Modeling Fire Evacuation of a Library Building based on the Numerical Simulation

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1 American Journa of Appied Sciences 8 (5): , 2011 ISSN Science Pubications Modeing Fire Evacuation of a Library Buiding based on the Numerica Simuation Withayavuth Jirasingha and Supat Patvichaichod Department of Mechanica Engineering, Kasetsart University, Si Racha Campus, 199, Sukhumvit road, Chonburi, 20230, Thaiand Abstract: Probem statement: This study investigates the fire evacuation probem of the ibrary buiding by using the Fire Dynamics Simuator with Evacuation (FDS+Evac.) programming. Approach: The assumption is made that the sprinker system is instaed in the buiding but the system is mafunction, which is considered as the worst case of the situation. The simuations are divided into 4 cases, which are case 1; the numbers of evacuating persons are 517 persons and the heat reease rate is 5 MW, case 2; the numbers of evacuating persons are 517 persons and the heat reease rate is 7 MW, case 3; the numbers of evacuating persons are 788 persons and the heat reease rate is 5 MW and case 4; the numbers of evacuating persons are 788 persons and the heat reease rate is 7 MW. Resuts: The resuts are shown that the 1st case and the 2nd case have the evacuation times of 8.63 and 8.81 min, respectivey. There is no dead person found from both cases. For the 3rd and the ast case, the evacuation times are and min, respectivey. The 3rd case has 1 dead person and the ast case has 18 dead persons, respectivey. Concusion: The number of evacuating person and a size of fire have a directy impact on the evacuating person. The reasons are the crowded situation of evacuation and a higher toxicity that is occurred. So, the stairway of the buiding has to be improved and changed to be the fire escape. This brings to the increasing in the capabiity of the evacuation. Key words: Fire evacuation, numerica simuation, ibrary buiding, Fire Dynamics Simuation (FDS), evacuation time, Fraction Effective Dose (FED), Air Handing Units (AHU) INTRODUCTION The fire evacuation is a necessary activity required in various emergency situations for exampes, the fire occurrence, the earthquake, a gas eak, the hostage situation and the bombing. The evacuation time depends on various components, which are the user characteristics, the buiding characteristics and the buiding ayout. Athough the buiding ayout is we designed, the testing, the efficiency measurement and the capacity of means of egress have to be often impemented. Merchant (1982) mentioned about the 3 parts of escape time (Tescape) components as shown in Eq. 1. Tescape = Tp + Ta + Tt (1) Where: Tp = A perception time of fire occurrence Ta = An action time of fire occurrence The simuation program of evacuation in this research is Fire Dynamics Simuator with Evacuation (FDS+Evac) that is abe to cacuate ony for the evacuation time but the program has not got a function to cacuate the perception time and the action time. However, the program is abe to assign the initia time of evacuation or the response time in which the evacuating person can perceive the fire occurrence and react to the evacuation time. In addition, there are other important factors infuencing on the trave time, which are a popuation size, the evacuation speed, the congestion of the peope, the door width, the evacuation route, the distance to the safe pace, the buiding shape and dimension, behavior and famiiarity to the pace and the increment of toxicity in combustion process emerged from the decoration materia in the buiding. Using the simuation program of evacuation is a choice to determine the potentia or the faut of evacuation area. The time and cost wi be saved in case of the evacuation pan is prepared in advance. The buiding modification is required by the evacuation pan. A ot of Tt = A trave time to a safe pace researchers contributed to the evacuation and numerica Corresponding Author: Supat Patvichaichod, Department of Mechanica Engineering, Kasetsart University, Si Racha Campus, 199, Sukhumvit road, Chonburi, 20230, Thaiand 452

2 simuation such as, Ma and Quintiere (2003) and Xin et a. (2005). Zhang et a. (2007); Lin and Chuah (2008); Roh et a. (2009); Qin et a. (2009); Mouieau and Champassith (2009); Kwaire et a. (2009); Merry et a. (2009); Zahim et a. (2009); Momani (2010) and Majee and Roy (2010). MATERIALS AND METHODS Buiding fire modeing: The ibrary buiding under studied size is 22.8 m (W) m (L) 15.8 m (H) having 4 stories and the eft stair is a fire stair but the right stair is norma stair, as shown in Fig. 1. From the NFPA 101, Life Safety Code (2009), the category of ibrary is cassified by the types of the assemby buiding. In case of the users are more than 50 persons, the simuation modes then are divided into 2 cases. The first case is referred by the rea data of maximum number of user (517 persons) and the second case is referred and cacuated from the NFPA 101, Life Safety Code (2009) (788 persons). Water and Wan (2005) mentioned the heat reease rate of modes used in Asia as shown in Tabe 1 in which the poyurethane is used in their research. There are 2 cases of the modeing. The first case has 5,000 kw of therma energy and 5 m 2 of sectiona area. And the second case has 7,000 kw of therma energy and 7 m 2 of sectiona area. Both cases have the 1,000 kw m 2 of heat reease rate per area. Assume that the fire source occur at air handing units of the 3rd foor as shown in Fig. 2. CFD numerica modeing: This study used Fire Dynamics Simuation (FDS) for the tunne smoke fow simuation. FDS is a fuid dynamics program deveoped by Nationa Institute of Standards and Technoogy (NIST Specia Pubication , 2010; NIST Specia Pubication , 2010). FDS is targeted for ow Mach number heat and fow fied anaysis. The computer program can be used to anayze fire reated probems, such as temperature, veocity and concentration distribution. Hu et a. (2006) used FDS to study the maximum smoke temperature under the tunne ceiing. Predicted FDS resuts for near fire fied agreed fairy we with the experiments. FDS soves fow equations numericay. The physica equations incude Navier-Stokes equations for fow anaysis, energy conservation equations for temperature distribution and other scaar equations for smoke and particuates transport. Governing equations are described as foows. Conservation of mass: ρ + ( ρ u) = 0 Conservation of momentum: u ρ ( + (u )u) + ρ=ρ g+ f + τ Conservation of energy: Dp ( ρ h) + ρ hu = q''' qr + k T Dt + h( ρd) Y (2) (3) (4) Conservation of species: Fig. 1: Depicts the top view of ibrary buiding Fig. 2: The source of a fire at the 3rd foor 453 ρ + ρ = ρ + ( Y) Yu ( D) Y W''' (5) The resuts from a numerica anaysis are sensitive to the grid size used. The proper grid size is discussed ater as reated to the parameters such as the fire size and the properties of air. Grid resoution is required to compare with the fire characteristic diameter. Grid independent test has to be conducted for the grid size seection. This grid anaysis is required to obtain viabe computer simuation resuts. Specificay, grid size determination is important for fied near the arger gradient ocation such as near the fire site. Tabe 1: Heat reease rate Types of buidings HRR (kw) Airport and rai station > 7,000 Department store and pubic buiding 5,000 Ha in the buiding or open area in buiding > 7,000 Barrier in rai station 1,000

3 Fig. 3: Depicts the temperature vaues for monitoring equipment no. 16 of the 3rd foor Case 1: The rea maximum number of the evacuating person is 517 persons and a size of fire is 5 MW. Case 2: The rea maximum number of evacuating person is 517 persons and a size of fire is 7 MW. Case 3: The number of evacuating person cacuated by the NFPA 101, Life Safety Code (2009) is 788 persons and a size of fire is 5 MW. Case 4: The number of evacuating person cacuated by the NFPA 101, Life Safety Code (2009) is 788 persons and a size of fire is 7 MW. Fig. 4: Depicts the temperature vaues for monitoring equipment no. 17 of the 3rd foor Tabe 2: Grid resoution anaysis Number of grid Grid size CPU Resoution NPX NPY NPZ ΔX ΔY VZ time (h) Coarse Moderate Fine Grid resoution anaysis: To determine the suitabe grid size in the mode, the experiment is conducted by reducing the grid size. The change of the equipment is then examined to seect the grid size by the desired resoution for using the mode. Tabe 2 shows the CPU time to cacuate the grid size by sizes of the fire mode. From Fig. 3 and 4, the temperatures of 3 grid sizes are presented. The highest vaues of the temperatures beong to the coarse grid size, which is represented by A. The center ine and the bottom ine show the moderate ( B ) and fine grid size ( C ), respectivey. The monitoring equipment is instaed in front of the source of a fire. The differentiation between the coarse and moderate grid size or 0.5 =>0.375 is more than the differentiation between the moderate and fine grid size or 0.375=>0.25. Then, the differentiation of grid size with and 0.25 has a sma change in a graph and does not have a significant effect on the resut. In addition, the grid size of uses the run time faster than the grid size of The grid size of is then seected to be run in the next 4 cases: The combustion product anaysis: The product from the combustion is the toxic quantity that can be a cause of death to the evacuating person. In this research, ony gases that make the evacuating person unconscious are investigated. Whereas the density ratio of Purser (1995) or the Fraction Effective Dose (FED) is shown in Eq. 6: FED = FED HV + FED (6) tot 2 2 O2 In addition, the ratio of that is harmfu or can decrease the abiity is shown in Eq. 7: FED = (C ) t (7) where, C is the percentage of density by voume of. The ratio of O 2 that is harmfu and is a cause of hypoxemia is shown in Eq. 8: FED O2 t = 60exp[ (20.9 C )] O2 (8) where, is the percentage of density by voume of 2 O 2. The factor of 2 that is a cause of suffocation is further shown in Eq. 9: HV exp(0.1930c ) 2 = (9) 2 where, 7.1 C2 is the percentage of density by voume of 2. Tabe 3 and Tabe 4 show vaues of resistabe temperature of human and quantity in periods. These vaues are foowed by the NFPA 130, Standard for Fixed Guideway Transit and Passenger Rai Systems, 2000 Edition (Nationa Fire Protection Association, 2000). 454

4 RESULTS In Tabe 5, the resuts of 4 cases of evacuating person are shown by various number of evacuating person and sizes of fire. In Tabe 6-9, the average temperatures of 4 foors of the case study buiding are concuded, whereas Fig depicts the smoke movement inside the ibrary buiding of. The source of a fire starts at the Air Handing Units (AHU) of the 3rd foor. The smoke moves from the source room to the 4th foor and passes to the right stairway. Some smoke moves to the book store of the 3rd foor. The smoke moving at the 4th foor is faster than the 3rd foor because the 4th foor is the open air area. The smoke moves to the fire stair on the eft hand side of the buiding and then moves out form the fire stair at the 3rd foor, the 2nd foor and the 1st foor. The smoke moving from the right stairway of the 3rd foor expands to the 2nd and the 1st foor. After that the smoke moves to the front of the buiding at the main entrance. The smoke suffocation is occurred from both of front and back sides of the buiding. Except for the case 1 and the case 2, the smoke does not move to the 1st foor immediatey because the simuation time is rather short. Tabe 10 and 11 show the O 2 and quantity of the 3rd foor, which is the source of a fire. Tabe 3: Shows the resistabe periods of human by various temperatures Temperature Resistabe period 140 F (60 C) 2-3 sec 120 F (49 C) Less than 6 min Tabe 4: Shows the resistabe periods of human by various quantities Resistabe period 2,000 PPM 2-3 sec 1,500 PPM Less than 6 min 800 PPM Less than 15 min 50 PPM Residue from the burning Tabe 5: Presents the tota time of evacuation from the ibrary buiding Number of Size of Evacuation Number of Case no. evacuating person fire (MW) time (min) dead person Tabe 7: Shows the average temperature of the 2nd foor Front of eft Centra Front of right Case no. stairway ( C) area ( C) stairway ( C) Tabe 8: Shows the average temperature of the 3rd foor Front of eft Centra Front of right Case no. stairway ( C) area ( C) stairway ( C) Tabe 9: Shows the average temperature of the 4th foor Front of eft Centra Front of right Case no. stairway ( C) area ( C) stairway ( C) Tabe 10: Shows the O 2 quantity of the 3rd foor O 2 quantity of the 3rd foor (%) Case no Tabe 11: Shows the quantity of the 3rd foor quantity of the 3rd foor (PPM) Case no Fig. 5: Depicts the movement of smoke at 100 sec of Tabe 6: Shows the average temperature of the 1st foor Case no. Centra area ( C) Front of right stairway ( C) Fig. 6: Depicts the movement of smoke at 200 sec of

5 Fig. 7: Depicts the movement of smoke at 300 sec of Fig. 12: Depicts the movement of smoke at 800 sec of Fig. 8: Depicts the movement of smoke at 400 sec of Fig. 13: Depicts the movement of smoke at 900 sec of Fig. 9: Depicts the movement of smoke at 500 sec of Fig. 14: Depicts the movement of smoke at 1000 sec of Fig. 10: Depicts the movement of smoke at 600 sec of Fig. 15: Depicts the movement of smoke at 1100 sec of Fig. 11: Depicts the movement of smoke at 700 sec of 456 Fig. 16: Depicts the movement of smoke at 1200 sec of

6 DISCUSSION Most peope choose the right stairway. Because the right stairway is arger than the eft stairway. In case 3 and 4, peope are dead in front of the right stairway of the 3rd foor where the temperature is the highest eve. Average temperatures, whie peope died about 200 C, which is higher than the peope wi be abe to endure according with NFPA 130, the highest temperature that peope can toerate is 60 C for a few seconds. Indicators that show peope were kied are Fractiona Effective Dose (FED) is equa to 1, which is the resut of adding together the percentage of, 2 and O 2. NCLUSION The ocation that found the dead peope is at the 3 rd foor in front of the right stairway of the buiding. This ocation has the highest temperature compared with other foors because it coses to the source of a fire at 200 C. Generay, the resistabe temperature of human is 49 C with ess than 6 min. The percentage of O 2 and quantity has the effect on the number of dead peope, which is considered from the Fraction Effective Dose (or FED). The FED is a tota of O 2, and 2 ratios, which equas to 1 and is a cause of human death. In addition, the study is aso found that the increasing in the number of evacuating peope and the toxic quantity has a direct effect on the evacuating peope. The reason is high number of evacuating peope that are waiting in a ong period in front of stairway makes the increasing in the toxic quantity. So, the right stairway of the buiding has to be improved to increase the evacuation abiity. REFERENCES Am. J. Appied Sci., 8 (5): , 2011 Hu, L.H., R. Huo, W. Peng, W.K. Chow and R.X. Yang, On the maximum smoke temperature under the ceiing in tunne fires. Tunne. Underground Space Techno., 21: DOI: /j.tust Kwaire, A.A., H.M. Faih and H.A. Abdu Bari, Modeing of three phase system with Non- Newtonian iquid using computationa fuid dynamics mode. Asian J. Ind. Eng., 1: Lin, C.J. and Y.K. Chuah, A study on ong tunne smoke extraction strategies by numerica simuation. Tunne. Underground Space Techno., 23: DOI: /j.tust Ma, T.G. and J.G. Quintiere, Numerica simuation of axi-symmetric fire pumes: Accuracy 457 and imitations. Fire Safety J., 38: DOI: /S (02) Majee, N.C. and A.B. Roy, Asymptotic behavior of an artificia neura network defined on mutipartite directed graph. OnLine J. Bio. Sci., 10: DOI: /ojbsci Merchant, E.W., Modeing Fire Safety and Risk. In: Fire and Humans Behavior, Canter, D. (Ed.). Wiey, New York, pp: Merry, K., P. Bettinger and J. Hepinsta, Physica and bioogica responses of forests to tropica cycones affecting the united states Atantic ocean and guf of Mexico coasts. Am. J. Environ. Sci., 5: DOI: /ajessp Momani, N.M., Business continuity panning: Are we prepared for future disasters. Am. J. Econ. Bus. Admin., 2: DOI: /ajebasp Mouieau, Y. and A. Champassith, CFD simuations of atmospheric gas dispersion using the Fire Dynamics Simuator (FDS). J. Loss Prevention Process Indus., 22: DOI: /j.jp Nationa Fire Protection Association, NFPA 130, Standard for Fixed Guideway Transit and Passenger Rai Systems Edn., Nationa Fire Protection Association, Massachusetts. NFPA 101, Life Safety Code, Edition Nationa Fire Protection Association Nationa Fire Protection Association, Massachusetts. NIST Specia Pubication , Fire Dynamics Simuator (Version 5) Technica Reference Guide, Nationa Institute of Standards and Technoogy. Maryand. NIST Specia Pubication , Fire Dynamics Simuation (Version 5) User s Guide, Nationa Institute of Standards and Technoogy. Maryand. Purser, D.A Toxicity Assessment of Combustion Products. In: SFPE Handbook of Fire Protection Engineering, Nationa Fire Protection Association, Massachusetts, pp: 2/28-2/146. Qin, T.X., Y.C. Guo, C.K. Chan and W.Y. Lin, Numerica simuation of the spread of smoke in an atrium under fire scenario. Bui. Environ., 44: DOI: /j.buidenv Roh, J.S., H.S. Ryou, W.H. Park and Y.J. Jang, CFD simuation and assessment of ife safety in a subway train fire. Tunne. Underground Space Techno., 24: DOI: /j.tust

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