CHAPTER 7 - Portable Fire Extinguishers
CO2 agent is stored under a pressure of _________, and why?
-823 psi -which keeps the CO2 in liquid form at room temperatures
1. Ordinary dry-chemical fire extinguishers - -
-Introduced during the 1950s, -rated only for Class B and C fire
CO2 disadvantages 1 2 3 4 5
-Weight: -Range: -Weather: CO2 does not perform well at temperatures below 0ºF, in windy or drafty conditions -Confined spaces: CO2 dilutes the oxygen in the air. -Suitability: CO2 extinguishers are not suitable for use on fires involving pressurized fuel or on cooking grease fires.
Class K fires are identified by what color/shape
-a pictograph showing a fire in a frying pan. -Because the Class K designation is new, there is no traditional system alphabet graphic for it.
Most extinguishers stop the burning by - -
-cooling the fuel below its ignition temperature, -by cutting off the supply of oxygen, or by combining these two techniques
stored-pressure water-type extinguisher details: -range at solid stream -weight -discharge time is
-range of 35' to 40' -30 lbs -approximately 55 seconds
1. Loaded-stream fire extinguishers
-subject In areas that are subject to freezing i. These extinguishers combine an alkali metal salt and water.
1. Backpack fire extinguishers
-tank capacity of 5 gallons -weigh approximately 50 lb when full. -do not carry numeric ratings -designed to refill easily in the field, from a lake or a stream, through a wide-mouth opening at the top
The hazard classification for each area should be based on what 2 things
-the actual amount -the type of combustibles that are present
1. Two key factors must be considered when determining which type of extinguisher should be placed in each area: - -
-the class of fire that is likely to occur -potential magnitude of an incipient fire
1. Pump tank fire extinguishers
-water in these units is not stored under pressure -The pressure to expel the water is provided by a hand-operated, double-acting, vertical piston pump, which moves water out through a short hose on both the up and the down strokes
Fire Extinguishers primary uses - -
1- Extinguish incipient fires 2-Control fires where traditional methods of fire suppression are not recommended
A. Carbon Dioxide weight compared to gas
1. Carbon dioxide is a gas that is 1.5 times heavier than air. a. Colorless, odorless, and nontoxic
what hazard classification -woodworking shops; -service or repair facilities for cars, aircraft, or boats; -kitchens and other cooking areas that have deep fryers
1. Extra (high) hazard
A. Class D Fires
1. Involve combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium
portable fire extinguisher part -prevents accidental discharge of the extinguishing agent
1. Locking mechanism
portable fire extinguisher part - where extinguishing agent is expelled
1. Nozzle or horn
what hazard classification -retail stores with on-site storage areas, -light manufacturing facilities, -auto showrooms, -parking garages, -research facilities, -restaurant kitchens
1. Ordinary (moderate) hazard
portable fire extinguisher part -stored-pressure extinguisher has sufficient pressure to operate properly
1. Pressure indicator
portable fire extinguisher part -mechanism that is squeezed or depressed to discharge the extinguishing agent
1. Trigger
Wetting-agent fire extinguishers expel water that contains a solution to reduce surface tension
1. Wetting-agent and Class A foam water-type extinguishers
An extinguisher that is rated 1-A contains the equivalent of
1.25 gallons
1. Wheeled extinguishers typically contain between__________________________________of extinguishing agent.
150 and 350 lb (68-158 kg)
A typical Class A extinguisher contains _____________________________ of water and has a ___________ rating
2.5 gallons (9 L) 2-A rating
what size is our water can at CSD
2.5-gallon model with a 2-A rating
a. The bottom of an extinguisher should be at least -distanceTo ground
4" (10 cm) above the floor.
An extinguisher rated 40-B should be able to control a flammable liquid pan fire with a surface area of
40 ft2
Certification testing is performed by trained experts; therefore, the numerical rating is about.....
40% of the area that an expert can extinguish
what indicates that the extinguisher must not be used on that type of fire because doing so would create additional risk
A red slash across an icon
what dry chemical multipurpose dry chemical (and why)
Ammonium phosphate is commonly called a multipurpose dry chemical agent because it can be used on Class A, B, and C fires.
1. Light (low) hazard -
Areas where most materials are noncombustible or arranged so that a fire is not likely to spread
Involve ordinary combustibles,
Class A Fires
what fire class is this -Natural vegetation, such as grass and trees
Class A Fires
Involve flammable or combustible liquids -what class
Class B Fires
CO2 is rated for what fires
Class B and C fires only
what class solid red square
Class B fires
Involve energized electrical equipment, -what class
Class C Fires
Involve combustible metals, -what class
Class D Fires
what class -solid yellow five-pointed star
Class D fires
what class shows a fire in a frying pan symbol
Class K
Involve combustible cooking oils and fats
Class K Fires
what class shows fire in the frying pan
Class K fires
A. Class K Fires
Involve combustible cooking oils and fats
A. Class C Fires
Involve energized electrical equipment, which includes any device that uses, produces, or delivers electrical energy
A. Class B Fires
Involve flammable or combustible liquids, such as gasoline, oil, grease, tar, lacquer, oil-based paints, and some plastics
A. Class A Fires
Involve ordinary combustibles, such as wood, paper, cloth, rubber, household rubbish, and some plastics
CO2 advantages over dry chemical extinguishing agents
It does not conduct electricity and has two significant advantages over dry chemical agents: it is not corrosive and it does not leave any residue
what hazard classification -offices, classrooms, churches, assembly halls, and hotel guest rooms
Light (low) hazard
what NFPA -the recommendations for placing and mounting portable fire extinguishers and the recommended mounting heights
NFPA 10
a chemical process that occurs when a fuel is combined with oxygen, resulting in the formation of ash or other waste products and the release of energy as heat and light.
Oxidation aka burning
process begins when the fuel is heated to its ignition temperature
The combustion process
who is the organization that developed the standards, classification, and rating system for portable fire extinguishers.
Underwriters Laboratories
A. Pictograph Labeling System -screenshot
Uses symbols rather than letters on the labels
most common fire extinguishing agent to put out Class A
Water is the most commonly
process of Water-Type Fire Extinguishers putting out fire
When applied to fire, water converts from liquid into steam, absorbing heat in the process
portable fire extinguishers have six basic parts (Figure 7-16): 1 2 3 4 5 6
a. A cylinder that holds the extinguishing agent b. A carrying handle c. A nozzle or horn d. A trigger and discharge valve assembly e. A locking mechanism to prevent accidental discharge f. A pressure indicator
what dry chemical is rated for Class A fires
a. Ammonium phosphate rated for A,B,C
A. Dry-Chemical Fire Extinguishers work how (3-ways) 1 2 3
a. First, the finer particles of the chemical vaporize when they reach the high temperature of the flame and release a vapor that interrupts the chemistry of the flame. b. Second, the particles of the dry chemical shield the fuel surface from the flame radiation, thereby reducing the rate at which the burning fuel is being vaporized. c. Third, when extensive dry chemical is applied and reaches the surface of the fuel, it can smother the fire by forming an insulating blanket.
what dry chemical is More corrosive than the other agents
a. Potassium chloride
when to use a Water mist fire extinguishers -also range
a. Should be used where regular extinguishers may cause excessive damage, such as in museums and hospitals -effective within 5-12 ft
five primary compounds used as dry chemicals extinguishing agents are 1 2 3 4 5
a. Sodium bicarbonate a. Potassium bicarbonate a. Urea-based potassium bicarbonate\ a. Potassium chloride a. Ammonium phosphate
-Dry chemical extinguishing agents advantages over water extinguishers: 1 2 3
a. They are effective on Class B (flammable liquids and gases) fires. b. They can be used on Class C (energized electrical equipment) fires because the chemicals are nonconductive. c. They are not subject to freezing.
1. seven types of extinguishers described include: 1 2 3 4 5 6 7
a. Water-type fire extinguishers b. Dry-chemical fire extinguishers c. CO2 fire extinguishers d. Class B foam fire extinguishers e. Halogenated-agent fire extinguishers f. Dry-powder fire extinguishers g. Wet-chemical fire extinguishers
how does Carbon Dioxide Fire Extinguishers work
a. interrupts the combustion process by reducing the amount of oxygen that can reach the fuel. b. A blanket of CO2 over the surface of a liquid fuel can also disrupt the fuel's ability to vaporize.
The effectiveness of Class B extinguishers is based on the
approximate area in square feet
Pictograph Labeling System -Class A fires is a
burning trash can beside a wood fire
Portable fire extinguishers are classified and rated based on their - -
characteristics capabilities
what class flame and a metal gear
class D icon is a
portable fire extinguisher part -The body of the extinguisher
cylinder
Agents that will not conduct electricity, such as _________________________ or ___________________________, must be used on Class C fires.
dry chemicals carbon dioxide
Pictograph Labeling System -Class K fires
fire in the frying pan
Pictograph Labeling System -class D icon is a
flame and a metal gear
Pictograph Labeling System -Class C icon is a
flame and an electrical plug and socket
1. All fires require three basic ingredients:
fuel, heat, and oxygen.
dry chemical a. Sodium bicarbonate rated for
i. Rated for Class B and C fires only
Pictograph Labeling System -Class B fire extinguisher icon
is a flame and a gasoline can
Areas are divided into three risk classifications—
light, ordinary, extra hazard
a. Potassium chloride is
more corrosive than the other agents
burning is called
oxidation
combustion process begins when the fuel is what
process begins when the fuel is heated to its ignition temperature
1. Wetting-agent and Class A foam water-type extinguishers -reduce what
reduce surface tension
what symbol Class C fires
solid blue circle
Symbol for Class A fires are identified by the
solid green triangle.
what class
solid green triangle.
what symbol Class B fires
solid red square
Class D fires are identified by -what color and shape?
solid yellow five-pointed star
One disadvantage of dry chemical extinguishers is
that the chemicals, particularly the multipurpose dry chemicals, are corrosive and can damage electronic equipment
1. The primary disadvantage of fire extinguishers is
that they are "one-shot" devices. once they are out they are out
1. Multipurpose dry-chemical fire extinguishers Introduced in
the 1960s
The most popular kind of stored-pressure water-type extinguisher is
the 2.5-gallon model with a 2-A rating
A red slash across an icon indicates that
the extinguisher must not be used on that type of fire because doing so would create additional risk
NFPA 10 lists
the recommendations for placing and mounting portable fire extinguishers and the recommended mounting heights
Class A and Class B fire extinguishers also include a number, indicating
the relative effectiveness of the fire extinguisher in the hands of a nonexpert user
Fire extinguishers weighing more than 40 lb should be mounted so that
the top of the extinguisher is not more than 3' (1 m) above the floor
a. Fire extinguishers weighing up to 40 lb should be mounted so that
the top of the extinguisher is not more than 5' (2 m) above the floor.
The recommended hazard classifications for different types of occupancies are guidelines based on __________________
typical situations.
a. Reducing the surface tension allows
water to spread over the fire and penetrate more efficiently into Class A fuels.
