Fire Investigation Processes - Essay Example

FIRE INVESTIGATION PROCESSES (Student Name) (Course No.) (Lecturer) (University) (Date) Introduction Within the construction industry, fire safety is an important aspect that every design needs to consider. Several factors cause fire; therefore, fire investigators need to develop methods that would guarantee early detection before the occurrence. Smokes can increase the negative effects of fire disasters. Fire investigation as a systematic line, it is an inquiry method with an aim of determining where and how the fire began. To achieve such objectives, there need to respond to the fire scenes, observe the fire patterns, and considering the circumstances surrounding the incident. Most fire investigation methods often involve systematic approach that follows a series of steps. As a scientific approach, systematic method of fire investigation involves recognition of the principles and procedures while pursuing knowledge and involves recognition and formulation of the problem, collection of information by observing and conducting experiments. According to The Scottish Government, smoke from the fire often spread very fast (The Scottish Government, 2016). Smoke and poisonous gases that it contains are very dangerous which is most cases are the major factors that hurt people not the flames. Smoke and Fire Incidences To reduce the level of risks to people from fire, it is significant to consider the methods of controlling or restricting the spread of smoke and fire. Most people always succumb to deaths and injuries in fires since they are overcome by smoke. To evaluate the risks, fire investigators need to appreciate the manner in which fire grows and how the smoke spreads within the building. Fire in a building normally generate smoke which in most cases is thick and black; as a result, it obscures vision, causing breathing difficulty, and blocking the escape routes. Smoke is a serious threat to the lives of people and does not require underestimation. Fire usually spreads through convection, convection, and radiation methods. Convection spread method causes a great proportion of the injuries and deaths. Whenever fire starts within a building, the smokes rise from the fire and become trapped within the ceilings before spreading in various directions (Furness & Muckett, 2007, 15). Consequently, the smoke forms an ever-deepening layer over the whole spaces within the room. The smoke then passes through the holes or gaps within the walls, ceiling, and floor to other parts of the buildings resulting into massive destruction. The heat from the fire is trapped within the building and the temperature rises with certain materials used for construction absorbing the heat rapidly. Such materials include metal beams that absorb heat through conduction where it can set fire on combustible materials, which are in contact with heated materials. Smoke Detection Mechanisms With the increasing level of technology, several devices and programmes have been developed to monitor fire and smoke activities. Moreover, there are fire alarms in most building to detect fire incidences or extreme increment in temperatures. the mostly used programmes and devices include Fire Dynamics Simulator (FDS), Smokeview (SMV), and FDS+Evac. FDS is computational fluid dynamics (CFD) model used in analyzing and detecting fire-driven flows such as smokes. Besides, the programme solves any numerical form of the Navier-Stokes equations majorly appropriate for the thermally driven flows, low speed, and much consideration on the smoke and heat transportation from the fires (Crawford, 2002, 133). However, SMV is visualization programme that majorly displays the output generated from the FDS and simulations from the CFAST. FDS+Evac is a simulation model used for evacuation used with FDS. Majorly, the fire investigators use the programme in stimulating the movements of the people during evacuation situations. It is possible to integrate the evacuation simulations with fire simulations to guarantee proper safety within a building. Currently, the computational modelling is applicable in different fire scenes. FDS plays a significant role in modelling different types of fire incidents. However, for its success, there is need to enter thermal parameters that relate to the reactions occurring during fire incidences into the mathematical model. As a result, it is used together with fire reconstruction and actual fires. Modelling is used in cases of fires in different buildings. For example, the simulations of the heat detectors are used in detecting fires within the buildings. Furthermore, the National Institute of Standards and Technology (NIST) utilized the FDS programme in conducting extensive investigation and reconstruction of various fire scenarios, which resulted in the collapse of the World Trade Centre Towers. Figure 1: Images Generated from SMV Fire Investigation Progress The process involves analysis of all fire related incidents upon extinguishing the fire by the fire fighters. The incident area requires preservation for collection and analysis of accurate evidence. Moreover, the process includes undertaking a close survey on the damages of the scene to establish the fire origin and cause. To effectively examine and evaluate the fire scenes, it is significant that the investigators have knowledge on chemistry and behavioural features of fire and effects. For fire to occur there is need for a fuel source, sufficient heat energy, and an oxidant. It is important to note that solid and liquid materials do not actually burn, but the heating processes make them to produce vapours that burn through pyrolysis. Flame colour often vary depending on the nature of the combusting materials and determined by the wavelength of the light emitted. Ignition Ignition only occurs if all the conditions for starting a fire are met that produces either smouldering or flaming fire. Such activities are induced through addition of heat to a fuel in the air. The temperature required for the occurrence of ignition varies with fuel. The minimum temperature at which the favour of the fuel is ignited momentarily is the flash point while the flame point is the minimum at which sufficient vapour is produced to allow continuation of combustion. Smouldering Not every fire produces smouldering that is a form of flameless combustion occurring at the surface if the material in a cellulosic substance that forms on the solid char. The availability of the smouldering fire is featured through extremely localized combustion and production of a smoke that is thick and tarry. The surface temperatures links to the colour of the smouldering since colours produce significantly different temperatures (Liu & Cassady, 2014, 20). However, the propagation rate depends on the combusting material and the amount of oxygen available. For smouldering combustions to occur there is need for low concentration of oxygen. With adequate supply of oxygen, the smouldering fire often produces flame. The common cause of smouldering fire is the cigarettes left in contact with the upholstered furniture. Spontaneous Combustion Spontaneous combustion involves sudden ignition of the material without any external ignition source such as flame of sparks. The process occurs due to the exothermic chemical reaction that occurs within the material and release heat. When the materials are piled together, it is almost impossible for heat to dissipate effectively which makes the temperatures with the materials to rise. Consequently, such temperature increments cause acceleration of chemical reactions, which produces, even more, heat. Such temperature can rise to an extent that it causes ignition. The spontaneous combustion is often characterized by the apparent fire source being at the material centre as dissipation of the heat occurs readily from the surface which results in centers reaching highest temperatures. Fire Scene investigation The main objective of fire investigation is to establish the origin and cause of the fire and make conclusions whether natural accidental, or deliberate. The process is vital to establishing the cause of fire and ensures such events do not occur. The major concern within the fire incident scene is the safety. Such areas present increased risk factors of potential hazards associated with heated materials, damages of electricity and gas mains, structural collapses, and toxic substances in the air (Liu & Cassady, 2014, 22). Therefore, it is important to conduct a dynamic risk assessment, declare the scene safe, and avail protective wears such as hardhats and fire resistant overalls. Before commencement of the investigation, there is need to switch of the gas and power supplies. Several sources of information exist for the fire investigators. Besides the programmes and simulation systems, the fire investigator might as well acquire information from the witnesses. Witnesses often provide information of the building prior to the occurrence of fire and information regarding the fire such as suspicious activities and the colour of the smoke. To some extent, the witnesses take photographs or video recordings. Moreover, the planning department might provide details of the content and layout of the building. However, it should be noted that witnesses might be unreliable. Fire fighters also provide critical information on the source of fire, any unusual condition noticed, and distances made while extinguishing the fire. Scene examination is also important. There is need to restrict movements within the fire scene with cordon with an aim of preserving the evidence and allowing access to authorized personnel. Moreover, the plan is required is to establish specific location of objects with considerations that fire fighters might have caused disturbances. Scene examination needs to commence with external examination of the area, which allow the fire investigator to identify the entry points, signs of the forced entry, indications of the possible origin and causes of fire, and other important safety measures (Fire Protection Association, 2015, 214). Examination of the doors and windows is important to establish whether they were locked during the fire incidence or not though it is important to note that the fire extinguishers might have smashed the entry points while providing ventilations. External examinations also allow searching for relevant items to the fire incident including tools used to break into the building and containers of substances considered flammable. Nonetheless, temperatures and wind could affect both the smoke and fire in terms of propagation and direction. Internal examination is also important. Establishing the Origin The important aspect of the forensic fire investigate is to establish the origin or the seat of fire. Numerous factors are available to determine the possible fire origin. The areas of origin usually burn for long duration, hence experiences the worst damages. Fire always burn upwards; thus, reflecting the existence of the seat of fire at the lower point. However, the concept might be unreliable as fire can spread downwards due to availability of the fuel sources. The effects on some materials could indicate the fire direction. The deposits of the smoke on various objects might suggest the direction of origin with materials such as glasses and plastics bending towards the fire. Therefore, distortion of such materials might act as fire directional indicators. Damages on the building might as indicate the fire origin. In some cases, building might collapse in a manner that the area first weakened by the fire is clear suggesting the area that fire damage first occurred. However, the method might not be accurate as collapse and damages of a building could have been affected by different factors. It might as well be possible to determine the origin of the fire based on the operations of the smoke and fire alarms. In most building, the fire alarm systems or the simulation programmes record information on the areas were first to experience fire within the room. There could as well be multiple sources of fire origin with some cases indicating activities of the arsonists. Nonetheless, burning the wallpapers or debris could as well produce apparent distinct ignition points. Due to the range of factors influencing the fire origins, it might not be possible to point of fire ignition. As a result, the fire investigators need to define their radius of errors. From the analysis of the potential causes of fire, it is clear that there are several factors likely to trigger the scenario. The fact that smoking activities in some cases triggered the occurrence of fire incident does not translate to it being the major cause of fire. The fire investigators have to examine properly the potential cause of fire incidents rather than hypothetically viewing smoking activities as the major cause. Conclusion Fire accidents caused by smoking activities have been on the rise. However, it does not stand out as the major cause of fire incidences occurring within the buildings. Therefore, the fire investigators need to employee adequate measures that would assist to establish the potential cause of fire rather hypothetically assuming the smoking incidences. Determination of the fire cause is assisted through location of the seat of fire or objects associated with ignition. The aim of the investigators is to establish whether the cause of fire was deliberate, natural, and accidental. The evidence linked to the fire incident might be found at the point of origin like fuel sources, electrical appliances, and incendiary. With the current rate of technology, there are programmes and devices that act sources of evidence that make it easy to undertake scene examination. The programmes include FDS and SMV. References Crawford, J. A. 2002. Fire prevention: A comprehensive approach. Retrieved from https://www.pearsonhighered.com/program/Crawford-Fire-Prevention-A- Comprehensive-Approach/PGM36336.html Fire Protection Association. 2015. Fire safety and risk management: For the NEBOSH National certificate in fire safety and risk management. London: Routledge, Taylor & Francis Group. Furness, A., & Muckett, M. 2007. Fire safety foundations. Introduction to Fire Safety Management, 7(4), 1-29. doi:10.1016/b978-0-7506-8068-4.50007-5 Liu, Y., & Cassady, S. 2014. A modified critical velocity for road tunnel fire smoke management with dedicated smoke extraction configuration. Case Studies in Fire Safety, 2(1), 16-27. doi:10.1016/j.csfs.2014.09.001 The Scottish Government. 2016. Consultation on a Revision to Fire Safety Guidance for Care Homes and the Quality Assurance of Persons who Offer Fire Risk Assessment Services. Retrieved April 21, 2016, from http://www.gov.scot/Publications/2012/04/5893/12 Read More