Extinguisher Info

Fire is the rapid oxidation of a substance, often with the evolution of heat and light in varying degrees of intensities.

Misconception:

Fire burns the actual chair, piece of wood or fuel. It is, actually, the gasses given off by an object that burns. Heat causes objects to give off these flammable gasses. When the gasses reach their ignition temperature you see the light given off during the oxidation process we know as fire. The fire itself, generates more heat to the object, thus an endless cycle begins, until all of the gasses have been exhausted from the object, leaving carbon particles or solid ash (unburned carbon).

When looking at the candle (below), it appears the wick is burning but it really is not.

The concentration of gasses around the wick are too high to allow ignition and there is insufficient oxygen to support combustion. As the gasses spread away from the wick they ignite due to the already present heat being generated by the fire.

The Fire Tetrahedron (shown below) is very similar to the familiar Fire Triangle, the difference is the Fire Triangle did not represent a previously unrecognized critical component:

Chemical Chain Reaction.

​​​​​​​The Fire Tetrahedron represents all the known components of fire:

Extinguishing a fire is based upon removing or separating any one of these components.

The most common component to be removed is heat, most easily eliminated by using water which absorbs heat extremely well. Without the objects being exposed to heat there can be no flammable gasses given off to burn.
​​​​​​​
The third component, oxygen, is usually the hardest to remove. Oxygen removal can be accomplished with a Carbon Dioxide extinguisher.

Finally, the chemical chain reaction can be considered the reaction of the reducing agent (fuel) with the oxidizing agent (oxygen). An example, of an extinguishing method by disrupting the chemical chain reaction, is the Halogenated fire extinguishers.

BOILING POINT - The temperature at which a liquid changes to a gas (vapor) at normal atmospheric pressure.

BACKDRAFT - The beginning of a backdraft occurs from a fire in a structure being deprived of necessary oxygen. The fire smolders giving off unburned carbon particles and other flammable products. Then, suddenly the smoldering fire is given a sudden influx of oxygen causing combustion to restart possibly at devastating speeds consistent with an explosion.

FIRE POINT - The temperature at which a liquid fuel will produce sufficient vapors to support continuous combustion once ignited.

ABC DRY CHEMICAL: MONOAMMONIUM PHOSPHATE

STRENGTHS: Works on all types of fires, except metal fires. Adheres to hot surfaces, helping to prevent re-flash. Chemical of choice for most applications.

DRAWBACKS: Acidic, therefore, corrosive. Can cause extensive damage to sensitive electronic equipment. Chemical dust is very fine and clean-up is time consuming.

BC DRY CHEMICAL: SODIUM BICARBONATE

STRENGTHS: Non-corrosive. For use on flammable liquid and electrical fires. Not to be used in restaurant or commercial kitchens where vegetable oils are used as cooking media!

DRAWBACKS: Will not work on Class A fires. Does not adhere to hot surfaces allowing re-flash in some situations. Chemical dust is very fine and clean-up is time consuming.

CLASS D POWDER

Involve extremely high temperatures and highly reactive fuels. For example, burning magnesium metal breaks water down to hydrogen gas and causes an explosion; breaks halon down to toxic phosgene and fluorophosgene and may cause a rapid phase transition explosion; and continues to burn even when completely smothered by nitrogen gas or carbon dioxide (in the latter case, also producing toxic carbon monoxide). Consequently, there is no one type of extinguisher agent that is approved for all class D fires; rather, there are several common types and a few rarer ones, and each must be compatibility approved for the particular hazard being guarded. Additionally, there are important differences in the way each one is operated, so the operators must receive special training. Some example class D chemistries include:

METL-X, finely powdered sodium chloride (table salt) propelled by Carbon Dioxide or Argon. After a crust at least 50 mm (2 inches) thick has formed over the burning metal, it is picked up with a long handled shovel and placed in a bucket of salt or very dry sand, and additional agent poured on top. Suitable for sodium, potassium, magnesium, titanium, aluminum, and most other reactive bulk metal fires, but not lithium or finely powdered metals.​​​​​​​

Finely powdered graphite, applied with a long handled scoop, is preferred for fires in fine powders of reactive metals, where the blast of pressure from an extinguisher may stir up the powder and cause a dust explosion. Graphite both smothers the fire and conducts away heat.

Finely powdered copper propelled by compressed argon is the currently preferred method for lithium fires. It smothers the fire, dilutes the fuel, and conducts away heat. It is capable of clinging to dripping molten lithium on vertical surfaces. Graphite can also be used on lithium fires but only on a level surface.

Other materials sometimes used include; powdered sodium carbonate, powdered dolomite and argon gas.
Very dry sand may be used to smother a metal fire if nothing better is available. It should be applied with a long-handled shovel to avoid the operator receiving flash burns, then the molten mass transferred to a bucket of dry sand. Note that even the smallest trace of moisture may result in a steam explosion, spattering burning molten metal around. For this reason salt is sometimes preferred, since it is more obvious if it becomes damp.

Finely powdered graphite, applied with a long handled scoop, is preferred for fires in fine powders of reactive metals, where the blast of pressure from an extinguisher may stir up the powder and cause a dust explosion. Graphite both smothers the fire and conducts away heat.

Finely powdered copper propelled by compressed argon is the currently preferred method for lithium fires. It smothers the fire, dilutes the fuel, and conducts away heat. It is capable of clinging to dripping molten lithium on vertical surfaces. Graphite can also be used on lithium fires but only on a level surface.

Other materials sometimes used include; powdered sodium carbonate, powdered dolomite and argon gas.
Very dry sand may be used to smother a metal fire if nothing better is available. It should be applied with a long-handled shovel to avoid the operator receiving flash burns, then the molten mass transferred to a bucket of dry sand. Note that even the smallest trace of moisture may result in a steam explosion, spattering burning molten metal around. For this reason salt is sometimes preferred, since it is more obvious if it becomes damp.

CLASS K: WET CHEMICAL

Only Class K extinguishing products or UL300 listed range hood suppression systems will put out fires involving vegetable oil frying mediums in deep fat fryers!

Until recently, most commercial deep fat fryers and the range hood suppression systems and portable fire extinguishers in commercial kitchens were designed for use with animal-fat based oils and grease. Due to a number of factors, the cooking industry has switched to use of vegetable-based oils and greases. These vegetable-based frying mediums cook at a higher temperature than the equivalent animal-fat based products. Once a fire starts in a deep fat fryer using this new frying medium it cannot be extinguished by traditional range hoods or portable extinguishers using Class B extinguishing agents

Restaurant fires throughout the country have resulted in code changes to address this problem. Many businesses have already upgraded their cooking fire protection equipment by converting to UL300 listed range hoods and portable Class K extinguishers.

CO2: CARBON DIOXIDE

STRENGTHS: Clean agent that leaves no residue or clean-up problems.
​​​​​​​
DRAWBACKS: Of all fire extinguishing agents CO2 is the least effective. CO2 extinguishers are very heavy and awkward to use for the inexperienced user. The agent is very cold (-108°F) and can create thermal shock to sensitive electronic equipment. Will not work on Class A fires. Because the agent is a vapor re-flash can occur.

STRENGTHS: Works very well on Class A fires. Clean-up is fairly easy.
​​​​​​​
DRAWBACKS: Will not work on Class B & C fires. If used on flammable liquid fires water can cause the fire to spread, sometimes violently. If used on energized electrical fires water poses a serious shock hazard.

STRENGTHS: Clean agent that works exceptionally well on sensitive electronic equipment. Leaves no mess or residue. Will not harm electronic equipment.
​​​​​​​
DRAWBACKS: Has been determined to be an agent that contributes to the ozone depletion. (Manufacturing was stopped in 1996 in conformance with the Montreal Protocol) Halon can produce toxic by-products when the agent comes in contact with fire. Has only limited effectiveness on Class A fires.

STRENGTHS: Clean agent that works exceptionally well on sensitive electronic equipment. Leaves no mess or residue. Will not harm electronic equipment.
​​​​​​​
DRAWBACKS: These materials are claimed to have all the advantageous properties of HALON 1211, but lower toxicity, and zero ozone depletion potential. They require about 50% greater concentration for equivalent fire quenching.

Pull > the pin at the top of the extinguisher. Twist or pull the pull pin to break the plastic seal that holds the pull pin.
Aim > at the base of the fire not the flames. This is important – in order to put out the fire, you must extinguish the fuel.
Squeeze > the lever completely to release the agent in the extinguisher.
Sweep > from side to side using a sweeping motion, move the fire extinguisher back and forth until the fire is completely out. Operate the extinguisher from a safe distance, at least 8 feet away, and then move towards the fire once it starts to diminish.

Note: Be sure to read the instructions on your fire extinguisher – different fire extinguishers recommend operating from different distances.

P > A > S > S