibited chemical chain reaction
oxygen % required for flaming fire
at least 14-16%
oxygen % required for smoldering fires
as little as 8%
define temperature
the degree of sensible heat of a body as measured by a thermometer
a measure of the degree of molecular activity relative to some reference point (freezing point of water)
define “heat”
a form of energy characterized by the vibration of molecules and capable of initiating and supporting chemical changes and changes of state
or. the amount of energy require to maintain or change the temperature of an object
what are the two units of heat energy?
joule
calorie (1 cal = 4 J
Define “heat transfer”
energy that is transferred between objects due to a temperature difference
which direction does heat transfer move?
from the hotter object to the colder object
Heat transfer is measured in units of what?
Watts
How many watts are in a megawatt?
1,000,000 W
Define “heat flux”
The measured rate of heat transfer to or from a defined area or surface.
does high pressure always flow to low pressure, or low to high?
high to low
what law does this represent?
PV=nRT
Ideal gas law
what is the key point to Ideal Gas Law?
If the pressure increases, then temperature increases.
if the temperature increases, then the pressure increases.
and the same if there is a drop
Name the 3 modes of heat transfer
Conduction
Convection
Radiation
What type of heat transfer involves the movement of a fluid?
convection
Which type of heat transfer is with electromagnetic waves?
radiation
which mode of heat transfer is through direct contact
conduction
Define “Thermal Conductivity”
the rate at which heat passes through a specified material
Does steel have a high or low thermal conductivity?
high
what are the two types of convection heating?
Natural (think of a car radiator and how fresh air goes across it)
Forced (heater with a mechanical fan)
How is smoke and radiation heat associated?
smoke consists of tiny, dark, solid carbon particles and each one is radiating heat.
this means, the dirtier and darker the smoke, the more radiation it will emit (high emissivity)
Define Pyrolysis
The chemical decomposition of a compound into one or more substances due to heat alone.
Remember that “radiant heat created pyrolysis products and these products burned”
What are the two types of changes to fuel turning to vapor?
phase changes which is reversible (melting or evaporation)
Thermal decomposition which is irreversible (pyrolysis)
What is the term for the amount of heat released when a known amount of a substance burns completely?
Heat of Combustion
Define “heat of combustion”
the amount of heat released when a known amount of a substance burns completely
Define “Heat Release Rate”
the amount of heat energy released by the fire per unit time
What units are used to measure HRR?
kW or MW
How is HRR used to define a fire?
often used to describe the “size” of a fire
What is the single most important factor in characterizing fire behavior
HRR because it helps explain the thermal conditions in a room or how it might ignite other nearby fuels via heat transfer
What four things control the HRR of an object
- chemical and physical properties
- geometry of the fuel and containment
- ventilation
- surrounding fuels
What is the approx. peak HRR of a cigarette?
5 W
What is the approx. peak HRR of a match?
80 W
What is the approx. peak HRR of a upholstered sofa?
3MW to 5 MW
At what phase of a fires development is the idealized HRR curve highest?
fully developed or post flash-over
Define “ignition”
the process of initiating self-sustained combustion
What are the 2 types of ignition?
piloted ignition and autoignition
What is piloted ignition?
when an external ignition source ignites flammable vapors
What does a competent ignition source include?
- enough energy
- will be in contact with the fuel long enough to raise it to the fuel’s ignition temperature
Define “thermal Inertia”
the measure of how fast the surface temperature of a material will rise
what is the measure of how fast the surface temperature of a material will rise?
thermal inertia
What 3 things determine an objects thermal inertia?
- thermal conductivity - the material’s ability to conduct heat
- the material’s density
- the material’s capacity to store heat
Does low kpc (thermal inertia) mean fast or slow ignition
fast.
what is the measurement for something considered thermally thin?
a thickness of 2mm or less
flashpoint for flammable liquid is
less than 100F
the flashpoint for combustible liquid is
100 or more?
is gasoline a flammable or combustible liquid?
flammable
which state of matter (solid, liquid, or gas) require the least amount of energy to ignite?
gas
what state of matter does flaming fires occur?
in the gas phase. all solid and liquid fuels must first pyrolyze and/or vaporize to burn
what are the 2 types of flames?
premixed and diffusion
premixed or diffusion, what is a match flame?
diffusion
what is an example of a premix flame?
when a gas and oxgen are within there explosion range.
What is the sudden conversion of potential energy (mechanical or chemical) into kinetic energy with the production and release of gases under pressure or the release of gas under pressure?
an explosion
what are the 2 types of diffusion flames?
laminar and turbulent
What type of diffusion flames are most real fires?
turbulent
for most common fuels, is flame temperature essentially the same regardless of fuel type?
yes
Define “concurrent flame spread”
its when a flame preheats and pyrolyzes the next section of fuel, then ignition occurs. (fire going up a wall)
What is the melting temperature of aluminum?
1220F
What is the melting temperature of copper?
1981F
What is the melting temperature of steel?
2760F (losing tensile strenth at 1000F)
What is the melting temperature of steel?
2760F (losing tensile strength at 1000F)
What are the two type of melting plastics?
Thermoplastics and Thermoset
How does thermoset polymer respond to heat?
Char, not melt
Which plastic melts, softens, and flows under exposure to heat and continues to burn?
thermoplastics
What causes the annealing of springs
Temperature but also by accidental means. A large person sitting on a couch over a period of time, will cause annealing.
Define “fire effects”
visible or measurable physical changes, or identifiable shapes, formed by fire effect or a group of fire effects
Define “fire pattern analysis.”
The process of identifying and interpreting fire patterns to determine how the patterns were created and their significance.
Basically, determining the fire intensity and movement.
Name the seven steps of the scientific method
recognize the need
define the problem
collect data
analysis data
develop hypothesis
test hypothesis
select final hypothesis
What are the 3 types of bias?
presumption
expectation
confirmation
what is presumption bias?
developed before data collection
What is expectation bias?
A premature conclusion without consideration of all data, typically based on a previously formed assumption(s).
What is confirmation bias?
Only collecting data to support the investigator’s hypothesis.
what is it when an investigator only collects data to support the investigator’s hypothesis?
confirmation bias
What is it when an investigator develops a hypothesis before data collection?
presumption bias
What is it when an investigator prematurely comes to a conclusion without consideration of all data?
expectation data
What specific training & education have you received in fire and/or explosion investigation?
I have received training through the State of Missouri Department of Fire Safety and am certified in the following levels:
Fire Investigator (Proboard)
Fire Inspector 1 (Proboard)
Fire Officer 2 (Proboard)
Fire Instructor 1
Incident Safety Officer (Proboard)
National Fire Academy Fire Investigation Essentials R0772
Over 70 hours of CFItrainer.net programs (online and tested training for Fire Investigators through the IAAI) covered the four various topics listed in NFPA 1033: fire science, scene safety, building systems, and fire investigation.
Law Enforcement training consisting of the Springfield Police Academy and Springfield Police Major Crime Investigator school.
Ried Technique Interview and Interragation
Marpa Group: Statement analysis and interviewing class
FBI Hazardous Device School in Huntsville AL.
Overall, over 450 hours of continuing education since Sept. 2020, but that is not counting the 27-week-long police academy.
Plus, additional classes from the NFA, MU, private companies, and departments during my career dealing with firefighting tactics and strategies, building construction, training, leadership, hazardous materials, and many more.
What specific training have you received in fire and/or explosion dynamics
MO state Fire Investigator 1
NFA Fire Investigation Essentials
at least 7 hours of CFITrainer.net online training.
Participated in and conducted at least seven training burns to study fire growth and development inside structures.
How many fires scene have you actually physically examined in or to render expert opinions?
As a Fire Marshal, I have conducted over 50 Origin and Cause Investigations.
How many fire and explosion investigations have you investigated?
As a Fire Marshal, I have participated in over 70 fire investigations. I can not tell you how many I participated in during my time as a firefighter or company officer.
Do you hold any licenses, registrations, or certifications in your profession?
Yes, I hold the following:
Fire Investigator
Fire Inspection 1
Fire Instructor 1
Fire Officer 2
Incident Safety Officer
Class A Peace Officer
MO POST Specialized Instructor for arson, bomb, and hazmat.
Hazardous Device Tech.
Hazard Materials Operations
Firefighter 2
Can you describe your Fire Science Library?
The department has a library in our office available for us to use for research and training, including books like the Ignition Handbook and various explosive materials book. I have a small collection of textbooks and reference materials, including:
NFPA 921
NFPA 1033 (2014 & 2022 ed.)
Kirk’s fire investigation 8th ed.
Scientific Protocols for Fire Investigation 3rd Ed.
Fire Investigator 6th ed.
2 books on Electrical Failure Analysis
Forensic Fire Scene Reconstruction 3rd ed.
Plus, various other textbooks such as Fire Officer, Instructor, and training materials from courses I have attended.
Have you taught or lectured to organized groups pertaining to fire investigation?
I assist in the Fire and Police Academies, including the basic academies, basic and advanced fire officer academies, teaching topics such as:
Fire Investigation and fire dynamics
Building Construction
Fire Inspections
Hazardous Materials inspections and response
Fire Protection Equipment
plus on-the-job training when conducting O&C investigations for anyone who seeks to understand our job better.
Are you a member of any organizations?
Yes,
International Association of Bomb Technicians & Investigators (2023-current)
NAFI – National Association of Fire Investigators (2022-current)
IAAI – International Association of Arson Investigators (2020-current)
MO IAAI – Missouri International Association of Arson Investigators (2019-current)
Missouri Professional Fire & Fraud Investigators Association (2019-current)
IAFF – International Association of Firefighters, AFL-CIO (2007-current)
What is NFC 1
the fire prevention code
NFC 70?
National Electric Code
NFC 101?
The life safety code
NFPA 921
Guide for Fire and Explosion investigations
NFPA 1033
The standard for fire investigator professional qualifications
Do you consider the national fire codes authoritative?
I do if adopted by the authority having jurisdiction.
Define Competent Ignition Source
3.3.37 Competent Ignition Source.
An ignition source that has sufficient energy and is capable of transferring that energy to the fuel long enough to raise the fuel to its ignition temperature. (See 19.4.2.)
Define flame
3.3.84 Flame.
A body or stream of gaseous material involved in the combustion process and emitting radiant energy at specific wavelength bands determined by the combustion chemistry of the fuel. In most cases, some portion of the emitted radiant energy is visible to the human eye.
Define Fire dynamics
3.3.73* 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.
What property determines the heigh of a fire plume?
the rate of heat release of the fuel
What property determines the height of a fire plume?
the rate of heat release of the fuel
Define flashover
the transition in a compartment when everything becomes ignited
define the rate of heat release of a material
reate at which it gives off heat energy when burning
What is the definition of the specific heat of a material?
amount of energy needed to raise its temperature
What is a material’s ignition temperature?
The ignition temperature of a substance, in a solid, liquid, or gaseous state, is the minimum temperature required to start or cause combustion, regardless of an igniting element.
What are electro-magnetic waves?
its a form of radiation
how are electro-magnetic waves related to radiated heat?
radiant heat travels by electro-magnetic waves
How is radiated heat related to flashover?
Radiated heat is main energy transfer mechanism leading to flashover
What is NIST?
national institure of standards and tehnology
What is BERL?
building and fire research lav of NIST
What is FPEtool?
fire protection engineering tool. one of NIST’s computer fire models
What is FAST?
computer fire model
What is HAZARD 1 & HAZARD II?
computer fire models
define radian heat flux
the amount of radiant heat energy transfer
What is the critical heat flux for flashover to occur?
20 KW per square meter
what is the definition upper layer temperature in a compartment fire?
average temperature of hot gas cloud in a room
what is generally accepted critical upper layer temperature for flashover to occur?
1112F
define heat shadowing
Heat shadowing occurs when one object blocks the travel of heat from the heat source to the substance behind the shadowing object
define fire origin
The general location where a fire or explosion began
define fire pattern
he physical changes, or identifiable shapes, formed by a fire effect or group of fire effects.
define movement pattern
