Fire dynamics

The minimum ignition energy (MIE) of most hydrocarbons is:

.25 mJ.

What is the approximate average number of firefighters killed in the line of duty each year from 2000-2010?

100

From 2002-2011 approximately how many civilians were killed by fire each year?

3,000-4,000

How many firefighters died in the Sofa Super Store fire in 2007 due to lack of understanding of fire dynamics?

9

What is a premixed flame?

A flame where air is introduced before the point of combustion

What is a laminar flame?

A flame with a clearly defined combustion zone

What is a turbulent flame?

A flame with oxidation occurring within a generalized area but not in a steady geometric pattern

The open cup test of a liquid's flash point involves which of the following?

A heating unit being adjusted to raise the liquids temperature slowly, the operator recording liquid temperature periodically, then introducing a pilot flame across the surface, the flash point being recorded as the temperature that occurred immediately before a flash fire is witnessed

Which BEST describes the temperature scale known as Fahrenheit?

A measurement of temperature used most commonly in the United States where 32 degrees is the freezing point of water

What is the definition of a sphere?

A perfectly round ball that contains volume

NFPA 921 defines fire as which of the following?

A rapid oxidation process, which is a chemical reaction, resulting in the evolution of heat and light in varying intensities

Which BEST describes the temperature scale of Kelvin?

A scale using absolute zero, where water freezes at 273.15 degrees and boils at 373.13 degrees

What is a coordinate system?

A system using X, Y, and Z coordinates

Which BEST describes the Rankine temperature scale?

A temperature measurement scale where all molecular movement ceases at zero degrees and water freezes at 491.67 degrees

Which BEST describes the temperature scale of Celsius?

A temperature scale based on the fixed points zero degrees as the freezing point of water and 100 degrees as the boiling point

Which of the following describes an endothermic reaction?

Absorbs energy heat

Which choice describes the endothermic process of pyrolysis?

Absorbs heat/energy

What is the heat of gasification?

Amount of energy that is required to produce a unit mass of flammable vapor from a combustible that is initially at ambient temperatures

Increasing the oxygen concentration causes:

An increase in temperature

What defines a gaseous state?

Atoms that collide but are not on a fixed arrangement and assume the shape of a container

The temperature to which a mixture of fuel gas and air must be raised to initiate combustion without any external heat source is called:

Auto ignition temperature

Three known conditions that can lead to firefighter fatalities are flashover, rollover, and:

Backdraft

Flammable liquids have a flash point (per NFPA 30):

Below 100 degrees Fahrenheit

How will the presence of char affect the burning rate of a fuel?

Burning rates will be slowed, and the energy required increases

The energy required to raise one gram of water one degree centigrade is a:

Calorie

A Class K fire involves what types of materials?

Certain cooking media such as vegetable and animal fats and oils

What is the term for carbonaceous material that has been burned or pyrolyzed and has a blackened appearance?

Char

Under NFPA classification, which of the following presents the most significant threat of producing ignitable vapors at ambient conditions?

Class IA

Under NFPA classification, which of the following presents the least significant threat of producing ignitable vapors at ambient conditions?

Class IIIB

A Class D fire involves what types of materials?

Combustible metals

_________, including butadiene and neoprene, are items that have been created to match the properties of natural rubbers

Elastomers

Fire prevention professionals involved in inspections are charged with identifying conditions that:

Exceed design criteria for fire protection systems, adversely affect passive fire protection elements, and hinder active fire protection and detection elements

Under the Federal Hazardous Substances Act, ignitable liquids are classified as which of the following?

Extremely flammable, flammable, or combustible

A Class B fire involves what types of materials?

Flammable gases and flammable or combustible liquids

What is a Class 4 hazardous material per the U.S. Department of Transportation?

Flammable solid

What is the main measurement used when considering the ignitability of liquids?

Flash point

_________, are plastics created with pockets of air throughout the fuel

Foams or cellular plastics

Melting is a physical change of a substance:

From solid to liquid

The fire triangle consists of which of these components?

Fuel, heat, and oxygen

fire protection professionals must utilize a full knowledge of what topics?

Fuels and fuel geometry, detection, and suppression

Caution should be used when evaluating gases because:

Gases not listed as flammable can sometimes ignite under certain conditions

Which of the following describes an exothermic reaction?

Gives off energy heat

The _______ of a material refers to the amount of energy emitted per unit of fuel mass consumed, and it varies by fuel

Heat of combustion

_______ is used to describe the amount of energy that is required to produce a unit mass of flammable vapor from a combustible that is initially at ambient temperatures

Heat of gasification

The rate at which the heat energy is generated by burning is termed:

Heat release rate

Why do aerosols ignite so easily?

High surface to mass ratio

Cellulosic materials consist of all of the following EXCEPT:

Hydrocarbons

Liquids evolving vapors that can undergo combustion with relative ease are considered to be:

Ignitable liquids

The variables considered when determining a fuel's heat release rate include all of the following EXCEPT:

Ignition temperature

The four ideal fire growth curves include all of the following EXCEPT:

Infinite

Flame spread of the soundproofing used at the Station Night Club was known to fire-testing agencies and professionals, but was not considered during which phase?

Installation and fire code inspection

The predominant factor that led to the large number of deaths at the Cocoanut Grove fire was:

Inward swinging doors

The energy required to move one kilogram one meter per second over a distance of one meter is a:

Joule

The energy required to change a liquid to a vapor is termed what?

Latent heat of vaporization

What is a liquid's flash point?

Lowest temperature of a liquid, as determined by specific laboratory tests, at which the liquid gives off vapors at a sufficient rate to support a momentary flame across its surface

The _____ is the loss of mass over time from the fuel's surface when undergoing combustion

Mass burning flux

The _________, often referred to as the burning rate, is the rate at which the fuel is losing mass while undergoing combustion and is usually expressed in kilograms per second (kg/s) or grams per second (g/s)

Mass loss rate

Temperature is a measurement of:

Molecular movement

Which of the following sets a basis for classification of flammability of liquids?

NFPA 30

A Class C fire involves what type of materials?

Natural and synthetic materials like rubber and plastics, which are energized by electrical circuits, wiring, motors, and other equipment

Should the combined gas law be used to calculate the pressure in a BLEVE?

No, due to the high pressure and unknown quantities of vapor/liquid in the container

A Class A fire involves what types of materials?

Ordinary cellulosic materials such as wood and paper as well as similar natural and synthetic materials like rubber and plastics

What are fire investigators primarily tasked with identifying?

Origin, cause, spread, responsibility, and circumstances

Investigators must first seek the ___________ and then the ____________ of a fire in order to ascertain what happened.

Origin; cause

Smoldering combustion is characterized by which of the following?

Oxidation reaction in the solid phase that produces light, and oxidation reaction in the solid phase that produces heat

What is the major source of fuel in upholstered furniture?

Polyurethane foam

What is the term used to describe the evaluation of conditions before emergencies?

Preplanning

Study of fire dynamics helps to:

Provide safety for humans and structures

Solids undergo ______ as they chemically break down to become fuel gases that can burn in the gas phase

Pyrolysis

As altitude changes, the vapor pressure of a liquid:

Remains the same

Having definite shape and volume describes what state of matter?

Solid

Heat release rates of pool fires are dependent on which of the following?

Surface area exposed to air and heat of combustion of the fuel

The standard time-temperature curve does not take into account what kind of fuels that are common today?

Synthetic Materials

What is a liquid's fire point?

Temperature at which the substance must be raised to produce sufficient vapors to sustain burning after the initial flash

Flammability limits are dependent on which of the following?

Temperature, pressure, and oxygen concentration

The combined gas law relates what three properties?

Temperature, pressure, volume

What is the effective heat of combustion?

The actual amount of energy that is released when fuel oxidizes in air

Which BEST describes rate?

The amount of energy over time or another unit of measure

What is circumference?

The distance around a circle

What is the stoichiometric mixture?

The exact proper mixture (mass of each reactant) of chemical for a chemical reaction

Smoke is defined as:

The gases, vapors, and small particles that come off from a burning substance

What is the upper explosive limit?

The highest percentage of fuel to air where combustion can occur

The term fire dynamics refers to:

The interrelationship of fuel, heat, oxygen, chemical reactions, and the physical world

What is the lower flammable limit?

The percentage of air and fuel where the lowest amount of fuel will combust

Flame spread refers to:

The speed with which the flame front (oxidation zone) moves across a fuel's surface

Miscibility and solubility are terms used interchangeably to describe which of the following?

The tendency of materials to become solutions or to retain their initial characteristics

What is a flame?

The visible, luminous body where the oxidation reaction is occurring

What is one factor responsible for the rapid fire development in today's built environment?

The volume of commodities and synthetics

Plastics that are not cured or hardened during the manufacturing process and that soften and melt when exposed to heat are:

Thermoplastics

Plastics that have been hardened into a defined shape during manufacturing and that when heated will typically not soften or melt but produce char, are called:

Thermosetting plastics

What is the definition of volume?

Three-dimensional measure expressing total space occupied by an object or contained within a compartment and expressed in cubic measure

Nearly all metals burn under the right conditions

True

What is the definition of area?

Two-dimensional measurement to determine quantity of space contained

Which BEST describes the English system of measurements?

Uses inches, feet, and miles

Which BEST describes the metric system?

Uses increments of 10

Specific gravity of vapors and gases is termed:

Vapor density

What term describes the pressure exerted by vapors leaving the liquid surface?

Vapor pressure

The auto ignition temperature of liquids is which of the following?

Well above the boiling point, ignition absent of an ignition source, identified by raising the temperature of a liquid in a controlled environment until ignition occurs

unconfined vapor cloud explosion (UVCE) is:

an explosion in a vapor cloud that is outdoors and not confined by walls and ceiling on all sides

Thermal radiation is sometimes referred to as:

power density