Types of Extinguishers
Q. State different types of extinguishers. Which one is effective ?
The following types of extinguishers are portable, and in smaller sizes, can be operated with ease by one person. These extinguishers are primarily intended to one against fires in their initial stage, at the seat of the fire.
- Dry Powder Extinguishers : It contains an inert powder such as chalk china clay, add to a small quantity of bicarbonate of soda. To prevent caking, when the powder contact the fire, the substance is mixed with a little fine sand. This powder can be usefully used against most classes of small fires, so long as it can be applied in a quantity sufficient to exclude the from the burning material. As already stated, it can be used where “live” wires exist, with care in application
- Foam Extinguisher : This may contain aluminium sulphate -acid solution, and alkali-bicarbonate soda-water solution mixed with a foaming ingredient. This entire solution creates a foam eight to ten times the initial volume of the solution, and a two litres of size produces 16 to 20 litres of foam. The foam is about 90 percent air : but as the remainder is water, this extinguisher is not suitable for use against electric and incendiary bomb fires, it is however suitable for use again oil spirit, fats celluloid and similar fires .
- Carbon Dioxide Gas Extinguisher : It contains CO2, in liquid form and this, when allowed to expand on release,quickly returns to its normal gaseous state. It forms a some what snow like cloud which is cold, dry, non corrosive, non residue and non-poisonous. It is not likely to affect persons unless inhaled in high concentration, but as it Occupies air space, it may result in asphyxiation under certain conditions. Because of the gasification process and the heavyness of gas burning at high temperature continue to burn in the presence of CO2, gas.
- Water Extinguisher : The appliance is filled with water, the liquid is expelled by compressed be or carbon dioxide,after plunger similar released into the water filled container. Because of its content, this extinguisher is not suitable for use against electric incendiary bomb, oil and similar fires.
- Soda Acid Extinguisher : The appliance is filled with a solution of water and bicarbonate of soda. When a plunger or similar device is actuated, an internal container of sulphuric acid is broken, and, this acid mixes with the aforementioned solution. This results in the ejection of a CO2 gas charged liquid, extinguisher is not suitable for electric, incendiary bomb, oil, spirit, fats and similar fires.
The first 1, 2, 3, 4 and 5 types are suitable for extinguishing fires caused by electric faults when parts are electrically alive. The last two i.e. 6 and 7 are not suitable for live electrical parts. Port can be used when electric parts are not alived but dead.
