Higher Growth of Fire in the Compartment with Installed Sprinklers or Protected Corridor vs a Compartment without Sprinklers - Essay Example

Name : xxxxxx Tutor : xxxxxx Title : FIRE DYNAMICS Course : xxxxxx Institution : xxxxxx @ 2010 Table of contents Introduction……………………………………………………………..............1 Experimental / Theory…………………………………………………………..4 Experimental procedures………………………………………………………..5 Results…………………………………………………………………………..5 Discussion……………………………………………………………………….6 Conclusion………………………………………………………………………7 References……………………………………………………………….. …....8 FIRE DYNAMICS Introduction: Introduction of the proposal in regards to the high rise structure was suggested by a group of private developers their main aim was to construct fire sprinklers in the kitchen and living areas and if necessary and they will also come up with smoke extract which will remove fire gases at a rate of 0.5 m3 /s. The building being a typical accommodation for the students consists of different apartments in line. In regards to the study each individual apartment contains a total of two bed rooms, 1 bathroom, 1 dinning room, kitchen and finally an apartment house unit Fowell (1994). After a careful review of the approval authorities that deals with the regulations of high rise buildings, it is clearly indicated that they can not approval the proceeding of the structures. Due to unsatisfied information within the proposal. The authorities have just realized that the proposal does not comply with the regulations and the set standards within the approved data in the documentation B (ADB) procedures and guidelines, That clearly stipulates that, each building and apartment requires a well structured fire resisting corridor in order to accommodate a safe escape through passage for the people within the building in case of fire or any other cases of emergencies Mehaffey (1988). However the company in regards to the development indicated that in most cases the targeted structural design will be enhanced in that is fire-engineered, meaning the developers will have to install the sprinklers in both the kitchen and the living rooms of the structures. Furthermore the installation of a smoke extract will be highly encouraged; this will help in the process of removal fire gases. Hence from this directional design the developers will achieve high security safety that is stipulated within the Approved Document B (ADB). In most case the CFAST model was deployed to indicate conditions and issues related with the fire policies and finally to produce observed conditions and to support the developer’s arguments. The structure The structure that was proposed is a high rise building that is meant for the accommodation of students, the building will be (9) nine m 9m wide by 7.5m deep and 2.4 stories tall. In reference to research the structure had the same floor plans and layouts. The structure or the building consists of a dinning kitchen, two bed rooms found in the rear. Furthermore the building contains an open balcony in the front Mehaffey (1988). According to the proposal by the developers, the main entrance for each and every apartment is connected on the right site side of the corridor. Finally the apartment phase consists of an open air area comprising of a dinning place and the kitchen while the bathroom area is situated within the center of the bed rooms. A compartmented wall was seen separating the main living room in cooperation with the bed rooms Fowell (1994). Figure 1, Plan of the house used for simulation Mehaffey (1988) The Scenarios In reference to this study, the fire simulation was applied during the night, as it could be the worst case scenario that all the doors and the windows were closed, so that the only source of combustion air was from the leakage paths in the balcony doors, and it has been applied in three different manners. Firstly, by using only a protected corridor, then by using only sprinklers in the kitchen and the living area and finally by using only sprinklers and smoke extract. The fire was set in a sofa in the living area, and the output of each case was analyzed and given in spreadsheets Krasny (2001) Experimental / Theory: The fire burned for only 20 minutes in normal conditions. The leakage paths provides small amount of air, which vents the smoke. The combustion produced large amount of unburned fuel and high quantities of CO and CO2 gases. It is widely believe that, under such a fire conditions, when the door is opened, the air which flowing out is replaced by the ambient air which carrying the oxygen to the fuel. Therefore, when the mixture ignites, severe flames will extend from the door. So, the CFAST model was used to measure the fuel amount that could be collected from the fire area, which could feed the fire for the observed period of time Krasny (2001). Computer Analysis: The compartment was modeled as a single apartment with the same dimensions of 9 m by 7.5 m by 2.4 m. The living area was modeled as 9 m by 2.7 m by 2.4 m height. The bedrooms were modeled as 2.8 m by 3.6 m by 2.4 m, connected to the bathroom. All these dimensions were provided in the handout layout. The initial fire was assumed to be a slight increase in heat release rate (HRR) from 0 – 135 kW within only 100s, from the actual data on the burning sofa. Then the fire transitioned in to a fire with a peak heat release rate of 7.0 MW Mehaffey (1988). Results (Graphs). Figure 2; Graph of Height against time Mehaffey (1988) Smoke extract and sprinklers: Figure 3, Graph of oxygen Mehaffey (1988) Figure 4, Graph of oxygen, carbon dioxide and carbon dioxide Mehaffey (1988) Figure 5, Graph of fire temperature against time Mehaffey (1988) Discussion: At the installation of the corridor the magnitude of the fire increased tremendously within the simulation period and later fell abruptly because the level of oxygen had gone down. The carbon monoxide concentration grew as the fuel remaining after burning gathered in the apartment volume in higher levels but the oxygen and carbon dioxide levels did not change. After simulation had been done for about two minutes the height of the layer fell to zero. It remained without any change up to the time the layer of smoke started disappearing. The uppermost layer had its temperature reaching its optimum at 593 °K at which time the burning had also gone to its highest. As burning went down it fell to under 150 °C. The temperature of the lower layer grew slightly and then stagnated Mehaffey (1988). Sprinklers alone were used in the second simulation experiment. Fire grew then tremendously and then dropped down slowly. At the same time the levelof oxygen dropped initially and then rose. The amount of carbon monoxide increased and then abruptly dropped with the activation of sprinklers and control of the fire in the apartment. At first the height of the layer fell within the first few minutes then stagnated. The upper layer temperature went to its optimum and later fell at the time when the lower layer temperature is standing still Krasny et al (2001). The heat levels in the living room went up but later fell to zero. The compartment in which the sprinklers are had little increase of fire as compared to the compartment that has the protected corridor. In comparison with the results of the protected corridor there is a drop in gas concentration. In the last experiment in which there was the installation of the smoke extract and the sprinklers the fire increased and then later reduced slowly. The amount of oxygen felland then grew afterwards Fowell (1994). Nevertheless the amount of carbon monoxide in the upper layer increased and then abruptly dropped while carbon dioxide and oxygen levels were unaltered. Within the first few minutes the height of the layer fell then stagnated for some time before growing to over1.8m. The upper layer temperature in the simulation setting reached optimum and later dropped as the lower temperature remained unchanged. The heat levels in the kitchen and living room went to the peak then quickly fell to zero Krasny et al (2001). According to the results there is a similarity in the results between the concentration of smoke and growth of fire in a compartment with sprinklers and a smoke extract and another compartment with sprinklers alone. Conclusion The compartment with installed sprinklers tends to have a lower spread and increase in comparison to a compartment without sprinklers. A compartment with a protected corridor has a higher growth of fire as compared to one with sprinklers. A compartment with both sprinklers and smoke extract has an equal amount of growth of fire with that compartment with sprinklers alone installed in it. The general observation form those compartments with sprinklers as well as those without indicates that the presence of sprinklers in a compartment reduces the growth of fire. References Andrew J. Fowell, - 1994 Fire and flammability of furnishings and contents of buildings; American Society for Testing and Materials John Krasny, William J. Parker, Vytenis Babrauskas - 2001 Fire Behavior of Upholstered Furniture and Mattresses - Page 321 Mehaffey J. R.1988; Mathematical Modeling of Fires Read More