Suppressant Agents and Strategies for Suppression of Fires - Term Paper Example

Suppressant Agents and Strategies Suppressant agents and strategies are used to control fires in wildfires and in residential areas. While water is the first fire suppressant that people generally think of, there are various ways of deploying it in the middle of a fire. There have also been many chemical agents that aid in suppressing fires. Also, suppressing strategies can be broken into two main categories. These are called active fire protection and passive fire protection. As their names imply, active fire protection deals with agents in an active manner. They generally refer to measures that require some sort of motion or movement. Passive fire protection refers to measures that are generally built into buildings during construction in accordance with fire codes. The following will outline various modes and techniques of both suppressant agents and of fire suppressing strategies. In the suppression of wildfires, it should first be noted that wildfires that do not threaten human habitation generally are allowed to burn. Wildfires are part of a natural process, and as such they are not considered to be a bad thing. Where wildfires become a problem is when they threaten human habitation. Water is the most common fire suppressant agent, but the mode of delivery depends upon the location and terrain of the wildfire. For instance, water can be delivered by plane or by helicopter. These same planes or helicopters can be used to deliver various chemical fire suppressing agents as well. Firefighters also repel or parachute, which is referred to as smoke jumping, into areas in order to set up pre-emptive fire suppressing measures. On the ground, firefighters use small water or chemical agent pumps in order to douse and control small fires from spreading. Additionally, they will carry chainsaws in order to construct firebreaks, which is simply removing combustible materials from an area in order to prevent the spread of fire. Furthermore, tanker trucks carrying thousands of gallons of water are utilized to deliver water or other suppressant agents to where they are needed (Berry 2007). Human life is considered the most important factor in fire suppression. After this, various aspects such as the protection of property, health, safety, and ecological factors are taken into consideration. In the worst cases of enormous fires, the preservation of human life is the only possible action that can be taken. Cost and safety or firefighters is taken into consideration as well. Another technique in wildfire suppression is the creation of control lines. Control lines are areas which have had all combustible material removed in order to prevent the spread of the wildfire beyond them. One technique to accomplish this is to physically remove all combustible material. Another technique is so institute small controlled burns. Firefighters will carry torches or flares in order to start small, controlled fires. One option is to let these fires burn up the available fuel in the area in order and then extinguish the fires. Another option is to let the control line fire meet with the wildfire, thus both the control fire and the wildfire fuels are expended. A third option is to douse the combustible material in a control line with chemical agents which work as flame retardants. These materials generally either work by reducing the flammability of the material or by obstructing the fuel from being able to catch fire in the first place (Berry 2007). Fire suppressant gels work by soaking up soaking up water hundreds of times their own weight and encasing them in in a polymer shell. Bubblets are formed; whereas a bubble is water that is filled with air, a bubblet is a polymer shell filled with water. These bubblets stack on top of each other and forms layers. Fires must go through these layers one by one in order for the gels to evaporate. Ideally, fire suppressant gels work anywhere between six to thirty-six hours. Once the water has evaporated from the polymer shells, the gels lose their fire resistance and are useless. Gels are generally used to either protect structures or are applied directly to fires as suppressants (Meidl 1970). Fire suppressant foams work in a similar manner to the layering of the bubblets of fire suppressant gels. Foams work by cooling fires and by preventing contact between the air and the fuel. Various types of foams can be utilized depending upon what type of combustibles are the base fuel of the fire. For instance, alcohol-resistant foams can be used in fires that have combustibles that are liquid based. Fire suppressant foams also work best for certain types of fires. Water is the most commonly used fire suppressant agent, though it is ineffective for certain types of fires, such as oil fires. Foams were developed specifically as an alternative to water for oil fires. The foams were first developed in the late 1880’s, and various improvements upon foams were developed in the 1940’s, 60’s, and 70’s (Meidl 1970). As mentioned, there are active and passive fire suppressing strategies. Active strategies include various techniques such as the installation of fire extinguishers and water sprinkler systems. Extinguishers utilize various substances to act as fire suppressing agents. These devices are pressurized, and as a result the agent is ejected from the extinguisher as it’s being used. There are various ways to pressurize fire extinguishers. Depending upon the type of agent used, at times fire extinguishers are pressurized by storing the pressure in the tank along with the fire suppressing agent. Nitrogen is often used if the chemical agent is dry. At times they utilize the types of fire suppressing foams as previously mentioned. Some fire extinguishers even utilize pressurized water as the suppressing agent. The other way to pressurize fire extinguishers is to have the propellant agent stored in a container on the side of the extinguisher. Once the seal is broken on the container, the fire suppressing agent is introduced to the pressurized agent. This types of fire extinguishers are generally used in areas that are at high-risk for fires. They are used because they are more easily and quickly recharged (Licht 2003). Sprinkler systems are installed at ceiling level, and they are supplied by various types of reservoir systems. Upon detection of a fire, sprinkler systems automatically release water. These systems are usually installed within large buildings, such as department stores, or other types of areas which particularly are prone to fires. The heads of the sprinklers have been developed to where they now can release a mist which is a more effective agent. Beyond sprinkler systems, active fire suppressing strategies include fire detection systems. Various aspects of fires are able to be detected, such as heat or smoke. These systems are in place in large buildings, such as department stores, to warn people of the threat of fire in order for a safe evacuation to take place. Homes are also supposed to have smoke detectors installed for safety and insurance purposes (Licht 2003). In regards to passive fire suppressing strategies, these are typically aspects that are built into the design of buildings, and as such they typically must follow and are part of building codes for fire safety. For instance, compartmentalization is a passive fire suppressing strategy. What compartmentalization entails is for buildings to be separated into smaller compartments in such a way as to keep fires from spreading too rapidly. They are also intended to prevent the spread of smoke and gasses. The individual compartments are intended to contain the fire and limit the amount of damage that other compartments receive. Compartmentalization can also be utilized in the construction of various structures such as airplanes, tunnels, ships, and submarines. Making structures able to be easily evacuated is part of compartmentalization (Gann 1997). As for further examples of fire suppressing methods, often walls, glass, and floors are rated for their fire resistant properties. There are various ratings that walls, glass, and floors can receive in regards to their fire resistant nature. Also, many structures can be coated with fire resistant materials. These can include intumescent or endothermic paints, or they can be types of plasters that are sprayed on structures which are fire resistant. There are many structures that are built with the specific purpose of fire suppression. Grease ducts that are built into large industrial cooking equipment is an example of this. Grease fires can be particularly dangerous, and grease ducts serve to separate grease from sources of combustion and to keep grease away from fires that might have already started. Enclosures are another strategy utilized in passive fire suppressing strategies. These are typically either fire-resistant boxes or fire resistant wrapping that encloses items of specific importance to fire suppression, such as valves or electrical wiring (Gann 1997). Lastly, fire prevention is also considered part of passive fire suppressing strategies. For example, fire prevention can include limiting sources of ignition to prevent fires from starting in the first place. Also, fire prevention can include the proper education of people who are to be using or coming in contact with combustible materials. Simply knowing the proper handling and care of combustible materials can drastically reduce the number of fires that are caused accidentally within various work situations. While there are many more strategies and types of suppressant agents, the previous has been an overview of the majority of agents and strategies. As just mentioned, education is probably the main factor to help with the prevention and suppression of fires. Works Cited -----------. (2001). “Wildland fire policy.” Retrieved on February 2, 2009. Available from http://www.fs.fed.us/fire/management/policy.html Berry, Alison (2007) “Forest policy up in smoke: Fire suppression in the US.” PERC. Retrieved on February 2, 2009. Available from http://www.perc.org/pdf/Forest%20Policy%20Up%20in%20Smoke.pdf Gann, Richard (1997) “Next-generation fire suppression technology.” Helen Options Technicha; Working Conference. Retrieved on February 2, 2009. Available from http://www.springerlink.com/content/uv9j5exqh6tdtmuk/ James H. Meidl (1970) "Flammable Hazardous Materials", Glencoe Press Fire Science Series, Beverly Hills. Licht, Richard (2003) “Clarifying the issue of fire protection balance.” Retrieved on February 2, 2009. Available from http://www.fireengineering.com/articles/article_display.html?id=196217 Read More