Application of Portable Fire Extinguishers

Given a selection of portable extinguishers, full personal protective equipment, and a controlled instructional environment, the student will be able to demonstrate the proper techniques of inspecting, selecting, and using portable extinguishers...

• Shock hazard when water or water-based extinguishers are used

Notes: Use full PPE and SCBA because of dangerous by-products

• Extinguishment

Notes: Use non-conducting agents such as: aluminum, magnesium, titanium, zirconium, sodium, potassium, lithium, calcium, zinc

• De-energize: treat as Class A or B

• Temperature reduction and full removal

Class D: combustible metals

• Fires which occur in combustible metals

• Extremely high temperature, burns at 2,000+EF: water and other agents are rendered ineffective

• Water reverts to essential elements

• Hydrogen: burns again

• Oxygen: self support for combustion

• Very hazardous or explosive in powdered form

Notes: Full PPE and SCBA.

• Extinguishment: no single agent will always control these fires. They require special extinguishing agents designed for metal fires

• Cover and smother the burning materials

• Isolate materials and test in accordance with MSDS/ NAERG recommendations

• Use only enough personnel to accomplish the assigned task

III. Types of Agents (1-3)

Notes: IFSTA Unit 5 S #1

Water and water-based foams

Notes: IFSTA Unit 5 S #2

• Water cools fuel (heat side of triangle)

• Absorbs heat and reduces temperatures of the fuel(s) to a point where it does not produce vapors to burn

• Class A fires: ordinary combustible materials

• Foam covers fuel (oxygen side of triangle) (AFFF extinguisher)

Notes: IFSTA Unit 5 S #3

• Keeps oxygen away

• Keeps fuel vapors from forming

• A:B rated: ordinary combustible materials, and liquids, greases, and gases

Carbon dioxide, B:C rated (oxygen side of triangle)

Notes: IFSTA Unit 5 S #5

• Displaces oxygen and can inhibit chain reaction

• Has a slight cooling effect

• A Snow buildup can ruin computer micro-chips (little dry ice crystals)

• Is non-toxic, but will build up a static electrical charge. Keep grounded while operating

Dry chemical

Notes: IFSTA Unit 5 S #6

• All dry chemical extinguishing agents: A:B:C or strictly B:C rated

Agent: sodium bicarbonate,potassium bicarbonate, ammonium phosphate, potassium chloride, UREA - potassium bicarbonate

• Leave messy residues

• React with fuel molecules to prevent oxidation by inhibiting the chain reaction

• Sodium bicarbonate, B:C rated (baking soda)

• Is not compatible with foam

• Breaks down gas bubbles (relieves indigestion)

Notes: Dry powder used on Class D fires.

• Potassium bicarbonate, B:C rated (Purple K): powder extinguishing agent

• Foam compatible

• Developed for crash fire rescue (CFR)

Notes: S-1-5

• Monammonium phosphate, A:B:C: multipurpose dry chemical rated

• Forms crust on Class A fuel

• Forms emulsion in Class B fuel

• Is not compatible with B:C dry chemical (neutralizing effect)

• Corrodes electrical equipment almost immediately

• Is corrosive to aircraft parts

Notes: IFSTA Unit 5 S #7

Dry powder

• For Class D fires only

• Smothers fire by forming crust

Notes: S-1-6

Halon: (halogenated hydrocarbons) chemically reacts with flame to interrupt chain reaction. B:C rated because it is a chemical compound that contains carbon plus one or more elements from the halogen series (fluorine, chlorine, bromine, iodine and astatine)

Notes: IFSTA Unit 5 S #4

• Halon 1211 (parts) 1301 called BROMOCHLORODIFLUROMETHANE 1301

Notes: Interrupts the chain reaction of the combustion process.

1 Carbone 1

2 Fluorine 3

1 Chlorine 0

1 Bromine 1

• Numbers = amount of each agent

• Halon 1211 used in portable extinguishers is stored as a liquified compressed gas; nitrogen is added to increase discharge pressure and reach of stream

• Halon 1301 used in total flooding systems: B:C rated - called BROMOTRIFLUOROMETHANE found in information processing rooms, computers, and shipboard compartments

Notes: Except for onboard, aircraft fire support systems.

• Both should be considered toxic and heavier than air

• Halon will be phased out by the year 2000 due to its ecological effects on the ozone layer

• It has a low Class A rating in extinguishers greater than 9 lbs.

• First halon was Halon 104 (carbon tetrachloride)