Passive and Active Fire Protection Systems, Types of Fixed Fire Fighting Installation - Literature review Example

Running Header: Fire Protection Student’s Name: Instructor’s Name: Course Code & Name: Date of Submission: Contents Introduction ………….. Fire Protection Introduction To begin with, the following are the important things to cover in the assessment of fire protection, the assessment will focus on: - safety designs solution, passive and active fire protection systems, types of fixed fire fighting installation, building construction materials, and identification of appropriate building codes and approved documents. There are two fire protection designs. The prescriptive fire protection design and the performance based fire protection design. The prescriptive design has some design limitations; it does not provide many details about the performance of structures under high temperatures. This information is very important in avoiding collapse disproportionately. Performance –based –fire design (PBFD) is very popular because of its flexibilities especially on the performance objectives. This is a design which ensures high safety levels. (Kodur 1992, p.35-54) Passive and active fire protection systems The passive fire protection federation (2005), defines passive fire protection as all the primary criteria integrated within constructions or buildings, with an aim of providing congenital fire safety and most importantly, by responding against heat, smoke and flames; they hold all the crucial essentials of a building, providing safe exits, stability of structure, compartmentation, and separating fire. They basically achieve their function by advancing the resistance of structures, offering protection to the structure from the effects of fire. They also reduce the spread of fire through re-ignition ,passive designs restricts motion of flame and smoke thus minimizing dangers of distortion or collapsing of buildings. The passive fire protection design comprise materials for protecting fire, safeguard the structure of the building and belittle costs for rebuilding and serviceability after a fire outbreak. Fire compartmentation limits the severity of fire by dividing a building into various compartments resisting fire, this is mainly done through putting up fire resisting walls, doors and floors, and they offer physical barriers to fire. The main intention of compartmentation is to control fire from the source and avoid spreading to other parts. According to Hui Xie et al (2007, p.17-41), non combustible construction is one of the passive fire protective systems; these are building materials which cannot catch fire easily. These are constructions which are fully fire resistive; a building in which the materials used cannot get ignited and burn when there is a fire. These materials may be the linings, floors, walls, and roofs. Fire dampers are used in ventilations and air conditioning ducts mainly to prevent fire from spreading and also prevent smoke from entering a building. Fire dampers are mainly installed by contractors made of sheet metals inside the ducts. They are used in the maintenance of the right rating of fire barriers. i.e. floors, partitions and walls, when infiltrated by ductwork. When there is increase in temperatures, the fire damper closes and prevents any spread of fire across the barrier. Fire resistant cables resist high temperatures. They are used in fire resistant management circuits, conditions where installation requires high temperatures and in the public address and exigency voice systems used in communication mostly in multistoried buildings. Fire barriers are placed within the premise to control spread of fire; they are non combustible mattresses which are flexible, they are galvanized on one side with a wire mesh. They are available in two forms, either unfaced or one faced with a foil on one or two sides. Barriers are mainly used where large cavities requires compartmentation. For example in cavities found under metal, concrete and decks which are timber made cavities which are above suspended ceilings, and in timber roofs. According to Phil and ED (2009, p. 277), active fire protection is the designs for automatic control and prevention of fire. They are fitted in areas which are of high risk such as kitchens. The devices use chemicals, water, and gas to extinguish fire. Active Fire Protection within the building include: fire extinguishers; this is a protective device used mainly in controlling small fires in emergency situations, it mainly not intended to control fires which are beyond or out of control. There are three types of fire extinguishers. The first one is powder extinguishers; these are extinguishers that can be used in various classes of fire, they get excellent fire put off. They are mostly be used in fires involving electrical faults, they cool down fire very fast. In some instances powder extinguishers create visibility problems and breathing problems, therefore, they require a specialist. They must not be used on metal fires. Carbon dioxide extinguisher is the second type of extinguishers; they are used for fires mostly involving electrical equipment, this is because they don’t cause any further damage. The last type is the wet chemical extinguisher mainly for commercial catering; this type works by hungering fire of oxygen because they varnish the burning fluid thus preventing the burning vapor from reaching the atmosphere. Fire doors are the closed doors, and fire resistant doors, they are kept closed for use during emergencies. They restrict spread of fires and offer escape routes when there is an outbreak of fire within a premise. Automatic smoke and heat ventilations collects smoke and heat concentration it in a special place at a high roof level, releasing it outside. This help in maintaining layers of smokes above the height of the head and allows people to use escape routes.hey are used together with smoke alarms; they sense smoke automatically and raise an alarm ,alerting people of an emergency. Figure 1 Fire extinguishers fitted on walls, used to put off small fires. (Neil 1999, p.26) Automatic fire detection is fitted within the premise to raise alarm and create awareness, when there is an outbreak of fire. Automatic fire detectors control emergency measures such as release of water or emitting gases to control a fire. The creation of emergency exits is a major boost to the efforts in fire protection. These are doors and window located in a special way and places within a premise, with it main aim being escapes when there is an outbreak of fire within the premise. Smoke ventilations also serve a very important role in active fire protection because they pass smoke outside a building. This is crucial in preventing deaths which arise from choking when smoke concentrates within the building. There is also fitting of automatic sprinklers within the building to release water in case of a fire outbreak. The sprinklers are automated to release water when they sense or detect fire outbreak. Pressurisation is a method of using pressure to pump clean air and eliminate toxic air in escape routes within a building. Figure 2 figure 3 Fire barriers (Neil 1999, p.61) Chars from burnt wood. (Neil 1999, p.133) How fire sprinklers work Fire sprinklers are automated to control spread of fires within the premise. According to Minnesota Department of Public Safety, a sprinklers head is made of plugs which are held by trigger mechanisms mostly made of glass ampules and filled with a glycerin liquid. This liquid expands when exposed to heat. This liquid is designed that it expands and breaks the tubes at a certain temperature; the most common being at 155 degrees centigrade. The plug is pushed out by the pressurized water which is placed behind it. It is deflected away by the edges. The water sprays over the plate and distributed in an even pattern by the design of the plate. This goes on until the main value is shut down. A small smoldering fire basically acts like a heat engine, it increases the air temperature which placed directly above the sprinkler when the hot air rises, it fans to the ceiling and heats the sprinkler head which I near it. Immediately when the mechanism trigger heats to the right temperature, it activates and water released cooling the heat source. Figure 4 An automatic sprinkler fitted on the ceiling of a building. The sprinkler is automatically triggered to release water incase of fire outbreak. (Neil 1999, p.102) Automatic fire suppression system operates mainly without the assistance of human being; this means that it is has the qualities of detection, propulsion and delivery. This system accomplishes its detection through electrical and mechanical means. The mechanical detection uses links which are fused or have thermo build detectors, designed separately at a very specific temperature; they eject tensions on a release mechanism. On the other hand Electrical detection makes use of heat detectors which are equipped with a self-restoring, commonly open contact which close when a preset temperature is gained. When this is achieved by means of installing pipes and nozzles, designed specifically to the agent used and coverage wanted. Fire suppression can also use remotes and local manual operation. Key effects of a fire on the building materials According to Martin (2011, p. 1-16), the kind of materials used in construction and the manner in which the materials respond when exposed to high temperatures, clearly shows how the building will respond in case of fire. Different materials respond differently to fire. Exposure of concrete to high temperatures makes it to crack; this reduces the strength of the building especially multistoried buildings. However fire loosens the bondage of the concrete as it makes concrete loose water. This is a threat to heavy buildings as they are likely to collapse. Brick wood and block woods can cope well within many structures, however, extreme heat makes the masonry blocks to expand and crack. Many people prefer steel as they argue it is the strongest material for construction, it is mainly used for reinforcing concrete. When steel heats up, its molecular structure weakens making it to loose strength. Steel expands when heated .This is likely to cause the collapse of structures. The main use of glass windows and doors; glass is very weak when exposed to heat, it has very little resistance to fire and cracks very quickly. Wood on the other hand is not resistant to extreme heat; it burns so fast. Even a little fire can warm up wood. Wood fire spreads so fast. Wood is in many cases used for doors, roofing, and ceiling of most buildings. Wood shrinks, forms chars and blisters when ignited. Wood starts by warming up, to completely burning to ashes. A wooden building completely gets destroyed by fire. Plastics are also used in construction, but their main disadvantage is that all plastics are combustible. A plastic melts very quickly when exposed to heat; if the heat is minimal plastic materials get coiled and lose shape. Most importantly nothing can be added to plastics to make them non-combustible. Dry and wet risers J.A,Eng and Fimech (1998, p.9-16), clarifies that a dry riser is a vertical pipe which distributes water to various levels of a premise as a whole element of systems of suppressing fire. There are two types of risers, the drier riser and the wet riser. In the wet riser the pipes are kept full of water, they manually and automatically fight fire. In the UK they are mainly controlled by the building, regulations 2000, and the minimum standards. A dry riser on the other hand is the pipes which uses pressurized air instead of water. The air in dry risers holds remote controllers called dry pipe valves which are in a shut place and found in a heated place. These valves for the dry pipes keeps away water from getting in the pipes until when flames causes sprinklers to work when this comes about, air escapes then the dry pipe controllers releases and water then goes in the pipes, and flows through the open sprinklers onto the fire extinguishing it. See figure below for more details. Figure 5 Dry and wet riser (Neil 1999, p.69) Types of fixed fire fighting installation There are various fire fighting installations, mostly installed within the buildings for example, automatic fire sprinklers, emergency lighting, pressurized stairwells, fire doors, fixed smoke ventilation And Automatic smoke alarms. Fire Codes and approved documents There are many codes meant to streamline fire protection within buildings as indicated by the National Fire Protection Association; the authority that oversees the safety of fire, electrical and buildings. Among this codes include:- NFPA 1 fire code, NFPA 3,recommended Practice on commissioning and Integrated Testing Fire protection and life safety systems, NFPA 10 standard for portable fire Extinguishers, NFPA 12 standard of carbon Dioxide Distinguishing Systems, NFPA 13 standard for installation of Sprinkler Systems, NFPA 70E Standard for Electrical Safety in the workplace, NFPA 72 National Fire Alarm and signaling code, NFPA 80A Recommended Practice for Protection of Buildings from Exterior fire exposure, NFPA 101 life safety code, NFPA 220 standard on type of Building Construction, NFPA 257 Standard on Fire test for Window and Glass Assemblies, NFPA Standard for Combustible Mental among many others. These codes and many others must be adhered to by all constructions and premises to help maintain the right standards for fire safety. Among the approved documents for buildings include: - The fire safety for buildings, structure of the building, the ventilation documents and the electrical safety document .There are also regulations such as the building act 1984 and the building regulation 2000 which are applicable to new building works for example the construction, and extension of materials. These regulations impose which cover: - Compartmentation to prevent spread of fire means of escape in case of fire, reduction of spread of flame over surfaces of walls and ceilings, the stability of structures and fire resistance of elements of structure. A new construction must have all these approved by the local building control body before it commences. Conclusion Fire has been known to be one among the leading disasters in the world. There has been a major concern on fire outbreak management and protection. Though many countries have been fighting effortlessly to prevent deaths arising from fire within buildings, much more have to be done especially in these days of improved technology. According to fire statistics monitor (2008), Total fires in buildings in the UK fell by 6% to 84, 500, this is a continuous decline from the previous 4% in June the same year. This decline was attributed to the rise in awareness on fire protection both from within the government and the private sectors. There is also need to improve the fire fighting facility by equipping them with modern equipments and manpower so as to completely minimize fire outbreaks. As much as we carry on with our daily chores, public must be sensitized thoroughly on fire control and how best they can avoid reckless fires. Law enforcement is the key to solving fatalities from fire, by ensuring all the premises and buildings have adhered to the set standards and codes as set aside by the National Fire Protection Association .This war fire protection will be won if all the involved stake holders come together for a common goal. Reference Fire Statistics Monitor 2008, fire statistics, viewed 26 March 2011, Hui Xie et al 2007, ‘Signate Legibility Distance as a Function of Observation Angle’ Journal of Fire Protection Engineering ,vol. 17,no.5,pp. 17-4. J.A ,Eng and Fimech 1998,Smoke Control by Pressurisation, 3rd edn,Flakt Woods Ltd.pp.9-16 Kodur, V.1992, ‘Introduction of Basic Concepts’, Journal of Fire Protection Engineering, vol.7, no.3, pp.35-54. Martin, G 2011, ‘Fire resistance of structures’ Viewed 26 March 2011, National Fire Protection Association 2011, Codes and standards, viewed 26 March 2011, Nail, W 1999,Images of Fire: Fire fighting, David and Charles Publishers, United Kingdom. Passive fire Protection Federation 2005, passive fire, viewed 25 March 2011, Phil, H. & Ed, H. 2009, Introduction to Health and Safety at Work, 4th edn, Elsevier Ltd, United Kingdom. Read More