The Origin of Fire - Assignment Example

1. Give a definition of fire, include an appropriate diagram Fire originates from release of intense thermal as well as luminosity from express grouping of oxygen and additional substances. For a fire it is necessary that a flammable material must be there, the process of combustion requires high temperature and ample oxygen to maintain express incineration. The flame, which produces the illumination, is a collective energy of several shining particles of smoldering substance and shimmering gases. The fire consists of “vaporized fuel, oxygen, carbon dioxide, carbon monoxide, water vapor etc.” The chemical equation responsible for fire is as follows: “C3H8 + 5O2 --> 3CO2 + 4H20” 2. Identify the different stages of fire growth, include an appropriate diagram There are five stages involved in the “Fire Growth” 1. Detonation 2. Pre-flashover stage 3. Flashover 4. Post-flashover stage 5. Cooling stage 3. Explain the difference between pre-mixed and diffusion flames, and provide some practical examples of each. In a diffusion flame, oxygen and fuel diffuse mutually; at the point of meeting the occurrence of flame takes place whereas, in a premixed flame, the oxygen and fuel are pre-mixed previously leading to the generation of an entirely unusual category of flame. An instance of a premixed flame is a standardized flammable mixture enclosed within a tube that is ignited by a sparkle generating a blaze alongside with tube. The ratio of fuel oxidizer is stable in premixed flames whereas in the diffusion flames it differs all the way through out the fire. Candle flames are the finest example of the diffusion flames. 4. What are the 5 functional requirements of Approved Document B? The five practical necessities of Approved Document B are as follows: a) The structure should be designed and constructed with ample supplies for precipitate fire caution systems and suitable, secure and strong escape route to abandon in case of fire. b) To control the intensification of fire within construction the objects utilized in coating inside structures is necessary to reasonably oppose the fire dispersion over it and if ignited a sluggish rate of temperature release or conflagration growth, sensible as per circumstances. c) The inner structure is supposed to be designed and built in a approach that in case of fire it ought to be stable for the utmost period and it must oppose the flames diffusion among two buildings with an enough arrangement for the smoke discharge. d) The outside walls and roof of formation should defy the fire to swell over from a building to another having hold to operation, height and pretense. The blueprint of structure should be well architected to ease fire-fighters in defending lives with a satisfactory supply of coherent facilities. e) It must also offer sufficient gap for the fire equipments to pierce into the building. 5. There are two broad standards for the design methods of fire resistance of buildings: prescriptive and performance-based. Explain the difference between them. Prescriptive method describes a building’s inferno design somewhat precise in basics of the resources concerned, outline and amount of structural fundamentals, intensity of fire safety equipment and erection detail etc. The blueprint proposals are generally foundational on the practice with identical or parallel usual fire tests. Though, a performance oriented process for structural blaze design is similar to the protocol of scheming constructions to wind loads and seismic impacts. The part of a structural module will be explicit and a set of intent tests will be set that allots the evaluation of fire performance in relation to the key realistic important factor. 6. What are the two categories of fire testing? Explain the difference between them The two categories of fire testing include lab tests to estimate detonation and the stretch area of flames and UL2221 tests to assess the resistance power of a material against fire. The major segregation between the duet techniques are that UL2221 tests measure a material’s power of endurance to uphold its basic configuration for the interval of a conflagration while, the DIN 4102 tests are intended to measure the detonation timing of a material and inferno distribution resolves the instant engaged by the combustion to ignite and broaden in a specific area of a room. 7. Why is it important to carry out more than one experiment to test the same parameter? It is very important to execute more than one experiment due to the undeniable fact that different techniques adapted in the different tests can possibly reveal different outcomes due to the potential cause of fire. While performing only one test, there’s an increased chance of getting positive result. To double check the outcome it is essential to perform more than one experiment on the same parameter in array to avoid wrong results. 8. What factors influence the severity of a fire within a compartment? There are a number of aspects which influence the severity of a fire in surroundings of a compartment, some of these are: Smoldering behavior of materials, together with mass failure and energy discharge rates Behavior of totally urbanized fires, together with the role of aeration, heat development and time interval. Structural reaction to conflagration Kind of construction material used. Outcome of heat rise inside the structural member on the applicable properties of the member Applied structural load intensity Dimensions of compartment Model thermal reaction of assemblies. Vent location Fuel load 9. How is heat transferred in a compartment fire? Include a diagram Primarily, there are only two methods of heat transfer in a compartment fire. Heat is energy conveyed due to a heat disparity. It can happen due to conduction and radiation where: Conduction is a molecular energy conveyer Radiation is an electromagnetic energy conveyer starting from a body owning thermal energy designated by the high temperature. Conduction is represented by “Fourier’s law” which affirms that “flux-energy flow rate per unit” area is straightforwardly relative to the temperature rise. 10. Explain the term “flammability limits”. The utmost and the least concentration of the gas within which fire can stretch are called “Flammability Limits.” Flammability limits are dependant on the stress and heat. 11. Draw a graph/ diagram to illustrate the flammability limits of flammable vapors 12. Define the term “limiting oxygen index Limiting Oxygen Index is utilized to verify the oxygen index, which is the least oxygen concentration requisite to prop up candle like downward burning incineration. It in fact serves as a measure of the easiness of extermination of material. This investigation method is proficient of generating statistical data covering a very extensive range of responses but is out of place as a interpreter of real scale fire performances. This experiment is generally used as a quality control tool in the manufacturing units. 13. What does it mean if a sample has a high LOI or a low LOI Higher LOI in a sample signifies superior fire retardancy whereas; the lower LOI represents the inferior fire retardancy. The test technique is usually reproducible to an accurateness of “+ 0.5%” and the LOI has been utilized comprehensively to assess the qualified flammability of “rubbers, textiles, paper, coatings and other materials” 14. Explain the ignitability test? This technique is utilized to assess the fire performance of a structure material subjected to an impingement by an undersized flare, for instance the blaze of a match. The method is used to endow with substantiation in the purpose of whether a construction material possibly will be allocates the “Euroclass E.” build materials that do not congregate the necessities of this construction material rank are selected as “Euroclass F.” 15. The cone calorimeter can be used to measure a number of different parameters from experimental fires, what are they and which one is the most important in determining the fire hazard performance of materials? The parameters are ignition time, mass loss rate, combustion products, heat release rate and additional parameters linked with the matter’s flaming properties like smoke-specific annihilation area and effectual heat of incineration. It also contains resolvance of rate of progression of toxic gases for instance CO, HCL, and HCN. The acquired results are possibly employed for evaluation of fire vulnerability and in forecasting the full-scale conflagration performance, via links or all the way through PC fire modeling. 16. What are the criteria for when flashover will occur There are several criteria for flashover to occur, some of these are: 1) The upper gas temperature. 2) The radiant heat flux and 3) The heat release rate 17. Once ignition has occurred what is required to maintain combustion? 18. What are the basic two types of uncertainty found in measurements? Give an example of each. The two types of measurements uncertainty are: 1) heat release rate measurement uncertainty 2) quantitative indication measurement uncertainty 3) Presented below are 10 heat release rates for a piece of laminated wood at 25.00kW/m2. 19. Calculate the range, the mean, the standard deviation and then the uncertainty in the mean and the uncertainty in the standard deviation. Test 1 2 3 4 5 6 7 8 9 10 Heat Release Rate @ 25.00kW/m2 44.80 42.15 42.97 43.60 43.88 44.80 42.79 45.10 41.62 43.74 20. In the table below there is a set of results obtained from the “Bang Box” experiment. Plot a graph which will best show your results and state what the results show. Fuel Acetone Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Number of Drops 2 6 10 12 14 16 18 20 Height attained by lid (cm) 0 20 40 80 120 150 110 90 21. What are the four main classes of ignition The four main classes of ignition are Straight heating Encouraged ignition Frictional heating, and Reflexive impact 22. In relation to the characteristics of building materials give definitions for the following terms: a. Combustibility, b. Fire propagation, c. Fire resistance, and d. Surface spread of flame. Combustibility – the capability of a substance to act as a fuel to facilitate the process of combustion in the presence of air to release ample heat energy. Fire propagation - Fire resistance - fire-resistance rating usually refers to the time period for which a reflexive fire shield system can endure against a regular fire resistance test. This can be quantified merely as a calculation of time, or it might need a congregation of other criterion, concerning other facts of functionality or robustness for rationale. Surface spread of flame – 23. Explain what the two major mechanisms of burning are The two major mechanisms of burning are: 1. Gas phase flaming combustion 2. Glowing combustion 24. How can fire spread between buildings There are two ways in which fire is possible to spread between two buildings, which are: a. By the uncontrolled blazes from a conflagration in one structure unswervingly impugning on an adjoining building, or b. Via radiated heat from the structure on fire igniting the adjoining building. 25. Define the term “fire plume”. Identify and explain the different regions within a fire plume. Read More