The Power of Fire and Fire Dynamics - Assignment Example

Enclosure Fire Dynamics Student’s name Institutional affiliation Enclosure Fire Dynamics Question 1 In a burning compartment, there is the concentration of a variety of gases, changes in atmospheric pressure and temperature. The concentration levels of the emitted gases depend on the burning fuel, the aeration area, and the capacity of the structure. When temperatures are too high in the burning furnace, the atmospheric pressure on the surroundings also drops. When combustion occurs, apart from the products formed, light and heat are also emitted. According to Solomons (2012, pg 68-69), these high temperatures will decompose some of CO2 to CO. This is the reason behind the presence of some traces of CO a few meters from a burning furnace with a 5MW bouncing fire. The power of this fire can decompose CO2 naturally found in free air. Therefore, since CO itself is toxic to humans and other animals, staying around a burning structure without risk is dangerous. Question 2 PMMA [Poly(methyl methacrylate)] is a polymer that is formed by condensation of –[CH2-C(CH3)-CO-OCH3] (methyl methacrylate); which is its repeating unit. PMMA has a brittle behavior that makes it fit for car windows; in a case of an accident, no glass cuts to victims. PMMA produced via radical polymerization is very amorphous. Rubber toughening has been applied to it, making it tougher owing to its brittle value. During firebox experiments, PMMA is preferred. PMMA has a lower density than glass, which is 1.17 – 1.20gcm-3. PMMA is stronger as compared to both glass and polystyrene. PMMA catches fire at 4600C and burns to produce CO2, CO, H2O, and other low molecular weight compounds. It does not contain the harmful compound bisphenol-A, unlike other glasses such as polycarbonate. PMMA goes decomposition through end-chain scission. When a compound undergoes end-chain scission, obviously, it has a brittle value. At the same time, due to its slow decomposition, there is an indication that the forces holding its molecules together are very strong. That is why PMMA has showed a stronger value as compared to both glass and polycarbonate. All these characteristics listed above, PMMA becomes the most preferred compound to be used in a burning furnace or firebox experiments. Question 3 In ethene, the double bond linking the two carbon particles is two pairs of shared electrons. The fact underlying these two pairs of shared electrons is; they are not same as each other. During combustion, for instance, one of the bonds easily breaks as compared to the other Bond (Solomons 2012). One pair of the shared electrons is detained on the procession that links the nuclei of the two carbon atoms. Another pair of the electrons that are shared is detained in a molecular orbital above and below the procession amid the nuclei of the carbon atoms of the particle. A molecular orbital refers to a section inside a particular molecule where there is an elevated likelihood of finding shared electrons. The line linking the carbon atoms stands for a usual bond where you will expect the shared electrons to be. This is sigma bond. It holds one couple of the joint electrons in alkenes, and more specifically in ethene. The shaded region above represents the region that holds another pair of shared electrons. They are free to move anywhere in the region; between the two halves and it is called a pi bond. During combustion, the pi bonds break away first followed by the sigma bonds. This is because the pi bonds are not beneath the full management of the carbon nuclei. Since they recline just on top of the molecular plane and below it, they are easily broken by external factors such as combustion (Solomons 2012) Question 4 This structure is a carboxylic acid. This structure is an ethyl pentanoic acid. Bonds that will break away from this compound during combustion include the pi bonds, sigma bonds, C-O bonds and C-H bonds (Solomons 2012) Question 5 The Fire Association Protection (2008) give different meanings of types of burns as follows; burns that affect merely the superficial layers of the skin are commonly referred to as superficial burns. When damage infiltrates into a number of the layers beneath the skin surface, it is known as partial-thickness. With full-thickness, the injuries penetrate to each and every one of the skin layers, and sometimes muscle and bone. The kind of treatment required depends on how severe the burn is. Superficial burns can be managed with simple pain relievers such as cooling with running tap water. Partial-thickness burns require dressing after cleaning them with soap and clean water. The blisters should be left intact. Full-thickness burns require surgical treatment; skin grafting. An eschar is a piece of dead tissue that is usually cast off from the skin surface. An eschar can be allowed to cast off naturally or sometimes it can require surgical removal. Surgical removal is applied for infection prevention, especially to patients who are immunocompromised. If, for instance, an eschar is on a limb, assessment of peripheral pulses should be done to ensure circulation is not compromised. In case, the circulation is compromised, the indication of surgical incision is required. Substances that are used to slough off dead tissue are known as escharotics. These substances can be Medicines such as imiquimod. Other examples include metallic salts, CO2, acids, and bases (Fire Protection Association 2008). Lund and Browder's chart is the most accurate method for assessment of burns area, especially in children. However, the accuracy of the chart will depend on if it was correctly used. This chart is accurate because it gives compensation on variation in the shape of the body and age of a child. It is crucial to expose all the burn and assess it. The environment is kept warm and small portions of the skin exposed to maintain normal body temperature since the skin is no more working as a thermoregulatory organ; it is damaged. In a pigmented skin, all the loose epidermal layers are removed to calculate the size of the burn (Fire Protection Association 2008) Question 6 According to Karlsson & Quintiere (2008, pg 109), a fire model refers to a mathematical formulation that is intended to forecast or predict the character or nature of fire and the effects it can cause on its environs. A compartment fire model is commonly used to analyze the effects of fire on one or more compartments inside a building. These effects include the compartment temperature, gas species concentrations, smoke production rates, fire duration and visibility, and ventilation effects. Compartment fire models include zone and field. With zone fire models, during fire development a compartment can be divided horizontally into two zones: an upper zone where the hot gases and smoke produced during combustion can be stratified against the ceiling; and the lower zone where the fire burns. Examples of zone fire models include CFAST model and BR12 model. There are many types of field models that are available. One of the field models is a two-dimensional finite-difference that was developed to forecast the movement of smoke and hot gases and their concentration in the seating area of an aircraft cabin (Garbett and Pharr, 2011). The zone models have low memory requirements; they can represent large buildings or structures, they are easy to use, and they have a structured output. Their advantages include inaccuracies and a priori assumption; input parameters derived from empirical data. The fire field models are very accurate as compared to zone fire models. However, they require large and fast computers with more memory as compared to the zone fire models (Garbett and Pharr 2011). References Karlsson, B., & Quintiere, J. G. 2008. Enclosure fire dynamics. Boca Raton, FL, CRC Press. Gorbett, G. E., & Pharr, J. L. 2011. Fire dynamics. Upper Saddle River, N.J., Pearson. Fire Protection Association. 2008. Fire prevention. London, Fire Protection Association. Solomons, T. W. G. 2012. Organic chemistry. New York, Wiley. Read More