Understanding fire through combustion and oxidation chemistry

Fire and Fire Science

Fire science is defined as the study of all aspects of fire that include fire investigation and fire behaviors. Fire science uses science and engineering principles to understand the fire behaviors, fire prevention, fire suppression, and the strategy to combat the spread of fire. Additionally, fire science consists of fire investigation, fire behaviors, fire management, and hazardous material. Fire science is also the study of fire prevention and protection, which firefighting techniques follow in put out dire. Fire science also provides a detailed information to control, confine and extinguish the fire. (Delmar,2008). In a scientific term, fire occurs when there is a chemical reaction between fuel and oxidizer that include oxygen (O2) in the air. In other words, fire involves an evolution of energy and light. Overview of the fire behaviors reveals that it is not all light that produces a flame. For example, burning of hydrogen with oxygen produces only water vapor from its chemical reaction. While a significant energy is produced through this process, the flame is not emitted. However, another fire classification will lead to the glow of flame sufficiently to cause injury or damage to property. (Quintiere, 2017).

Fire is defined as a rapid oxidation process that involves chemical reactions resulting in the evolution of heat, and light in varying intensity. In other words, fire is referred as an exothermic chemical process of combustive reaction that emits light and heat as well as various reactive products. Delmar, (2008) categorizes fire as a burning combustion that occurs through the chemical reaction. Moreover, fire is a deflagration combustion that moves at below the speed of sound. Fire tetrahedron is referred as the assembly of fuel, heat, and oxygen with the self-sustaining chemical reaction.

Class A fire is the fire that involves the ordinary combustive materials, which include wood, paper, cloth as well as the plastic materials. Class B fires are the combustive liquids or flammable liquids, greases, flammable gases, rubbers, plastic materials and other similar materials. Class C fires are the fires that involve energized equipment involving using the electrical non-conducive equipment to extinguish the media and enhancing safety of employees.

The chemical process of fire involves the conversion of molecular oxygen to the combustive products that lead to a release of water and carbon dioxide. The carbon energy plays an important role in the combustion reaction that ignites the release of flames. Overview of the fire combustion shows that the flames play an important role in the fire visible portion. Moreover, the heat plays an important role in the fire outbreak, and the heat fuels need to be heated to start a fire. The chemical heat consists of series of chemical reactions while the mechanical heat is the friction of two mechanical materials rubbing against one another.

The flames consist of oxygen, water vapor, carbon dioxide and nitrogen. If the hot flame is saturated, the gasses will be ionized to produce light plasma. Fire can lead to a conflagration, which can consequently cause physical damage through burning. Moreover, fire has a potential and ability to cause physical damage to house, property and forest through burning. However, fire serves as an important process having the ability to maintaining the ecological systems and stimulating growth. The negative effects of fire are the hazard that it causes to property, life, water contamination and air pollution. ( Blanchard, et al. 2014).

Moreover, fire exposes the vegetation to soil erosion because it removes the protective vegetation. When the fire burns the vegetation, it provokes nitrogen to be released into the atmosphere, and the loss of nitrogen leads to the soil infertility. However, fire encompasses the visible effect of chemical reaction leading to the process of combustion. Fire occurs when there is a reaction between oxygen and fuel. Thus, it is critical for fuel to be heated to the level of ignition temperature to make combustion to occur, and the interaction of the fire triangle (fuel, oxygen and heat) should take place to make fire occur. On the other hand, combustion is the process of the reaction of fuel with oxygen to release the heat energy. Combustion can be fast or slow depending on the volume of oxygen available, and combustion that provokes the fast flame is referred as burning. However, fuels can be liquid, solid or gasses. When the chemical reactions that release fire occurs, fuels will be heated to the extent that it releases gases even if the fuels are in the solid form. Essentially, only gases have the ability to react with combustion since gases consist of groups of atoms called molecule. When the gases are hot enough, the molecules will break down and the molecular fragments rejoin the oxygen to form new molecular products such as carbon dioxide molecules (CO2) and water molecules (H2O). Thus, when heated molecules are loosened, they move apart to form gasses, and when the gas molecules combine with oxygen, the result leads to burning. However, when there are enough oxygen and fuel, the fire will continue burning. (Delmar,2008).

When a complete combustion occurs, the burning fuel will produce only carbon dioxide and water with flame typically blue. However, there should be enough oxygen that will combine with fuel gas. Contrarily, a combustion is incomplete when the flame produces carbon monoxide (CO), and carbon (C), and the incomplete combustion produces carbon dioxide and water. Typically, less energy is released in the process of incomplete combustion and burning flame is typically orange, red or yellow, and it produces smoke.

Fire Behavior

Fire behaves differently. Some fires burn evenly, and slowly. However, other fires burn fiercely, quickly and extremely hot. The flame of fires has different colors and some fires can start easily, however, some fires can produce deadly gasses, which can provoke killing if the house is not well ventilated. The fire behavior also depends on the availability of fuel. The weather such as relative humidity and wind is also important in the fire behavior. Moreover, a fire can behave according to the location and environment it is burning. The environment consists of elements that include topography, fuels, and weather and these elements react with one another. Werth, et al. (2016) believes that fire behavior triangle, which include weather, fuels and topography, interact to influence the burning of fire. Moreover, fire behaviors range from very little to the extreme high and active fire energy. (Delmar,2008). Fuels also constitute an important element of the fire behavior. In some ecosystems, such as subalpine forest, fire rarely occurs, however, fire can only occur in this location under the extreme weather conditions, in a steep slope and often burn intensively. In this kind of cases, the topography and weather influence fire behavior than fuels. Nevertheless, all fire behaviors are to be considered in the context of weather, fuels and topography. (Werth, Potter, & Alexander, 2016). However, there is still the issue of the extreme fire behavior where the fire is burning with full intensity. The extreme fire behavior has the same elements with the ordinary behaviors, however, the extreme fire behavior is characterized by the presence of high wind intensity, high rate of spread, prolific spotting or crowning and strong convention column. (Werth, 2011).

Weather is also an important element that influences the fire behavior. The weather condition such as temperature, wind and humidity influence the fire behavior. However, the wind is an important and critical factor that influences the fire behavior because it has capacity to intensify the power of fire by supplying the oxygen to the fire and push the fire to the source of fuel. In an environment where there is plenty of wind, when there is an outbreak of fire in this type of location, there is a possibility that the fire will be extreme. Moreover, the temperature can determine the behavior of the fire because fuels have the ability to absorbs the solar radiation thereby provoking the breakout of the fire. Generally, temperature influences the ignition of fire, and fire is more readily ignited at high temperature than low temperature. When the humidity is low, the fuels are dry thereby susceptible to catching fire more easily.

The fuel composition such as chemical makeup, density and moisture level determine the degree of flammability. For example, life trees contain a high amount of moisture, and their moisture contents as well as the fuel distribution determine the level the fire is spread. Moreover, the chemical makes up of the fuel also determines how fuel will burn. Some shrubs, plants and tree contain resin oils that influence combustion making them burning intensely than those without oils. While it is impossible to live without fire because of its positive roles for cooking and heating, however, the fire can provoke adverse effects on property and human life.

"Fire can have an adverse consequence on the natural environment These include contamination of the air via the fire plume and its subsequent diffusion, with deposition of particulate and other materials likely to contaminate soil and water, contamination of soil and water from fire suppression runoff, which might contain toxic or hazardous materials, and direct exposure to soil and water from hazardous materials whose containers / containment systems may fail due to fire." (Martin et al. 2016 p 2).

The best way to prevent the damage caused by the fire is to carry out the public education, implement the pre-incident planning, disaster and large incident response plan.

2, Fire Prevention

The best strategy to enhance public safety is to prevent the fire from causing a hazard. Fire prevention is the role of fire department that involves educating the public to take preventive measure to avoid the fire outbreak. Delmar (2008) argues that "preservation of life and property the cardinal mission of the fire service, and prevention is the most effective method of achieving the goal." (p 659).

Public Education

The public education is a proactive measure to prevent the potentially harmful effects of fire and reducing damage and emergencies caused by fire. "Under Section 19 of the Safety, Health and Welfare at Work Act 2005 (the 2005 Act)" (OSHA, 2015 p 1), it is mandatory for every employer to carry a fire risk assessment and store the findings in the company's Safety Statement. The risk assessment should include fire prevention, fire warning and detection, firefighting and emergency escape. Fire prevention triangle consists of oxygen, heat and fuel. Fire requires heat, fuel and oxygen to spread, and without one or more of these elements, it will be impossible for fire to spread or start. A key prevention strategy is to remove one or more of fuel, heat or oxygen. To prevent the eventual outbreak of fire, it is critical to provide the public education to enhance their greater understanding of the strategy to prevent fire at home or organization.

Prestemon, et al. (2010) argue that wildfire prevention involves using varieties of education strategies that include distributing brochures, public service announcements, and making presentations intended to prevent the outbreak of wildfires. Poisson model has been identified as an effective strategy to manage fire and prevent wildfire. The model identifies the public education as an effective strategy to manage fire and prevent the outbreak of wildfire. The Poisson model is statistically significant and the benefits exceed the costs incurred to implement the model. The goal of WPE (wildfire prevention education) is to prevent accidental ignition that causes a wildfire. The WPE is also aimed to prevent undesirable fire activity. In the last few years, the U.S. government has devoted a lot of resources to educate the public about the dangers associated with the accidental fire setting. (Hermansen-Baez, et al. 2013). The ignition of wildfire is provoked through various mechanisms that include equipment malfunctions, brush-clearing fires, debris fires, campfire escapes, vehicle sparking, fire play and crashes. Some of the causes the fires incidents can be prevented through the public education program to limit the conducts of people towards certain kind of activities.

The benefit of fire prevention education is demonstrated by the Florida government. Between 2002 and 2007, the Florida state government approved $500,000 annually for the wildfire prevention education, and the goal of the program was to prevent campfire escapes, debris-burning escapes, children playing with fire and other wildfires smoking materials. The government used the homeowner visits, media efforts, presentations, flyers and information brochures for the wildfire prevention education program. The program also mandated the public organizations, private organizations, and a private individual to install the smoke detectors to reduce the chance of fire outbreak. Essentially, the smoke detectors are effective in reducing the chance of mass causalities caused by fire. It is estimated that more than 900 lives will be saved annually with the aid of working smoke detectors

Fire Prevention - Water Supply

Water is a critical element for the firefighting operation, and the water supply dictates the extent of the fire flow capacity. Typically, the fire flow requirements are the volume of water needed to put out the fire. To effectively fight the fire, fire brigade needs a quantity of water and a large quantity of water is required to absorb the heat that fire produces. Water also cools the fuel and make its power below the ignition temperature.

There is a wide range of natural and manmade sources of water that the firefighter can use to fight fire in case of the fire breakout. However, it is essential to realize that water carries out a constant cycle of change. Sun can evaporate water and send it into the atmosphere. Moreover, water can condense into clouds and falls as rain. Some places have plenty of water why some places are between dry and rainy seasons. However, some areas are endowed with plenty of water, and although water may be frozen. Thus, the fire fighter should study the climate location of their areas and design appropriate strategy to source for water.

The ground water is one of the sources of water to prevent fire, and firefighters can have access to the ground water through wells or bore holes. Moreover, the fire brigade can source water from rain and collect it into the aquifers. Springs are the other sources of groundwater that flow over the surface. However, shallow wells are not advisable because it is prone to dryness, and contamination. On the hand, deep wells are more predictable for a constant supply of water and it has a lesser chance of being contaminated.

Another source of water for fire prevention is the surface water. Essentially, 75% of the earth are covered by water, and this water is found in the sea and oceans. Water can also be collected from man-made sources such as lakes, reservoirs, ponds, water tanks and swimming pool. However, mobile water apparatus is very important source of water for the fire brigade. The mobile water apparatus is essential for fighting small fires as well as fighting fires outbreak in the areas without a water supply. The water tender is the type of mobile water supply equipment used to fight fires. The tender that combines the portable water tanks can provide large quantity of water to fight a fire that breaks out on the ground surface. A water tender should have a small booster pump of 250 gpm, the fire pump should be at least 750 gpm and transfer pump at least 250 gpm.

It is also essential for the firefighter to have access to the water tank, cisterns and ponds. The want tank includes the underground water, elevated and ground level water. The water should have the hydrants for the drafting. The pond can also be developed for the fire protection in conjunction with the hydrants.

The water distribution system is critical for fire protection. The water distribution system components include a method of sourcing for water, treatment process, storage and distribution. However, it is essential to have a pumping station for a small ground water. The water can be supplied using the following method:

• Gravity water distribution method

• A direct pumping distribution method, and • The combination of gravity and direct distribution systems.

The goal of "Occupational Safety and Health Act of 1970 is:

"To assure safe and healthful working conditions for working men and women; by authorizing enforcement of the standards developed under the Act; by assisting and encouraging the States in their efforts to assure safe and healthful working conditions; by providing for research, information, education, and training in the field of occupational safety and health." (OSHA, 2015 p 2).

The law mandates that all organizations are to implement the safety procedure to suppress fire quickly in case of fire outbreak. Water is a critical element to suppress the fire, and adequate and abundant water supply is essential for fire service operations, and water must be available through the distribution system. The firefighter can source for water from fire sprinkler systems, fire standpipe systems, and from other water suppression system.

Another source of water from municipal water systems involves the distribution of water to the public. The municipal water systems are under the jurisdiction of the municipal water authority. The municipal systems also supply water to the private organizations or private property for the fire needs. The private property consists of the boundary between the public portion and privately-owned portion. On the other hand, private water system consists of pump, piping system and on-site tank. The on-site system is used to feed the private fire hydrants. However, in some rural areas where the water is not available, the only sources of water to fight fire are ponds, lakes, fountains, cisterns and swimming pools. Fire prevention also consists of multiple or single water sources connected to fire monitors, fire hydrants, and sprinkler systems. Water supplies for fire protection are referred as primary and secondary where the primary supplies do not require mechanical devices to supply water. However, secondary water supplies requiring using the mechanical devices such as fire pumps.

Fire Hydrants

Fire hydrants are another protective system against fire, and the fire hydrants allow the firefighters to have access to the water supply systems. The two major types of fire hydrants are dry and wet barrel hydrants. The dry hydrants consist of pipe system used for the drafting from the water static source. The wet barrel consists of water stored in the barrel that is used in the areas that are not experiencing freezing. The wet barrels also allow the outlet be controlled with the separate valve. The dry barrel should be used in the areas where there are freezing of the temperatures. The valve is at the base control, which is below the water ground. (Wu, & Lu, 2016). The efficient way is to make the entire hydrants shutting down the connection of the additional lines. The fire brigade can also use the dry hydrants, however, this is not a fire hydrant however, the fire hydrant can be used effective in the rural areas that have no water distribution, and it may be used in the urban and suburban areas to be used as the back-up water supply. The connection point is with the static water source such as stream or pond, where the pipe system relates to pumper suction to be used for the water distribution system. On the other hand, the specialty hydrants are the wall hydrants mounted on a building wall involving connecting the hydrant to the water supply systems. Moreover, the flush type of hydrant is mounted below the grade level and is found in the vault, and pit, which allows to have a water access.

Rural Water Supply

The rural water system supply system can be used anywhere especially in urban or suburban areas where the presence of hydrants is too far. Moreover, the rural water supply is effective for fire protection where there is large bridges and limited access highways. However, the water supply system requires a careful coordination and control, and the water distribution system allows the fire fighter supervisor to have a full authority over the apparatus operation that helps fire fighter to be assigned to the water supply. (Turns, 2011).

The portable water tanks are the other source of water for fire prevention that consists of mobile water apparatus effective in offloading water, however, the mobile apparatus is to have the portable water tank with the capacity greater or equal than its original tank size. Moreover, the inflatable or collapsible tanks should set next to the engine, which requires the jet dump speeds to unload the tanks. The operation of mobile water apparatus involves moving water between the full and dump site. Typically, the dump site is where the water is delivered for quick uploading. However, the full site is a location of the water source and optimum full site allows the fire fighter vehicle to move through the shuttles operation time. (NIST, 2010).

Ventilation

One of the effective strategies to prevent fire outbreak is through ventilation. The ventilation is the systematic and planned removal of smoke, fire gasses and heat and replacing them with cooler and fresh air. As fire consumes fuels, it starts generating heat, gasses and smokes, which consequently increase the internal pressure in the building. Thus, it is critical to educate the business owners, and public organizations for the effective fire prevention strategy using the ventilation method. To prevent non-compliance of the fire prevention using the ventilation method, it is critical for the Fire Prevention Bureau to carry out the field inspection to ascertain that private or public building comply with the applicable fire and building codes.

There are two major methods of design the ventilation to prevent fire. The horizontal and vertical ventilation is accomplished by breaking, cutting or opening the exterior to give the smoke, heat and combustion an avenue to exit. Moreover, features such as rooftop bulkheads, skylights and scuttles are employed to provide available ventilation. The vertical ventilation is by creating the overhead opening high up of the building very near the seat of the fire. The method allows the smoke, combustion and heat to travel out of the building structure. The natural features that include scuttle openings, skylights, and vent shafts facilitate the rapid movement of smoke, heat and combustion. It is also critical to provide the ventilation through the patio doors. Further ventilation is important through the window opening to support the horizontal ventilation, and the vertical ventilation is extended to the attic.

A building structure should also have the horizontal ventilation to create an opening on the floor to allow combustion, smoke, heat traveling horizontally out of a structural building without affecting the building structure. Mechanical ventilation in collaboration with other types of ventilations to make the ventilation more efficient. The mechanical ventilation is referred as hydraulic ventilation placed directly at window opening. The smoke, combustion and heat will escape through the window.

Pre-incident Planning, Disaster and Large Incident Response

Emergencies can take different forms. A physical peril such as fire can lead to a loss of essential utilities that include electricity, telephone and other utilities. Thus, an emergency that can suddenly disrupt economic position needs an immediate attention. Fire outbreak can lead to a large-scale catastrophic, thus, the immediate emergency plan is critical to address the problem. (Center for Domestic Preparedness, 2004). The pre-incident planning is critical to minimize the adverse effects of fire incidents because being unprepared can lead to loss of human life and assets. To prepare for fire emergencies, the communities should be able to deal with the unforeseen circumstances. (Meng, et al. 2012). The OSHA has developed the pre-incident plan to assist communities to deal with the emergencies, and the goal of pre-incident planning is to prevent the adverse effect of fire incidents, which is accomplished through the vulnerability assessment, risk assessment, and fire risk assessments. The strategy will assist in mitigating the risks. The following eight essential elements are required for the fire emergencies preparedness:

• Identification of the planning team

• Conducting capability and resource assessments

• Assessing and analyzing the threat

• Developing the fire incident response plan

• Identification of the potential targets

• Conduct training

• Conducting exercises and drills

• Conducting risk and vulnerability assessments.

Disaster and Large Incident Response

Incident fire response plan is essential because it provides the added protection against the fire incidents, and minimize the business risks. Incident response plan should be integrated with the disaster response plan. Incidents are the issues that can turn into a disaster if they are not handled properly. The best strategy to assess the severity of the incidents is to define the events that can lead to the incidents.

The first step to carry out the incident or disaster response plan is to form the team to implement the plan. The following team is recommended:

• Regional Management Incident Team

• Threat Assessment Center

• Damage Assessment Team, and • Local Management Incident Team.

An incident response plan will only be effective if it involves the senior management because the senior management has the potential to secure well -trained team to manage the incidents effectively. A way to carry out the incident response planning is to implement the threat assessment based on the national standards. The next step is the operational readiness, and this involves the training to counter the eventual fire incident. There should also be an adequate funding for the right supply of fire equipment, training and equipment maintenance. It is also necessary for the emergency team to carry out the exercises to test their skills. Conducting a small and large scale exercise will allow the team to test their operational readiness.

"Rescue station, firefighting system is needed to be designed to combat early fires before the arrival of rescue brigade. If firefighting is carried out at the early stage of a fire, fire can be avoided from spreading or can be extinguished with less difficulty. Thus, the loss of life and property can also be significantly reduced. However, little information about the design of this firefighting system for such railway tunnel rescue station can be found by far, as such design of rescue stations in tunnels is new. When a train on fire stops beside the platform of a rescue station, passengers evacuate through the platform. Therefore, the firefighting system should not only possess better cooling and heat blocking effect but also be clean and not hinder evacuation. Considering this, the water mist fire protection system was considered by designers to be a good choice at railway tunnel rescue station." Meng, 2012 p 139).

Fire Suppression

Chow, & Chan, (2011) "argues that the he water mist fire suppression system (WMFSS) is an environmentally friendly fire protection system, replacing the total flooding halon system. It is starting to be popular in Hong Kong with five systems approved." (p 157).

When there is an outbreak of fire, fire suppression is the next step to put out the fire or wildfire. The firefighters need to suppress all fires to enhance the public safety. To suppress the fire, it is important to put out one of the fire triangles. Fires need heat, oxygen and fuel to burn. Thus, one or more of the fire elements must be removed to put out the fire. While it may be impossible to remove the oxygen because air is everywhere, the best strategy that can be employed to suppress fire is to remove the fuel and heat components that are most vulnerable. The best strategy to remove the oxygen is to remove water and dirt to extinguish fires. The axe, shovel or rake can be used to extinguish a small fire. However, engines, bulldozers, pumps, an air tanker and helicopters are used put out larger fires. (Lentini, 2013).

Service Testing of Fire Hose

The fire hose is an important fire prevention method. The fire hose is defined as the high-pressure hose that distributes or carry water with the aim to extinguish the fire using the fire hydrants. It is essential to attach the fire hose on the private properties or properties of the public organizations. Moreover, it is essential to carry out the testing of the fire hose to prevent the fire hose failure when there is a fire outbreak. The procedure to test the hose should be in accordance with "National Fire Protection Associations (NFPA) Standards 1962, Standard for the Care, Use and Service Testing of Fire Hose Including Couplings and Nozzles." (Safety First, 2017 p 1).

Based on the guideline of the Safety First (2017), all private individuals and employees are to follow the fire hose guidelines. The length of the fire hose should be 300 feet however; it should not exceed 300 feet. Moreover, the hose should be as straight as possible. More importantly, it is essential to pre-inspect the fire service hose prior to testing "using the hose testing machine to identify" (Safety First, 2017 p 1) the damaged component in the hose.

Fire Brigade

Delmar, (2008) suggests that the effective way to prevent the fire outbreak is to form a fire brigade within an organization. The fire brigade composes of personnel forming training with the use of personal protective equipment. The employers should prepare a written policy that establishes the composition of fire brigade revealing its organization structure. The policy should also state the training program requirements, and function to be carried out. The employers should ensure that personnel to form for interior firefighting are capable of carrying out the tasks. Moreover, the employer should conduct annual training and education for the fire brigades, however, quarterly training is expected for the firefighter expected to perform the firefighting for the interior building. It is also critical to inspect and maintain the firefighting equipment annually to assure a safe operational condition for the firefighting equipment. A monthly inspection is to carry out the fire extinguisher, and it is critical to inspect respirators monthly. When carrying out the fighting operation, the brigades should wear protective clothing and put on the foot and leg protective materials, hand protection, body protection, eye, head, and face protection. The employer should also provide respiratory protection devices for fire brigade members to meet the OSHA requirements.

3: Fire Protection Systems

Fire protection system is the strategy of mitigating the effects of destructive effects of fire. The fire protection involves the method of investigating the behavior, and suppression of fire related to emergencies. It also involves the research of the method of investigating the fire systems. (Huang, 2009). However, a portable fire extinguisher is one of the fire protection procedures, and portable fire extinguisher can assist in preventing the major fire outbreak at home or within the organization.

Portable Fire Extinguisher

A portable fire extinguisher is an effective fire protection tool to be used as fire protection.

"The cost/benefit analysis of portable extinguishers is indisputable. The total lifecycle cost of are excellent a portable extinguisher ranges from a low of one-half of one cent to a high of just under fire protection four cents per square foot per year. This includes acquisition costs and all inspection, maintenance, and upkeep for the life of the extinguisher. This is probably some of the investment lowest cost fire protection available, and has shown to be very effective." (Fire Equipment Manufactures 2015 p 1).

An employer should provide the portable fire extinguisher for the use of employees. The employer must also locate, and mount the fire extinguisher in the strategy location so that employees will be able to access them without subjecting to possible injuries. The extinguisher classification consists of the following:

Class A consisting of ordinary combustibles (cloth, wood, and paper)

Class B -- greases, flammable liquids, and gases

Class C consisting of energized electrical equipment, and Class D consisting of combustible metals.

The general requirement of portable fired extinguisher is that it must be fully identified and mount in the location where they can be readily accessible. It is also essential to use only approved fire extinguishing materials as well as maintaining that the extinguishers are fully charged and in a good operable condition.

The portage fire extinguisher can consist of foam and water to suppress fire by taking away the heat, which is one of the major elements of the fire triangle. Moreover, the foaming agent assists in separating the oxygen from other elements of fire. However, water extinguisher should be used for the Class A fires only, and should not be used to extinguish Class B and Class C fires because the discharge stream in Class B and Class C could provoke a shock hazard. The carbon dioxide portable fire extinguisher can take away the oxygen element and remove the heat from the burning fire. The CO2 portable fire extinguisher can extinguish the Class B and C. fires. However, it is ineffective for Class A fires. Portable dry chemical extinguishers can interrupt the fire chemical reactions. This type of fire extinguisher has multiple purposes with the ability to extinguish Class A, B, and Class C fires because it creates a barrier between fuel and oxygen elements.

The dry chemical fire extinguisher is another fire protective systems that can interrupt the chemical reaction to extinguish fire through the interruption of the fire triangle. At present, the dry chemical multipurpose fire extinguisher is critical for fire protection of Class A, Class B and Class C fires. The agent is also effective in creating a barrier between the fuel and oxygen element in the Class A fires. However, ordinary dry chemicals are to be used for the Class B and Class C only. It is also important to use the proper and correct fire extinguishers against a type of fuel because the incorrect use of extinguisher can provoke fire to re-ignite after the fire has been extinguished successfully. (Jenft, et al. 2014).

The wet chemical extinguisher is a type of agent having ability to extinguish fire through the process of removing the heat from the fire triangle. Th wet chemical extinguisher also prevents a re-ignition of fire by creating a barrier between the fuel and oxygen elements. Moreover, the Class K wet chemical extinguishers were developing for high, modern and efficient fat fryers used in commercial cooking operation. Some chemical extinguishers may be used to extinguish Class A fires that break out in the commercial kitchens. Moreover, Clean or Halogenated extinguishers are the other fire protection systems that use the halon agents to extinguish the fire by interrupting the chemical reaction that occurs in the fire triangle. The clean extinguishers are used to extinguish the Class B and Class C fires. However, some larger clean extinguisher agents can be used to extinguish the Class A, Class B and Class C fires.

Dry powder extinguishers are other types of fire extinguishing agents that use the dry chemical to extinguish the fire by separating oxygen and fuel elements as well as removing the heating element from the fire triangle. However, dry powder extinguishers are only effective for the Class D fire or combustive metal fires. They are not effective to extinguish other class of fires. Water mist extinguishers have been identified as the recent development for fire protection, which is effective in taking away the heat from the fire triangle. Moreover, water mist extinguishers can be used as the alternative to the clean agent extinguishers where there may be a contamination. However, Water mist is effective to extinguish Class A fires. Although, it may be used to extinguish Class C fires. (Icove, DeHaan, & Haynes, 2013).

Chow, & Chan, (2011) point out that

"Five water mist systems were approved in Hong Kong based on the fire test certificate provided by the manufacturers. Four systems were selected in this paper for discussion. Conditions of the fire scenarios in which the approved systems would work are described. The test scenario encountered should match with real fires. Such systems would work satisfactorily in the application area proposed. They are good for enclosed rooms such as machinery spaces and plant rooms. But applying such systems for use in retail areas or libraries should be watched carefully, particularly those with high ventilation rates." (Chow, & Chan, 2011 p 157).

The Cartridge Chemical extinguishers can extinguish the fire through the process of interrupting the chemical reaction that occurs in the fire triangle. Thus, the dry chemical extinguishers are multipurpose, which is effective on Class A, Class B and Class C fires. The agent is also effective in creating a barrier between the fuel element and oxygen elements on the Class A fires. However, ordinary dry chemical extinguishers are for Class B and Class fires only. Moreover, it is crucial to use a correct extinguisher to put out the fire, and using the incorrect extinguishers can make the fire to reignite after the fire has been extinguishing successfully.

The benefits of fire extinguishers are indisputable because thousands of fires are put off annually in the United States with the aid of fire extinguishers. In 2009, 7,430,000 of fire outbreak occurred in the United States annually, however, 5% of these fires are put out using the fire extinguishers.

A report by Fire Equipment Manufactures (2015) shows "there was a total by portable fire of 7,430,000 residential fires in the United States annually. This includes both fires attended by a fire department, and those where the fires went unreported. However, five percent of the fires were put out using a portable fire extinguisher. This means that 371,000 residential fires were suppressed using portable fire extinguishers annually at the time of the survey." (Fire Equipment Manufactures 2015 p 1).

Rescue Procedures

Delmar (2008) defines the rescue procedures as the action of removing people from the imminent danger of fire as well as extricate people if they are trapped. Typically, firefighters are to be aware of the danger that can arise from the outbreak and minimize the risks using constant training to be up-to-date about the rescue procedures. The hazards associated rescue operation consist of rescue vision, and cost-benefit analysis procedure. The tunnel vision focusing on carrying out the operation without considering the consequences. However, the risk-benefit analysis is that the firefighter reassesses the safety procedures during the operation and consider the safe havens and exit point during the operations. Safe havens are the temporary safety location during a hazardous and dangerous situation. The safe haven consists of using an area for refuge, which can be utilized for trapped people while waiting to be rescued from the hazardous conditions. It is critical for the firefighters to identify the safe havens, which they should use for survival techniques and allow them to escape from the hazardous locations. However, safe havens should be temporary safe areas, tenable environment and away from the hazardous position. It should also be allowed for the self-rescue. The firefighters should employ survival and safety techniques upon their entry into a safe haven. They should also maintain a constant communication with their incident commanders, and crew members. It is also critical to position themselves away from dangerous and hazard. During the rescue procedures, the firefighters should work in teams preferable two or more firefighters should be working together while two firefighters should be standing outside. (Drysdale, 2011).

However, it is critical for the firefighter to search for fire and life before controlling the fire. However, the dangerous activities are to search the areas likely to have victims, and it is critical to be stationed at the fire floor towards the entry point. However, a secondary search is when the fire is under control or when the fire is out. Since the danger is out, it is crucial to carry out a more thorough search through debris and exterior of the building. The firefighters can also use the TICs (Thermal Imaging Cameras) to carry out the search that involves identifying potential hazard using the infrared energy. It is also important for the firefighters to form the rapid intervention team because 20% of firefighters may become the victims, thus, it is the responsibility of the rapid intervention team to locate and rescue them from the hazard.

Protective Systems

Protective systems are to be implemented during firefighting and rescue operation. The protective systems are the collection of the personal protective clothing designed for the firefighting hazards. The protective structural ensemble for firefighters are:

• Coats and trousers

• Gloves

• Helmets

• Eye protective devices

• Footwear

• Protective hoods

• Station and work uniform, and • Hearing protection

However, Wildland firefighting protective to address the specific needs and satisfy the requirements of wildland firefighters are:

• Lightweight and breathable

• Firm ankle support

• Hot ember protection

• The synthetic material should not be included in the wildland ensembles.

The technical rescue team that involves operations in structural collapse, confined space and trend should be armed with the following protective devices:

• Durable over-shirt and pant

• Lace-up leather boots

• Lightweight element

• Tight-fitting durable gloves

• Eye protection

• Hearing protection, and • Harness.

The protective devices at the areas with frozen recreation ponds and lakes are:

• Buoyant, and insulated suit

• Form-fitting face seal and hood

• A piece of the suit with sealed boots and gloves.

• Lightweight helmet, and chest harness face screen.

4: Fire Hydraulics - Fire hose and Appliances

Hydraulics are the study of water and its mechanical properties applied to the engineering purpose. Hydraulics regarding the firefighting is based on the relationships between the firefighting jets and pumping operations. The fire hose is used to achieve the fire hydraulics. Fire hoses are used to move water to areas of fire outbreak with the purpose of extinguishing the fire. The fire house should be flexible and adapters, couplings and appliances should be used to connect hose. The fire hose can be braided, wrapped, or woven. A hose maintenance involves a careful folding of the hose and put in a dry place. The hose bed should allow an air flow circulation to reduce the possibilities of hose damage. The coupling is used to join hose, which is made of aluminum, brass or an alloy. However, the coupling should always be clean, and store properly. The hose appliances are rollers, rope hose tools, clamps, rollers valves.

Nozzles and Fire Stream

In the firefighting environment, water is the tool to extinguish the fire, however, foam is added to the fire to enhance its extinguishing ability. Foam and water are delivered with the aid of the fire stream and nozzle. Fire stream consists of the distinguishing agent that assists in making the nozzle flow properly. The elements of the fire streams are water, pump, nozzle, and hose. A good stream should have a sufficient volume, direction and pressure to make it reaching its target. Essentially, nose appliances allow the extinguishing agent to work properly.

5. Firefighter Safety and Firefighting

Fire is a danger to firefighter and in carrying out their professional duties, they are exposed to a lot of risks and hazards.

"The National Institute for Occupational Safety and Health (NIOSH) requests assistance in preventing injuries and deaths of U.S. fire fighters due to structural collapse during firefighting operations. Structural collapse of a building during firefighting is a leading cause of death among fire fighters. Such collapse is very difficult to predict during firefighting, and it usually occurs without warning." (CDC, 1999 p1).

Thus, it is critical to design the procedure to protect the life of people and firefighter. The protective systems assist in guiding the lives of communities and firefighter. The detection systems allow helping to detect the presence of fire and alert the fire department or occupants. The suppression system assists the firefighters in controlling fire. The firefighting safety is the procedure of protecting the life of firefighters and save their life from danger. Thus, is it critical the firefighters have the PASS (personal alert safety system) to be activated when they are involved in rescue, firefighting and in other hazardous duties.

However, the safety of firefighters depends on prevention readiness that should be implemented through training, fitness for duty, task accountability and use of PPE (personal protective equipment). The PPE should be the first thing wear for protection. The personal accountability should involve personal size up, performance training, and fitness for the job. It is also essential for fire fighters to carry physical and mental fitness all the time. The fitness for duty should include:

• Hydration maintenance

• Resistance training

• Physical fitness

• Physical wellness

• Core strengthening

• Cardiovascular conditioning

• Nutritional balance, and • Flexibility improvement.

Since half of the death of firefighters occur the fire incidents, the best strategy to enhance safety and prevent injury is to form the team continuity and carry out the physical exercise regularly. Part of the firefighting safety procedure is also to use the air monitoring devices. The defensive operations and tactical response should include basic air monitoring, confinement and containment. Firefighters are required using the air monitoring equipment to test for the presence of oxygen, carbon monoxide and carbon dioxide. (Chow, Chow, Ma, & Mabel. 2011).

Terrorism

In the United States, firefighters are continually being trained to tackle the act of terrorism.

Delmar (2008) defines terrorism as a "violent act or an act dangerous to human life in violation of the criminal laws of the United States or any segment to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives." (Delmar, 2008 p 913).

The potential target of terrorism includes:

• Commercial buildings

• Exit of every community

• High-rise buildings

• FBI buildings

• Residential homes

• Bureau of Firearms, Alcohol, and Tobacco

• Military installations

• Internal Revenue Service, and • Social Security buildings.

However, terrorist attacks may lead to a breakout of fire, and collapse of building causing people to be trapped under the building. During the anti-terrorisms intervention, firefighters are called upon to carry out the rescue intervention. Thus, the fighter is to implement all the procedure to carry out the safety operations.

Fire Arson and Investigation

The overhaul and fire salvage operations are the events that many cause the fire outbreak. The basic premises relating to the salvage operations are to use the proper tool to remove harmful materials from the environment. The salvage covers should include plastic covers, and canvas durable covers with water resistance. Other tools required for salvage operations are scissors and knife. Some other salvage tools are nails, hammer and staple guns. It is also essential to use the salvage covers to prevent leak that can cause a fire outbreak.

Moreover, the role of fire department is to put out the fire and carry out the rescue operation by forcibly entering the dangerous zone in the building. Sometimes, a structural building may collapse, thus firefighters are required to understand the structural protocol of building construction. Typically, firefighters are to understand the concepts that are related to building construction, and elements of building such as loads and stress. In a building, types of loads are live loads and dead loads. However, specific terms related to living and dead loads are:

• Fire load,

• Design load,

• Concentrated load

• Undersigned load, and • Distributed load.

Moreover, the imposition of loads in the structural building are

• Axial load

• Torsion load, and • Eccentric load.

The building also has forces involving strain and stress referred as forces that include tension, compression and shear. Several variables determine the method building can resist fire degradation and gravity, which include:

• Mass and material type

• BTU development

• Surface-to-mass ratio

• Entire load imposed, and • Assembly method and type of construction.

Other variables that determine fire resistance of a building are

• Fire-resistive barriers

• Alterations (undersigned loading)

• Maintenance, care and age deterioration of the structure

• Firefighting impact loads.

Additionally, structural elements of the building consist of columns, beams walls, and connections. These elements influence resistance of building to fire. However, beams are loads that are perpendicular to the length. Type of beams are:

• Simple beam

• Cantilever beam

• Continuous beam

• Lintel

• Truss and Purlin

• Girder

• Joist.

On the other hand, columns are the structural components having the ability to transfer forces. Columns can be vertical, diagonally and horizontally to support a building. However, walls can be long or slender. Categories are load bearing walls, and non-load bearing walls. Fires can have effects on building materials. Thus, the structural elements of the building that include costs, adaptability, and engineering capability of a building should be considered before constructing a building.

7, Firefighters and Fire Departments

The mission of firefighter is to save people life and property. The mission of Midway Fire Department is as follows:

"We are organized to deliver fire prevention, life safety, fire suppression (extinguishment), and rescue services to the citizens of its protection area.

This will include response to conduct vehicle extrication, hazardous materials mitigation, confined space rescue, advanced life support emergency medical services, disaster response, and fire life safety code enforcement." (Delmar, 2008 p 24).

However, a fire department has a complex organizational structure and fig 1 provides the organization structure of fire department.

Fig 1: Fire Service Organization Structure

Part of the fire fighter team are

• Rescue specialist

• EMT (Emergency medical technician)

• Paramedic (EMT-P)

• Hazardous materials technician

The history of firefighting services is as far back as ancient Greeks. The recorded history shows that Hero Alexandria was the first person who created first fire pump. In the middle ages, the Great Fire of London was created in 1666. After 200 years, there had been a creation of fire protection institutions and fire departments. After some years, the fire insurance industry was created. In 1700, Boston developed fire wardens and in 1718 fire societies consisted of volunteer were created. Between 1870 and 1900, Fire Protection Association was developed, which designed the automatic sprinklers. In the 1900s, basic fire engineering started to study fire hydraulics, alarm systems, aerial apparatus, and powered steam fire pump. After the first and second world, several fire service companies started springing up across the United States.

Conclusion

This study provides the analysis of fire science, fire behaviors, fire prevention and fire prevention. The study explores the fire behaviors by discussing the fire triangle that includes heat, water and fuel. Different fire preventions are discussed that include public education, and the use of fire extinguishers. The study reveals that the strategy to suppress fire is to remove one or more elements of fire triangle and if these elements are removed, the fire will be put out. Additionally, water supply, pre-incident planning, and large incident response are other methods of fire preventions. The firefighting safety is also discussed providing a detailed strategy that firefighters can employ to protect themselves against the fire hazards. The study identifies the PPE, ladders, communication, self-contained breathing apparatus, emergency and air monitoring as the ways to enhance their safety against fire.

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