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Since the historical times fire has been very vital and is utilized for cooking raw food, warming houses and for providing light for seeing at night. In the earlier times fire was made by rubbing a piece of thin wood against a slab of wood till smoke appeared and eventually fire. Substances for example hydrocarbons can be burned thus generating heat by combustion phenomena. It is believed that a substance that burns contains another substance within it known as a phlogiston (Baptista van Helmont 1630).
Fire and combustion are very useful to humans but if not careful fire can cause disastrous conditions which lead to loss of property or life. Some of these substances are very flammable and therefore caution should be observed when working with them for example petroleum products for instance petrol, chemicals in deodorants pesticides are also very flammable. Caution was practiced in the earlier times by constructing chimneys which were used to remove possible harmful gases emitted when burning substances in houses or when cooking since carbon monoxide could be released if air was insufficient for burning especially coal burning.
Heating from combustion can be utilized in many household and industrial types of equipment for example in refrigerators, minerals reduction and other energy utilizing machines and weapons. Combustion and Fire Combustion mostly involves chemical reactions between a fuel and a compound capable of undergoing oxidation releasing light and heat. During combustion the substances burn in air leading to either compete combustion (sufficient oxygen) forming carbon dioxide and water or incomplete combustion (insufficient oxygen) forming carbon monoxide and water (Borghi, 1998).
Applications of combustion and water are enormous and include uses in moving rockets to the space releasing a lot of energy, for warming houses and for providing light especially at night. Combustion can be divided into several categories depending on the rate of combustion and the temperatures obtained. Rapid combustion involves prompt burning of the substance in air releasing a lot of heat. Rapid combustion is mostly applied to machines like the rockets that need fast production of energy to propel them at high speed towards space and maybe weapons for instance ballistic missiles.
Pressure maybe applied at times thus able to burn substances in other combustible compounds apart from oxygen. Other types of combustion can take place in plants and animas for instance slow combustion and low temperatures for example cellular respiration. Complete combustion involves burning of substances in presence of air and the products produced depend on the substance being burned for instance burning of carbon will yield carbon dioxide and water while nitrogen will yield nitrogen dioxide and water.
Incomplete combustion involves burning of substances in insufficient air yielding carbon monoxide instead of carbon dioxide. Compounds that do not burn effectively in presence of air can have catalyst added to burn faster in air. Sometimes flammable substances can be mixed, complexed and stored in structures thereby having a lot of pressure. When burned these substances release a lot of heat and energy in a short time. This is the technology behind propulsion of rockets and manufacture of weapons such as explosives. In this there is oscillation and is used to burn substances at a considerably thin flame at a steady speed.
Natural gases can be mixed with inert gases with the aim of controlling emission of harmful gases for example carbon dioxide. Combustion substances should be used with a lot of caution and safely because they can cause lot damage to both humans and the environment if uncontrolled. Control can be by using relatively safe gases that are not harmful and do not emit gases harmful to humans and the environment. Controls is by burning these gases at stable combustion flame and maintain a constant concentration of the gases involved for instance when using biogas the concentration of methane should be maintained at around 54%.
These gases should also be burned using standard burners and they should emit only a small percentage of gases like carbon dioxide and other harmful hydrocarbons. On the other hand uncontrolled combustion can occur especially when burning industrial and house hold wastes. This leads to production of hydrocarbons which can adversely affect humans and the environment. Combustion of substances can be done in enclosed environments where regulation of the air entering is vital to avoid conditions in which fire can spread thus uncontrollable.
In enclosed places for example houses the burned air goes up towards the ceiling where the air can be released to the outside by use of ventilation holes at the top houses. These holes are constructed with the aim of removing warm air which tends to rise. Doors can also be used as both inlet and outlet of air. In cases of fire houses with relatively high ceilings and small floor area will have intense heat near the source of fire and relatively cold because by then there will be a cooling effect by air from the outside. Fire appliances and combustive substances can lead to cases of uncontrolled fires due to improper use and poor maintenance.
Fire hazards can be caused by electrical appliances which are faulty or which are wet and also overloading sockets by using many appliances than the sockets can hold. These conditions can lead to fire for example if wet the water can lead to shot circuits, or overloaded sockets which can blow up. Gas cylinders may leak gas or gas pipes and can be easily ignited if fire is started near the leakage areas. Petroleum products should be used with a lot caution because they can easily cause explosions. Other substances that should be used carefully are for example paint and lighter liquids which should be kept away from heat sources.
When using most of these appliances manufactures manual of instructions should be critically observed. In cases of fire it is important to curb the fire fast and promptly before it spreads very much. As a result many types of equipment for example fire extinguishers have been adopted to fight house hold fires. Fire extinguishers either contain pressurized carbon dioxide or a mixture of water and soap (foam) Carbon dioxide removes oxygen from the flame thereby stopping the fire. In the other extinguisher the water is used to eliminate heat from the fire while the foam block oxygen thus no more spreading of the fire.
Some of the extinguishers can be refilled of recharged while others cannot and therefore replaced with new ones if used. Conclusion Fire is one of the most utilized heat sources since the ancient times. With continued developments the combustion of substances for production of energy and propulsion of some machinery for instance rockets was adopted. However, these substances should be handled with a lot care because of their capability to cause uncontrolled fire leading to loss of property and even life. Instructions on how to use heat utilizing appliances should be followed carefully to avoid cases of fire.
Preparation is also recommended by ensuring that recharged fire extinguishers are kept standby in institutions and major offices just incase accidental fires arise. Emergency doors should also be kept open at all times to allow people to escape fast in case of fire. Flammable chemicals and products should be kept far away from fire and heat sources. Proper maintenance of electrical and other appliances that are used for producing heat should be observed and followed as per the instructions. References Kuo, K. K, 2005. Principles of Combustion. 22 Ed. New York. John Wiley and Sons.