let’s start new topic Classification of Fire Extinguisher
The basic types of fire are classes are A,b,c and d as defined in the following subsections – Classification of Fire Extinguisher
- The common household fire in which the fuel is solid hydrocarbon such as wood, cloths, paper, rubber, cardboard, and many plastics where the fire may even be deep-seated and not only on the surface, is termed as A fire. Flame being on the surface at a higher temperature is put out by blowing while the glowing fire, which is a typical example of deep-seated fire could not be put out by mere blowing. It requires extinguishments, which not only lowers the temperature but cuts of the oxygen supply also.
- Above mentioned, combustible solid have a tendency to form deep-seated fires like in a coal furnace, rope, wood, or a cotton bale. The deep-seated fires have a tendency to travel without any explicit indication. Such fire is very common in godowns containing cotton bales, libraries, wooden houses, forests, and basements stores.
Blanketing and beating are good means of tackling early class A fires, water though the best extinguisher is likely to leave a dirty residue and wet other objects, which is undesirable in the library or godowns fires- Classification of fire Extinguisher.
- Class-B fires are caused by liquefied fumes of hydrocarbon products such as petrol, kerosene, oils, grease, coal tars, oil base paint, etc. There are two major aspects of class B fires. One is the low vapor pressure, hence a lower fire point of the fuel and the other is its immiscibility with water and hence the inability to dilute the fuel. The water being heavier settles down when poured on petroleum products. So we infer that class B fire as dreadful as they are generally fires in liquids, which are very prone to spread if spilled and are the best extinguished by cutting off oxygen with a chemical or mechanical blanketing- Classification of Fire Extinguisher.
- To appreciate how such a fire can aggravate by using water as an extinguisher, the same experiment can be repeated by putting the metal crucible in the pan filling it with petrol out of crucible and fire would spread inside the pan (extinguish the fire with cover.
- The class C fire is the fire, which is initiated due to the heating effect of electric current. A typical example of this is the insulation burns due to electric short circuit. British standard (B.S) lists class C fires involving gases.
The continuous heat is provided by electric current and even if the fire is put out temporarily by beating it would creep again as the source of heat has not been cut off. This type of fire generally occurs due to overloading a current line, which continued to provide a high-temperature source beyond fire point-classification of fire fighting
- These fires occur in the insulation materials, which can be any non-conducting insulation in class A or B category. These fires may also create fumes, which might not be only toxic but fatal also-classification of fire nfpa.
- The main problem with these fires is that is a continuous latent heat supply from the electric current and unless the current is cut off, all the efforts to extinguish a flame might be useless or hazardous. The only extinguisher to be used in their fires is Dry Chemical Powder (DCP) till the supply line cut off (to avoid any electrocution hazard).
- In class D fire metallic fires of different metals included combustible metals such as magnesium, titanium, sodium, lithium, potassium, and zirconium and powder aluminum. These fires are highly intricate for the following reasons and shall be tackled only by the experts in the field:
- These are high temperature; this ordinary extinguisher may not work on them. High temperatures, intense light, and fumes can be hazardous or even fatal. These are metallic fires and can be explosive; thus to be dealt with specific chemical .extinguishers to neutralize the effect fuel.
- Special fusing powders have to be employed to put out class D fires as most of the general extinguishers are ineffective and even dangerous. Smothering the fire to cut off oxygen is the only technique a common man should use before the professional help arrives- classify Fire.
- The colored sparks in Diwali crackers are seen due to burning iron and orange due to copper. Similarly, by putting a small amount of common salt on to the flame, it burns with bright orange flame characteristics of sodium.