Sunday, July 28, 2019
VII Hazardous Chemicals Multiple choice and two essay questions
VII Hazardous Chemicals Multiple choice and two questions - Essay Example In case the material does not drip but remains at the immediate site of combustion, they thermally decompose and ignites spreading the fire (Meyer, 2010). When polymeric material burn, they decompose producing a considerable amount of gases and vapour. As the decomposition process continues, the gas might migrate and accumulate elsewhere especially near the ceiling. Here, they mix with atmospheric air then ignite causing the flame to spread further. Through a phenomenon called flashover, decomposition of a polymer can be caused by heat conducted, or radiated from another point. Combustible gases produced by thermal decomposition ignites and spread the fire to other room or sections. At flashover, safe exit from a room is not possible, and the living condition of a room are usually unbearable with the rooms temperatures ranging from 600 - 800-degree centigrade (Meyer, 2010). In addition, the vapour and gases produced by polymeric fire are dangerous and fatal. They include nitrogenous, sulfurous gases. A high concentration of carbon monoxide is also produced. If in an enclosed area, the level of these gases soar to a dangerous level within few minutes. The fire may affect areas far away the source. The hot gases and vapour produced can spread by convection through ventilation systems and other openings and end up affecting people elsewhere in the building. Polymeric fire produces a considerable amount of soot that when inhaled draws toxic gases into the bronchi and lungs (Meyer, 2010). Of all the three gases produced, Carbon Monoxide(CO) can be the most dangerous to the Environment, Health and Safety or the Fire Services professional responding to the scene. Once inhaled, the gas combines with the haemoglobin in the blood circulation system and converts into carboxyhemoglobin that causes an ineffective delivery of oxygen to the body tissues. At concentration levels of
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