Scientific Principles for Fire Professionals - Essay Example

Scientific Principles for Fire Professionals Name Institution Name Course Name and Code Date 1. Describe, with the help of a suitable sketch and in detail, the working principle of a cone calorimeter. Assume that you are given a plaque of a solid material and asked to characterize the fire behaviour of it, as fully as possible, through cone calorimetric measurements: A cone calorimeter is made of different parts that are used to accomplish designed requirements (Schartel and Hull 2007). The different parts enable adjustment of several parameters, set, log and measure these parameters (Grexa and Lübke 2001). The following sketch presents information on the different parts that forms a cone calorimeter. Cone calorimetry testing analyses the behavior of materials and products when these are exposed to a source of ignition and heat (Grexa and Lübke 2001). The benefit of cone calorimetry testing is the low cost and quick method of fulfilling research requirements. The cone calorimeter can be used to measure different products and materials other in liquid or solid form (Morgan and Bundy, 2007). The cone calorimeter then collects information on temperature and oxygen to determine the behavior of the material or product (Spearpoint and Quintiere, 2001). In most instances, the product and material are tested in a horizontal position but sometimes the vertical approach is preferred if the product targeted is aimed to be installed vertically. Numerous advantages are associated with the use of a cone calorimeter (Spearpoint and Quintiere, 2001). Some of the advantages include lower test cost when compared with and cheaper since small samples are tested. The lower transportation costs mean that the sample can be tested without much obstruction (Morgan and Bundy, 2007). Multiple samples can be collected, which can be tested within a short time resulting in obtaining of comparison data. The comparison can be made on tests before the experiment and tests after the experiment. Hence, cone calorimeter provides numerous benefits in accomplishing research requirements. a. Briefly describe the experimental procedure you would adopt The experimental procedure usually takes four general approaches. The four approaches include specimen preparation, furniture calorimeter calibration, photography and test procedure (Morgan and Bundy, 2007). The test process starts with the placement of the sample in the holder. It is followed with the sample holder fitted into the cone calorimeter. The sample product is then exposed to the heating element (Grexa and Lübke 2001). A spark is then utilized to cause ignition of the sample (Zanetti et al. 2002). The combustion byproducts are then released and directed towards a duct where the emitted gases are then analyzed. The test is continued until a time in which the combustion is completed, or if time-based, the combustion is allowed to the end of the combustion. These numerous tests are premised on the principles of BS 476-15: 1993 and ISO 5660-1: 2002 (Morgan and Bundy, 2007). The calibrations are the integral component of the entire research because it provides information on measures that determines the behavior of the material and product (Spearpoint and Quintiere, 2001). The gas analyzers and the smoke measurement system for carbon dioxide, carbon monoxide and oxygen in the flue gases and therefore, these instruments are required to be active throughout the experiment (Grexa and Lübke 2001). In the measurement of the samples, the sample should be specific in size. For example, the standard specimen size is 100 × 100 mm2 while the thickness is 50 mm (Morgan and Bundy, 2007). The sample is enclosed in an aluminum foil in which a small space is left so that the exposure can be premised. The baseline is usually 60 seconds in which appropriate information and data can be collected and analyzed. b. What are the major experimental parameters that you could consider and measure? Numerous parameters are measured including the oxygen consumption, heat released and the temperatures (Grexa and Lübke 2001). During combustion period, oxygen is required to accomplish the combustion processes. In the process, heat is released, which is measured in terms of temperature (Spearpoint and Quintiere, 2001). Other physical components include physical changes that are directly linked with warping or intumescence, which can be accomplished through the use of restraining equipment. In addition, other factors can be obtained through testing. These includes time to ignition of the specimen, total heat release and smoke production (Morgan and Bundy, 2007). Others include the calorific value of the product, the physical behavior of the material, total heat release and total heat release plotted against time (Spearpoint and Quintiere, 2001). Furthermore, specialized software can be utilized for prediction of a material performance on the single burning item tests (Grexa and Lübke 2001). Hence, the experimental parameters are numerous that the cone calorimeter can be used to measure. In the experimental design, a direct relationship between the heating value and the oxygen consumed exists (Spearpoint and Quintiere, 2001). The heat release rate us obtained through calculation of oxygen concentration in the flue gases. The significance of the data and measurements are important in fulfilling the fire study requirements (Morgan and Bundy, 2007). The data can be utilized in developing new products and materials, ranking of materials based on fire performance, prediction of material fire behavior and fire modelling. Therefore, the cone calorimeter approach enables collection of different information, which are important in completing research requirements. c. Explain how you would determine the critical heat flux for this material Critical heat flux is the thermal limit of a product or material where a phase change results during the heating process (Grexa and Lübke 2001). The phase inhibits the heat transfer efficiency resulting in localized overheating of a specific point of the material (Spearpoint and Quintiere, 2001). It is the lowest amount of thermal load per unit area that starts the ignition process. Regarding the solid material, the critical heat flux occurs when the ignition begins because it prevents the transfer of thermal energy resulting in the fire incident. 2. Describe the toxic effects of combustion products in a real fire, paying particular attention to CO, CO2, HCN and oxides of nitrogen. The smoke that emits from any fire incident contains a mixture f chemicals and particles produced because of burning of carbon containing materials (Stec and Hull 2011). In most burning incidents, the emissions include particulate matter, carbon dioxide and carbon monoxide (Purser and McAllister 2016). Other consequences of combustion include dioxins, metals, styrene, toluene, benzene, polycyclic aromatic hydrocarbons, nitrogen oxides, sulfur dioxide, acid gases, and aldehydes. Exposure to combustion toxins affects the health condition of the person exposed (Assael and Kakosimos, 2010). Inhaling the toxic components of combustion for a short time can cause immediate effects. It includes irritation to the throat, nose, and eyes while also causing nauseating effects (Stec and Hull 2011). Exposure to carbon monoxide causes temporal changes in lung function creating breathing challenges. Inhalation of carbon monoxide decrease the effectiveness of the body to accumulate and distribute oxygen (Purser and McAllister 2016). Limited access to oxygen cause reduce alertness, headaches and worsens cardiovascular diseases (Assael and Kakosimos, 2010). Further exposure to the carbon components worsens medical conditions such as heart diseases and asthma, shortness of breath and respiratory irritation. Potential chronic conditions occur depending on the amount of exposure and extent of exposure (Purser and McAllister 2016). For example, long-term exposure increases chances of mortality especially to people such as firefighters (Assael and Kakosimos, 2010). The deaths result in either direct exposure to the smoke or additional complications associated with exposure to the smoke. The combination of the different chemicals and toxicities causes an addictive effect (Hajovsky and Pies, 2012). For example, the common toxins associated with combustion include carbon dioxide, carbon monoxide, and nitrogen oxides worsens the health condition of an individual (Assael and Kakosimos, 2010). Hypoxia is a common problem associated with the combination of carbon dioxide and carbon monoxide. However, the common problems are on HCN and carbon monoxide (Stec and Hull 2011). Carbon monoxide acts as an asphyxiant in that it binds with hemoglobin more than how it binds with oxygen. Extensive exposure to HCN contributes to penalization of asphyxiation and respiratory muscle (Purser and McAllister 2016). The HCN and carbon monoxide hurry death through working synergistically by attack the functions of respiratory inhibiting the effectiveness of oxygen use and oxygen delivery. Generally, exposure to carbon monoxide, carbon dioxide, HCN and oxides of nitrogen affects the human body because it limits the effectiveness of the respiratory system (Stec and Hull 2011). The fires reduce the amount of oxygen while the other toxicities binds to the body easily compared with oxygen; either exposure in the short term or long term, the common symptoms include irritation of the eyes and throats and limitation of lung functions (Anseeuw et al. 2013). Exposure to these toxins requires immediate medical assistance based on the nature of the fire, and health condition of the individual (Assael and Kakosimos, 2010). References Anseeuw, K., Delvau, N., Burillo-Putze, G., De Iaco, F., Geldner, G., Holmström, P., Lambert, Y. and Sabbe, M., 2013. Cyanide poisoning by fire smoke inhalation: a European expert consensus. European Journal of Emergency Medicine, 20(1), pp. 2-9. Assael, M.J. and Kakosimos, K.E., 2010. Fires, explosions, and toxic gas dispersions: Effects calculation and risk analysis. CRC Press. Grexa, O. and Lübke, H., 2001. Flammability parameters of wood tested on a cone calorimeter. Polymer Degradation and Stability, 74(3), pp. 427-432. Hajovsky, R. and Pies, M., 2012. Measuring System for Longtime Monitoring and Visualization of Temperature and Toxic Gases Concentration. Elektronika ir Elektrotechnika, 122(6), pp. 129-132. Morgan, A.B. and Bundy, M., 2007. Cone calorimeter analysis of UL‐94 V‐rated plastics. Fire and Materials, 31(4), pp. 257-283. Purser, D.A. and McAllister, J.L., 2016. Assessment of hazards to occupants from smoke, toxic gases, and heat. In SFPE handbook of fire protection engineering (pp. 2308-2428). Springer New York. Schartel, B. and Hull, T.R., 2007. Development of fire‐retarded materials—Interpretation of cone calorimeter data. Fire and Materials, 31(5), pp. 327-354. Spearpoint, M.J. and Quintiere, J.G., 2001. Predicting the piloted ignition of wood in the cone calorimeter using an integral model—effect of species, grain orientation and heat flux. Fire Safety Journal, 36(4), pp. 391-415. Stec, A.A. and Hull, T.R., 2011. Assessment of the fire toxicity of building insulation materials. Energy and Buildings, 43(2), pp. 498-506. Zanetti, M., Kashiwagi, T., Falqui, L. and Camino, G., 2002. Cone calorimeter combustion and gasification studies of polymer layered silicate nanocomposites. Chemistry of Materials, 14(2), pp. 881-887. Read More