Introduction.

Before you need to use a fire extinguisher read the label to make sure you fully understand the type of fire extinguisher it is. Also the type of fires it is appropriate and safe to use on. Water and foam based extinguishers should not be used on fires involving an electrical hazard, unless the power supply has been isolated, this is because the operator may receive a fatal electric shock. Before you can operate most extinguishers you are required to remove the safety pin, the only exceptions are hose reels, fire blankets and fire buckets. With hose reels you may have open a water valve before it can be used. Make sure before you tackle a fire you are between the fire and exit or escape route.

Index

• Water
• Water Spray
• Dry Powder (Multi-Purpose)
• Dry Powder (Standard)
• Dry Powder (Special Powders)
• Foam (AFFF)
• Foam Standard)
• Carbon di-Oxide
• Wet Chemical
• Fire Blanket
• Hose Reel
• Fire Bucket
• Extinguishing Agents

Water Extinguisher

	Signal Red
	Best For
	Fires involving organic solid materials such as wood, cloth, paper, plastics, Coal etc. Size for size, it offers up to 300% more fire fighting capability than traditional jet type water fire extinguishers. Available in 3 and 6 litres.
	Danger
	Do not use on burning fat or oil or on electrical appliances
	How to Use
	Point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.
	How it Works
	Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel. Instead of a jet nozzel a spray nozzel is used, with a higher pressure, which creates a fine spray . This allows for a given quantity of water to have a considerable increase in the surface area presented to the fire. This makes extinguishing more efficient by more rapid extraction of heat, formation of steam etc. They can also contain surfactants which help the water penetrate deep into the burning material which increase the effectiveness of the extinguisher.
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Dry Powder Extinguisher. (Multi-Purpose)

Dry Powder Extinguisher.(Standard)

	Blue
	Best For
	Liquids such as grease, fats, oil, paint, petrol etc but not on domestic chip or fat pan fires.
	Danger
	Safe on live electrical equipment, although does not penetrate the spaces in equipment easily and the fire may re-ignite. This type of extinguisher does not cool the fire very well and care should be taken that the fire does not re-ignite. Do not use on domestic chip or fat pan fires.
	How to Use
	Point the jet or discharge horn at the base of the flames and, with a rapid sweeping motion, drive the fire towards the far edge until all the flames are out. If the extinguisher has a shut-off control wait until the air clears and if you can still see the flames, attack the fire again.
	How it Works
	Similarly to almost all extinguishing agents the powders acts as a thermal ballast making the flames too cool for the chemical reactions to continue. Some powders also provide a minor chemical inhibition, although this effect is relatively weak. These powders thus provide rapid knockdown of flame fronts, but may not keep the fire suppressed.
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Dry Powder Extinguisher.(Special Powders)

	Blue
	Best For
	This specialist powder extinguishers are designed to tackle fires involving combustible metals such as lithium, magnesium, sodium or aluminium when in the form of swarf or powder. There are three special powders based on graphite, copper and sodium chloride.
	Danger
	Do not allow water to come in contact with the burning metal and the powder must be gently applied. Sodium Chloride is not recommended for Lithium.
	How to Use
	The lance enables the user to tackle fire at a safe distance and the low velocity applicator to reduce the energy of the jet allowing the powder to gently smother the surface of the burning material thus avoiding scattering of high temperature particles and stimulating the formation of a crust. The method of application is completely different from a standard extinguisher and user training is required. They are not suitable for use on live electrical fires.
	How it Works
	This extinguisher works by forming a crust which insulates the metal to prevent access to other combustible material nearby and smothering the fire to prevent oxygen from the atmosphere reacting with the metal
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Foam Extinguisher. (AFFF)

	Cream (Aqueous film-forming foam) (multi-purpose)
	Best For
	Fires involving solids. Liquids such as grease, fats, oil, paint, petrol,etc but not on domestic chip or fat pan fires. Can be used on class A fires but not recommended.
	Danger
	Do not use on domestic chip or fat pan fires.
	How to Use
	For fires involving solids, point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out. For fire involving liquids, do not aim the jet straight into the liquid. Where the liquid on fire is in a container, point the jet at the inside edge of the container or on a nearby surface above the burning liquid. Allow the foam to build up and flow across the liquid.
	How it Works
	They are mainly water based, with a foaming agent so that the foam can float on top of the burning liquid and break the interaction between the flames and the fuel surface.
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Foam Extinguisher.(Standard)

	Cream
	Best For
	Fires involving solids. Liquids such as grease, fats, oil, paint, petrol,etc but not on domestic chip or fat pan fires. Can be used on class A fires but not recommended. Less effective than AFFF foam
	Danger
	Check manufacturer's instructions for suitability of use on other fires involving liquids. These extinguishers are generally not recommended for home use.
	How to Use
	Do not aim jet straight into the liquid. Where the liquid on fire is in a container, point the jet at the inside edge of the container or on a nearby surface above the burning liquid. Allow the foam to build up and flow across the liquid.
	Howit Works
	These are mainly water based, with a foaming agent so that the foam can float on top of the burning liquid and break the interaction between the flames and the fuel surface.
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Carbon Di-Oxide Extinguisher.

	BLACK
	Best For
	Live electrical equipment when it is not possible to isolate the electric supply and flammable liquids such as grease, fats, oil paint, petrol etc. but not on domestic chip or fat pan fires.
	Danger
	Do not use on domestic chip or fat pan fires. This type of extinguisher does not cool the fire very well and you need to watch that the fire does not start up again. Fumes from CO2 extinguishers can be harmful if used in confined spaces: ventilate the area as soon as the fire has been controlled.
	How to Use
	The discharge horn should be directed at the base of the flames and the jet kept moving across the area of the fire.
	How it Works
	Carbon dioxide extinguisher works on classes B and C and works by suffocating the fire. Carbon dioxide will not burn and displaces air.
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Wet Chemical

	Canary Yellow
	Best For
	The specialist wet chemical extinguishers are ideal for Class F fires, involving cooking oils and fats, such as lard, olive oil, sunflower oil, maize oil and butter.
	Danger
	Check manufacturer's instructions for suitability of use. These extinguishers are not recommended for class B fires and home use.
	How to Use
	Apply the wet chemical using the extended applicator in slow circular movements, which give a gentle, yet highly effective application. Apply the fine spray onto the burning fat until the surface of the burning cooking oil changes into a soapy like substance, this then prevents re-ignition. The gentle application helps prevent hot oil splashing onto the user.
	How it Works
	Most class F extinguishers contain a solution of potassium acetate, sometimes with some potassium citrate or potassium bicarbonate. The extinguishers spray the agent out as a fine mist. The mist acts to cool the flame front, while the potassium salts saponify the surface of the burning cooking oil, producing a layer of foam over the surface. This solution thus provides a similar blanketing effect to a foam extinguisher, but with a greater cooling effect. The saponification only works on animal fats and vegetable oils, so class F extinguishers cannot be used for class B fires. The misting also helps to prevent splashing the blazing oil. Tests have established that a 6 litre extinguisher is capable of extinguishing a fire in a 75 litre capacity deep fat fryer. The extinguisher is easy to use producing a gentle but highly effective spray.
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Fire Blanket

	Fire Blanket Fire blankets are made of fire resistant materials. They are particularly useful for smothering flammable liquid fires or for wrapping round a person whose clothing is on fire. Fire blankets conforming to British Standard BS EN 1869 : 1997 are suitable for use in the home BS 7944 : 1999 is suitable for industrial use. These will be marked to show whether they should be thrown away after use or used again after cleaning in accordance with the manufacturers instructions.
	Best For
	Fires involving both solids and liquids. Particularly good for small fires in clothing and for domestic or commercial chip and fat pan fires provided the blanket completely covers the fire.
	Danger
	If the blanket does not completely cover the fire, it will not be able to extinguished the fire.
	How to Use
	Place carefully over the fire. Keep your hands shielded from the fire. Do not waft the fire towards you.
	How it Works
	Smothers the fireand prevent oxygen getting to the fire.
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Hose Reel

	Hose Reel
	Best For
	Fires involving organic solid materials such as wood, cloth, paper, plastics, coal etc.
	Danger
	Do not use on burning fat or oil or on electrical appliances before the electric supply has been isolated.
	How to Use
	Point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.
	How it Works
	Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel
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Fire Buckets

	A simple bucket of water can be used on Class A type of fires either to supplement a water extinguisher or as a first attack if an extinguisher is not immediately available. It also can be filled with dry sand and used as an absorbing agent or to dam a flow of flammable liquid. They do have serious disadvantages as they are often misused, left empty or allowed to be used as a refuse container.
	Best For
	Wood, Cloth, Paper, Plastics, Coal etc.Fires involving solids
	Danger
	Do not use on burning fat or oil or on electrical appliances before the electric supply has been isolated.
	How to Use
	Throw at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.
	How it Works
	Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel
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Extinguishing Agents

Water

Water is the most common for class A fires and is quite effective as one would imagine. Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel. The gaseous effect is minor for these extinguishers, but water fog nozzles used by fire brigades creates water droplets small enough to be able to extinguish flaming gases as well. The smaller the droplets, the greater the effect on flaming gases. With this in mind water spray extinguishers have bee developed, one example is the Hydro spray by Chubb. The Hydro spray Elite was developed in 1997 as a direct response to customer needs. It was felt that the while traditional 9 litre water extinguishers are very effective on class A fires made up of woods, solids or materials, a smaller, lighter version would be much easier for some people to use. Chubb developed the Hydro spray Elite. This 3 litre product is able to achieve the same fire ratings as a 9 litre water extinguisher, in a size that makes it easier for anyone to lift and manoeuvre.The unique nozzle that separates the water particles making it safe (as per the 35kV test) if it is accidentally used on an electrical fire.

In the past water based extinguishers also contain traces of other chemicals to prevent the extinguisher rusting but are now lined with plastic. Some also contain surfactants which help the water penetrate deep into the burning material and cling better to steep surfaces this is know as wet water.

Water may or may not help extinguishing class B fires it depends on whether or not the liquid's molecules are polar molecules. If the liquid that is burning has polar molecules, such as alcohol, there won't be any problem. If the liquid is non polar, such as large hydrocarbons, like petroleum, the water will sink through the oil until it reaches the heat layer and then be immediately converted to steam ejecting the burning contents in a violent eruption, known as a boil over. Alternately as water being heavier than oil it will sink to the bottom and replace the oil until the flaming oil flows over the edge of the container thus spreading the fire; this is known as a slop over. This is why you should never use water on oil fires.

Similarly, water sprayed on an electrical fire will probably cause the operator to receive an electric shock. However, if the power can be reliably disconnected, clean water will actually cause less damage to electrical equipment than will either foam or dry powders. Special spray nozzles, equipped with tiny rotating devices called spiracles will replace the continuous water jet with a succession of droplets, greatly increasing the resistance of the jet. These shall however be used by skilled personnel, since improper handling of the nozzle may restore continuity of the water jet.

Foams

Foams are commonly used on class B fires, and are also effective on class A fires. These are mainly water based, with a foaming agent so that the foam can float on top of the burning liquid and break the interaction between the flames and the fuel surface. Ordinary foams are designed to work on non polar flammable liquids such as petrol, but may break down too quickly in polar liquids such as alcohol or glycol. Facilities which handle large amounts of flammable polar liquids use specialised "alcohol resistant foam" instead. Alcohol foams must be gently poured across the burning liquid. If the fire cannot be approached closely enough to do this, they should be sprayed onto an adjacent solid surface so that they run gently onto the burning liquid. Ordinary foams work better if poured but it is not critical.

Protein foam was used for fire suppression in aviation crashes until the 1960s development of "light water", also known as "Aqueous Film-Forming Foam" (or AFFF). Carbon dioxide (later sodium bicarbonate) extinguishers were used to knock down the flames and foam used to prevent re-ignition of the fuel fumes. "Foaming the runway" can reduce friction and sparks in a crash landing, and protein foam continued to be used for that purpose, although FAA regulations prohibited reliance upon its use for suppression.

Dry Powder

Principally there are two types of dry powder extinguishers in use, they are BC and ABC.

Class BC dry powder is either sodium bicarbonate or potassium bicarbonate, finely powdered and propelled by carbon dioxide or nitrogen. Similarly to almost all extinguishing agents the powder acts as a thermal ballast and makes the flames too cool for the chemical reactions to continue. Some powders also provide a minor chemical inhibition, although this effect is relatively weak. These powders thus provide rapid knockdown of flame fronts, but may not keep the fire suppressed. Consequently, they are often used in conjunction with foam for attacking large class B fires. BC Powder has a slight saponification effect on cooking oils & fats due to its alkalinity and was used for kitchens prior to the invention of Wet Chemical extinguishers. Where an extremely fast knockdown is required potassium bicarbonate (Purple K) extinguishers are used. A particular blend also containing urea (Monnex) decrepitates upon exposure to heat increasing the surface area of the powder particles and providing very rapid knockdown. Sodium bicarbonate powders, unless specially treated, are not compatible with Foams. Purple-K, Monnex and ABC Powders are generally less damaging, and often are used with AFFF & FFFP, but compatibility must be borne in mind where powder and foam are used together and a higher application rate of foam allowed for.

Class ABC Powders are mixtures of ammonium phosphate and ammonium sulphate, ground to selected particle sizes and treated with flow promoting and moisture repellent additives. In addition to the particle surface extinguishing effect, ABC powders have low melting/decomposition points in the order of 150°C to 180°C. When these powders are applied to hot and smouldering surfaces, the particles fuse and swell to form a barrier which excludes oxygen and thereby completes the extinguishing process and prevents re-ignition. They are acidic in nature and are effective on Class A (flammable solids), Class B (flammable liquid/liquefiable solids) and Class C (flammable gas) fires. They are electrically non-conductive; however it is less effective against three dimensional class A fires, or those with a complex or porous structure. Foams or water are better in those cases. Most dry powder extinguishers in service, except aerosols, are ABC Powder. Different blends are available, the more ammonium phosphate, the more effective it is. Powder, specifically ABC powder is not permitted in or near aircraft as it can damage the metal superstructure.

Dry powders can also be used on electrical fires, but provide a significant cleanup and corrosion problem that is likely to make, especially sensitive electronics and electrical equipment unsalvageable.

Although modern powders are non-toxic, the discharge of a powder extinguisher in a confined space can cause a sudden reduction of visibility which may temporarily jeopardize escape, rescue or other emergency action. For this reason water-based extinguishers are to be preferred in hospitals, old people's homes and hotels. Powder extinguishers are prohibited to be used in PSV's and minibuses by UK statute law for the above reason.

When used on class B fires, the powder must extinguish the whole fire area in an uninterrupted application or flashback will occur, unlike foam there is no physical barrier, it's all or nothing. The lack of a securing blanket means there is a re-ignition risk. Also powder has no cooling properties, one of the reasons it is ineffective against class F fires, although it can extinguish the flame, the heat of the fat will cause immediate flashback.

There were available powders designed for fires in flammable metals and three main types in use were, Sodium Chloride for fires involving alkali metals such as sodium and potassium, also zirconium, uranium and powdered aluminium which extinguished metal fire by fusing to form a crust. This excludes oxygen from the surface of the molten metal and a carbonaceous rafting agent prevents the powder from sinking into the surface of molten metal. A copper extinguishing agent specially developed by the U.S. Navy for fighting lithium and lithium alloy fires. The copper compound smothers the fire and provides an excellent heat sink for dissipating heat. Copper powder has been found to be superior to all other known fire extinguishing agents for lithium. Finally Ternary Eutectic Chloride (TEC), developed by UKAEA for uranium fires, which works similarly to Sodium Chloride but it, is extremely toxic.

Wet potassium salts (Wet Chemical)

Most class F extinguishers contain a solution of potassium acetate, sometimes with some potassium citrate or potassium bicarbonate. The extinguishers spray the agent out as a fine mist. The mist acts to cool the flame front, while the potassium salts saponify the surface of the burning cooking oil, producing a layer of foam over the surface. This solution thus provides a similar blanketing effect to a foam extinguisher, but with a greater cooling effect. The saponification only works on animal fats and vegetable oils, so class F extinguishers cannot be used for class B fires. The misting also helps to prevent splashing the blazing oil.

Note: Saponify is a chemistry term which means to become converted into soap by being hydrolyzed into an acid and alcohol as a result of oil or fat being treated with an alkali.

Carbon dioxide

Carbon dioxide extinguisher (CO2) works on classes B and C and works by suffocating the fire. Carbon dioxide will not burn and displaces air. Carbon dioxide can be used on electrical fires because, being a gas, it does not leave residues which might further harm the damaged equipment. Carbon dioxide can also be used on class A fires when it is important to avoid water damage, but in this application the gas concentration must usually be maintained longer than is possible with a hand-held extinguisher. Carbon dioxide has a discharge horn on the end of the hose which slows down the jet of gas and prevents air being entrained. Due to the carbon dioxide being expelled from an extinguisher, the horn becomes extreme cold and should not be touched.

Halons

In the UK and Europe halon are illegal, except for certain specific aircraft and law enforcement uses. This appears to be at least partially in response to the Montreal Protocol and effort by the United Nations Environment Programme (UNEP) to combat release of quantities of harmful chemicals into the atmosphere.

Halon fire extinguishers are still legal in America and are very versatile extinguishers. They will extinguish most types of fire except class D & F and are highly effective even at quite low concentrations (less than 5%). Halon is a poor extinguisher for Class A fires, a nine pound Halon extinguisher only receives a 1-A rating and tends to be easily deflected by the wind. They are the only fire extinguishing agents that are quite suitable for discharge in aircraft as other materials pose a corrosion hazard to the aircraft. The major extinguishing effect is by disturbing the thermal balance of the flame, and to a small extent by inhibiting the chemical reaction of the fire. Halons are chlorofluorocarbons which cause damage to the ozone layer and are being phased out for more environmentally-friendly alternatives.

Halon extinguishers were used widely in vehicles and computer suites. It is mildly toxic in confined spaces, but to a far less extent than its predecessors such as carbon tetrachloride, chlorobromomethane and methyl bromide.

Phosphorous tribromide

Like Halon, phosphorous tribromide interferes with the chemical reaction of the flame, marketed under the brand name PhostrEx. PhostrEx is a liquid which needs a propellant, such as compressed nitrogen and/or helium, to disperse onto a fire. As a fire extinguisher PhostrEx is much more potent than Halon making it particularly appealing for aviation use as a lightweight substitute. Unlike Halon, PhostrEx reacts quickly with atmospheric moisture to break down into phosphorus acid and hydrogen bromide, neither of which harms the earth's ozone layer. High concentrations of PhostrEx can cause skin blistering and eye irritation, but since so little is needed to put out flames this problem is not a significant risk, especially in applications where dispersal is confined within an engine compartment. Any skin or eye contact with PhostrEx should be rinsed with ordinary water as soon as practical. PhostrEx is not especially corrosive to metals, although it can tarnish some. The U.S. EPA and FAA both approved PhostrEx, and the substance will find its first major use in Eclipse Aviation's jet aircraft as an engine fire suppression system.

Fluorocarbons

Recently, DuPont has begun marketing several nearly saturated fluorocarbons under the trademarks FE-13, FE-25, FE-36, FE-227, and FE-241. These materials are claimed to have all the advantageous properties of halon, but lower toxicity, and zero ozone depletion potential. They require about 50% greater concentration for equivalent fire quenching.

Specialised materials for Class D

Class D fires involve extremely high temperatures and highly reactive fuels. For example, burning magnesium metal breaks water down to hydrogen gas and causes explosions. It breaks halon down to toxic phosgene and fluorophosgene and may cause a rapid phase transition explosion. It continues to burn even when completely smothered by nitrogen gas or carbon dioxide, in the latter case 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. 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 class D extinguishing agents include finely granulated sodium chloride, copper and graphite applied by an extinguisher, shaker, scoop or shovel. These extinguishing agents are suitable for sodium, potassium, magnesium, titanium, aluminium, and most other metal fires.

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.

As a very poor last resort dry sand may be used to smother a metal fire if nothing else is available. It should be applied with a long-handled shovel to avoid the operator receiving flash burns. Sand is, however, notorious for collecting moisture and even the smallest trace of moisture may result in a steam explosion, spattering burning molten metal around.

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