Fire Triangle Science Essay

Fire Triangle Science EssayChemistry of Fire unit 36 Forensic Fire Investigation2/3/2015Windows UserContentsFire Tetrahedron scallywag 2Primary Sources of Ignition..Page 3 indirect Sources of Ignition..Page 4Methods of ExtinctionPage 5Heat Transfer..Page 6Different Types of Fire..Page78BibliographyPage 9Reference ListPage 10Fire TetrahedronHere is a diagram of the good time tetrahedron.This diagram shows the three elements that have to be present in order for a fire to occur. Combustion only occurs when flamm adequate vapours be mixed with group O and are ignited by a spark or flame.FuelA fuel is any substance that quite a little undergo combustion such(prenominal) as forest, plastics, rubber, fabric, petrol, cooking oil, nail vanish extractr, butane, natural gases and propane. This is needed to fuel the fire. constitutional fuels contain carbon hydrogen and oxygen in varying ratios in some cases, nitrogen will be present such as wood, plastics, gasoline, alcohol and natural g ases.Inorganic fuels contain no carbon and include combustible alloys such as magnesium or sodium. oxygenOxygen is need for a fire to begin beca put on when oxygen in the air combines with inflamm equal vapours admitn off by fuels they create a crop of heat at a molecular level.HeatHeat is produced in a fire when oxygen and flammable vapours from the fuels combine, once this happens a reference book of ignition is the needed to cause it to combust.Primary Sources of IgnitionIgnition is the act or process of initiating combustion. (dictionary.reference.com, 2012).A primary source of ignition is when you expose a flammable aspiration to an open flame and causes fire directly.Here are a number of primary sources of ignitionCooking AppliancesSpace-heating AppliancesElectric Wiring, Connections or Terminations otherwise Electrical Appliances e.g. washing machines, bed warmers and televisions.CigarettesMatchesGas LightersBlow-LampsBlow TorchesWelding torchesBonfiresCandlesSecondary S ources of IgnitionA alternate source of ignition is where a flammable object is heated until its burning point. During a house fire the primary source will be ignited which will consequently cause a secondary source to ignite which will ignite the furniture. According to the Journal of Fire Sciences An important aspect of many secondary sources is that they frequently occur in areas where they use cannot easily be controlled or restricted.Examples of secondary sources of ignition areWaste paper basketsSoft toysFurnitureCurtains/blindsNewspapersCarpetMethods of ExtinctionA fire can be extinguish if any of three components in the fire triangle that cause a fire (heat, oxygen and fuel) are removed.Removal of HeatTo remove heat from a fire or cool a fire, water is most commonly used. Water has great heat absorbing properties. The water is able to extinguish a fire as it is able to absorb more heat than the fire is generating.Removal of OxygenA fire can be extinguish by removing or lim iting its oxygen supply. To do this it is known as toping or smothering. You do not need to remove all of the oxygen supply to extinguish a fire, a reduction of oxygen below 6% is sufficient enough to extinguish a fire. Examples are snuffing prohibited a lit candle, placing a lid on a chip pan fire and closing doors and windows if there is a fire in a fashion it may burn itself out.Removal of FuelAccording to Chubb.co.uk, 2014A fire will go out if deprived of its fuel supply. A fire caused by a gas leak can be extinguished by turning off the gas. If pallets are stacked in the open, rather than against a store wall, they will eventually burn out, leaving the warehouse and its contents out of danger.Heat TransferHeat can be transferred from place to place by conduction, convection and radiation. Dark matt surfaces are better at absorbing heat energy than light shiny surfaces. Heat energy can be helpless from homes in many different ways and there are ways of reducing these heat losses. (bbc.co.uk, 2014)ConductionHeat energy can move with a substances by conduction, metals are very good conductors heat, whereas non-metals and gases are poor conductors of heat. The poor conductors are called insulators. The heat energy is conducted from the hot fetch up to the cool end of an object.The electrons in a piece of metal can leave their atoms and are free to move around in the metal as free electrons. The parts of the metal that have left behind atoms become charged metal ions, the ions are packed closely together and vibrate continually. The hotter the metal the more kinetic energy the vibrations gain, this energy is then transferred from the hotter parts of the metal to the cooler parts by the free electrons. As these electrons move around in the metal they collide with ions as they go. (Bbc.co.uk, 2014)ConvectionThe particles in liquids and gases are able to move around more freely, as they are not packed together similar solids. Convection occurs when parti cles in liquids and gases with a lot of heat energy move and take the places of particles with less heat energy, this is how heat energy is transferred utilize convection.RadiationAll objects give out and take in thermal radiation which is also known as infrared radiation. The hotter an objects gets the more infrared radiation it emits.Infrared radiations is a sign of electromagnetic radiation that involves waves instead of particles unlike convection and conduction. Due to this radiation can even work through the vacuum of space. This is why we are able to rule heat of the sun even though it is 150 million km away from the earth.Different Types of Fire fireside FiresHouse fires are fires that break out within the home and there are many different causes for them such asCareless smokingLit candlesElectrically appliances getting left onArsonCooking equipmentHeating equipmentChildren playing with fire insideInadequate wiringFlammable liquidsChristmas tree decorationsA house fire co uld spread by either conduction, convection or radiation depending on which one of the above started the fire. If the fire is a small fire within the house a fire blanket or water can be used to extinguish it. If you have access to fire extinguishers a water extinguisher is good for burning paper, wood or soft furnishings, a foam extinguisher is good for an arson fire, as petrol or other fuels would probably have been used. Then a CO2 extinguisher is good for putting out fires caused by electrical appliances. If the fire has spread through most of the house and is a lot bigger, then the fire brigade would put the fire out with water. Wet chemical extinguishers were designed to extinguish fires in the kitchen involving burning oil and deep fat fryers. House fires can be prevent by being careful when using appliances, flammable liquids, candles and decorations, they could also be prevented by getting your electrics check every socio-economic class or so.WildfiresWildfires are fires t hat break out in the wilderness, the causes of them includeArsonLightningUnattended campfiresBurning of debrisCarelessly discarding of cigarettesA wildfire would generally spread by convection, as they would be in contact with an open flame which could be one of the following. A wildfire could be extinguish by a helicopter or plane throwing water over the fire from above or by the fire brigade with water, They could also be put out with leaf blowers, as this will blow the fire in the direction that it has already been meaning it has nothing else to catch fire too. Wildfires can be prevent by using fire breaks, people to comply with laws and regulations and never leave a fire unattended.Petrol FiresPetrol is a dangerous substance and it is a highly flammable liquid. The petrol gives off a vapour which can easily be set on fire if it is not handled safely. The causes of a petrol fire areArsonPetrol LeakCar CrashSpark at Petrol Station e.g. using a mobile phone, smoking.Petrol fires ar e able to spread using conduction and convection, to extinguish these types of fires a foam extinguisher, CO2 extinguisher or a powder extinguisher is best being used. As these extinguisher will place a layer of powder or foam over the fire starving it of oxygen. These can be prevent by people not smoking or using their mobile phone at a petrol station and people comply with laws and regulations.Bibliographyhttps//answers.yahoo.com/question/ business leader?qid=20110106060151AAjbfWohttp//www.chubb.co.uk/utcfs/Templates/Pages/Template-66/0,,pageId=14542siteId=403,00.htmlJournal of Fire Science Standard Flaming Ignition Sources for Upholstered Composties, Furniture and Bed Assembly Tests.http//www.readersdigest.ca/home-garden/cleaning/top-10-causes-house-firesQMoRMblOIpwYaxGA.97http//www.hse.gov.uk/fireandexplosion/petroleum.htmhttp//www.fireservice.co.uk/safety/extinguishersReference ListChubb (2014) Methods of Fire Extinction. procurable at http//www.chubb.co.uk/utcfs/Templates/Pa ges/Template-66/0,,pageId=14542siteId=403,00.html(Accessed on 11th February 2015)Dictionary.com (2012) Ignition. Available at http//dictionary.reference.com/browse/ignition(Accessed on 10th February 2015)GCSE Bitesize (2014) Heat Transfer and efficiency. Available at http//www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/energy/heatrev2.shtml(Accessed on 11th Febrauary 2014)K.T. Paul S.D Christian. (1987) Standard Flaming Ignition Sources for Upholstered Composties, Furniture and Bed Assembly Tests. Journal of Fire Sciences, 178 (5), pp 179(Accessed on 11th February 2015)Chemistry of FirePage 1