1. Chapter 6 Portable Fire Extinguishers

2. Fire Extinguishment Methods Smothering Cooling Chain breaking Saponification

3. Fire Classifications Class A fires — Involve ordinary combustibles –Easily extinguished with water Class B fires — Involve flammable/combustible liquids, gases, greases –Special fire hazards; should not be extinguished until fuel gas shut off –fires get larger as fuel volume increases –Extinguishing agents: carbon dioxide, dry chemical, Class B foam Class C fires — Involve Class A or B fires created by electrical energy –Do not use water until electrical energy eliminated –Turn off or disconnect electrical power - it becomes a class A fire Class D fires — Involve combustible metals, alloys –Water can make combustion worse –Class D, dry powder extinguishers work best Class K fires — Involve combustible cooking oils –Animal and vegetable fats that burn at extremely high temperatures

4. Stored-Pressure Water Extinguishers  Air-pressurized water extinguishers or pressurized water extinguishers  Useful for all types of small Class A fires  Often used for extinguishing hot spots  Operation  Water stored in tank with air  Gauge shows pressurization  Pressure forces water up tube, out hose  Class A foam concentrate sometimes added

5. Wet Chemical Stored- Pressure Extinguishers  Contain special potassium-based low- pH agent to cool/suppress fires in unsaturated cooking oils  Specifically designed to control/extinguish Class K fires in deep fryers  Saponification

6. Aqueous Film Forming Foam (AFFF) Extinguishers Suitable for Class A, Class B fires Fires/vapors from small liquid fuel spills Different from stored-pressure water extinguishers –Tank contains specified amount of AFFF concentrate mixed with water –Air-aspirating nozzle aerates solution Water/AFFF solution expelled by compressed air or nitrogen To prevent disturbance of foam blanket, do not apply directly onto fuel; allow to rain onto surface/deflect off object

7. AFFF When AFFF/water mixed, finished foam floats on fuels lighter than water Vapor seal created by film of water extinguishes flame, prevents reignition Foam has good wetting, penetrating properties on Class A fuels; ineffective on polar solvents Not suitable for fires in Class C, D fuels Most effective on static pools of flammable liquids

8. Clean Agent Extinguishers  Designed as replacement for Halon 1211, use “clean agents” that discharge as rapidly evaporating liquids that leaves no residue  Cool/smother fires in Class A, B fuels  Nonconductive so can be used on Class C  Approved by U.S. EPA

9. Carbon Dioxide (CO 2 ) Extinguishers  Found as both handheld/wheeled units  Most effective in Class B, C fires  Have limited reach; gas can be dispersed by wind  Carbon dioxide stored under its own pressure as liquefied gas ready for release at any time

10. Dry Chemical Extinguishers  For Class A-B-C fires and/or Class B-C fires; dry powder used on Class D only  Commonly used today  Two basic types  Regular B:C-rated  Multipurpose and A:B:C-rated  Commonly used dry chemicals  Handheld units  Wheeled units

11. Controlling/Extinguishing Metal Fires Special extinguishing agents, application techniques developed to control/extinguish metal fires No single agent controls fires in all combustible metals Some powdered agents applied with extinguishers, others with shovel Portable extinguishers for Class D come in both handheld, wheeled units Regardless of applicator, powder must be applied in sufficient depth to completely cover burning area to create smothering blanket Operation –If small amount of burning metal on combustible surface, fire should be covered with powder –1 to 2 inch layer spread nearby, burning metal shoveled onto layer –After extinguishment, leave material undisturbed until cooled Burning Magnesium

12. Portable Extinguisher Rating System  Portable extinguishers classified according to types of fire they extinguish  Class A, B also rated according to performance capability  System based on tests by UL, ULC  A: Cubic feet  B: Square feet

13. Classifications  Class A — From 1-A through 40-A  Class B — From 1-B through 640-B  Class C — Conductivity only  Class D — Specific to material  Class K — Recognized by UL, ULC since 1996

14. Multiple Markings  Extinguishers for more than one class of fire identified by combinations of A, B, and/or C or symbols for each class  Most common are A-B-C, A-B, B-C  All must be labeled appropriately  Unlisted units should not be used  Ratings for each class are independent

15. Identification — Two Ways Geometric shapes of specific colors with class letter shown within shape NFPA 10 recommended: Uses pictographs to make selection easier; shows types of fires on which extinguishers should not be used

16. Extinguisher Selection Factors  Classification of burning fuel  Rating of extinguisher  Hazards to be protected  Size/intensity of fire  Atmospheric conditions  Availability of trained personnel  Ease of handling extinguisher  Life hazard/operational concerns

17. Extinguisher Selection Considerations  Select those that minimize risk to life/ property and are effective in extinguishing the fire type  Dry chemical extinguishers should not be selected for use in areas where highly sensitive computer equipment is located

18. Extinguisher Check  Immediately before use  External condition  Hose/nozzle  Weight  Pressure gauge  After selecting size/type for situation, approach fire from windward side

19. PASS Method

20. Fire Extinguisher Operation Be sure agent reaches fire Apply agent from point where stream reaches but does not disturb fuel After fire knocked down, move closer to achieve final extinguishment If extinguishment not achieved after entire extinguisher discharged –You screwed up! If fire is in solid fuel reduced to smoldering phase, may be overhauled using appropriate tool If fire in liquid fuel, it may be necessary to apply foam through hoseline or simultaneously attack with more than one extinguisher If more than one extinguisher used simultaneously, work in unison

21. Fire Extinguisher Inspections  NFPA 10 and most fire codes require portable extinguishers inspected once a year  Verify that extinguishers  Are in designated locations  Not tampered with or activated  No obvious damage/other condition  Servicing is the responsibility of property owner/building occupant  Firefighters should include inspections in building inspection program  Three factors determine value  Serviceability  Accessibility  Simplicity of operation  NFPA 10 describes procedures for hydrostatic testing of cylinders

22. Parts of Fire Extinguisher Inspections  Ensure extinguisher in proper location/accessible  Inspect discharge nozzle  Inspect extinguisher shell  Check for legible operating instructions on nameplate  Check locking pin, tamper seal  Determine whether full of agent, fully pressurized  Check for date of previous inspection  Examine condition of hose/fittings  If any items deficient, remove from service

23. Damaged Fire Extinguishers  Can fail at any time; could result in serious injury Exploding Fire Extinguisher Exploding Fire Extinguisher Exploding Fire Extinguisher  Leaking, corroded, otherwise damaged shells/cylinders should be discarded or returned to manufacturer for repair  Only slight damage/corrosion and uncertain whether safe — Should be hydrostatically tested  If allowed by SOP, leaking hoses, gaskets, nozzles, and loose labels can be replaced by firefighters

24. Obsolete Portable Fire Extinguishers  In 1969  American manufacturers stopped making inverting-type extinguishers  Manufacturing of extinguishers made of copper or brass with cylinders soft soldered or riveted together discontinued  Extinguishers using carbon tetrachloride and chlorobromomethane prohibited in workplace  If obsolete extinguishers are discovered and occupant requests, firefighters should follow SOP to dispose of them

25. Halon Fire Extinguishers  Included in Montreal Protocol  U.S. stopped producing halogens at end of 1993  Units may still be in service

26. On Your Face!!!