The Main Features of Radiation - Literature review Example

The main features of radiation Thermal radiation entails the emission of electromagnetic radiation from substances when they burn. The characteristics of the radiations highly depend on the temperatures on the material. One of the main features of radiation relates to the fact that radiation takes places place at diverse frequencies. This is even at a single temperature In this case, Plank’s radiation law shows how much radiation is released at each frequency. The other feature relates to the fact that as the temperatures increase, so do the frequencies and this directly relates to the range of radiation emitted from a material. The third feature of radiation entails the relationship between radiation and temperature increase. (Watts, 2003) In this case, as temperatures escalate, so do the total amount of radiation at all the available frequencies. This happens within a very short time span. Lastly, the absorption amount that a similar type of wave experiences is directly related to the pace of radiation of a specific type of electromagnetic wave. In this case, when a material radiates more red light thermally it means that its surface highly absorbs more red light. It is essential to note that in thermal radiation, only the travelling waves that are considered. (Kirk, 2006) Analysis of the radiating gases produced in combustion An analysis of combustion process shows that various radiating gases are usually released in the process. This highly depends on the substance or material that is being burnt. Combustion can be analysed in different ways. This is considering the fact that there is complete combustion, incomplete combustion, smouldering and rapid etc. When a hydrocarbon completely burns in oxygen, it releases water and carbon dioxide. (Rasbash, 2004) Common oxides are however released when iron, sulphur, nitrogen and carbon are completely burnt. In this case sulfur releases sulfur dioxide and nitrogen releases nitrogen dioxide etc. In situations where there is incomplete combustion, hydrocarbons emit carbon monoxide, carbon dioxide when burnt. It is common for large radiation gas quantities to be released in during rapid combustion. Role of radiation in fire spread between neighbouring buildings and discussion on requirements for space separation Radiation plays a great role in fire spread between neighbouring buildings. This is considering the fact that through radiation, heat is highly transferred into the air. This heat can easily cause burning of combustible materials. In this case, a burning building releases heat into the air which in turn affects walls of neighbouring buildings leading to fire spread. This works by the substances of materials adjacent to the fire absorbing heat, starts smouldering and finally burns. (Kirk, 2006) Fire can easily spread from one building to the next through radiation if there is minimal spacing between the two. It is highly recommended that during construction, fire safety staff need to check on adjacent building and give relevant advice. Further research however shows that a space of ten feet should always be allowed between buildings to avoid fire spread by radiation. In this case, this should be five feet from the property line of the two structures. (Diamantes, 2003) Analysis of effect of enclosure ventilation on combustion and the composition of smoke Enclosure ventilation has various effects on combustion. This is considering the fact that it allows oxygen into the premises. When large volumes of oxygen are allowed into a building, it leads to complete combustion. Minimal amounts of oxygen result in incomplete combustion that mostly releases toxic gases. (Kirk, 2006) Enclosure ventilation of a building has high effects on amount of oxygen that is allowed to enter the premises. It is essential to note that smoke composition highly depends on various combustion conditions. Houses with high ventilation allow a lot of oxygen and this results in minimal production of smoke. When the temperatures are very high, the smoke can be composed of hydrogen sulphide, sulphur dioxide or nitrogen oxides. The smoke is usually composed of ash and in large differences of temperature compressed aerosol of water is relaxed. When there is partial or combustion that is incomplete, the smoke is usually composed of toxic substances. These include ammonia, cyanide, hydrogen and carbon monoxide depending on the type of material. In situations where sulphur is present, carbon sulphide, sulphur dioxide, carbonyl sulphide and hydrogen sulphide can be produced. (Diamantes, 2003) Effect of varying compartment/building geometry and fire location on the production of smoke Varying compartment or building geometry and location of fire has various effects on smoke production. Research shows that smaller compartments tend to allow less oxygen that is very essential during combustion. This results in the release of large smoke quantities being produced than in larger compartments. There are also possibilities that the location where fire starts in a building has diverse effects on smoke production. (Lentini, 2006) When fire starts in a hall or the living room, there are high chances of less smoke being produced. On the other hand, when fire starts in the bathroom or washrooms which are normally small in size the smoke tends to be in larger quantities. This therefore shows that compartments and fire location have effects on smoke production. (Klinoff, 1997) Various plume types Smoke management in a building usually involves analysis of air flow that can allow smoke from a compartment. This sometimes calls for putting in place smoke control mechanisms such as smoke plumes. An adhered spill plume is a type of design made from a fire compartment in situations where the top opening has a vertically projecting wall and where there is no balcony. In this case, the plume adheres to the wall that is at the top of the opening. In this case, the flow of heat at the entrance of the compartment varies. An axisymmetric plume is mostly used in cases where fire can start on the floor of a building, a distance away from the walls of the building. This results in air being confined within the plume through its entire height. In this case, the fire size dictates the size axisymmetric plume that is to be incorporated. A window plume is usually relevant in situations where there the fire is already fully developed. This is considered to be a very exceptional application. Smoke control Many researchers assert that the main function of smoke control is to save lives. Other functions of smoke control include overall reduction of loss of property. The other function entails providing an environment where fire rescue personnel can easily carry out their fire fighting duties including rescuing people. (Kirk, 2006) The other function is to ensure that smoke does not reach elevator shafts, stairs and other smoke refuge rooms or areas within the premises. It is also aimed at inhibiting spread of smoke from the affected areas. Smoke control mechanisms need to be put in place during construction of buildings. (Klinoff, 1997) This can also be carried out as an emergency measure when a fire incidence occurs. Smoke control should be implemented in areas where fire can easily start such as kitchen or rooms where fire is commonly used. It should also be implemented in areas where occupants need to use during evacuation. These include elevator shafts, lifts and stairs. There are various methods that can be used to control smoke in a building. One of the ways is the use of plumes. These include the adhesive plumes, spill plumes, window plumes and axisymmetric. (Diamantes, 2003) These are used to control smoke from spreading throughout the building. Onshore and offshore applications are also commonly used as a way of controlling smoke within the affected premises. Pressurization method is also commonly used as a smoke control method. This is highly implemented at the stairways, the elevators and evacuation lifts to avoid smoke from accessing these areas. This is specifically implemented for to allow fire safety personnel to easily access buildings and rescue the occupants without being deterred by the smoke. Condensation protection and piping are also commonly used methods for smoke control. (Kirk, 2006) Standard curves A critical analysis of the standard curves used for determining fire resistance shows that they are not usually very accurate. This is considering the fact that there are differences in terms fire intensity and heat rate among the real and standard fire. It is also very clear that standard fire curves never represent fire conditions that are most severe. (Klinoff, 1997) These fires are very common during real life situations hence making the standard fire curves quite insufficient to use as a means of coming up with fire resistance mechanisms. The standard curve approach varies from onshore and offshore applications basing the fact that it is quite ideal. The onshore and offshore applications are quite practical and very applicable in real life situations as compared to the standard fire curves. (Rasbash, 2004) References; Diamantes, D. (2003): Fire prevention inspection and code enforcement. 2nd ed. Albany; NY: Thomson Delmar Learning Kirk, J. (2006): Fire Investigation; sixth edition; London; Oxford Press Klinoff, W. (1997): Introduction to fire protection; Albany, N.Y; Delmar Publishers Lentini, J. (2006): Scientific Protocols for Fire Investigation; London; University Press Rasbash, D. (2004): Evaluation of Fire Safety; John Wiley; London Watts, J. (2003): Fundamentals of Fire Safe Building Design; Fire Protection Handbook; 19th Ed; Vol. I, NFPA; Quincy MA; p. 2-37 to 2-49 Read More