Questions and Answers(SCORED A+)
Is NFPA 921 a guide or a standard? - ANSWER-It is the Guide for Fire and
Explosion Investigations
What are the six steps of the scientific method? - ANSWER-Recognize the need
Define the problem
Collect the data
Analyze the data
Develop a hypothesis
Test the hypothesis
What step of the scientific method is inductive reasoning? - ANSWER-Analyze the
data
What step of the scientific method is deductive reasoning? - ANSWER-Test the
hypothesis
What are the four parts of the fire tetrahedron? - ANSWER-Fuel (reducing agent)
Heat
Oxidizing agent
Uninhibited chemical chain reaction
What kind of reaction absorbs energy, an endothermic or an exothermic reaction? -
ANSWER-Endothermic
What is heat transfer by direct contact called? - ANSWER-Conduction
What is heat transfer by gas flow / air movement called? - ANSWER-Convection
What is heat transfer by microwave energy called? - ANSWER-Radiation
What is a fuel controlled fire? - ANSWER-A fire that is limited by the amount of
combustibles.
What is a ventilation controlled fire? - ANSWER-A fire that is limited by the amount of
oxygen.
What are the stages of fire growth? - ANSWER-Ignition
Growth
Flashover
Fully Developed
Decay
,What is a flashover? - ANSWER-The transition phase from growth to fully
developed, where all surfaces reach ignition temperature almost simultaneously.
What is ignition of the underside of the hot gas layer called? - ANSWER-Flameover
or rollover
What factors influence flashover conditions? - ANSWER-Size of the compartment
Height of ceiling
Ventilation
Amount of fuel
Layout of fuel
Location of fire in the compartment
What are fire patterns? - ANSWER-The physical manifestation of the affects of fire
on materials.
What are the different types of fire patterns on the walls and ceiling? - ANSWER-
Plume Generated patterns (often V shaped)
Ventilation generated patterns
Hot gas layer patterns (Line of demarcation)
What is spalling? - ANSWER-The separation of chunks of concrete with explosive
force caused by the expansion of water (moisture) trapped in the concrete as it turns
to steam
What is char? - ANSWER-Pyrolized carbonaceous material
What is oxidation? - ANSWER-Physical change in appearance of a material resulting
from the combination of oxygen.
What is alloying? - ANSWER-Mixing two metals heated then cooled to change their
properties. Often melts at a lower temperature.
What is a clean burn? - ANSWER-When there was enough heat to burn away all
carbon deposits (soot) on a surface leaving a "clean" surface. Occurs on non-
combustible surfaces.
What is soot? - ANSWER-Elemental carbon produced during incomplete
combustion.
What is calcination? - ANSWER-When chemically bound water is driven out of
gypsum walls by the heat of the fire.
Does a 25 Watt light bulb expand towards the fire or pull inward away from it? -
ANSWER-Bulbs 25 watts or less pull away. Bulbs greater than 25 watts will expand
towards the fire.
What causes heat shadowing? - ANSWER-An object blocking the travel of radiated
heat.
,What is a dead load? - ANSWER-The weight of things attached to the building, like
flooring, cloumns, and roof coverings.
What is a live load? - ANSWER-A load that can move, like people, furniture, wind,
water, and snow.
What is compartmentation? - ANSWER-Design features of a building that limit fire
growth to the room of origin.
What are the five building construction types? - ANSWER-Type I - Fire resistant
Type II - Non combustible
Type III - Ordinary
Type IV - Heavy timber
Type V - Wood frame
What is ordinary construction? - ANSWER-Exterior walls are masonry and frame is
wood.
What is wood frame construction? - ANSWER-Lightweight wood construction, used
in apartments, houses.
What is platform frame construction? - ANSWER-Each floor is a seperate platform.
What is balloon frame construction? - ANSWER-The wall studs extend from the
foundation to the roof.
What is Ohm's Law? - ANSWER-V=IR
(E = I x R)
What is voltage? - ANSWER-Pressure
What is current? - ANSWER-Flow
What is resistance? - ANSWER-Friction, opposition to the flow
What is an overload? - ANSWER-Power needs exceed the circuit's capacity.
Alternating Current VS Direct Current - ANSWER-Alternating current - the electrons
flow out from the source and then back to it, alternating directions.
Direct current - electrons flow one way.
Single Phase service - ANSWER-Residential. Three conductors: Two insulated
conductors at 120 V each, and a bare ground wire.
Three phase system - ANSWER-Commercial. Four conductors: Three insulated
conductors (480, 240, or 208 V), and a bare ground wire.
What is the difference between grounding and bonding? - ANSWER-Grounding
connects the system to the earth (ground). Bonding connects to systems together so
the charge stays the same between them.
, What is overcurrent protection? - ANSWER-A device that protects the system from
excess current. Includes:
Circuit breakers
Plug fuses
Type S fuses
Time delay fuses
Cartridge fuses
What are the colors of residential wires? - ANSWER-Hot - black or red
Neutral - gray or white
Ground - bare or green
What are some methods of electrical heat production? - ANSWER-Resistance
heating
Short circuit
Ground fault
Parting Arc
Excessive current
What is the difference between and arc and a spark? - ANSWER-Sparks are thrown
metal particles
Arcs are brief discharges of electricity
What is arc tracking? - ANSWER-Arc following salts, dusts, or liquids along a path.
What is arc mapping? - ANSWER-Mapping out of electrical damage in a circuit.
What is static electricity? - ANSWER-A stationary charge caused by movement of
one object against another. Lighting is a static disharge.
What are the five conditions nessecery for Static Arc Ignition? - ANSWER-A Means
of static generation
A means of accumulating and maintaining the charge
A static discharge with sufficient energy
A fuel source
Coexistence of the arc and fuel source
Name two fuel gasses: - ANSWER-LP (liquid petroleum)
Natural gas
What is the difference between tanks and cylinders for LP gas? - ANSWER-Tanks:
storage with greater than 1000 LBs water capacity.
Cylinder: Portable, usually consumer.
What are some human factors related to fire initiation in a structure? - ANSWER-
Improper maintenance and operation
Housekeeping
Product labels, warnings, and instructions
Recalls