Operating Portable Fire Extinguishers
Fire fighting agents are usually expelled from portable extinguishers in one of the following ways:
- Cartridge Type
An extinguisher from which the contents are expelled by pressure released from a gas Cartridge.
- Stored Pressure Type
An extinguisher from which the contents are expelled by the release of pressure stored within the body.
Extinguishers are easy to operate. With most extinguishers it is usually simply a matter of taking the unit from its mounting, removing the safety pin, aiming the nozzle at the base of the fire and squeezing the lever. If in doubt, check the instructions on the front of the extinguishers.
General Advice
Tackling a fire with the wrong type of extinguisher can be ineffective and even dangerous.
It is important to analyse all fire risks so that the most effective fire fighting appliance can be selected and sited in the correct position to deal with each hazard.
Nearly all fires develop slowly at first, and can be extinguished before serious damage is done if suitable firefighting equipment is at hand. Even a fire which flares up instantly can be checked at the point of outbreak by prompt action. Portable fire extinguishers provide the means for a rapid response, but if an appliance has to be brought some distance to the fire the smallest outbreak can extend beyond its capability.
It is also important to remember that the discharge of a portable appliance is limited as its weight must be kept low enough for quick and easy handling. The correct sitting of portable fire extinguishers, and knowledge of their uses, is fundamental to tackling fires efficiently.
Extinguishers should be conspicuous and readily accessible, and at least one unit should be near the rooms exit. Where possible, portable fire extinguishers should be mounted on brackets or suspended at a convenient height for quick handling (approximately one metre from the floor to the carrying handle).
Extinguishers should be marked with easily understood written and pictorial instructions in compliance with SABS regulations, as not all types are operated in the same way, ideally all the units in a building should be activated by the same method.
Extinguishers must also be properly serviced and maintained at least annually in accordance with SABS 1475 Part 1-1989.
When selecting and positioning portable fire extinguishers, the advice of a reputable manufacturer, preferably with SABS approval, is essential.
| Type | Colour | Extinguishing Action | Class of Fire | Method of Use |
| Water | Expelled in a limited quantity under pressure forming a jet, approximately six metres in length, which cools the burning material by absorbing heat. The discharge of water is controllable to maximise performance. | Class ADanger: Do not use on live electrical equipment. | Aim the jet at the base of the fire moving it from side to side. Follow a vertically spreading fire using the same procedure. Damp down the surrounding area to stop the fire spreading further. | |
| Foam-AFFF(Aqueous film forming foam) | Produced by forcing a solution of foam concentrate and water under pressure through foam making branch pipe. This entrains air, aspirating the solution and converting it into foam which blankets the surface of the burning material/liquid excluding oxygen. | Class A & BDanger: Do not use on live electrical equipment. | If the liquid has been ignited by gas or electricity, as in the case of a fat fryer, turn off the source of heat if possible. Do not plunge the jet into the burning liquid. Aim it at the inside surface of the container, or at a surface close above, so that the foam flows gently over the top of the liquid, until the fire is extinguished. Foam must be applied gently to control a fire quickly. | |
| Carbon Dioxide (Co2) | Expelled under great pressure in a powerful concentration reducing oxygen in the air. | Class B & CSuitable for live electrical equipment. Non-toxic and clean in use. Harmless to most delicate mechanisms and machinery. | Aim the jet at the base of the flames and move continuously from side to side, across the area of the fire.Warning: Co2 extinguishers can cause freeze burns if the nozzle or base comes into contact with skin, due to their low operating temperature. Co2 has little cooling effect, so reignition can occur. Take extra care and reapply C02 if the fire reignites.Danger: Co2 can asphyxiate in a confined space. After extinguishing the fire, leave the room closing the door and do not re-enter until it is safe to do so. Ventilate before re-entry. | |
| Halon (BCF) – Bromochloro-difluoromethane | Knocks down flames by chemically inhibiting combustion. | Classes B & C and small surface burning Class A Fires.Suitable for live electrical equipment. Considered to be non-corrosive, has a low toxicity level and is clean in use. Harmless to delicate fabrics and machinery. Have long-life storage properties. | If the fire is caused by flammable gas, shut off the source of fuel if possible. Do not aim the jet into the base of burning liquid as this can spread the fire. Aim the jet at the flames and move continuously from side to side across the area of the fire.Warning: Halon (BCF) has little cooling effect, so reignition can occur. Take extra care and reapply Halon (BCF) if the fire reignites.Danger: Fumes can be harmful if Halon (BCF) is used on hot metal in confined spaces. After extinguishing the fire, leave the room closing the door and do not re-enter until it is safe to do so. Ventilate before re-entry. | |
| Dry Powder – All Purpose Powder (ABC) | Knocks down flames by chemically inhibiting combustion. | Class A, B & CSuitable for live electrical equipment and “mixed risk areas”. Causes widespread dust when used inside buildings. | If the fire is caused by flammable gas, shut off the supply of fuel if possible. Aim the jet at the base of the flames. Drive the flames towards the far edge with a rapid sweeping motion until extinguished.Warning: Dry powder does not readily penetrate the inside of electrical equipment, and although it has some cooling effect, is not as efficient as other agents, so reignition can occur. Take extra care and reapply dry powder if the fire reignites. | |
| Dry Powder – Standard (BC) | Knocks down flames by chemically inhibiting combustion. | Classes B & CSuitable for live electrical equipment.Warning: Will not deal with Class A fires. Generally used in areas of special risk, for example, in the petrochemical industry. | Follow the directions for all purposes dry powder extinguishers above | |
| Hose Reel | Cools the burning material by absorbing heat. | Class ADanger: Do not use on live electrical equipment, or burning liquid. | Aim the jet at the base of the fire moving it from side to side. Follow a vertically spreading fire using the same procedure. Damp down the surrounding area to stop the fire spreading further. | |
| Fire Blanket – Light Duty | Excludes oxygen. | Suitable for burning clothing and small burning liquid fires. | In the case of a fat fryer turn off the heat if possible. Place the blanket carefully over the fire, shielding the face and hands. | |
| Fire Blanket – Heavy Duty | Excludes oxygen. | Suitable for industrial use. Resistant to penetration by molten materials. | Place the blanket carefully over the fire, shielding the face and hands. |
