Aspects of Fire Behaviour - Article Example

FAILURE MODES Name Class Date Aspects of fire Behaviour Fire always behaves differently depending on the circumstances it is on. Generally, fire may burn quickly, fiercely and extremely hot while others may burn evenly and slowly. All these different fires also burn with different colours. They produce toxic fumes when they burn and in unventilated area they can cause death. The aspect of fire behaviour depends on the fuel that supports combustion. In order for a fire to burn there are several conditions that are to be available in the situation. These variables can include oxygen availability, weather conditions, fuel and terrain (Hoard, 1967). In the absence of these conditions fire might not combust at all. Therefore this paper aims in enumerating the aspects of fire behaviour of plastics, wood, steel and concrete in fire conditions. It also seeks to identify different types of failure modes occurring in structures and signs of collapse and its hazard in construction. The aspect of fire in plastics is examined through different ways based on the standards one wants to consider in. These considerations will enable us to retard fire by examining the possible effect of fire under additives and extinguishers. According to Gabriel (1991), additives give self-extinguishable power to the property, and when it burns it produces toxic fumes to the environment. The fumes emitted are highly corrosive in nature and the cause damages to electronics and other appliances. Many studies of the aspect of fire have proved that plastic combustion produces mainly toxic gases which cause danger to the people and their environment. In conducting the aspects of fire on plastics we have to evaluate it using the product type, its gases to emit, laws behind combustion and its effect on polymer. Therefore the behaviour of plastics in fire will depend on the self- extinguishable grade, oxygen index and the flammability of the plastic (Gabriel, 1991). These aspects enable the combustion process to occur. Wood material supports combustion thus when heat temperatures are raised, wood structure also begins to change. The wood will begin to decompose tending to the increased thermally temperatures of the polymeric components of the wood producing highly volatile gases (Harada, 2007). When the appropriate air to volatile gas is reached, oxidation takes place which leads to combustion of the wood. The combustion of wood therefore leads to production of smoke and other toxic fumes to the atmosphere which also cause damages to human beings and their inhabitants. This study showed the aspects that can lead to combustion of fire by analysing on the rate of flame produced, rate of ignition and ease of extinction, smoke and toxic gas evolution and rate of heat release. Therefore we can conclude that wood can combust fire in the presence of thermally decomposing elements that leads to oxidation of wood elements to support fire burning (Harada, 2007). Wood burns highly in fire to release smoke and other toxic gases to the atmosphere which are dangerous to all inhabitants. Steal are mainly used in the architecture area due to their resistance change in fire they can provide. Steal can be exposed to more than 600 degrees Celsius and still no damage can occur in the building. This gives an advantage in the construction of high-rise building in the world. According to Serah (2003), if steal structures do experience collapse due to exposing them in extreme temperatures, the collapse will remain localized only to that area that experienced the high temperatures. Many low carbon steel maybe used but when exposed to high temperatures they will become flexible hence they will cause topple and sagging of structures. The use of structural steel is the best to be used. In high temperatures of fire of more than 600 degrees it still resist and it cannot bend to cause topples like the low-carbon steel. In more than 900 degrees the structural steel only depreciates by 10%. Hence the aspect of steal in fire varies depending on the type of steel used for combustion (Serah, 2003). Concrete are materials that are mixed together from filler materials and water embedded together in binder to fill the space and glued together. Concrete materials also can be exposed to fire of different temperatures either low or extremely high temperatures. The aspect behaviour of fire in concrete determines the durability of structures built. Concrete has more resistant to fire than many steel used in the structural this is because it has lower heat conductivity thus lasting longer (Harada, 2007). Concrete has been used as a shield against fire and it offers protection to steels too. Concrete has been used in building for missile launcher due to their resistance in combustion. Therefore the behaviour of these concretes shows that are the best elements being used in the structural area due to fire resistance capability. Types of Failure modes A failure mode refers to the situation where a machine or equipment may failure to work in its operation. Failure modes occur almost daily in our lives (Shebl, 2009).Therefore in order to understand these failure modes; we are going to look out the types of failure nodes we encounter in our lives. Premature operation is a type of failure mode that occurs before the operation is implemented. In construction, buildings may reveal premature operation in all phases. Collapse of concrete walls is a sign of premature operation that has taken place before the building if fully completed. From this phase there shows preliminary errors in the construction of the structure (Hoard, 1967). Failure to operate at the prescribed time is a failure that only reveals itself during the time of execution. Lack of executing the intended purpose will exhibit failure mode to operate at the prescribed time. Failure to operate at the prescribed time shows that the process is done incorrectly hence changes should be considered. This is the time where structure is supposed to behave in a way expected by the experts yet it never goes through (Hoard, 1967). This type of failure is discouraging since most parts of the structure are completely done and they show errors thus a failure mode to operate at the prescribed time. Failure to cease operation at the prescribed time is a type of failure mode that is caused by errors in the structure construction. The machine will not stop at the intended moment their leading unfortunate error (Shebl, 2009). Experts were gladly that the equipment was in good position to handle services. By giving it a try it had errors that it couldn’t stop at the exact time it is supposed to stop. This type of error is the failure to cease operation at the prescribed time. Failure during operation is a type of error that occurs as the machine or equipment is going on with the operation. The operation will stop as the machine encounter this failure mode. This failure mode is distructictive in nature as it causes damages to the structures (Shebl, 2009). Degraded or excessive operational capability a failure mode that produces less amount or more amount than the required level. This may lead to inferior products and increase costs of production of the structures (Shebl, 2009). Signs of collapse and collapse hazards in construction Collapse in construction has been a major issue to use sophisticated methods in construction of these building structures. Some of the signs of collapse in building constructions include cracks on the walls of the building, poor foundation that does not support more storey building construction, weather changes and fire. Cracks on walls are key elements revealing the building durability. Cracks show shoddy work hence any moment the building can collapse (Lancaster, 2005). Poor foundation layout also reveals the sign of collapse among large storey building construction. Other secondary signs of collapse include weather condition such as earthquakes and hurricanes and also the availability of terrorism threat is huge signs of collapse. Many of these construction sites exhibits collapse hazards of various kinds. These collapse hazards include exposure to energized electrical wiring, hazardous materials, flammable natural gas and other toxic gases, airborne diseases and dust, water leakages in sewer, insufficient oxygen, structural instability and explosives devices by terrorists (Lancaster, 2005). All of them render a collapse construction structure in a hazardous state. References Gabriel. P. H., and Macskasy. M. J., (1991). Plastics: Their Behaviour in Fires. Elsevier Science Ltd. Harada, T. Y., and Nakashima, A. Y., (2007).The effect of ceramic coating of fire-retardant wood on combustibility and weather ability. Wood Science: 53(3):249–54. Hoard, A. C., And Taylor, R. J., (1967). Design Analysis Procedure For Failure Modes, Effects and Criticality Analysis (FMECA). Society for Automotive Engineers. ARP926. Lancaster, G. V., and Lynne. N. K., (2005). Concrete Vaulted Construction in Imperial Rome. Innovations in Context. Cambridge University Press. Shebl, N. A., Franklin, B. D., and Barber N. T., (2009). Is failure mode and effect analysis reliable? 2009, 5: 86–94. Serah, I. L., (2003). Structural use of steelwork in buildings. Code of practice for fire resistant design 59(5):8-23 Read More