Firefighting Tactics and Forensic Awareness - Article Example

FIREFIGHTING TACTICS AND FORENSIC AWARENESS Name: Institution: Tutor: Subject: Date: The main operating standard procedure for responding to fire outbreaks has been to force entry, pull lines and to set up PPV fan to aid interior operations. This method was useful in the past but due to advanced technology, new methods have been developed. This paper describes fire fighting tactics and the speed of response. An effective fire fighter is the one who consider the changing dynamics of structural fire. There are several causes of fire such as synthetic fuel, lightweight construction. In the homes today most of the furniture is made of synthetic fibre that are air-opened and they can develop fires quickly. Structures made of lightwood frames burns easily. These includes wood truss for supporting the roof and the floor. The combustion rate of lightwood construction materials is higher than the traditional materials. Fire need to be investigated to establish the cause, the origin or the conditions. According to NFPA921, 2011 edition, there are some methods that can be used to investigate the fire. The most recommended method is scientific method. The method provides an organization with desirable analytical processes that are important for successful fire investigation. The Scientific method is a basis for engineering processes such as fire investigation. It follows some steps that include: Receiving the assignment- the person who is responsible for investigation should be notified his/her role. For example, if he is expected to identify the cause, write a report, make recommendations, etc. The other step is preparation for the investigation that involves plan development for investigation. This step is very critical because it determines the efficiency of the investigation. It involves acquirement of resources, personnel, equipment and tools for the investigation. After planning, the investigation is carried out in the fire scene. In the scene, all relevant data is collected from the eye witnesses for analysis purpose or presentation to the court. The next step after data is collected it is to analyze using scientific method principles. The origin of the fire should be explained in detail. This require the establishment of a hypothesis. This method ends with a conclusion where a final hypothesis is formulated. This is followed by reporting the outcomes. Kirk’s fire investigation, the seventh edition was written by John D. DeHann (Forensic scientist) and David J. Icove. This edition is up to date with detailed essential skills. It relates closely with NFPA 2011 edition 921: Guide for Fire and Explosion Investigation and NFPA 2009. Kirk’s investigation addresses all the kinds of fire and covers areas such as fire behaviour and building construction, electrical causes of fire, explosion and explosive combustion, ignition sources, laboratory services and arson as a crime. Fire is grouped into four classes; A, B ,C, D and K. class A fire is made up of ordinary combustibles such as wood, trash, papers, etc. These compounds leave ash when burnt. Class B fires consist of flammable liquids which include oil, gasoline among other liquids. This class can be stopped by any agent that prevents oxygen from being supplied to the fire. Class C is mainly electrical energy fires. Class D is composed of combustible metals such as Titanium and Magnesium. Finally, class K fires mainly originate from the kitchen and are caused by cooking oil, fats or grease. In the UK, fire services and fire standards were officially established by Home Office in1958. Subsequent revision and re-definition of the services have been made. This guidance consists of categories that describe fire risks and the formulas for determining fire grading. Home office set criteria that require fire services to respond to an emergency must meet the minimum requirement about speed and weight of attack. Category “A” is for the large cities with big industrial and commercial properties and the probability of fire to spread are high. The least suggested first response is three pumps to attend, two to attend within five minutes and one to attend within 8 minutes. This recommendation is expected to be achieved in about 75% of such incidences. The other category “B” is built up in small towns with small industries, factories and wide-ranging shopping centres. In this category, two pumps were recommended, one to arrive within 5 minutes and the other one within 8 minutes. Category “C” is for residential areas that are dominated by flats or flats and light industries. Only one pump is suggested and should attend within 8 minutes. Lastly, category “D” is built on rural premises, farms and villages. Like “C”, only one pump is needed to attend the scene within 20 minutes. This standard faced some criticisms recently, and many complained that it was not operating 24 hours and for this reason, new standards have been set. This new standard increased the achievement of the risk categories A and B, which are mainly commercial areas. The standard also aims at improving life risk response as the commercial risks’ response is maintained. In responding to fire crisis some tactics for fire fighting (NIST, 2008), water is used to extinguish the fire. While using water, firefighters should apply water immediately to an accessible compartment especially from outside IDLH environment. This tactic of using water is appropriate to departments with less number of staff. Water extinguishers are suitable in fighting fires related to flammable solids such as wood and papers. It can also be used to extinguish fires caused by alcohol. This tactic should not be used in flammable liquids, gases and alkaline solutions because there will be sharp reaction Research has shown that, when water is applied using a solid pipe quickly through a window to the affected room, cooling is enhanced before entry without pushing the heat or fire through the structure as it was traditionally believed. Another tactic used to fight fire is the use of foams like CAFs. Compressed air foams (CAFs) have high demand in the market because of their ability for rapid response and portability. They are also used to produce class B foam that is useful for extinguishing flammable liquids and hydrocarbon responds. CAFs have the ability to control fires in a variety of environment. Use of CAFs in first-line emergency response uses several applications that include: helideck and heliport fire protection according to CAP 437. Burner CAFs (16-30) are appropriate for small fire fighting public buildings, vehicles, airports, fuel transportation systems refineries, mines and petrochemical sites. They are highly demanded in most parts of America. CAFs are suitable for tetrahedron fire shape because it covers all corners with “foam blanket” preventing the fuel from mixing with oxygen. It cools the scene by insulation where the air is trapped between the bubbles which prevent excess heat. CAFs also stop chemical reaction that could promote fire. CAF, therefore, works by creating a barrier between the fire and the fuel. This tactic is better than water. Fire can also be controlled by use of dry agents and chemical additives. Dry chemical is developed for use in A, B and C fire disasters. They can be installed with pipes, be standard skid or trail mounted. They are integrated as large pressurized extinguisher cylinder. They work by creating a barrier between the oxygen and the fuel for class A fire events. Dry powders are also used to distinguish fire and they work in the same way as dry chemical. The only difference is that it creates a barrier between the fire and oxygen by the heat from the fire. This type of extinguishers is only suitable for class D fire caused by combustible metals. Other chemical additives that are used to put off the fire are the clean agents. The clean agent also known as halogenated extinguishers uses halogen agents, and the most recent clean agent uses halocarbon that does not deplete the ozone. These extinguishers stop the fire by interrupting the chemical reaction of the fire. The clean agent is suitable for class B and C fires although larger extinguishers can be used for class A. Carbon dioxide fire extinguishers work by removing the oxygen element in the fire and also cool the fire by applying a very cold substance. They are effective in class B and C fires and not appropriate for class A fires. Strategic ventilation is another effective tactic for controlling fire spread. Ventilation is the removal of fire gases, smoke and heat in a systematic way while replacing them with a cooler air (IFSTA, 2007 p 541). It is a process that involves the exchange of air inside with that from the outside atmosphere. However, ventilation allows the supply of oxygen which encourages fire, therefore, strategic ventilation is recommended. Ventilation is useful in fire tetrahedron. Sufficient supply of oxygen affects the combustion of fuels, and this is influenced by ventilation profile of a compartment. Large amounts of ventilation increase the rate of heat release to the needed amount of flash over and lowers the time of flashover. This results in heat loss and the gas and smoke leaves the compartment. The thermal loss discourages the development of fire because there is a limited supply of oxygen to sustain flaming. Thermal heat loss also minimizes the rate of chemical reaction within the compartment. There are factors influencing a compartment ventilation control; the size of the compartment, its structure and ventilation profile. Openings increase oxygen supply to the fire, and thus fire inlets should be reduced so that a compartment becomes ventilated controlled. Extreme fire cases can be experienced in a ventilation controlled buildings (Hartin, 2008). The speed difference between fire flashover and backdraft can cause an extreme fire. Backdraft involves explosion that results in rapid release of energy while ventilation flashover increases the speed of heat release. Tactical ventilation requires some critical decisions to be made. These decisions include direction and location: this answers the question on the direction of removed smoke and heat. The ventilation here is indicated either as horizontal or vertical and the exhaust location, as well as inlet location, are also identified. Ventilation tactic method should involve the use of pressure and buoyancy of hot smoke and gases in combination with ambient wind conditions. This is referred to as natural ventilation and in most cases this is not sufficient and the addition of energy by use of hydraulic and mechanical methods. To control fire, ventilation should be sequenced properly. For example, ventilation tactics should not be operated before hose lines are placed to increase the rate of air supply. The advantages of tactical ventilation are: it reduces fire spread, faster fire fighting, minimal fire extreme behaviour and less property damage. Isolation of fire is an approved practice by Fire Indication Panel. This practice is applied in buildings, galleries and in places where live events are carried out. The practice is placed in areas where naked flames, smoking, vapour, etc. online isolation procedures include: fire detection system, fire suppression system and fixed installation such as fire pump. The request for fire isolation should follow a procedure. Fire alarms should also be installed in buildings and commercial premises so that, in the case of fire outbreak the concerned persons will be notified in time. In conclusion, it is important to investigate fire to establish its origin, cause and effects among several other things. NFPA921, 2011 edition outlines the scientific approach to fire investigation. There are several tactics that can be used for fire fighting and it includes: use of water, foams, carbon dioxide, dry chemicals and dry agents. REFERENCES . Waxman and Markey, Reps., “American Clean Energy and Security Act of 2009,” US Congress, HR2454, 15 May 2009. Hodges, S. E. and McCormick, S. J.,(2009). Evaluation of Fire Suppression Agents for Protection of Occupied Spaces in Military Ground Vehicles, Proc. Ground Vehicle Survivability Symposium (GVSS). International Fire Service Training Association (IFSTA). (2007) Essentials of firefighting, (5thed.). Stillwater, OK: Fire Protection Publications. Gary Bawker (2015). Firefighting Tacticsto Beat 21thcentury Fire. Retrieved from: .http://www.firerescue1.com/fire-attack/articles/1315403-Firefighting-tactics-to-beat-21st-century-fires NFPA 33, Standard for Spray Application Using Flammable orCombustible Materials, 2011 edition NFPA 53, Recommended Practice on Materials, Equipment, and Systems Used in Oxygen-Enriched Atmospheres, 2011 edition. National Institute of Standards and Technology(NIST) (2008, March 22). NIST evaluatesfirefighting tactics in NYC high-rise test. ScienceDaily. Retrieved March 27, 2008, from http://www.sciencedaily.com /releases/2008/03/080318182728.htm Hartin, E. (2008, April). Extreme fire behavior: Understanding the hazards. Paper presented at IV Stručni Skup Vatrogasaca, Opatija, Croatia Read More