Chapters 1 & 2 Flashcards
Heat is described as
a condition of matter in motion
What the 5 general heat categories
chemical, electrical, mechanical, nuclear, solar
Which fibrous material are poor conductors?
felt, cloth, and paper ( they are heat insulators)
Fire spread by convection is mostly in what direction?
Upward, however air currents can carry heat in any direction.
Although it appears to the eye that solids and liquids burn only___________. burn
gases
Fuel gases evolving from solid fuels ( decomposition of a substance through the action of heat)
Pyrolysis (sublimation)
What are the 4 classes of fire
Class A ordinary combustible
Class B flammable combustible liquid
Class C energized electrical
Class D combustible metals
What are the four methods of extinguishing a fire?
- reducing temp
- eliminating available fuel
- excluding oxygen
- stopping the uninhibited chemical chain reaction
Finished foam extinguishes and/or prevents fire by what methods?
separating, cooling, suppressing ( smothering)
Class B foam concentrates are designed specifically for which type of fuel?
Hydrocarbons ( will not extinguish polar solvent fuel)
What is the storage life of class A foam?
indefinite
What are the 3 ratios of foam expansion
low expansion 20:1
med 20:1 - 200:1
high 200:1 - 1,000:1
When using foam and dry chemical agents is called?
multi agent attack
Why should caution be taken when using Class A foam that might get into a waterway?
The lethal effect it has on fish
What is the measurement for determining the stability of finished foam?
The rate at which the foam blanket drains ( breakdown)
Short drain time means?
rapid wetting
Long drain time means?
foam blanket holds water and provides and insulating foam layer for an extended period of time.
What elements affect the drainage process?
Fuel temperature
heat of the fire
size of the flame front ( ambient temp and wind)
Which finished foam ratio (class A) has a quicker knockdown?
Low expansion
What temperature does finished foam breakdown?
near and over 212 degrees F
What can affect regular protein foam?
Freezing and thawing
also not compatible with dry chemical agents.
What is oleophobic?
oil shedding
Which foam can be used with freshwater or saltwater?
Film Forming Fluroprotein Foam (FFFP)
Aqueos Film Forming Foam (AFFF)
What is the most commonly used concentrate used today?
AFFF
AFFF is adversely affected by fuels in excess of ___degrees F
140
Project Light water originated where?
U.S. Navy the 3M company later trademarked the term
LIGHT WATER
Which foam concentrates create a membrane rather than a film over the fuel?
Alcohol Resistance Aqueos Film Forming Foam
AR-AFFF
Can AR-AFFF be premixed?
no , not designed for premixed applications
Which hydrocarbons can AR-AFFF be used in sub-surface injection?
Gasoline, Krosene, and jet propulsion fuels
Which classes of fire are emulsifiers used on?
Class A and B
emulsifiers are designed to mix with the fuel, breaking into small droplets.
What is the purpose of doubling?
slows foam drainage when dealing with post fuel fire
What is the most common storage containers (foam) used by fire and emergency services?
5 gallon plastic pails
How are 5 gallon foam pails tested?
designed to pass several 4 foot drop tests with contents frozen.
Foam proportioning devices operate by one of two basic principles.
Induction and Injection
What are the four types of portable foam eductors?
- In-line
- self educting hand line foam nozzles
- self educting master stream foam nozzle
- portable around the pump proportions
Experts in the foam industry and fire service consider which type to be the most efficient pieces?
simple in-line foam educator
- should not be higher than 6 feet form the concentrate container form which it is drawing
Portable around the pump (ATP) proportioners operate on which side of the engine?
on the suction or SUPPLY side of the pump , rather that the discharge side of the pump.
What psi will shut down an ATP down?
more than 14.7 psi
must maintain incoming supply pressure @ 10 psi or less
Installed in-line eductors are most commonly used to proportion which type of foam concentrate?
Class B
What is the most common type of built in proportioner installed in mobile fire apparatus today?
Around the Pump (ATP)
- also installed on some fixed systems
What is the simplest means to proportion foam?
Batch mixing
What are the four types of chemical reactions?
- Heat of combustion
- Spontaneous heating
- Heat of decomposition
- Heat of solution
What materials according to author make good conductors?
aluminum , copper, and iron
The cause of heat movement through structures from floor to floor , room to room , and area to area?
convections currents
What is the primary consideration on regarding ignitability?
surface to mass ratio
What does the density of a solid determine?
the rate at which the solid absorbs heat and reaches it IGNITION TEMP
Every basic hydrocarbon except the lightest one, has a vapor density greater than 1. What is the lightest one?
Methane
The higher the vapor pressure of a liquid, the greater the rate at which it evaporates and?
the lower its boiling point becomes
A fuel may be classified as either flammable or combustible depending on?
Flashpoint
What is fire point?
fuel produces enough vapor to support combustion once its ignited.
usually a few degrees above flashpoint
flashpoint is the LFL of the fue
NFPA determine flammable & combustible liquids differences
flammable less than 100 degeesF
combustible more than 100 degrees F
Fire burns in two combustion modes they are?
flaming and smoldering
At what point does a fire intensity begin to decrease?
below 18% oxygen concentration
oxygen concentrations below 15% do not support combustion
What is burning in a Rollover ( Flame over)
the gases
Fires have been known to reach the flashover stage in less than?
2 minutes, but can occur as late as 8 minutes as well.
Polar solvents are?
Flammable liquids that have an attraction for water and are miscible ( dissolve in water)
examples of polar solvents
alcohols acetones esters aldehydes ether
Combustible metals are particularly hazardous in what form?
powdered , given a suitable ignition source can cause powerful explosions
What is the safest extinguishment procedure when dealing with Class C fires?
Turning off the power
then treat as a Class A or B fire
What percent foam concentrate should you use for fire attack & overhaul with a standard fog nozzle?
0.2 to 0.5%
Protein based foam concentrates degrade at what rate?
2 to 8 days
Synthetic foam concentrates degrade at what rate?
20-40 days
Foams with a ____can be used for fixed systems subsurface injection into storage tanks.
high fuel resistance
AFFF, FFFP, Fluoroprotein foams posses a fuel resistance that prevents contamination of foam
What type of foam is referred to as smart foam?
Alcohol resistant
they adjust their chemistry when they detect a polar solvent
What is meant by Quarter life?
Time in minutes for 1/4 of the total liquid solution to drain from the finished foam.
also called 25% drainage time , or
Quarter drain time
Class B foam concentrates are used at what percentage?
3% hydrocarbons
6% polar solvents
new multipurpose concentrates use 3% regardless of fuel types
What should be the application rate when using AFFF, FFFP, or AR-AFFF?
discharge rate should be equal to 10% of the area of the spill.
Foam breaks down rapidly as the fuel temperature rises and will perhaps become ineffective when the fuel’s temperature is near or over
150 degrees
Most finished foam breaks down when the fuel temperature is near or over
212 degrees
UL-Listed foam concentrates must be pourable and easily proportioned at temperatures as low as
35 degrees
Viscosity is affected by?
temperature
The amount of Foam concentrates on fire and emergency service pumpers range from
20 - 200 gallons
ARFF apparatus my carry foam concentrates in excess of
600 gallons
AR-AFFF is prone to
evaporation
Foam tenders capacity ranges from
1500-8000 gallons
5 gallons foam pails are designed to pass several drops tests at
4-foot with contents frozen
Foam barrels are designed to withstand falls from
5 feet with contents frozen
One of the most common gasses released by pyrolysis?
Carbon Monoxide - CO
Flashover temperature ranges between
900 - 1200 degrees F
The ignition temperature of Carbon Monoxide is
1,128 degrees F
Water requires approximately _____ of additional heat to completely turn into steam
970 Btu
At 212 degrees F a cubic foot of water expands approx.
1,700 times
At 500 degrees F a cubic foot of water expands
2,400 times
At 1,200 degrees F a cubic foot of water expands
4,200 times
