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75 Cards in this Set

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What is the name of the process that produces gaseous fuel from the decomposition of solid fuel?
Pyrolysis
Does pyrolysis of wood products always result in combustion?
No, because the temperature required for their pyrolysis (less than 400ºF) is far less than the temperature required for the ignition of vapors (1000º to 1300ºF)
At what temperature does free burning occur when dealing with wood and paper products?
932º F
At what temperature can piloted ignition of wood and paper products occur?
536º F to 931º F
Solid fuels become easier to burn as their ______ to _______ ratios increase.
Surface-to-mass
Why does solid fuel burn more readily when it's oriented in an upright position?
Convection carries heat upwards and increases the rate of burning.
What term describes the amount of heat energy released by a certain weight of a solid fuel?
Heat of combustion (expressed in kJ/g)
What term describes the energy released per unit of time as a given fuel burns?
Heat release rate (HRR) -- expressed in kW
What has a higher HRR --- a cotton mattress or a dry christmas tree?
A dry christmas tree does. Its HRR is around 500-650 kW, whereas the mattress has an HRR around 140-350
What has a higher HRR --- cotton furniture of polyurethane furniture?
Polyurethane furniture has roughly seven times higher HRRs than cotton furniture
Why is it important to know that synthetic building materials have a higher HRR than wood?
This reinforces the fact that newer homes and buildings, once they begin burning, behave much differently from older buildings. Newer, synthetic buildings release more heat and also have the potential to emit deadly gases.
What is the primary oxidizing agent in most fires?
Oxygen in the air around us
What are some other common oxidizers and their uses?
Calcium hypochlorite (granular solid) -- used to chlorinate swimming pools

Chlorine (gas) -- used for water purification

Ammonium nitrate (granular solid) -- fertilizer

Hydrogen peroxide (liquid) -- industrial bleaching; pulp, paper, and chemical manufacturing

Methyl Ethyl Ketone Peroxide -- Catalyst in plastics manufacturing
At normal temperatures, what percentage of ambient oxygen concentration is required for ignition and burning?
14%
When ambient temperatures are high, ______ concentrations of oxygen are required for flaming combustion.
Lower
According to OSHA respiratory protection regulation 29 CFR 1910.134, an atmosphere having less than _____ percent oxygen is "oxygen deficient" and dangerous to people not wearing SCBA.
19.5%
According to OSHA respiratory protection regulation 29 CFR 1910.134, an atmosphere having less than _____ percent oxygen is "oxygen enriched" and presenting an increased fire risk.
23.5%
What happens to Nomex® fabric (used to make firefighter clothing) when it's heated and presented with flame in an environment containing 31% or more oxygen?
It burns vigorously
Where might you find an oxygen enriched environment?
Nursing homes, hospitals, some industrial occupancies, some private homes where occupants keep and use supplemental oxygen
Define "flammable range"
The range of concentrations of oxidizers and fuels between the upper flammable limit and lower flammable limit in which a substance can be ignited
Fuel concentrations that exceed the upper flammable limit (UFL) are said to be too ____ to burn.
Rich
Fuel concentrations that are lower than the lower flammable limit (LFL) are said to be too ____ to burn
Lean
Increases in temperature generally _____ the flammable range, whereas decreases in temperature generally _____ it.
Broaden, narrow
List some common flammable gases and liquids and their flammable ranges
Methane: 5%-15%
Propane: 2.1%-9.5%
Carbon monoxide: 12%-75%
Gasoline: 1.4%-7.4%
Diesel: 1.3%-6%
Ethanol: 3.3%-19%
Methanol: 6%-35.5%
Which three common flammable gases and fluids have the widest flammable ranges?
Carbon monoxide (12% to 75%)

Ethanol (3.3% to 19%)

Methanol (6% to 35.5%)
What is the main difference between flaming combustion and smoldering combustion?
Flaming combustion requires the presence of a self-sustained chemical reaction, and it spreads much faster
What happens when flaming combustion occurs and a self-sustained chemical reaction begins?
The fuel and oxygen react, creating heat, free radicals, and new chemical compounds, which then react with one another, creating more heat, more free radicals, different chemical compounds, and the resulting heat ignites even more fuel, and it goes on and on...
What two products of fire have the most detrimental effect on firefighters?
Heat and smoke
What is carbon monoxide?
Carbon monoxide is a colorless, odorless, dangerous gas, that's both toxic and flammable. It is created by the incomplete combustion of carbon. It combines more than 200 times as quickly with hemoglobin as oxygen, thus decreasing the blood's ability to carry oxygen.
What is carbon dioxide?
A colorless, odorless, heavier-than-air gas that neither supports combustion nor burns. It's used in portable fire extinguishers as an extinguishing agent to extinguish class B or C fires by smothering or displacing oxygen.
Fuel concentrations that exceed the upper flammable limit (UFL) are said to be too ____ to burn.
Rich
Fuel concentrations that are lower than the lower flammable limit (LFL) are said to be too ____ to burn
Lean
Increases in temperature generally _____ the flammable range, whereas decreases in temperature generally _____ it.
Broaden, narrow
List some common flammable gases and liquids and their flammable ranges
Methane: 5%-15%
Propane: 2.1%-9.5%
Carbon monoxide: 12%-75%
Gasoline: 1.4%-7.4%
Diesel: 1.3%-6%
Ethanol: 3.3%-19%
Methanol: 6%-35.5%
Which three common flammable gases and fluids have the widest flammable ranges?
Carbon monoxide (12% to 75%)

Ethanol (3.3% to 19%)

Methanol (6% to 35.5%)
What are common ailments suffered by those lacking adequate protection from heat?
Burns
Respiratory tract damage
Dehydration
Exhaustion
What, exactly, is smoke?
Smoke is an aerosol composed of gases, vapor, and solid particulates
Are most components of smoke toxic?
Yes
What is the most common dangerous gas created in structure fires?
Carbon monoxide
Besides carbon monoxide, what deadly gas is commonly found in structural fire smoke?
Hydrogen Cyanide (HCN)
What common household items result in the production of hydrogen cyanide?
Polyurethane foam, which is commonly used in furniture and bedding
How does hydrogen cyanide act as an asphyxiant?
It prevents you from using oxygen at the cellular level
Carbon dioxide ______ respiratory rate.
Increases
What is acetaldehyde?
Colorless liquid with a pungent choking odor, which is irritating to the mucous membranes and especially the eyes. Breathing vapors will cause nausea, vomitting, ehadache, and unconsciousness
What is acrolein?
Colorless-to-yellow volatile liquid with a disagreeable choking odor, this material is irritating to the eyes and mucous membranes. The substance is extremely toxic -- inhalation of concentrations as little as 10 ppm can be fatal within minutes
What is asbestos?
A magnesium silicate mineral that occurs as slender, strong, flexible fibers. Breathing of asbestos dust causes asbestosis and lung cancer.
What is benzene?
A colorless liquid with a petroleum-like odor. Acute exposure to benzene can result in dizziness, excitation, headache, difficulty breathing, nausea, and vomiting. It's a carcinogen.
What is benzaldehyde?
Colorless-to-clear yellow liquid with a bitter almond odor. Inhalation of concentrated vapor is irritating to eyes, nose, and throat
What is formaldehyde?
Colorless gas with a pungent, irritating odor that is highly irritating to the nose. 50-100 ppm can cause severe irritation to the respiratory tract and serious injury. High concentrations can injure the skin.
What is glutaraldehyde?
Light-yellow liquid with a weak, suffocating odor. Causes nausea, headache, vomiting
What is hydrogen chloride?
Colorless gas with sharp, pungent odor, mixes with water to create hydrochloric acid. Corrosive and irritating.
What is nitrogen dioxide?
A reddish brown gas or a yellowish brown liquid, which is highly toxic and corrosive.
What is a Class A fire?
A class A fire involves ordinary combustible materials such as wood, cloth, paper, rubber, grass, and many plastics. Put water on it.
What is a Class B fire?
A class B fire involves flammable and combustible liquids and gases such as gasoline, oil, lacquer, paint, mineral spirits, and alcohol. Shut off gas source and apply proper dry agent and/or foam.
What is a class C fire?
A class C fire involves energized electrical equipment. Will cause Class A and/or Class B fires, depending on the fuels available. De-energize, then douse appropriately. Any firefighting efforts prior to de-energizing must involve non-conductive materials.
What is a Class D fire?
A class D fire involves combustible metals such as aluminum, magnesium, potassium, sodium, titanium, and zirconium. Usually these burn at extremely high temperatures, and some medals react violently to water. They may also create highly toxic gases when burned. Consult MSDS and ERG.
What is a Class K fire?
A class K fire involves cooking oil. Usually these are dealt with by using a process called saponification (or soapification :) that involves applying specific alkaline compounds that turn grease into a soapy film.
Define "compartment"
An enclosed room or space within a building.
What's a compartment fire?
A fire that occurs within an enclosed room or space within a building
When sufficient oxygen is available, what controls the development of a fire?
Characteristics and configuration of fuel
When fire development is limited by the air supply, the fire is said to be ___________ __________.
Ventilation controlled
What are the four stages of a compartment fire?
Incipient, growth, fully developed, decay
Define "incipient stage."
First stage of the burning process in a confined space in which the substance being oxidized is producing some heat, but the heat has not spread to other substances nearby. During this phase the oxygen content of the air has not been significantly reduced.
What is the event that starts the incipient stage?
Ignition
What two types of ignition exist, and what is the difference between the two?
Piloted ignition (open flame or spark causes ignition) and nonpiloted ignition (autoignition -- occurs when matter is heated to its autoignition point)
What is "mushrooming?"
The phenomenon in which hot air generated by an incipient fire travels upward, hitting the ceiling and spreading horizontally. Scientifically, the correct term for a "mushroom" is a "ceiling jet."
OSHA requires a RIT to be present when responding to any fire beyond the _____ stage.
Incipient
Define "growth stage."
The early stage of a fire during which fuel and oxygen are virtually unlimited. This phase is characterized by a rapidly increasing release of heat.
Where in a room will a fire grow the fastest?
In the corner
Define "thermal layering."
Outcome of combustion in a confined space in which gases tend to form into layers, according to temperature, with the hottest gases found at the ceiling and the coolest gases at floor level.
What are two other terms that are used to describe the phenomenon of thermal layering?
Heat stratification
Thermal balance
What effect does thermal layering have on pressure in the compartment?
Pressure is higher in the hotter layer, and the hotter layer will push lower and out windows, doors, and openings as it expands. Pressure is lower in the cooler layer, and air will be drawn into the compartment from the outside in this layer.
What is the term that describes the interface of the hot and cooler gas layers, as the hotter gases exit through an opening, where pressure is neutral?
Neutral plane
What is "ghosting?"
Ghosting is a phenomenon in which pockets of flammable gases in the hot gas layer are observed igniting, creating plumes of flame that travel through the hot gas layer.
What does ghosting indicate?
Ghosting indicates that some flammable gases are within their flammable range and are reaching their ignition temperature. It also foreshadows more serious events such as flashover.