Hazardous materials are agents or items that either solely or with the aid of other factors endanger people, living organisms or our environment. The materials exist in the three states of matter, i.e. solid, liquid, and gas (Shafer, 2005). They may include commonly available domestic, industrial and pharmaceutical chemicals. The term broadly includes hazardous waste. Hazardous waste refers to any unused and unwanted material, or the unwanted byproduct of at factory. Examples of hazardous materials includes, welding fume, petrol pesticides, cosmetics and paints.
Fire and combustion plays a key role during power generation. There is research aimed at establishing ways of having efficient combustion that are less dangerous. For instance, there is research on minimizing amount of pollutants that a factory or automobiles emits (Williams et al, 2007).
Industrial hazardous materials include mercury, radiological substances and laboratory chemicals. There are elaborate rules that guide how hazardous materials are handled in factories. These rules directs how the materials are stored and for how long, persons entrusted with receiving and transporting them and the sort of registers to be maintained. Various industries employ qualified and responsible hazardous substances professionals to help in their management (Williams et al, 2007).
Several household commodities are potentially dangerous and should be kept away from fire and from the reach of children. Common products like Air Fresheners may contain lethal chemicals and it is advisable enquire substantially before purchasing. If bleach and ammonia are combined, lethal fumes may be emitted. Therefore, some household commodities should be placed in well ventilated places. Flammable gases and liquids should be stored in a shed outside the house so as to minimize losses in case of an accident (Lawther et al, 1965). Others domestic hazardous substances are farm inputs like pesticides and fertilizers. One should wear protective clothes such as gloves during the application of these inputs to avoid bodily harm.
There are several classifications of hazardous materials. In accordance with the American ecological laws, hazardous materials are classified into two broad classes: listed and characteristic materials. Characteristic hazardous materials are those that demonstrate risky attributes such us: ignitability, corrosion, toxicity and reactivity (Shafer, 2005). Ignitable materials are those that can cause fire in a spontaneous manner if certain preconditions exist or those that ignite at a temperature below 60 °C. Examples comprises of certain solvents and oils. Corrosive materials include strong bases and acids that corrode metal containers, like barrels, drums and tanks, e.g. sulfuric acid. Reactive materials are precarious under ordinary conditions. They cause toxic fumes or explosion when compressed, heated, or placed in water, e.g. lithium (Williams et al, 2007). Toxic materials contain concentrations of some substances exciding the regulatory threshold. They are thus anticipated to cause illness or harm to people, environment or other living organisms.
Listed hazardous materials are those that the American Agency for environmental protection specifically lists as hazardous material. Listed hazardous wastes are of two classes. Firstly there is the procedure waste that results from the general actions, i.e. the F-listed and those resulting from some particular industrial actions, the K-listed. The second class is that of the unstipulated or unused chemicals, i.e. the P-listed and other chemical substances, the U-listed (Shafer, 2005). These substances possess biological, chemical and physical characteristics that can cause health problems such as skin rashes, poisoning, and cancer. They can also lead to physical harm like emission of corrosion, explosion and fire.
Hazardous materials cannot be stored or disposed off through common methods. Depending on its state and the degree of harm, a dangerous material can for example be treated or solidified while being disposed. As a precautionary measure, burning as a means of disposal of substances should be done by specialists in a controlled environment such as in the incinerators or industrial furnaces. Incinerators are primarily used during waste destruction while industrial furnaces are used for material and energy recovery. When incineration is performed correctly, it destroys any toxic organic component in the hazardous material and reduces the waste’s volume. Unlike the incinerators, boilers are enclosed devices using controlled combustion aimed at reclaiming and exporting energy as steam or hot fluid (Stauffer et al, 2008). They are commonly used as constituents of industrial plants.
A flammable substance is whatever solid, gas or liquid that will readily ignite or burn speedily. A fire is caused when an oxidizer is added with combustible substance and then ignited. Fire is an oxidative reaction that is exothermic. Flames are commonly produced although certain solids smolders without producing flames. If combustion happens in a confined place, pressure may develop and that can result in explosions (Almirall et al, 2004). For a material to support burning it should be heated until its ignition point is reached.
There are multiple and varied effects of hazardous substances on fire. The effects include the type of flames exhibited and the residue that remains. Many of these substances burn rapidly with intense emission of heat and probably light. This is a chemical process involving oxidation with production of carbon monoxide, carbon dioxide, and water. Other end products depend with the initial substance. For instance, if sulfur was a constituent of the fuel, sulfur dioxide may result (Williams et al, 2007).
A flame intensity and color is affected by the type of the substance that is being burnt. Flame is a glowing composition of gases that is undergoing a combustion process. Generally, a flame results when a mixer of a specific gas and oxygen is ignited. Such a gas may be carbon monoxide or hydrogen. Every combustible substance needs a specific amount of oxygen for the burning to be complete. If oxygen is absent, combustion cannot be complete. This is evident when we sustain burning in a controlled environment of pure chlorine.
Oxygen supply affects the color of a flame. The color depends on the degree of combustion of carbon. For instance, at the base of a burner where carbon get consumed instantly, the flame is non luminous. Such a portion of the flame is very hot and can reach a temperature of 1600o C. When oxygen mixed with acetylene is burnt, the color of the flame exhibited is bluish-green and its temperature can reach 3500oC. If oxygen is reduced, the flame burns in four portions: invisible, luminance, bluish-green and non luminous portions. The bluish-green portion signifies insufficient oxygen supply. The outermost portion of a flame has excess oxygen and this makes it invisible.
The residue as a result of combustion is influenced by the type of material. In complete combustion, the resulting ash is inorganic (Stauffer et al, 2008). For example Calcium Phosphate is found in the ash resulting from combustion of bones while Iodine is present in the ash resulting from burning sea plants. Other inorganic ashes include sodium and potassium carbonates.
Fire has many uses such as lighting, heating and cooking. Fire is used in industries to heat fuel in order to produce electricity. It however presents challenges and risks to humans that include the destructive effects of burns, wildfires and difficulty of control. There are natural fires that are started by volcanoes and lightning and they destroys landscapes and wildlife. Careless and hasty disposal of hazardous materials can led to many disastrous fires (Almirall et al, 2004). Hazardous substances like coal and oily rags can ignite spontaneously and this usually happens when flammable materials are piled in large heaps in an environment with inadequate air circulation (Masek, 1971). This happens because chemical reactions like fermentation and oxidation occurs inside the heap releasing heat which then increases a heat-generating reaction eventually igniting the piled flammable substances.
The common hazardous solid materials include coke, peat, and coal. Their combustion leads to decomposition with the generation of volatile matters whose flames may be sooty. Their rate of burning is defined by how oxygen diffuses to their surfaces. To increase their rate of combustion, these substances are powdered and mixed with oxygen. Some beneficial uses of combustible solid are the application in military rockets. In the rockets, solid fuels such as cordite and nitrocellulose are mixed with oxygen to ensure spontaneous combustion if heated. The danger during transportation and use of these rockets is so immense such that great expertise is required. There are many examples of detrimental effects of fire involving combustible hazardous materials. For instance, coal dusts have been established as the main cause of mine fires (Masek, 1971). At home, a fire is notably accelerated by floor dust.
Hazardous materials in gaseous and liquid forms include alcohol, benzol, gasoline and fuel oils. These are variable materials meant for use in furnaces, internal combustion engines, and multiple other areas. However, they pose great danger because a small amount is adequate to cause ignition and fire in which they are involved is difficult to control since they spread readily (Pert et al, 2006). Great care is required in situations where an air-fuel mixer of substances like natural gas is to be used in burners. An optimum oxygen amount is used and the mixer should be allowed to leave burner ports with a greater velocity than that of the flame extension so that the flame does not flashback causing the burner to explode (Lawther et al 1965). Nonetheless, an extremely high velocity may blow off the flame from the burner.
If these substances and air are not premixed, the flames exhibited as they burn are cool and smoky. This explains why burning oil mines emits so much smoke. However, some may still produce very high temperature when ignited in air. For instance, the temperature of natural gas combusting in the air exceeds 1930° C (Stauffer et al, 2008). Beneficial uses of liquid and gaseous forms of combustible materials includes preparation of fuels for space exploration rockets . Many uses liquid fuels like hydrazine and kerosene prepared with liquid oxygen, hydrogen peroxide, or nitric acid. Many accidents have occurred such as the space shuttle that exploded and burnt in Columbia. The accident was aggravated by the spontaneous combustion of these fuel materials.
It is important to familiarize ourselves with categories of fire and fire extinguishers. This knowledge will assist us to effectively get rid of unwanted fire rapidly. According to European Standards, every fire extinguisher container must be colored red and have at least 5% of the label area showing a color that denotes the content. There are five categories of fire plus an electrical risk. Each category is extinguished in a unique way depending on the substance in combustion.
Water Extinguishers are used to extinguish Class A fires. Class A fires results when materials like wood, textile, fabric and paper are burnt. For this fire, water is sufficient to put it off. These extinguishers come in 6 and 9 liter capacity containers. Form Spray Extinguishers are used to put out fire that involves flammable liquids like oils, greases, spirits, certain plastics and fats. The form blankets the fire depleting it of oxygen thereby extinguishing it. Such extinguishers have to be certified through a test on electrical conductivity. They are placed in containers with 2 liter, 6 liter and 9 liter capacity.
The ABC/Dry Powder Fire Extinguishers puts out fire of classes A, B, C, and E that are caused by characteristic corrosive hazardous materials. The extinguishers can be used on all fire types apart from those involving metal. The powder cause a hindrance to the burning process extinguishing the flames altogether. It is vital to remember that even though dry powder extinguishes fires on machinery and electrical equipments, one should be careful since it may impair the equipment. They are packed in 1kg, 2kg, 4kg, 6kg, and 9kg. Class D/Dry Powder Fire Extinguishers are used on Class D fires. They are used on fires caused through metal combustion. Such metals include Potassium, Sodium, Lithium or their alloys.
CO2 Extinguishers are suitably used on fires of class B and E. Used on fires caused by combustible liquids like fat, oil and solvents, and those causes by electricity. CO2 does not conduct or corrode and therefore does not destroy machinery and electrical appliances (Stauffer et al, 2008). It depletes fire of oxygen smoldering it and therefore avoiding re-ignition. They are contained in 2kg and 5kg containers. Wet Chemical Fire Extinguishers are used on Class F fires that are caused by characteristic Ignitable hazardous materials. These extinguishers are mainly meant to extinguish kitchen fires that results from cooking oils and fats. They are available in 6 liter capacities.
Statistics available in North America shows that losses as a result of fire are more than those of natural disasters such as flood and tornadoes put together. Therefore, there is a great need focus on fire productivity and learn how to prevent or extinguish unnecessary fires. This is why fire safety personnel and scientists combine efforts to assist people in using fire productively and safely. They help install automatic sprinklers and smoke detectors at a workplace or home to reduce death, injury and property loss caused by fire.
Scientists are developing advanced fire-proof materials to be used in automobiles, buildings, and furniture. They have also developed new codes, standards and engineering approaches that make buildings safer without necessarily increasing the cost of building. There have been remarkable achievements though not exhaustive. With more political, academic and financial support, losses that results from unwanted fires can be greatly minimized.