Fire Behaviour with Regard to Spread and Mode of Extinction - Term Paper Example

Fire Behaviour with Regard to Spread and Mode of Extinction Introduction This research is aimed at investigating fire behaviour with regard to spread and mode of extinction. This research is very important as it will provide information to the different departments that engage themselves in fire fighting. It will also be essential to the public who at many times are caught unawares. Information from this research will provide the public with general information on how to handle fire from its onset before trained fire extinguishers arrive. Trying to mitigate the effects of a fire helps in reducing the damage associated with the fire. Investigating and learning fire behaviour will help fire fighters come up with better strategies during the fire fighting process. In addition, the fire extinguishers will become more competent in dealing with any unplanned situation that comes up. The research is going to achieve this through the study of various aspects of fire through experimentation. Objectives General Objective To determine fire behaviour by looking at its nature of spread and associated impact. Specific Objectives 1. To identify basic elements on fire size and behaviour 2. To identify the rate of spread of fire 3. To determine how much flow rate is favourable 4. To identify the most inflammable materials 5. To identify the most effective mode of extinguishing fire Literature Review Fire is a great menace if not handled appropriately. A slight delay in extinguishing fire results to great damages. Learning and understanding fire behaviour is very imperative for effective fire fighting. To understand fire behaviour in a more comprehensive way, it is important to witness all the developmental stages of a fire in a practical setting. Through training on different fire fighting techniques, one is able to calculate his or her actions in a more prudent way so that these actions will be successful in extinguishing the fire as well as saving trapped victims. Fire fighting is a very dangerous practice and several fire fighters have lost their lives in this line of duty. Fire Behaviour The term fire behaviour is used to give a description of the direction, magnitude and strength of the fire spread. Magnitude is with regard to velocity of the leading edge of the flame and is measured in m/s. Direction is in accord with the bearing of the leading edge of the flame and measurable in terms of degrees. Strength or intensity is the energy that is liberated from the fire in a certain area hence; J/m2. There are two types of fires known in the UK; compartment fire and building or structure fire. As the name suggests, compartment fire is that which occurs within a confined area. A structure fire on the other hand involves several compartments. This is due to the fact that several compartments make up a structure (Chitty 1994). Fire developmental Phases To get a full understanding of fire, it is important to look at its developmental phases. Fire occurrence starts with the incipient phase. At this stage potential fuel is heating up through combustion processes like flaming, radiant and smouldering. Growth is the subsequent development phase of the fire. It is recognized through ignition. Ignition begins with a small fire that is localized within a compartment. Smoke also accumulates and together with the accumulated combustion products, a hotter upper is formed. The bottom layer is cool and cleaner. With available fuel and oxygen, the fire grows and continues to release hot gases and combustion products to the hotter upper layer. As this upper layer becomes thicker, it begins to descend. A flashover may occur after this growth phase. The flashover is due to the upper hot layer and radiation emerging from the burning flame leading to ignition of combustible materials that have not yet burned. Subsequently, the entire compartment is filled with fire and smoke. Later, the fire enters its full blown stage. This stage is known as the fully developed phase. At this stage, the fire’s heat rate is at its maximum while the burning rate is substantially stable. This is the most sensitive stage of a fire as it is at this stage that the compartment fire turns to be a structure fire resulting into structural and widespread damages. However, this can be prevented through fuel or ventilation control thus the essence of extinguishing fire. In as far as the developmental stage of fire is concerned, once the fire has burned for a certain period of time, the burning rate reduces as all combustible materials have been consumed. The fire then gets into the decay phase. Subsequently, after all combustible materials have been entirely consumed, energy release ends and so does the fire (Bailey, 2003). Flow Rate According to research by Sardqvist, 307 fires in London indicated that most fires could be extinguished using 600 litres/min flow rate. In addition, 75% of these fires did not increase after the fire brigade arrived due to counteraction of the spread through an applicable flow rate. A small fire can be used to study fire in all its aspects. Flow rate is very important as it the force of water or any other media used to suppress fire. Critical flow rate, which is the least amount of flowing water needed to put out a fire, is 380 litres per min. However, it is varied depending on the size of compartment and/or structure. Sardqvist also found out that out of 120 fires that were evident in London, only 50% could be put out while in the decay phase (Grimwood 2008). Flow rate is a very important parameter that should be taken account during the fire fighting process. It is this flow rate that determines the success of a fire extinguishing exercise. Despite the fact that there is the standard developmental phase of fire, the material that is on fire is also an important factor that needs to be put into considered. The kind of material determines fire behaviour. On the other hand, too much flow rate is not safe either. Therefore, the intensity of flow should be within the parameters mentioned. Case In Blania, Gwent, two fire-fighters lost their lives as they were trying to save a child who had been trapped in a smoke filled compartment. The fire-fighters had attended what had appeared to be a usual job with no apparent flame; only smoke and an orange glow from the rear of the kitchen were visible. Upon arrival, the fire fighters managed to save the first child. However, while attempting to save the second child, they became trapped in the compartment. Any efforts to save the trio were futile as a fireball led to the eruption of the entire building (Baglin 1996). This occurrence was a huge blow to the Home Office Fire Experimental Unit. It was an indication that the fire fighters had not received adequate training and therefore they were unable to handle the situation. It is therefore very important to have a full understanding on the concept of fire so as to have the capability of handling any emerging issue. In addition, one is able to calculate what is likely to happen hence; prepare in advance. Methodology The research will employ the use of an experiment to study fire behaviour. This will help in the better understanding of fire behaviour from a more practical approach. The experiment will entail the use of a waste-bin fire that will be used to burn different materials so as to observe the rate at which different materials burn. After setting the bin on fire, I will then try to extinguish it using a water sprayer at different flow rates. This experiment is simple but I believe it will enable me to identify the rate at which fire spreads with regard to the material that is burning. It will also enable to identify the appropriate magnitude of force (flow rate) that should be used to counteract the fire. I will repeat this experiment using soil, blankets and a commercial water fire extinguisher to put out the fire. This will enable me to find out how different fires respond to different modes of fire extinction. From the observations that I will derive from these experiments, I will then put down my findings on paper. From the observations, I will analyze information based on the findings as per the given objectives. These findings will enable me to come up with different explanations to different questions and could also be used to test several hypotheses. Timescale The entire research will take a time frame of one year as indicated by the gant chart below: TASK POSSIBLE START DATE LENGTH OF TIME 1. Identification of research topic January 2010 2 weeks 2. Literature review January-February 2010 6 weeks 3. Preparing the research questionnaires March 2010 4 weeks 4. Coming up with data collection tools. April 2010 1 month 5. Determining methods of data analysis May 2010 2 weeks 6. Preparing my research proposal May 2010 2 weeks 7. Submitting the research proposal document to my supervisor. June 2010 1 day 8. Defending my proposal June 2010 1 day 9. Collection of data July 2010 8 weeks 10. Analysis of data September 2010 2 weeks 11. Preparation of the research thesis. October 2010 6 weeks 12. Submitting the thesis to my supervisor. December 2010 1 day References Baglin P 1996, “Editorial,” Fire Engineers Journal, Vol. 56 No.185, pp13-17 Bailey, C 2003, Fire Behaviour, University of Manchester, Retrieved on 24 January 2010, < http://www.mace.manchester.ac.uk/project/research/structures/strucfire/Design/perfor mance/fireModelling/fireBehaviour/default.htm#top> Chitty, R 1994, “A Survey of Backdraught, Home Office. Fire Research and Development Group,” HMSO, London Grimwood, P 2008, Euro Firefighter, Jeremy Mills Publishing Ltd, West Yorkshire. Read More