Landuse analysis of Famagusta Walled City Essay

Landuse analysis of Famagusta Walled City - Essay Example If this trend continues unabated the city will be hollowed out both physically and socially; what is known as the doughnut syndrome. Moreover land is a finite resource and for an island like Cyprus which is an aggregarian island and much of its income depends on what it is able to grow, because this encroachment upon its green field not only eats up arable land but also destroys its biota. Even though several researches have been conducted on this specific area but they have offered palliatives rather than concrete or practical tools for implementation. This paper aims to highlight sustainable ways in which the city should be allowed to expand and develop and to bracket ways in which the theories advanced can be implemented in the city. Implementing this theory would mean redesign and development of the unused spaces according to smart growth theories and principles that oppose everything negative growth stands for. This constitutes tools for compact urban development which include the development of Brownfield sites, infill and mixed use of development and transit oriented

Competitive brand management plan Assignment Example | Topics and Well Written Essays - 2500 words

Competitive brand management plan - Assignment Example The brand activation at this occasion will allow the Co operative healthy brand to build strong relationship with the consumers by helping them to form New Year’s resolution regarding healthy eating and lifestyle. This will also make it easy for the Co operative healthy brand to develop direct associations in the mind of the customers between healthy eating and the Co operative healthy brand. Background Situation: There has been drastic increase in the overall obesity rate all over the globe. In the region of UK around quarter of the adult population are classified as obese (NHS, 2012). This in turn has increased the health concerns among the people. The consumers are shifting towards healthier lifestyle and are giving preference to the healthy and balanced food items as shown in the image below: (Kimmell, 2009) There has been growing shift in the overall consumer purchase behaviour as consumers are giving preference to the foods and drinks which are providing more health bene fits as shown in the image below: (Datamonitor, 2009) This increasing preference for the healthy food items has provided opportunity to the health retailers and supermarkets to provide the customers with different health foods. This in turn has given rise to different own health brands. Co operative food healthy brand is also competing in this category and is trying to increase the market penetration and improve the overall brand image. Brand Positioning: Brand positioning is used in order to present and describe the competitive advantage of a particular brand against other competitors in the industry. This means that brand positioning presents how the brand will compete with the competitors in effective and efficient manner. It is important to keep in consideration different elements and factors in order to come up with effective and long lasting brand positioning (Kapferer, 2008). Goals and Objectives: The goal of the co operative healthy brand is to become the most preferred heal thy brand in the region by increasing overall awareness of its healthy products and encouraging the consumers to shift towards healthy life style and eating. For achieving this goal certain brand objectives have to be fulfilled, which are as follow: The co operative healthy brand should increase the interaction with consumers in order to improve the overall brand awareness and image The co operative healthy brand should provide customers with more value and benefits The co operative food have to provide more promotion and shelf space to its own healthy brands The co operative food healthy brand should improve the overall brand experience of the customers Brand Inventory: It is important for the brand to maintain and manage attractive and easy to access brand inventory in order to increase the brand interaction and awareness. The brand inventory can include brand colour, the logo, tag line, and even the physical location (Keller, 2008). The Co operative food and healthy brand use gre en and other fresh colours

Groups and Teams Paper Essay Example | Topics and Well Written Essays - 750 words - 1

Groups and Teams Paper - Essay Example Harvey Dubin (2005) stresses the need for high performance team: "A high-performing team will produce innovations and results that take the company to the next level." He further adds that this "will reduce costs, increase productivity, shorten time for research and development, and get products and services to market faster." With these advantages, high performance teams are a "must have" for any business organization. The establishment of high performance teams should be commenced by the individual employees' commitment. In starting any specific task, a team can only function efficiently if each of the members vows their total devotion and dedication to the job to be accomplished. Each of the members should not be bound by their past experience but should seek to commit and perform in ways they never have before, opening themselves to new skills and perspectives. According to Harvey (2005): Building a high-performing team is not about people's skills, abilities or knowledge. It's about their commitment. It is not about putting together the right team. It's about putting together the right challenge. It is not about avoiding or overcoming setbacks and corporate resistance. It's about embracing difficulties and leveraging them to galvanize the team in a relentless pursuit of results. A research conducted by the Filine Institute c... Good communication is really a key in achieving process gains. Communication enables the dispensation of relevant information which will aid the whole organization in transferring ideas, evaluating possibilities, and promotes harmonious relationship between group members. Good communication also eliminates probable errors which can be brought about by miscommunications. Cohesion or interdependence is another key in boosting the performance of a team. The realization within the group that they are a part of a cohesive whole whose goals can only be achieved by strong coordination will motivate each member to do best for the group. Cohesion also cultivates each member's sense of belongingness. Meanwhile, Donald J. Bodwell (2002) recognized that high performance teams consistently displays trust, respect, and support for each team member. He argues that "team members need to be coached in the need to trust and support each other" (Bodwell 2002). He emphasizes t he value of support which involves keeping an eye on each team member as well as offering help when needed. In order to become a high performance team, members should constantly show that they are strongly and tightly united in order to achieve a common goal. Nowadays, the new trend in business organizations is diversity hiring. As companies come to recognize the contribution of workplace diversity, it is widely observed that players are closely monitoring the extent of diversity in its human resource. The rationale in favoring a human resource with different origins, backgrounds, interests, and status is fairly simple: diversity will is able to pool together various talents, ideas, skills, and knowledge

Competitive brand management plan Assignment Example | Topics and Well Written Essays - 2500 words

Competitive brand management plan - Assignment Example The brand activation at this occasion will allow the Co operative healthy brand to build strong relationship with the consumers by helping them to form New Year’s resolution regarding healthy eating and lifestyle. This will also make it easy for the Co operative healthy brand to develop direct associations in the mind of the customers between healthy eating and the Co operative healthy brand. Background Situation: There has been drastic increase in the overall obesity rate all over the globe. In the region of UK around quarter of the adult population are classified as obese (NHS, 2012). This in turn has increased the health concerns among the people. The consumers are shifting towards healthier lifestyle and are giving preference to the healthy and balanced food items as shown in the image below: (Kimmell, 2009) There has been growing shift in the overall consumer purchase behaviour as consumers are giving preference to the foods and drinks which are providing more health bene fits as shown in the image below: (Datamonitor, 2009) This increasing preference for the healthy food items has provided opportunity to the health retailers and supermarkets to provide the customers with different health foods. This in turn has given rise to different own health brands. Co operative food healthy brand is also competing in this category and is trying to increase the market penetration and improve the overall brand image. Brand Positioning: Brand positioning is used in order to present and describe the competitive advantage of a particular brand against other competitors in the industry. This means that brand positioning presents how the brand will compete with the competitors in effective and efficient manner. It is important to keep in consideration different elements and factors in order to come up with effective and long lasting brand positioning (Kapferer, 2008). Goals and Objectives: The goal of the co operative healthy brand is to become the most preferred heal thy brand in the region by increasing overall awareness of its healthy products and encouraging the consumers to shift towards healthy life style and eating. For achieving this goal certain brand objectives have to be fulfilled, which are as follow: The co operative healthy brand should increase the interaction with consumers in order to improve the overall brand awareness and image The co operative healthy brand should provide customers with more value and benefits The co operative food have to provide more promotion and shelf space to its own healthy brands The co operative food healthy brand should improve the overall brand experience of the customers Brand Inventory: It is important for the brand to maintain and manage attractive and easy to access brand inventory in order to increase the brand interaction and awareness. The brand inventory can include brand colour, the logo, tag line, and even the physical location (Keller, 2008). The Co operative food and healthy brand use gre en and other fresh colours

Motivational statement for joining Army Medical Corp Reserve Essay

Motivational statement for joining Army Medical Corp Reserve - Essay Example military as a field officer, my immediate objective to joining the Army Medical Corp reserve is to help solders who suffer from both medical and psychological injuries together with their families. This is majorly because I want my country’s defense force to have a positive image of a safe profession that can attract dedicated personnel. By working hard as a medical officer, and through influencing dedication among other members of the reserve, I hope to elimination permanent disabilities among wounded officers, and subsequent psychological instability among their family members. This will not only be a motivational factor to serving army personnel and their families but will also motivate others who currently perceive the military as a risky profession, to join the forces in protecting our country. My interest in adventure, structures, and challenging encounters, opportunities that are available within the reserve’s scope, are also motivators to my desire to join the Army Medical Corp reserve. I am also dedicated to exercise the expected level of discipline that is required within the

Nutrition and The Journey of Life Essay Example for Free

Nutrition and The Journey of Life Essay Caring for and fueling our bodies requires for the mother to take prenatal vitamins in order to meet us to keep a balanced nutrition. Just as our bodies The nutritional needs of the growing fetus. need the right nutritions so does a embryo, futons and baby in order to grow and develop properly. Nutrition and pregnancy The mother must make good nutritional The first eight weeks after fertilization which choices such as eating foods such as the ones is known as the embryonic stage the embryo gets its illustrated above rather then processed foods and nutrition from the lining of the uterus, but after week snacks that will provide little nutrients, these good 9 of development the growing fetus will get its nutritional habits can be practiced after birth and oxygen and nutrients from the placenta. Can be taught to the baby. The fetus is growing everyday which requires a If the nutritional needs of the fetus are not met variety of nutrients such as calcium, copper, folic acid, several health concerns may occur such as iron,vitamins A, B6, C, D and E. The demand for these Complications with fetal development, fetal size nutrients by the fetus will have to be met by having a organs, brain, and may cause a miscarriage and proper and Healthy diet, but it may also be necessary death of the infant and or mother. Post Birth Nutrition Additional Information From conception to birth the process of creating Having the proper knowledge of the nutritional baby requires a lot of energy and nutrient for the mother needs of the body before conception and post and the developing fetus, after the birth of the baby the child birth is very important for the well being newborn will continue to need nutrient in order to grow of the mother, fetus, and baby. The are several and develop. The baby will receive it nutrient from milk resources that people can use to learn more for the first year of its life so it is important to decide about the nutritional needs of the mother and weather the baby will consume breast mil or formula. fetus, listed below are some of these resources. Breast milk VS. Formula 1. Chosemyplate.gov Breast milk is the perfect food for babies it contains all 2. Medline Plus webpage and call center the nutrients that the baby will need to grow and 3. Baby center develop . Unlike formula breast milk contains properties 4. Seek the advice of your doctor that protect against infections such as white blood cells  also breast milk can pass on immune shots that the mother  may receive such as a flu shot. Formula are getting better  through he years to mach the ingredients found in breast   milk such as DHA and ARA. References Choose my plate. (2016). Retrieved from http://www.choosemyplate.gov/pregnancy-breastfeeding/pregnancy-nutritional-needs.html Grosvendr, M., Gmolin, L. (2012). Visualizing Nutrition Everyday Choices (2nd ed.). Retrieved from .

Water Mist Replacement for Halon Extinguishers

Water Mist Replacement for Halon Extinguishers CHAPTER ONE: 1.1: Introduction Choosing the best fire suppression technology is not an easy task. It even involves discussing risks and operations with insurance companies. The most relevant concern of a fire safety engineer is the protection of life which entails the safe evacuation of personnel. The starting point of a suppression system is a risk analysis to reduce the potential occurrence of a fire. This is followed by the control of the damage and the recovery effort or emergency response associated with the means of fire suppression adopted. The quality of installation, efficiency and maintenance of the suppression system adopted cannot be over-emphasised. The phase out of halons, due to environmental concerns, has lead to forceful development of new fire prevention strategies and technologies that are efficient, as well as environmentally friendly technologies. Fire protection halons were phased out of production in developing countries due to the quest to regulate the use of ozone depleting substances(ODS) as reflected in the Montreal Protocol,1987(London Amendment 1990, and Copenhagen amendment1992). Fire suppression agents have two (2) toxicological aspects to them: The toxicity of the agent The toxicity of combustion products of the agent. Several new fire suppression systems have been developed such as inert and halocarbon gaseous systems, water mist systems, gas and aerosol generators. Fire has been extinguished with water since ancient times. Water in the normal form is not a suitable suppression medium of all classes of fire. The efficiency of water in suppression is enhanced by its use of water in form of mists. Survey by Mawhinney and Richardson in 1996 showed that about 50 agencies worldwide are involved in the research and development of water fire mist and suppression systems. Water mist in fire suppression does not behave like true gaseous agents and is affected by fire size, the degree of obstruction, ceiling and the ventilation conditions of the compartment. To effectively suppress a fire, a water mist system must generate and deliver optimum sized droplets with an adequate. 1.2: Objectives and Structure of Dissertation This project aims at studying the water mist as a replacement for halons systems in the extinguishment of fires. This replacement is a direct consequence of the phase out of halons due to environmental issues and the need to find a drop-in replacement or a suitable alternative in areas where high level of fire safety is required and the cost of fatalities is too high. Chapter 2 2.1: Overview of Fire Suppression To suppress fires, the type of fire needs to be identified. The class of the fire to be extinguished also determines the type of extinguisher that can be used. There are six (6) types of fires: Class A FIRES: These involve flammable or combustible solids such as wood, rubber, fabric, paper and some plastics. Class B FIRES: These are fires involving flammable and combustible liquids or liquefiable solids such as oil, alcohol, petrol, paint and liquefiable waxes.[9] Class C FIRES: These are fires involving flammable gases such as natural gas, hydrogen, propane, butane.[9] Class D FIRES: These are fires involving combustible metals, such as sodium and potassium.[9] Class E FIRES: These are fires involving any of the materials found in Class A and B fires, but including electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire, with a resultant electrical shock risk if a conductive agent is used to control the fire.[9] http://www.sqa.org.uk/e-learning/FirstLineO2CD/page_06.htm Class F FIRES: These fires involve cooking fats and oils, especially in industrial kitchens. The temperature of these fats and oil on fire is much greater than that of other flammable liquids. 2.2: Means of Fire Suppression The aim of fire suppression is to provide cooling, control the spread of the fire as well as extinguish the fire. The behaviour of a fire is charcterised by the fire triangle which has fuel, oxygen and heat as its three sides. Combustion process is represented by: Fuel + O2 HEAT H2O + CO2 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn2.1 The combustion process is an exothermic reaction, involving a fuel and oxygen. The ratio of fuel to air must be within the flammability limits of the fuel for combustion to occur. The Lower Flammability Limit (LFL) is the minimum concentration of fuel vapour in air, below which a flame cannot be supported in the presence of an ignition source. The Upper Flammability Level (UFL) is the maximum concentration of fuel vapour in air, above which a flame cannot be supported. Stoichiometric Mixture is the ratio of fuel in oxygen that requires minimal energy to support a flame. A branch of the triangle must be removed for the fire to be extinguished. Fires can either be smoldering or flaming combustion. Smoldering occurs when solids such as wood or plastics burn at or on the surface. It usually involves the release of toxic gases and can be difficult to extinguish. Flaming combustion is a gas phase phenomenon that involves the release of visible and infrared radiation. This type of fire generates much more heat. The extinguishing of a fire involves either chemical or physical mechanisms. Physical mechanism: Involves the removal of one side of the fire triangle. This can be done by either blanketing the fire (causing the fuel and air to be separated) or by removing the heat source using an agent with a high heat capacity/ latent heat of vaporization (this will cool the flame by absorbing the heat). Physical mechanism could be thermal or dilution. Thermal physical effect involves adding non-reactive gas to a fire plume leading to a reduction in the flame temperature. This is achieved by the distribution of the heat generated to a larger heat area. The heat capacity of the introduced agent determines the efficiency of the process. On the other hand, for dilution physical effect, the collision frequency of oxygen molecules with the fuel is lowered when the additional gas is introduced into the fuel-air mixture. This effect is quite minimal and negligible. Chemical mechanism: This is the use of an extinguishing agent or its degradation product to disrupt the chain reaction for sustaining combustion. This entails inhibition by halogen atoms. Most good suppressants apply both the physical and the chemical mechanisms. The type of hazard associated with an area determines the fire protection system that will be put in place. Halons have been used in a wide range of applications. Other alternatives include: Water Sprinkler Systems: This is a very common type of fixed protection that offers safe protection to limit structural damage. The cost of installing water sprinkler systems into existing structures is quite expensive. They are better at protecting structures than its contents [11]. The reliability of water sprinkler system has encouraged its wide use. Accidental discharge is uncommon with water sprinkler systems. Water sprinklers have a much slower response than other systems. They also cause a considerable secondary damage. They cannot be used on live electrical equipment and flammable liquids, but they are used widely in computer and control rooms as well as storage rooms in the USA. Detectors: This involves the use of high sensitive smoke detection. This is not exactly an active fire protection approach but it serves as an initiator to other fire protection systems [2]. Carbon dioxide: Carbon dioxide is widely used in gaseous based fire extinguishing systems. There are two types of carbon dioxide system depending on the manner by which they are stored. These are high pressure and low pressure carbon dioxide systems. It is a clean agent and has a good penetrating ability. This makes it safe for use on live electrical equipment. They are also used in unoccupied spaces such as computer and control rooms. Carbon dioxide causes very minimal direct or secondary damage and allows the installation being put back to immediate use after a fire. It is however toxic and cannot be used in total flooding situations. Carbon dioxide cannot also be used in situations where weight and space are important. High concentrations of carbon dioxide are required for extinguishment and as such they are bulky and heavy. They cannot be used in manned areas because they reduce the oxygen concentration to levels below life support and thus cannot be set in automatic mode. Carbon dioxide systems are generally fast acting and cost effective. Carbon dioxide has also found use in record storage, flammable liquid fires, chemical processing equipment, turbine generators, marine applications, computer rooms and shipboard machinery. Inert Gases: inert gases in use for fire suppression are majorly argon and nitrogen mixtures. These are electrically non-conductive fire suppressants. The mechanism behind their use is the lowering of the oxygen concentration of air to that below the lower flammability point (LFL). They are not liquefied gases and they are bulky because they are stored at high pressure. The concentration of inert gases released in the hazardous area is high because they have densities that are similar to that of air. Their response time is not very fast and so they are not efficient in situations where the rate of fire spread is high. Inert gases do not decompose thermally and thus they form no breakdown products [2]. Inert gases can cause an extreme decrease in the composition of oxygen in the body accompanied by an increase in the concentration of carbon dioxide leading to loss of consciousness or death and as such health and safety issues have to be considered in its use. Inert gases have found wi de acceptance because they pose no environmental problems. They are not ozone depleting substances neither do they contribute to global warming. They are employed in computer and control rooms, record storage, flammable liquid fires and shipboard machinery [2]. Halocarbon Gases: These are hydrofluorocarbons and perfluorocarbons with zero ozone depleting potentials. They are however greenhouse gases and are governed by the Kyoto protocol and hence its release counts towards the national emissions inventory of global warming gases. Halocarbons are electrically non-conductive, are clean agents and are not bulky in terms of space and weight. Foam Systems: Foam systems could be low, medium or high expansion systems. Foam systems are efficient for extinguishing liquid pool fires and large cable fires. In this case, the foam acts as a barrier between the fire and the supply of oxygen. The use of chemical dispersants to clean up after its use has limited the wide use of foam systems. Furthermore the use of smoke detectors for its activation limits its speed of response. They cannot be used to protect any substance that reacts violently with water. Foams systems are often used with water sprinklers. This increases the efficiency of the systems. Foam systems have found use in the extinguishment of flammable liquid fires, engine compartments and shipboard machinery. Dry Powder: Powders have very high response time for extinguishing fires but have no cooling effect. They thus become ineffective as soon as it settles [2]. They are limited in application to extinguishing flammable liquid fires as well as engine spaces. Fine Solid Particulates: This system is used in combination with halocarbon gases and inert gases [2]. They have the advantage of reduced wall and surface losses relative to water mist and particle size is easier to control[2]. They however pose problems to sensitive equipment and cannot be used for explosion suppression applications because they are generated at high temperatures. Fine solid particulates can only be used in unmanned areas because of the problems associated with inhalation of particulate substances. Water Mist: This employs the use of fine water sprays, usually less than 100 microns in diameter. Water mists can be used on flammable liquid fires, as well as electrical equipment. They are not as effective on small or slow burning fires. Water mist installations pose problems in their design and fabrication. Hybrid Systems: Hybrid systems combine one or more of the above fire protection system. A common example of this is the combination of water mist systems and carbon dioxide. There are two methods of applying fire extinguishing agents-Total Flooding and Local Application. Total Flooding: They are operated automatically and manually. It entails applying an extinguishing agent to an enclosed space to achieve a concentration of the extinguisher that is capable of putting out the fire. This method is the most common system of application Local Application: The agent is applied directly onto the fire plume or the affected enclosure. Portable fire extinguishers are the most common forms of this approach. This method is also known as streaming application. There is an increase in the need for the phasing out of halons and this has brought the search for the perfect or drop-in replacement. The department of trade and industry in 1995 listed checklists for the selection of alternatives to halons in critical uses situations as: Fire fighting effectiveness: This involves the speed of fire suppression, the post fire hold time, the ability of the alternative to permeate, the elimination of the risk of reignition, the suitability of the alternative to the fire hazard. Ease of Installation: Ease of maintenance, pipe work, and cost of installation, cost of refill, floor space and weight, system re-instate time, and availability of the extinguisher. Hazards to occupants: Toxicity, noise levels, pressurisation, inhalation, visibility, safety as regards electrical work, thermal decomposition products [2]. Discharge effect on equipment: water damage, clean up, corrosion, thermal shock. Environmental acceptability: Ozone depletion potential, atmospheric lifetime, and global warming potential. Discharge damage: This entails clean up of the agent after use, water damage, thermal shock and corrosion. Esso Australia, while looking for alternatives to halons on their installations considered the following issues [14]: Effectiveness at extinguishing fires Environmental effects (a zero ozone depleting and global warming potential) of the agent before use and after thermal decomposition. Toxicity level and a safety margin between its No Observed Adverse Effects Level (NOAEL value) and the extinguishing concentration required Third party approval from regulatory bodies and safety partners such as International Maritime Organisation (IMO), NFPA, and EPA or Underwriters laboratory Organisations. Level of engineering required to modify an existing halon protected installations. Availability as regards to installation and maintenance at a reasonable cost. 2.2: Health and Safety Issues Considering the health and safety in the UK, there is no specific regulation as regards choice of fire extinguishing systems. Otherwise fire risks and risk from the use of extinguishment can be categorised under risks at work. The Management of Health and Safety at Work Regulations 1992 stipulates all risks at work are to be assessed and prevented where ever it is reasonably practicable, controlled. In cases where fire extinguishing systems contain toxic substances then the Control of Substances Hazardous to Health Regulations 1988 (COSHH regs) will also apply. The basis of the two regulations is the prevention rather than control of the risk. 2.3: Environmental regulations The International Maritime Organisation (IMO) has prohibited the use of new halon systems from 1994, but accepts the use of existing ones. The EU has banned its use onboard vessels by the end of 2003. The following are regulations that are put in place to phase out the use of halons. The Montreal protocol on Substances that Deplete the Ozone layer- the Montreal protocol, signed by 25 countries on the 16th of September, 1987 is an international treaty for the control of the production and use of ozone depleting substances. It involves the restriction and eventual prohibition of the production, distribution and use of Ozone Depleting Substances. A copy of this document is attached in Appendix 1. The EC regulations: This European legislation was put in place to further tighten the restriction on the ban of ozone depleting substances. EC Regulation 3093/94 came into force on the 23rd of December 1994. EC Regulation 3093/94 is directly binding in all EU Member States and does not require any national implementing legislation. The new Regulation EC 2037/2000 came into force on 1 October 2000, replacing the Regulation 3093/94. The enforcement requires the use of bodies such as the HM Customs and Excise concerning import of controlled substances. The Department of the Environment proposes to implement these arrangements through enforcement regulations made under both the Environmental Protection Act 1990 s.140 and the European Communities Act 1972.(EC REGULATION) The new requirements are applicable to the production, distribution, use and recovery, and control of hazardous substances. The regulations also require the recovery of used controlled substances from certain equipment, s uch as fire protection systems, for disposal or recycling, during servicing and maintenance procedures of equipment. A copy of the regulation is attached to Appendix 2. The Victorian Environment Protection Legislation for the Control of Ozone Depleting substances (Victorian Government Gazette No.S57, 1990) this piece of legislation depicts the Australian governments compliance, reliance and advocacy to the implementation of the Montreal protocol on the phasing out of halon use [14]. Environmental Protection agency: Under the Clean Air Amendment, the United States Environmental Protection agency, EPA analysed various substances that could substitute fire extinguishing agents that destroy the ozone layer. These substances also have low global warming potential and low Atmospheric lifetime. The SNAP program (Significant New Alternatives Policy) is used by the EPA to replace the use of halons with environmentally friendly systems in the United States. The Clean Air Act was signed into law in 1990. With this Act, the US banned the production and import of new halons 1211, 1301 and 2402 from the 1st of January 1994 in compliance with the Montreal Protocol. The US government also imposed excise tax on halons through specialized training and proper recycling and disposal. Chapter Three: Halon Systems Halon is the generic name for bromine contained halogenated hydrocarbons. Halons systems were first installed in the late 1960s and early 1970s. In the gaseous form, halons are excellent fire extinguishers. Halons are mostly employed in situations where fire safety standards are high. Halons are identified by a four digit number. The numbering system is assigned by the number of carbon, number of fluorine, chlorine and bromine atoms respectively. Halon 1301, containing carbon, fluorine and bromine is used in total flooding applications while halon 1211, containing carbon, fluorine, chlorine and bromine is used as hand held portable extinguishers. The two common halon types described are effective in extinguishing classes A, B and C fires. These halons are preferred because they exhibited: high efficiency in suffocating combustion, availability in volume at reasonable cost, high storage stability, low electrical conductivity, as well as acceptable toxic properties. 3.1: Characteristics of Halons Halons interfere with the chemical reactions which take place during a fire. The properties of halons allow for its use in most situations and thus most of its applications are linked to particular characteristics. These principal applications include: Clean fire fighting agent: Halons leave no residue after use. This eliminates secondary damages and keeping loss caused by the fire to a minimum [12]. Electrically non-conductive: This property makes it suitable for safe application on fires involving electrical equipment. It will prevent exposure of fire fighters to electric shock. Low toxicity: This property makes halons acceptable and in most cases halon flooding systems are set in automatic mode by default. They can also be used to extinguish fires while people are present in the protected room. Halon flooding systems do not displace so much oxygen which can lead to suffocation[12] Rapid response: Halons are effective for rapid knockdown of flames. This property is mostly essential for class B fires involving liquid and liquefiable solids. Low concentration requirement: This means low quantity or amount of halons are required for extinguishment. It minimizes weight and space allowance [12]. Gaseous state: This allows for good penetration and effective extinguishment in confined spaces. Boiling point: The boiling point of about -4 allows it to be discharged (in the case of hand-held extinguishers) as a liquid for a while before it vaporises. This is a key requirement in some manual fire fighting applications.[12] Low heat of vaporisation: Halons will not condense to form water or ice in halon flooding systems. The most important advantage of halons is in its cost effectiveness. Halon fixed systems are the most cost effective of all extinguishing systems. 3.2: Extinguishing Mechanisms of Halons Halons extinguish fires both chemically and physically. Chemically they interfere with the chemical reactions that take place during the fire. This characterises halons as inhibitors. Radicals released during combustion to keep the fire burning are suppressed chemically by halons. This reaction is anti-catalytic. When halons are heated during combustion, they produce free radicals which compete with those produced by the original combustion process [2]. Halon 1301 produces bromine radicals which react with hydrogen free radicals to produce hydrogen bromide. The hydrogen bromide then reacts with hydroxyl radical to form water and bromide. The bromide released reacts with the combustion fire again and the whole cycle is repeated. The hydrogen and hydroxyl free radicals produced by combustion are greatly reduced in concentration by combining with the halogen free radicals produced by halons [3]. Where RH is the combustible fuel, XBr is a halon agent RH + O2 ENERGY OH + R †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn3.1 XBr ENERGY Br + X†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.2 RH + Br HBr + R†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.3 HBr + OH H2O + Br†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.4 RH ENERGY R + H†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.5 H + Br HBr†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.6 The combination of bromine and hydroxyl radical is also an ozone destructive reaction: HOBr UV Br + OH†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..eqn3.7 OH + O3 HO2 + O2..eqn3.8 Br + O3 BrO + O2†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.9 BrO + HO2 HOBr + O2 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..eqn3.10 3.3: HALONS AND THE OZONE 3.3.1: The ozone layer The earth is enclosed by the atmosphere. This atmosphere is made up of a mixture of numerous gases in varying proportions. The atmosphere is further subdivided into three regions depending on temperature. These regions are: Mesosphere, Stratosphere and Troposphere. The word ozone is from a Greek word, ozein, for to smell. It is an allotropic form of oxygen having three atoms in each molecule. It is a pale blue, highly poisonous gas with a strong odour. [10] In its thickest part in the stratosphere, it is only a trace gas.. Ozone is highest in concentration, about 97%, in the stratosphere (15-60 kilometers above the Earths surface) where it absorbs the ultraviolet radiation from the sun. Ozone is also highly concentrated at the Earths surface in and around cities. The buildup of ozone on the earths surface in and around cities is a result of industrial activities and is toxic to organisms living at the Earths surface. Table 3.1 shows the percentage volume composition of the constituents of atmospheric air *variable gases http://www.physicalgeography.net/fundamentals/7a.html Ozone is very reactive and a stronger oxidising agent than oxygen. It is used in purifying water, sterilising air, and bleaching certain foods. Ozone is formed when an electric spark is passed through oxygen. Ozone is prepared commercially by passing cold, dry oxygen through a silent electrical discharge [7]. Ozone formed in the atmosphere is from nitrogen oxides and organic gases emitted by automobiles and industrial sources [7]. This is achieved by short wavelength ultraviolet. This is actually a health hazard, and it may cause crop damage in some regions. Ultraviolet wavelengths less than 200 nanometer reacts with oxygen molecules to make ozone. O2 UV O + O†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.11 O + O2 O3 + Heat†¦Ã¢â‚¬ ¦.eqn3.12 The heat released here is absorbed by the atmosphere and results in a rise in temperature of the atmosphere. The structure of ozone has 3 oxygen atoms, but steric hindrance prevents it from forming a triangular structure, with each O atom forming the expected 2 bonds. Instead each atom of oxygen forms only 1 bond, with the remaining negative charge being spread throughout the molecule.[7] Ozone is very unstable. It is decomposed either by collision with monoatomic oxygen or by ultraviolet radiation on it. The decomposition causes ozone to form oxygen molecules. Heat is also released to the atmosphere by this reaction O + O3 O2 + O2†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn3.13 O3 UV O2 + O + Heat†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn3.14 Ozone is decomposed in the stratosphere to prevent highly energetic ultraviolet radiation from reaching the surface of the earth. 3.3.2: Halons and ozone depletion The ozone layer is mainly depleted by compounds containing chlorine and bromine. Halogens are a chemical family containing fluorine, chlorine, bromine and iodine; any carbon compound containing them is known as a halocarbon. While all halogens have the ability to catalyze ozone breakdown, they have an unequal impact on the ozone layer. The quantity of halons released into the atmosphere is small relative to the number of gases present in the atmosphere. Yet they are more active in destroying the ozone or disrupting the ozone balance for two reasons: Ozone is in a constant state of imbalance, as it is destroyed and produced by natural processes. This process is controlled by solar input that does not undergo significant fluctuations. The stability of halons makes it transportable from the troposphere to the stratosphere where halogens are made active and broken down very fast, destroying ozone in the stratosphere. . The impact is described as depletion potential of the halocarbon. The OZONE DEPLETING POTENTIAL (ODP) is a simple measure of its ability to destroy stratospheric ozone. The ODP of compounds are calculated with reference to the ODP of CFC-11, which is defined to be 1. Thus ODP is a relative measure. A compound withan ODP of 0.2 is, roughly speaking, one-fifth as bad as CFC-11. The ODP of a compound x is expressed mathematically as the ratio of the total amount of ozone destroyed by a fixed amount of compound x to the amount of ozone destroyed by the same mass of CFC-11[8]: Global loss of Ozone due to x ODP(x) == †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..eqn3.15[8] Global loss of ozone due to CFC-11. The above expression depicts that the ODP of CFC-11 is 1.0 by definition. The uncertainties experienced in evaluating the global loss of ozone due to a compound are eliminated here since the mathematical expression is a ratio. Evaluating the ODP of a compound is affected by the following: The quantity of chlorine or bromine atoms in a molecule. The nature of the halogen, as bromine is a more ozone- destructive catalyst than chlorine. Atmospheric lifetime of the substance: The atmospheric lifetime of the halon is the time it takes for the global amount of the gas to decay to 36.8% of its original concentration after initial emission. Compounds with low atmospheric lifetimes have lower ODP because it is destroyed in the troposphere. Molecular mass of the substance: This is because ODP is evaluated by comparing equal masses and not number of moles. Table3.2 gives time-dependent and steady-state ODPs for some halocarbon in wide use. Compound Formula Ozone Depletion Potential 10yr 30yr 100yr Steady State CFC-113 CF2ClFCl2 0.56 0.62 0.78 1.10 Carbon tetrachloride CCl4 1.25 1.22 1.14 1.08 Methyl Chloroform CH3CCl3 0.75 0.32 0.15 0.12 HCFC-22 CHF2Cl 0.17 0.12 0.07 0.05 Halon-1301 CF3Br 10.4 Water Mist Replacement for Halon Extinguishers Water Mist Replacement for Halon Extinguishers CHAPTER ONE: 1.1: Introduction Choosing the best fire suppression technology is not an easy task. It even involves discussing risks and operations with insurance companies. The most relevant concern of a fire safety engineer is the protection of life which entails the safe evacuation of personnel. The starting point of a suppression system is a risk analysis to reduce the potential occurrence of a fire. This is followed by the control of the damage and the recovery effort or emergency response associated with the means of fire suppression adopted. The quality of installation, efficiency and maintenance of the suppression system adopted cannot be over-emphasised. The phase out of halons, due to environmental concerns, has lead to forceful development of new fire prevention strategies and technologies that are efficient, as well as environmentally friendly technologies. Fire protection halons were phased out of production in developing countries due to the quest to regulate the use of ozone depleting substances(ODS) as reflected in the Montreal Protocol,1987(London Amendment 1990, and Copenhagen amendment1992). Fire suppression agents have two (2) toxicological aspects to them: The toxicity of the agent The toxicity of combustion products of the agent. Several new fire suppression systems have been developed such as inert and halocarbon gaseous systems, water mist systems, gas and aerosol generators. Fire has been extinguished with water since ancient times. Water in the normal form is not a suitable suppression medium of all classes of fire. The efficiency of water in suppression is enhanced by its use of water in form of mists. Survey by Mawhinney and Richardson in 1996 showed that about 50 agencies worldwide are involved in the research and development of water fire mist and suppression systems. Water mist in fire suppression does not behave like true gaseous agents and is affected by fire size, the degree of obstruction, ceiling and the ventilation conditions of the compartment. To effectively suppress a fire, a water mist system must generate and deliver optimum sized droplets with an adequate. 1.2: Objectives and Structure of Dissertation This project aims at studying the water mist as a replacement for halons systems in the extinguishment of fires. This replacement is a direct consequence of the phase out of halons due to environmental issues and the need to find a drop-in replacement or a suitable alternative in areas where high level of fire safety is required and the cost of fatalities is too high. Chapter 2 2.1: Overview of Fire Suppression To suppress fires, the type of fire needs to be identified. The class of the fire to be extinguished also determines the type of extinguisher that can be used. There are six (6) types of fires: Class A FIRES: These involve flammable or combustible solids such as wood, rubber, fabric, paper and some plastics. Class B FIRES: These are fires involving flammable and combustible liquids or liquefiable solids such as oil, alcohol, petrol, paint and liquefiable waxes.[9] Class C FIRES: These are fires involving flammable gases such as natural gas, hydrogen, propane, butane.[9] Class D FIRES: These are fires involving combustible metals, such as sodium and potassium.[9] Class E FIRES: These are fires involving any of the materials found in Class A and B fires, but including electrical appliances, wiring, or other electrically energized objects in the vicinity of the fire, with a resultant electrical shock risk if a conductive agent is used to control the fire.[9] http://www.sqa.org.uk/e-learning/FirstLineO2CD/page_06.htm Class F FIRES: These fires involve cooking fats and oils, especially in industrial kitchens. The temperature of these fats and oil on fire is much greater than that of other flammable liquids. 2.2: Means of Fire Suppression The aim of fire suppression is to provide cooling, control the spread of the fire as well as extinguish the fire. The behaviour of a fire is charcterised by the fire triangle which has fuel, oxygen and heat as its three sides. Combustion process is represented by: Fuel + O2 HEAT H2O + CO2 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn2.1 The combustion process is an exothermic reaction, involving a fuel and oxygen. The ratio of fuel to air must be within the flammability limits of the fuel for combustion to occur. The Lower Flammability Limit (LFL) is the minimum concentration of fuel vapour in air, below which a flame cannot be supported in the presence of an ignition source. The Upper Flammability Level (UFL) is the maximum concentration of fuel vapour in air, above which a flame cannot be supported. Stoichiometric Mixture is the ratio of fuel in oxygen that requires minimal energy to support a flame. A branch of the triangle must be removed for the fire to be extinguished. Fires can either be smoldering or flaming combustion. Smoldering occurs when solids such as wood or plastics burn at or on the surface. It usually involves the release of toxic gases and can be difficult to extinguish. Flaming combustion is a gas phase phenomenon that involves the release of visible and infrared radiation. This type of fire generates much more heat. The extinguishing of a fire involves either chemical or physical mechanisms. Physical mechanism: Involves the removal of one side of the fire triangle. This can be done by either blanketing the fire (causing the fuel and air to be separated) or by removing the heat source using an agent with a high heat capacity/ latent heat of vaporization (this will cool the flame by absorbing the heat). Physical mechanism could be thermal or dilution. Thermal physical effect involves adding non-reactive gas to a fire plume leading to a reduction in the flame temperature. This is achieved by the distribution of the heat generated to a larger heat area. The heat capacity of the introduced agent determines the efficiency of the process. On the other hand, for dilution physical effect, the collision frequency of oxygen molecules with the fuel is lowered when the additional gas is introduced into the fuel-air mixture. This effect is quite minimal and negligible. Chemical mechanism: This is the use of an extinguishing agent or its degradation product to disrupt the chain reaction for sustaining combustion. This entails inhibition by halogen atoms. Most good suppressants apply both the physical and the chemical mechanisms. The type of hazard associated with an area determines the fire protection system that will be put in place. Halons have been used in a wide range of applications. Other alternatives include: Water Sprinkler Systems: This is a very common type of fixed protection that offers safe protection to limit structural damage. The cost of installing water sprinkler systems into existing structures is quite expensive. They are better at protecting structures than its contents [11]. The reliability of water sprinkler system has encouraged its wide use. Accidental discharge is uncommon with water sprinkler systems. Water sprinklers have a much slower response than other systems. They also cause a considerable secondary damage. They cannot be used on live electrical equipment and flammable liquids, but they are used widely in computer and control rooms as well as storage rooms in the USA. Detectors: This involves the use of high sensitive smoke detection. This is not exactly an active fire protection approach but it serves as an initiator to other fire protection systems [2]. Carbon dioxide: Carbon dioxide is widely used in gaseous based fire extinguishing systems. There are two types of carbon dioxide system depending on the manner by which they are stored. These are high pressure and low pressure carbon dioxide systems. It is a clean agent and has a good penetrating ability. This makes it safe for use on live electrical equipment. They are also used in unoccupied spaces such as computer and control rooms. Carbon dioxide causes very minimal direct or secondary damage and allows the installation being put back to immediate use after a fire. It is however toxic and cannot be used in total flooding situations. Carbon dioxide cannot also be used in situations where weight and space are important. High concentrations of carbon dioxide are required for extinguishment and as such they are bulky and heavy. They cannot be used in manned areas because they reduce the oxygen concentration to levels below life support and thus cannot be set in automatic mode. Carbon dioxide systems are generally fast acting and cost effective. Carbon dioxide has also found use in record storage, flammable liquid fires, chemical processing equipment, turbine generators, marine applications, computer rooms and shipboard machinery. Inert Gases: inert gases in use for fire suppression are majorly argon and nitrogen mixtures. These are electrically non-conductive fire suppressants. The mechanism behind their use is the lowering of the oxygen concentration of air to that below the lower flammability point (LFL). They are not liquefied gases and they are bulky because they are stored at high pressure. The concentration of inert gases released in the hazardous area is high because they have densities that are similar to that of air. Their response time is not very fast and so they are not efficient in situations where the rate of fire spread is high. Inert gases do not decompose thermally and thus they form no breakdown products [2]. Inert gases can cause an extreme decrease in the composition of oxygen in the body accompanied by an increase in the concentration of carbon dioxide leading to loss of consciousness or death and as such health and safety issues have to be considered in its use. Inert gases have found wi de acceptance because they pose no environmental problems. They are not ozone depleting substances neither do they contribute to global warming. They are employed in computer and control rooms, record storage, flammable liquid fires and shipboard machinery [2]. Halocarbon Gases: These are hydrofluorocarbons and perfluorocarbons with zero ozone depleting potentials. They are however greenhouse gases and are governed by the Kyoto protocol and hence its release counts towards the national emissions inventory of global warming gases. Halocarbons are electrically non-conductive, are clean agents and are not bulky in terms of space and weight. Foam Systems: Foam systems could be low, medium or high expansion systems. Foam systems are efficient for extinguishing liquid pool fires and large cable fires. In this case, the foam acts as a barrier between the fire and the supply of oxygen. The use of chemical dispersants to clean up after its use has limited the wide use of foam systems. Furthermore the use of smoke detectors for its activation limits its speed of response. They cannot be used to protect any substance that reacts violently with water. Foams systems are often used with water sprinklers. This increases the efficiency of the systems. Foam systems have found use in the extinguishment of flammable liquid fires, engine compartments and shipboard machinery. Dry Powder: Powders have very high response time for extinguishing fires but have no cooling effect. They thus become ineffective as soon as it settles [2]. They are limited in application to extinguishing flammable liquid fires as well as engine spaces. Fine Solid Particulates: This system is used in combination with halocarbon gases and inert gases [2]. They have the advantage of reduced wall and surface losses relative to water mist and particle size is easier to control[2]. They however pose problems to sensitive equipment and cannot be used for explosion suppression applications because they are generated at high temperatures. Fine solid particulates can only be used in unmanned areas because of the problems associated with inhalation of particulate substances. Water Mist: This employs the use of fine water sprays, usually less than 100 microns in diameter. Water mists can be used on flammable liquid fires, as well as electrical equipment. They are not as effective on small or slow burning fires. Water mist installations pose problems in their design and fabrication. Hybrid Systems: Hybrid systems combine one or more of the above fire protection system. A common example of this is the combination of water mist systems and carbon dioxide. There are two methods of applying fire extinguishing agents-Total Flooding and Local Application. Total Flooding: They are operated automatically and manually. It entails applying an extinguishing agent to an enclosed space to achieve a concentration of the extinguisher that is capable of putting out the fire. This method is the most common system of application Local Application: The agent is applied directly onto the fire plume or the affected enclosure. Portable fire extinguishers are the most common forms of this approach. This method is also known as streaming application. There is an increase in the need for the phasing out of halons and this has brought the search for the perfect or drop-in replacement. The department of trade and industry in 1995 listed checklists for the selection of alternatives to halons in critical uses situations as: Fire fighting effectiveness: This involves the speed of fire suppression, the post fire hold time, the ability of the alternative to permeate, the elimination of the risk of reignition, the suitability of the alternative to the fire hazard. Ease of Installation: Ease of maintenance, pipe work, and cost of installation, cost of refill, floor space and weight, system re-instate time, and availability of the extinguisher. Hazards to occupants: Toxicity, noise levels, pressurisation, inhalation, visibility, safety as regards electrical work, thermal decomposition products [2]. Discharge effect on equipment: water damage, clean up, corrosion, thermal shock. Environmental acceptability: Ozone depletion potential, atmospheric lifetime, and global warming potential. Discharge damage: This entails clean up of the agent after use, water damage, thermal shock and corrosion. Esso Australia, while looking for alternatives to halons on their installations considered the following issues [14]: Effectiveness at extinguishing fires Environmental effects (a zero ozone depleting and global warming potential) of the agent before use and after thermal decomposition. Toxicity level and a safety margin between its No Observed Adverse Effects Level (NOAEL value) and the extinguishing concentration required Third party approval from regulatory bodies and safety partners such as International Maritime Organisation (IMO), NFPA, and EPA or Underwriters laboratory Organisations. Level of engineering required to modify an existing halon protected installations. Availability as regards to installation and maintenance at a reasonable cost. 2.2: Health and Safety Issues Considering the health and safety in the UK, there is no specific regulation as regards choice of fire extinguishing systems. Otherwise fire risks and risk from the use of extinguishment can be categorised under risks at work. The Management of Health and Safety at Work Regulations 1992 stipulates all risks at work are to be assessed and prevented where ever it is reasonably practicable, controlled. In cases where fire extinguishing systems contain toxic substances then the Control of Substances Hazardous to Health Regulations 1988 (COSHH regs) will also apply. The basis of the two regulations is the prevention rather than control of the risk. 2.3: Environmental regulations The International Maritime Organisation (IMO) has prohibited the use of new halon systems from 1994, but accepts the use of existing ones. The EU has banned its use onboard vessels by the end of 2003. The following are regulations that are put in place to phase out the use of halons. The Montreal protocol on Substances that Deplete the Ozone layer- the Montreal protocol, signed by 25 countries on the 16th of September, 1987 is an international treaty for the control of the production and use of ozone depleting substances. It involves the restriction and eventual prohibition of the production, distribution and use of Ozone Depleting Substances. A copy of this document is attached in Appendix 1. The EC regulations: This European legislation was put in place to further tighten the restriction on the ban of ozone depleting substances. EC Regulation 3093/94 came into force on the 23rd of December 1994. EC Regulation 3093/94 is directly binding in all EU Member States and does not require any national implementing legislation. The new Regulation EC 2037/2000 came into force on 1 October 2000, replacing the Regulation 3093/94. The enforcement requires the use of bodies such as the HM Customs and Excise concerning import of controlled substances. The Department of the Environment proposes to implement these arrangements through enforcement regulations made under both the Environmental Protection Act 1990 s.140 and the European Communities Act 1972.(EC REGULATION) The new requirements are applicable to the production, distribution, use and recovery, and control of hazardous substances. The regulations also require the recovery of used controlled substances from certain equipment, s uch as fire protection systems, for disposal or recycling, during servicing and maintenance procedures of equipment. A copy of the regulation is attached to Appendix 2. The Victorian Environment Protection Legislation for the Control of Ozone Depleting substances (Victorian Government Gazette No.S57, 1990) this piece of legislation depicts the Australian governments compliance, reliance and advocacy to the implementation of the Montreal protocol on the phasing out of halon use [14]. Environmental Protection agency: Under the Clean Air Amendment, the United States Environmental Protection agency, EPA analysed various substances that could substitute fire extinguishing agents that destroy the ozone layer. These substances also have low global warming potential and low Atmospheric lifetime. The SNAP program (Significant New Alternatives Policy) is used by the EPA to replace the use of halons with environmentally friendly systems in the United States. The Clean Air Act was signed into law in 1990. With this Act, the US banned the production and import of new halons 1211, 1301 and 2402 from the 1st of January 1994 in compliance with the Montreal Protocol. The US government also imposed excise tax on halons through specialized training and proper recycling and disposal. Chapter Three: Halon Systems Halon is the generic name for bromine contained halogenated hydrocarbons. Halons systems were first installed in the late 1960s and early 1970s. In the gaseous form, halons are excellent fire extinguishers. Halons are mostly employed in situations where fire safety standards are high. Halons are identified by a four digit number. The numbering system is assigned by the number of carbon, number of fluorine, chlorine and bromine atoms respectively. Halon 1301, containing carbon, fluorine and bromine is used in total flooding applications while halon 1211, containing carbon, fluorine, chlorine and bromine is used as hand held portable extinguishers. The two common halon types described are effective in extinguishing classes A, B and C fires. These halons are preferred because they exhibited: high efficiency in suffocating combustion, availability in volume at reasonable cost, high storage stability, low electrical conductivity, as well as acceptable toxic properties. 3.1: Characteristics of Halons Halons interfere with the chemical reactions which take place during a fire. The properties of halons allow for its use in most situations and thus most of its applications are linked to particular characteristics. These principal applications include: Clean fire fighting agent: Halons leave no residue after use. This eliminates secondary damages and keeping loss caused by the fire to a minimum [12]. Electrically non-conductive: This property makes it suitable for safe application on fires involving electrical equipment. It will prevent exposure of fire fighters to electric shock. Low toxicity: This property makes halons acceptable and in most cases halon flooding systems are set in automatic mode by default. They can also be used to extinguish fires while people are present in the protected room. Halon flooding systems do not displace so much oxygen which can lead to suffocation[12] Rapid response: Halons are effective for rapid knockdown of flames. This property is mostly essential for class B fires involving liquid and liquefiable solids. Low concentration requirement: This means low quantity or amount of halons are required for extinguishment. It minimizes weight and space allowance [12]. Gaseous state: This allows for good penetration and effective extinguishment in confined spaces. Boiling point: The boiling point of about -4 allows it to be discharged (in the case of hand-held extinguishers) as a liquid for a while before it vaporises. This is a key requirement in some manual fire fighting applications.[12] Low heat of vaporisation: Halons will not condense to form water or ice in halon flooding systems. The most important advantage of halons is in its cost effectiveness. Halon fixed systems are the most cost effective of all extinguishing systems. 3.2: Extinguishing Mechanisms of Halons Halons extinguish fires both chemically and physically. Chemically they interfere with the chemical reactions that take place during the fire. This characterises halons as inhibitors. Radicals released during combustion to keep the fire burning are suppressed chemically by halons. This reaction is anti-catalytic. When halons are heated during combustion, they produce free radicals which compete with those produced by the original combustion process [2]. Halon 1301 produces bromine radicals which react with hydrogen free radicals to produce hydrogen bromide. The hydrogen bromide then reacts with hydroxyl radical to form water and bromide. The bromide released reacts with the combustion fire again and the whole cycle is repeated. The hydrogen and hydroxyl free radicals produced by combustion are greatly reduced in concentration by combining with the halogen free radicals produced by halons [3]. Where RH is the combustible fuel, XBr is a halon agent RH + O2 ENERGY OH + R †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn3.1 XBr ENERGY Br + X†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.2 RH + Br HBr + R†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.3 HBr + OH H2O + Br†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.4 RH ENERGY R + H†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.5 H + Br HBr†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.6 The combination of bromine and hydroxyl radical is also an ozone destructive reaction: HOBr UV Br + OH†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..eqn3.7 OH + O3 HO2 + O2..eqn3.8 Br + O3 BrO + O2†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.9 BrO + HO2 HOBr + O2 †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..eqn3.10 3.3: HALONS AND THE OZONE 3.3.1: The ozone layer The earth is enclosed by the atmosphere. This atmosphere is made up of a mixture of numerous gases in varying proportions. The atmosphere is further subdivided into three regions depending on temperature. These regions are: Mesosphere, Stratosphere and Troposphere. The word ozone is from a Greek word, ozein, for to smell. It is an allotropic form of oxygen having three atoms in each molecule. It is a pale blue, highly poisonous gas with a strong odour. [10] In its thickest part in the stratosphere, it is only a trace gas.. Ozone is highest in concentration, about 97%, in the stratosphere (15-60 kilometers above the Earths surface) where it absorbs the ultraviolet radiation from the sun. Ozone is also highly concentrated at the Earths surface in and around cities. The buildup of ozone on the earths surface in and around cities is a result of industrial activities and is toxic to organisms living at the Earths surface. Table 3.1 shows the percentage volume composition of the constituents of atmospheric air *variable gases http://www.physicalgeography.net/fundamentals/7a.html Ozone is very reactive and a stronger oxidising agent than oxygen. It is used in purifying water, sterilising air, and bleaching certain foods. Ozone is formed when an electric spark is passed through oxygen. Ozone is prepared commercially by passing cold, dry oxygen through a silent electrical discharge [7]. Ozone formed in the atmosphere is from nitrogen oxides and organic gases emitted by automobiles and industrial sources [7]. This is achieved by short wavelength ultraviolet. This is actually a health hazard, and it may cause crop damage in some regions. Ultraviolet wavelengths less than 200 nanometer reacts with oxygen molecules to make ozone. O2 UV O + O†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦eqn3.11 O + O2 O3 + Heat†¦Ã¢â‚¬ ¦.eqn3.12 The heat released here is absorbed by the atmosphere and results in a rise in temperature of the atmosphere. The structure of ozone has 3 oxygen atoms, but steric hindrance prevents it from forming a triangular structure, with each O atom forming the expected 2 bonds. Instead each atom of oxygen forms only 1 bond, with the remaining negative charge being spread throughout the molecule.[7] Ozone is very unstable. It is decomposed either by collision with monoatomic oxygen or by ultraviolet radiation on it. The decomposition causes ozone to form oxygen molecules. Heat is also released to the atmosphere by this reaction O + O3 O2 + O2†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn3.13 O3 UV O2 + O + Heat†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦.eqn3.14 Ozone is decomposed in the stratosphere to prevent highly energetic ultraviolet radiation from reaching the surface of the earth. 3.3.2: Halons and ozone depletion The ozone layer is mainly depleted by compounds containing chlorine and bromine. Halogens are a chemical family containing fluorine, chlorine, bromine and iodine; any carbon compound containing them is known as a halocarbon. While all halogens have the ability to catalyze ozone breakdown, they have an unequal impact on the ozone layer. The quantity of halons released into the atmosphere is small relative to the number of gases present in the atmosphere. Yet they are more active in destroying the ozone or disrupting the ozone balance for two reasons: Ozone is in a constant state of imbalance, as it is destroyed and produced by natural processes. This process is controlled by solar input that does not undergo significant fluctuations. The stability of halons makes it transportable from the troposphere to the stratosphere where halogens are made active and broken down very fast, destroying ozone in the stratosphere. . The impact is described as depletion potential of the halocarbon. The OZONE DEPLETING POTENTIAL (ODP) is a simple measure of its ability to destroy stratospheric ozone. The ODP of compounds are calculated with reference to the ODP of CFC-11, which is defined to be 1. Thus ODP is a relative measure. A compound withan ODP of 0.2 is, roughly speaking, one-fifth as bad as CFC-11. The ODP of a compound x is expressed mathematically as the ratio of the total amount of ozone destroyed by a fixed amount of compound x to the amount of ozone destroyed by the same mass of CFC-11[8]: Global loss of Ozone due to x ODP(x) == †¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..eqn3.15[8] Global loss of ozone due to CFC-11. The above expression depicts that the ODP of CFC-11 is 1.0 by definition. The uncertainties experienced in evaluating the global loss of ozone due to a compound are eliminated here since the mathematical expression is a ratio. Evaluating the ODP of a compound is affected by the following: The quantity of chlorine or bromine atoms in a molecule. The nature of the halogen, as bromine is a more ozone- destructive catalyst than chlorine. Atmospheric lifetime of the substance: The atmospheric lifetime of the halon is the time it takes for the global amount of the gas to decay to 36.8% of its original concentration after initial emission. Compounds with low atmospheric lifetimes have lower ODP because it is destroyed in the troposphere. Molecular mass of the substance: This is because ODP is evaluated by comparing equal masses and not number of moles. Table3.2 gives time-dependent and steady-state ODPs for some halocarbon in wide use. Compound Formula Ozone Depletion Potential 10yr 30yr 100yr Steady State CFC-113 CF2ClFCl2 0.56 0.62 0.78 1.10 Carbon tetrachloride CCl4 1.25 1.22 1.14 1.08 Methyl Chloroform CH3CCl3 0.75 0.32 0.15 0.12 HCFC-22 CHF2Cl 0.17 0.12 0.07 0.05 Halon-1301 CF3Br 10.4