Case Study by Team Japan. Underground Car Park

Transcription

1 11th Conference on Performance Based Codes and Fire Safety Design Methods Case Study by Team Japan Underground Car Park Ai Sekizawa,Tokyo University of Science Ayako Tanno, Akeno Facility Resilience Inc. Jun Kitahori, Akeno Facility Resilience Inc. Kiyoshi Fukui, Nikken Sekkei Corp. Masahito Kikuchi, Akeno Facility Resilience Inc. Moyu Seike, Akeno Facility Resilience Inc. Samon Kobayashi, Japan Fire Equipment Inspection Institute Shuji Moriyama, Nihon University Yoshikazu Minegishi, Takenaka Corp. Yusuke Shintani, Takenaka Corp.

2 Contents Executive Summary 1 Chapter 1 Strategy for Fire Safety 1.1 Japanese code for underground car park Strategy for fire safety 2 Chapter 2 Design Fire 2.1 Design fire when the sprinkler system is not activated Design fire when the sprinkler system is activated 9 Chapter 3 Smoke Analysis 3.1 Smoke control strategy Analysis method and settings Simulation results and discussions 20 Chapter 4 Life Safety of Occupants 4.1 Evacuation Strategy Tenability Criteria Verification of Evacuation Safety Results and Evaluation of Evacuation Safety 44 Chapter 5 Effective Firefighting Plan 5.1 Objective of Firefighting General Planning and Firefighting Scenarios Verification of Firefighting Strategy Conclusion of Firefighting plan 66 Chapter 6 Conclusion 6.1 Conclusion 67 Appendix Calculation Results of Smoke Analysis 68 Computer Evacuation Modelling 76 Travel Speed in Smoke and Visibility 79 Calculation Results of Evacuation Analysis using Sim Tread 81

3 EXECUTIVE SUMMARY For this case study, we focused on the combustibles and fire behavior in the underground car park. Since most of the materials of car are inflammable and covered by steel and glass coverings, we assumed that fire of a car is slower and more moderate than our expectations. Based on the study on the experiment data before, we made sure that a car fire could spread to the neighboring cars, but never spread to the cars on the other side of the drive way. So, for this fire protection design, we install and set up as least fire safety facilities and equipment as we can. We compartmentalized car park into three zones. Each zone was separated by fire resistant wall and openings with active smoke barriers. Each zone has two stairs for evacuation with vestibules pressurized to restrain smoke invasion. Under these conditions, we verified our fire safety design by FDS and multi-agent simulation software for evacuation, SimTread. With FDS, we simulated the movement of smoke in this car park and checked the safety of evacuation and firefighting activity with parameters such as smoke height, smoke density, density of CO2 and temperature of surrounding air. As a result, our fire safety design is verified to be safe enough. CHAPTER 1 STRATEGY FOR FIRE SAFETY 1.1 Japanese Code for Underground Car Park First we premised that this underground car park is constructed following Japanese Building and Fire codes. Building Standards Law of Japan Fire compartment Maximum area should be less than 3,000 m2 (with automatic fire distinguishing system) Smoke exhaust system for evacuation Smoke exhaust system more than 1 [m 3 /m 2 min ] should be installed. Evacuation stairs No requirement because car park is not a room where people stay for a long time. However, we usually install several evacuation stairs according to the size. Emergency Lighting No requirement because car park is not a room where people stay for a long time. However, we usually install it. The illumination should be more than 1 [Lx ]. Fire Service Act Fire Extinguishing systems We install one of following system. Foam extinguishing system Water spray extinguishing system Inert gas extinguishing system Halogenated hydrocarbon extinguishing system Powder extinguishing system 1

4 We usually install foam extinguishing system for the car park excluding mechanical parking facilities. Fire department standpipe Sprinkler system with hose connection Standpipe wit hose connection Fire extinguisher Automatic fire alarm system Luminaire for emergency exit system Smoke exhaust system for fire fighting Smoke exhaust system more than 1 [m 3 /m 2 min ] should be installed. Positive pressure smoke exhaust system should be installed for the staging area. 1.2 Strategy for Fire Safety In our case study, we set up the strategy for fire safety considering following issues Facilities for smoke and fire protection Compartmentalization Fire compartment is important to localize the spread of fire and smoke. However, as for fire in car park since combustibles are only cars mostly covered by steel, it would take certain time for fire to spread from the car of fire origin to the adjacent car. In addition fire could not spread over the drive way of cars. And since this is a very huge car park, smoke also may not spread wide area of this car park. So, we divide all the area of car park into three zones by fire resistant wall, but we install just active smoke barrier where the drive way of cars cross the wall. Each zone, divided by fire resistant wall, has a pair of evacuation stairs and one ramp for cars. Smoke control system Smoke exhaust system is necessary for car park following the prescriptive regulations, but we think it can be reduced considering the characteristics of fire in car park described above. Smoke of B1F could be exhausted in each zone through the ramp to outside. For the fire in B2F we installed a smoke shaft beside the ramp. Fresh air from outside could be provided through the ramp in the zone next to the fire origin zone. Fire shutters are installed to the ramp of B1F and activated only in case of fire on B2F. Shutters prevent the B1F floor from being contaminated by smoke in case of B2F fire. We also install positive pressure smoke exhaust system to each vestibule of stairs for firefighting. Fire Extinguish system In Japan, foam extinguishing system is usually installed to such an underground car park, because most of combustible of fire in car park is resin material and gasoline and extinguishing system by water is not suitable for them. But in this case study the comparison between two cases with sprinkler and without sprinkler is demonstrated to verify these two cases. 2

5 In addition, sprinkler system with hose connection is installed in both cases. But it is not activated by smoke detector, and it is only used by firefighters for hose connection. Sprinkler heads and piping can be used for both sprinkler system. a Smoke Zone B Zone A Fresh air b Fresh air a b Zone C Smoke Shaft from B2F Figure1.1. Compartmentalization and smoke control system Vestibule pressurized 2.9m 2.0m a-a Active smoke barrier Figure1.2. Border of each zone b-b 3

6 Figure1.3. Active smoke barrier Active smoke barrier:automatically hang down if smoke is detected Smoke Shaft GROUND F B1F B2F B1F fire Smoke Shaft GROUND B1F B2F B2F fire Figure1.4. Smoke movement in case of B1F and B2F fire 4

7 1.2.2 Evacuation planning Since this is a huge underground car park, we cannot expect sunlight if the lighting system loses its function by fire, and the occupants have to evacuate long distance in a dark space. We took such characteristics into our consideration to set up the evacuation strategy. Compartmentalization to three zones Each zone has two stairs and one regular elevator, and occupants in each zone can evacuate to one of these two stairs. Occupants can also evacuate to the neighboring zone, and it assures the redundancy of evacuation. Safe refuge area Vestibules next to stairs as a temporary safe refuge area are pressurized not to be contaminated by smoke. Emergency lighting and luminaire for emergency exit system Emergency lighting and luminaire for emergency exit system are installed. Refuge space for wheelchair For wheelchair users we prepare a refuge space in front of stairs. Stairs for evacuation Smoke shaft Elevator Figure1.5. Compartmentalization and evacuation items Fire resistant wall &Active smoke barrier 5

8 CHAPTER 2 DESIGN FIRE The main combustible items in car parks are automobiles. Therefore, the design fire was chosen based on the burning behavior of an automobile. Fire scenarios were chosen considering the effects of a sprinkler and the location of a fire origin. The chosen scenarios are shown in chapter 3 and Design Fire When the Sprinkler System is not Activated The design fire was chosen based on the fire spread between automobiles. The total HRR was the sum of the HRR of automobiles burning simultaneously. The time required for a fire to spread was determined based on the experimental results of fire spread between automobiles. The heat release rate curve of a automobile, Qi, was calculated using the following equation. Q i = min( αt 2, Q ) (2-1) max where α is the fire growth rate [kw/s 2 ] and Qmax is the maximum heat release rate[kw]. The fire growth rate and maximum heat release rate were obtained using statistical processing of experimental data [1]. The histograms of the fire growth rate and maximum heat release rate are shown in Figure 2.1.and 2-2, respectively. The lognormal distribution was assumed as shown in the figures. The design value was obtained as α = and Qmax = 8900kW such that the probability of non-exceedance was equal to 95 %. number of data average = design value = lognormal (0.0362, ) fire growth rate α [kw/s 2 ] Figure 2.1. A histogram of fire growth rate of automobiles 6

9 number of data average=4260 design value =8900 lognormal (4260, 2449) maximum heat release rate Q max [kw] Figure 2.2. A histogram of maximum heat release rate of automobiles [1] The value of the fire growth rate of automobiles adopted for two level stackers was the same as the former design value, but the value of the maximum heat release rate was twice as much as the design value. The time required for a fire to spread to adjacent automobiles was obtained based on the experimental results of the fire spread between automobiles. The times required for a fire to spread in the experiments are listed in Table 2.1. The design value of the time required for a fire to spread was 17 min, which was the minimum value obtained in the experimental results. Table 2.1. Time for a fire to spread between automobiles [2] Test No. Direction Distance [mm] Time for a fire to spread [min] (1) To right side (1) To left side (1) Backward (1) To left side (2) To right side (2) To left side (3) To left side Fire spread to the opposite side of the lane was studied as shown in figure 2.3. The radiation heat flux to the surface of the automobiles in the opposite side was calculated using the following equations [3]. χq q = max 2 cosθ = 9.49kW m q 2 crit 4πr / (2-2) where χ is the radiative fraction (=0.35), r is the distance from the center of the fire to the surface of the automobile in the opposite side, θ is the angle shown in figure

10 The radiation heat flux to the surface was lower than critical heat flux of wood, qcrit = 10 [kw/m 2 ] [4]. Therefore a fire would not spread to the opposite side. 2.5m 5m Fire area r=8.5m(=5/2+6m) 6m θ Q=8900kW, χ=0.35 Opposite side Figure 2.3. Fire spread from burning automobiles to the automobiles in the opposite side of the road Summarizing the above, the HRR curves when the sprinkler system is not activated are shown in Figure ,000 50,000 two level stackers HRR[kW] 40,000 30,000 20,000 fire spread to adjacent automobiles non-stacked 10, time[min] Figure 2.4.HRR curve when the sprinkler system is not activated 8

11 2.2 Design Fire When the Sprinkler System is Activated Fire scenarios Usually, in Japan, the foam extinguishing systems are installed in underground car parks. But in this case study, we verify the case that sprinkler system is installed in this car park. In a building where the sprinkler system is installed, we assume the 4 fire scenarios as shown in Figure 2.5. Fire Sprinkler works S1 Succeed to extinguish S2 Succeed to control Sprinkler doesn t work S3 Design fire, when the sprinkler is activated. Failure to control Q f : Heat release rate [kw] Q sp : Heat release rate on a sprinkler s activation time [kw] S4 Fire spread Figure 2.5. Fire scenarios when the sprinkler systems is installed in a building [5] When the sprinkler system is activated and a fire is extinguished (S1), the occupants and the fire fighters in the building are safe. If the sprinkler system is activated but a fire could not be suppressed (S3), the fire may spread. In this case, we assume the same with S4, when the sprinkler system is not activated. Therefore, we verify S2 case as the design fire when the sprinkler system is activated and a fire is controlled. 9

12 Calculation of activation time of sprinklers We calculated the activation time of sprinklers when the temperature of the thermal part of sprinkler head becomes the detecting temperature. The temperature of the thermal parts of the sprinkler heat was calculated using the following equations by Heskestad, et al. [6] and Bill [7]. dt dt e = 1/ 2 u RTI ( T T ) g e (2-3) where Te is the temperature of the thermal part of sprinkler head [deg C] Tg is the air temperature of near the thermal part of sprinkler head [deg C] u is fire-gas velocity of near the thermal part of sprinkler head [m/sec] RTI is the response-time index of sprinkler head [m 1/2 sec 1/2 ] The air temperature and gas velocity near the sprinkler head were calculated using the following equations as a function of heat release rate and position for steady-state fires by Alpert [8]. 3 3 ( Q ) 2 / / H 5 / ( r / H 0.18) 16.9 T g = (2-4) / ( Q 2 / / H 5 / )( r / H ) ( r / H > 0.18) 3 ( Q / H ) ( r / H 0.15) 1/ 3 1/ 2 5/ 6 Q H / r ( r / H > 0.15) 0.95 u = (2-5) 0.20 where Q is heat release rate [kw] H is ceiling height [m] r is horizontal distance from fire source [m] Tg is temperature rise near ceiling [deg C] (Horizontal distance r from fire source, ceiling height is H) Q is defined as Q=αt 2 (α=0.112: based on Chapter 2.1), it goes up until the sprinkler system activate. The detecting conditions of the closed type sprinkler head which we adopted are shown in Table 2.2. Table 2.2. Calculation conditions of the activation time of the sprinkler Items Value Detecting temperature of thermal point of sprinkler head [degc] 72 Horizontal distance from fire source to sprinkler head [m] 2.8 (Effective water-sprinkled radius of high-sensitive sprinkler head) Response-time index of sprinkler head [m 1/2 sec 1/2 ] 32 Ceiling height [m]

13 Results of calculation The result of the activation time of sprinkler system is shown in Figure 2.6. As shown in this figure, the activation time is 84sec, and the heat release rate is 861kW at that time. Based on the above data, we supposed the maximum heat release rate Qmax is equal to 1MW when the sprinkler system is activated. Near the thermal point temperature Tg [deg] Nominal Activation Temperature of SP Head = 72 [deg.] 84sec(Heat releace rate Q=861kW) Time[sec] Case : α=0.122 RTI=32 Figure 2.6. Activation time of sprinklers REFERENCES 1. MZM. Tohir, M. Spearpoint, Distribution analysis of the fire severity characteristics of single passenger road vehicles using heat release rate data, Fire Science Reviews, Vol. 2, No. 5, T. Wataru, K. Norichika, S. Yusuke, H. Kazunori, M. Takanori, M. Hideaki, G. Tatsunori, Experimental Investigation of Burning Behavior of Automobiles, Architectural Institute of Japan, Summary of Technical Papers of Annual Meeting, 2003, pp SFPE, Engineering guide, Assessing Flame Radiation to External Targets from Pool Fires, A. Tewarson, Chapter 3-4 Generation of Heat and Chemical Compounds in Fires, 2002, The SFPE HANDBOOK OF Fire Protection Engineering 3 rd edition, SFPE, pp I. Yuka, Y. Jun-ichi, D. Yoshikazu, N. Daisuke, T. Takayoshi, Study on reliability of sprinkler system for evacuation safety method, Architectural Institute of Japan, Summary of Technical Papers of Annual Meeting, 2012, pp Heskestad,. G., and Smith, H. F., Investigation of a New Sprinkler Sensitivity Approval Test: The Plunge Test, Factory Mutual Research, FMRC Serial No RC 76-T-50 December Bill, R. G.., Thermal Sensitivity Limits of Residential Sprinklers, Fire Safety Journal 21, pp Alpert, R.L., Calculation of Response Time of Ceiling-Mounted Fire Detectors, Fire Technology, Vol. 8, pp

14 CHAPTER3 SMOKE ANALYSIS 3.1 Smoke Control Strategy Purposes of smoke management in this underground car park are as follows; 1) Prevention of horizontal smoke spread 2) Prevention of vertical smoke spread 3) Smoke exhaust for fire-fighting For this purpose, we proposed the following smoke management devices and system; 1) Dividing the plan into three zones by fixed and active smoke compartments 2) Installing smoke shafts to B2F of each three smoke zone 3) Installing fire shutters around ramp voids of B1F 4) When a fire occurs at B2F, smoke will be exhausted through the smoke shafts 5) When a fire occurs at B1F, smoke will be exhausted through the ramps 6) Ramps and smoke shafts of non-fire compartments work as routes for makeup air intake 7) Horizontal smoke spread is prevented by those smoke compartments, smoke vents and air intake Besides the above, pressurization system are installed to fire-fighters staging areas. In this section, performance of above smoke management system is examined. Diagram of the smoke control system and examples of the activation are shown in Figure 3.1 to Figure

15 Zone B GF Zone A B1F B1F GF Full height fixed smoke compartment Active smoke compartment Fire shutter Smoke shaft Staging area pressurization Fire compartment B1F Zone C GF B2F Figure 3.1. Diagram of smoke control system Fresh air is induced from ramp openings at GF Active smoke compartments between non-fire zones are not activated unless smoke reaches here Fire shutters of non-fire zones are not closed Zone B GF Zone A B1F B1F Fresh air is induced from adjacent zone through openings under active smoke compartment Staging area pressurizations of fire zone are activated GF Fire shutters of fire zone around ramp are closed Smoke is exhausted through smoke shaft Smoke is exhausted to outside through opening of GF Zone C B1F Pressurization air is leaked to fire zone GF Figure 3.2. Example of activation of smoke control system 13

16 Zone C Zone B, Zone A Smoke is exhausted through ramp opening Fresh air is induced from adjacent zone through openings under active smoke compartment Active smoke compartment Fresh air is induced from ramp openings at GF Ramp opening Ramp opening GF Ramp Ramp B1F Ramp Ramp B2F Figure 3.3. Diagram of smoke control system, Section (Fire occurs at B1F) Smoke is exhausted through smoke shaft Smoke shaft Fresh air is induced from adjacent zone through openings under active smoke compartment Active smoke compartment Fresh air is induced from ramp openings at GF GF B1F B2F Figure 3.4. Diagram of smoke control system, Section (Fire occurs at B2F) Fire shutter Ramp opening Ramp Ramp Fresh air is induced from adjacent zone through openings under active smoke compartment Active smoke compartment Ramp Ramp Ramp opening Fresh air is induced from ramp openings at GF GF B1F B2F Figure 3.5. Diagram of smoke control system, Section (Fire occurs at B2F) 14

17 3.2 Analysis Method and Settings We use Fire Dynamics Simulator (FDS) to confirm the properties of smoke layer Settings of simulation model Among the three zones, we chose the most severe scenario that a fire occurred in zone C. The reason is as follows; 1) Compared with other zones, staircases arrangement of zone C is the worst. In particular, there is a long dead end in zone C, and it is difficult to escape from there. 2) The fire source in the zone C is the biggest because there are two level stackers. Also, we assumed three fire sources in zone C. 1) The fire source at two level stackers. (The biggest fire source) 2) The fire source at the parking space next to stairc-2. 3) The fire source at the parking space next to stairc-1. The position of these fire sources are shown in Figure 3.6. Scenario-f1 α=0.122 Qmax=17.8MW Scenario-s1 α=0.122 Qmax=1.0MW Scenario-f3 α=0.122 Qmax=8.9MW Scenario-s3 α=0.122 Qmax=1.0MW Scenario-f2 α=0.122 Qmax=8.9MW Scenario-s2 α=0.122 Qmax=1.0MW Figure 3.6. Example of activation of smoke control system 15

18 3.2.2 Simulation models 1) A fire origin floor The fire at B1F is not so dangerous, because smoke is exhausted through the ramps to outside. On the other hand, the fire at B2F is dangerous, because smoke may spread to B1F. So, we assume that a fire occurs at B2F. 2) Vents The area of the smoke vent shaft at B2F is 23m 2 (23m 1m), and vent area above the ramps at B1F is about 18m 2. We unified the area of the vent at B1F and B2F to 18 m 2, and set the vent at the top of the FDS model. 3) FDS models and mesh This car park is so large that it takes long time to run the simulation. So we made two simulation models to shorten the running time. One is the whole model that consists of all zones, the other is the partial model that consists of only zone C. Whole model is built for the simulation of fire fighting (0-20 minutes after a fire occurred. hereinafter referred as the fire fighting phase). And partial model is built for the simulation of evacuation (0-10 minutes after a fire occurred. hereinafter referred as the evacuation phase). [Whole model] This model consists of all zones, and use uniform mesh. The cell size is shown at Table 3.1. The openings are arranged in each smoke compartment. As the positive pressure smoke exhaust system, supply vents are installed at vestibule C1 and C2. The velocity of supply air was calculated based on the Fire Services Law of Japan. We assume the system starts 5 minutes after a fire occurred. The parameters for supply vents are shown at Table 3.2. Table 3.1. Uniform Mesh Parameters Dir(X,Y,Z) Cell Size Zone A Zone B Zone C X 0.5m 0.5m 0.5m Y 1.0m 0.5m 0.5m Z m m m (2.9m divided by 6) (2.9m divided by 6) (2.9m divided by 12) Time [min] Table 3.2. Parameters for supply vents Supply vent C1 Supply vent C2 Volume Velocity Volume Velocity Flux of air Flux of air [m 3 /h] [m/s] [m 3 /h] [m/s] ,400 15, note from an opening for release pressure From the door firefighters open 16

19 Whole model is shown in Figure 3.7. Figure 3.7. Whole model 17

20 [Partial model] This model consists of only zone C, and use non-uniform mesh to confirm smoke properties in the upper space in detail. The cell size is shown at Table 3.3. and Figure 3.8. Table 3.3. Non-Uniform Mesh Parameters Dir(X,Y,Z) Cell Size X 0.5m Y 0.5m 0.1m(1.5m-2.9m) Z 0.3m(0.0m-1.5m) Figure 3.8.Non-Uniform Mesh Zone C is divided into 12 rectangular grids and installed some devices at the center of each grid. Also, some devices are installed at the exits. The devices output the properties as follows. Temperature Smoke layer height Light extinction coefficient Mass fraction of carbon dioxide FED Figure 3.9. Partial model 18

21 4) Heat Release Rate (HRR) Settings of each fire source are shown in table 3.4. Scenario Sprinkler α Table 3.4. Heat Release Rate of each scenario Qmax [MW] tqmax [s] HRR [kw/m 2 ] Fire area [m 2 ] Scenario-s1 Success Scenario-f1 Fail Scenario-s2 Success Scenario-f2 Fail Scenario-s3 Success Scenario-f3 Fail ) Soot Yield Rate To evaluate visibility, soot density should be predicted. Soot yield rate is strongly governed by the material of fire source. Therefore, supposed material of fire source should be specified. Fire in this underground car park is assumed as a car fire. And in many cases, source of fire will be gasoline. But, in general, chemical component of gasoline is not identical. Besides, other part of cars will be fire source; for example, interior, exterior, and tires, etc. Representative materials used and stored in cars are listed in Table 3.5. Considering the evacuation phase (early stage of fire), there is little possibility of heavy burning of interior. And, if considering the fire-fighting phase, as many kind of material are burning, so, soot yield rate is defined as 0.1 Table 3.5. Representative fire source material of cars 1) Part of cars Representative materials ys Gasoline Heptane Octane Benzene Toluene Interior Polyurethane foams GM Exterior ABS Polypropylene Tire Hydrocarbon

22 3.3 Simulation Results and Discussion Horizontal smoke spread Evacuation phase 1) Whole model, Scenario-f1/s1 Figure 3.10 shows the temperature distribution of z=1.93m at 600s after ignition of a fire. In this case, sprinkler activation failed. Figure shows the temperature of sprinkler succeeded case. In both cases, smoke spread to zone B is largely restricted. In sprinkler activated case, temperature rise in zone C is not so high; about 60 o C near the fire origin and o C in an average area of the zone. On the other hand, the temperature of in sprinkler failed case is quite high; about 500 o C near the fire origin and o C in an average area of the zone. 2) Partial model, Scenario-f1/s1 From the above results, it is considered that the smoke hardly influence on evacuation safety of adjacent zone. On the other hand, it is necessary to examine a fire occurred zone (zone C) in more detail. So, we use partial model for this simulation. Figure and Figure shows the temperature distribution of z=1.80m of scenariof1 and s1. The section height is slightly different (z=1.80m), but the temperature distribution shows a tendency like the whole model. Figure and Figure shows visibility of z=1.80m of scenario-f1 and s1. In the scenario-f1, the smoke reaches to the dead end about 320 seconds later, and in the scenario-s1, the smoke reaches to there about 390 seconds later. It is thought that people in the dead end cannot notice the fire easily. 20

23 [Whole model] Temp. [ o C] Figure Temperature distribution at Z=1.93m, Sprinkler failed case, t=600s (Scenario-f1) Temp. [ o C] Figure Temperature distribution at Z=1.93m, Sprinkler succeeded case, t=600s (Scenario-s1) 21

24 [Partial model] 60s 240s 90s 300s 120s 420s 180s 600s Temp. [ o C] Figure Temperature distribution at Z=1.8m, Sprinkler failed case (Scenario-f1) 22

25 60s 240s 90s 300s 120s 420s 180s 600s Temp. [ o C] Figure Temperature distribution at Z=1.8m, Sprinkler succeeded case (Scenario-s1) 23

26 60s 240s 90s 300s 120s 420s 180s 600s Vis_Soot. [m] Figure Visibility distribution at Z=1.8m, Sprinkler failed case (Scenario-f1) 24

27 60s 240s 90s 300s 120s 420s 180s 600s Vis_Soot. [m] Figure Visibility distribution at Z=1.8m, Sprinkler succeeded case (Scenario-s1) 25

28 Fire-Fighting phase 1) A fire occurred in a zone of two level stackers Figure 3.16 shows the temperature distribution of z=1.93m at 1200s after ignition of a fire. In this case, sprinkler activation failed. Figure 3.17 shows the temperature of sprinkler succeeded case. In both cases, smoke spread to adjacent smoke compartment through the openings on the drive way is largely restricted. As an example, air flow around opening of smoke compartment and smoke shaft is shown in Figure and From this figure, prevailing airflow is from non-fire compartment to fire compartment through smoke compartment opening and smoke is exhausted through smoke shaft. In sprinkler activated case, temperature rise in fire occurred compartment is not so high; about 40 o C near the fire origin and o C in an average area of the compartment. On the other hand, that of in sprinkler failed case is quite high; about 200 o C near the fire origin and o C in an average area of the compartment. 2) A fire occurred near the staircase located at dead end of the car-lot Figure 3.20 shows the temperature distribution of z=1.93m at 1200s after ignition of a fire. In this case, sprinkler activation failed. Figure 3.21 shows the temperature of sprinkler succeeded case. In both cases, smoke spread to adjacent smoke compartment through the openings on the drive way is largely restricted. But, the temperature of the dead end area is relatively high because there are no smoke exhaust measures there. In sprinkler activated case, the temperature at dead end area is about 45 o C and the temperature at center of the smoke compartment (near the ramp) is about 25 o C. In sprinkler failed case, the temperature at dead end area is about o C and temperature at center of the smoke compartment (near the ramp) is about 50 o C. 3) Smoke control area of smoke spread Even if the temperature rise in a fire origin smoke compartment differs depending on fire scenarios, smoke spread is almost limited within a fire origin compartment. Thus, at least, fire-fighters are able to search and rescue the remaining occupants easily and safely. More detail of feasibility of fire-fighting, especially in a fire origin compartment are discussed at following Chapter 5. 26

29 Temp. o C Figure Temperature distribution at Z=1.93m, Sprinkler failed case, t=1200s (Case-f1) Temp. o C Figure.3.17.Temperature distribution at Z=1.93m, Sprinkler succeeded case, t=1200s (Case-s1) 27

30 Non-fire compartment Smoke curtain Fire occurred compartment 2.9m 2.0m Figure 3.18.Velocity distribution, t=1200s / Section A (Case-s1) Opening of smoke shaft 2.9m Figure Velocity distribution, t=1200s / Section B (Case-s1) Velocity [m/s] Section A Section B 28

31 Temp. [ o C] Figure Temperature distribution at Z=1.93m, Sprinkler failed case, t=1200s (Case-f2) Temp. [ o C] Figure Temperature distribution at Z=1.93m, Sprinkler succeeded case, t=1200s (Case-s2) 29

32 Prevention of Vertical Smoke Spread When a fire occurs in B1F, smoke is exhausted through ramp openings. But, when a fire occurs in B2F, smoke spreads into B1F through ramps. Therefore, we installed fire shutters around the ramps of B1F to prevent smoke spread to B1F. And, to exhaust smoke in B2F, we installed smoke shafts to B2F (Figure 3.22.). In this given building, ramps are directly open to outside, thus, smoke ascends into ramps and smoke can be exhausted to outside directly, and there is little concern of smoke spread to GF. But, in the first stage of this engineering design, plan of GF was not decided. So, we consider the possibility that ramp openings would not be directly open to outside. In this case, there would be possibility that smoke in B2F ascends through smoke shafts to GF. This smoke might descend to B1F, if the area of opening at GF is small. Or the area of opening of smoke shafts and its openings are large. And, if considering this smoke descent, occupants at the B1 have to recognize fire and start evacuation quickly (Figure 3.22.). Finally, smoke shafts are located directly open to outside, but, we decided the area of smoke shafts, opening of smoke shafts, and opening of ramps not for smoke to descend to B1F (Figure 3.23.). Fire compartment Smoke will descend to B1F through ramp Smoke shaft Smoke will spread horizontally Occupants in B1F have to evacuate quickly Ramp Ramp GF Fire shutter B1F Active smoke compartment B2F Figure Diagram of smoke control system (Fire occurs at B1F) Fire compartment Smoke will descend to B1F through ramp Smoke shaft There is no needs for immediate evacuation Large area of opening Ramp Ramp GF Fire shutter B1F Figure Diagram of smoke control system (Fire occurs at B1F) 30

33 To simplify the simulation model, only one of the three smoke compartment is modeled to simulate vertical smoke spread. And, openings between other smoke compartments are modeled as openings being connected to outside. Size of opeings are listed in Table 3.6. And as the most severe case, a fire is supposed to occur in a zone of two level stackers and sprinkler failed. With this setting, it is comfirmed that smoke descent to B1F is prevented as shown in Figure 3.24(next page), time historcal smoke spread simulation. Because of time limitaion of this case study, we could not conduct repetitive calculation. Those values would be more rationalized by continuing simulation. Table 3.6. Areas of vent opeings Openings Area Between smoke zones 28 m 2 2 Section of smoke shaft 46m 2 Openings of smoke shafts at GF 23m 2 Openings of smoke shafts at B2F 23m 2 Between ramp and outside at GF 23.2 m m 2 31

34 GF Opening between ramp and outside at GF 23.2m 2 Openings of smoke shafts at GF 23m 2 Zone C Fire occurred at B2F Fire at two level stackers Qmax=17.8MW B1F B2F Zone B Opening between ramp and outside at GF 23.2m 2 Section of smoke shaft 46m 2 Opening between smoke zones 28m s 150s 300s Figure Smoke spread behavior (Fire occurs at B2F, Fire at two level stackers, Qmax=17.8MW) 600s REFERENCE 1)The SFPE handbook of fire protection engineering fourth edition, Chapter 4 Generation of Heat and Gaseous, Liquid, and Solid Products in Fire, pp to 3-146, SFPE/NFPA,

35 CHAPTER 4 LIFE SAFETY OF OCCUPANTS 4.1 Evacuation Safety Problems to be solved of underground car park Underground car park has the following characteristics about evacuation. Space with limited illumination: Underground car park cannot have opening to outside. Occupants have to evacuate under limited illumination. Spaces with limited illumination have such problems as down of evacuation speed and losing sight of the direction. Closed space: Though smoke exhausting system is important for safety of occupants and firefighters, it is difficult to exhaust smoke in such closed space without smoke exhausting equipment. If the smoke cannot be exhausted, the room condition may be getting worse. For example, the temperature rise of the smoke and an outbreak of flash-over may occur. Huge space: This car park is very huge space of about 14,000m 2. Therefore, occupants have to spend long time for evacuation. Evacuees who do not get used to this huge car park may lose the direction and might be surrounded by smoke before noticing emergent situation. In such a place, evacuees have difficulty to reach an exit Evacuation Planning Considering the above characteristics of this car park, we set up following strategy for evacuation. Installation of emergency light and exit sign For ensuring the luminosity required for evacuation, we installed the appropriate emergency lighting and exit sign. Installation of smoke shaft We use ramps of car park as a smoke exhaust shafts, and also set up the smoke shaft in each zone to get out smoke in case of fire. Smoke can be removed by a natural ventilation without activation and it cannot be interrupted by electrical power failure. Compartmentalization to three zones We compartmentalized this huge car park into three zones. Each zone has a two stairs and one elevator, and occupants in each zone can evacuate to one of these two stairs. Occupants can also evacuate to the neighboring zone, and it assures the redundancy of evacuation. 33

36 Temporary refuge area for wheelchair For occupants with wheelchair we prepare a temporary refuge area next to stairs. It is also next to EV that could be used for evacuation in emergency. It is also possible to wait for the rescue of the fire fighters in this refuge area. The temporary refuge space is also pressurized to prevent invasion of smoke. Overview of temporary refuge area is shown in Figure Stairs Temporary Refuge Area EV Size of wheelchair Area required for wheelchair waits Figure 4.1. Planning of temporary refuge area 34

37 Fire resistant wall & Active smoke barrier Residence or Office Underground car park Stairs and safety space EV Stairs Smoke shaft Figure 4.2. Conceptual diagram of evacuation safety measures 35

38 4.2 Tenability Criteria Safety of evacuees must be secured while evacuating to safe space without influence of fire and smoke. Tenability criteria to be evaluated for evacuation are shown below. Also, flowchart of verification is shown in Figure 4.4. The smoke layer height should not be lower than the height of the evacuees. If evacuees are exposed to the smoke, smoke layer must be in the condition that does not affect to evacuees. Criteria of smoke layer height are the following. Height of the smoke layer: Hs [m] 1.8 [m] If evacuees are exposed to the smoke, it is necessary to consider toxic and visibility of smoke. These criteria are the followings. Toxic of smoke Extinction coefficient Cs [1/m] 0.5 [1/m] *1(Reference Height =1.5 [m]) Toxic gasses CO2 [%] 0.5 [%] *2 Smoke temperature Ts [deg C] 44.8 [deg C] (Reference Height =1.8~2.8 [m] (Average)) *3 Visibility of smoke Visibility distance of up to exit sign V [m] The distance between the exit sign and evacuees L (20m) [m] *4 Limited temperature of exit sign 140 [deg C] Temperature of smoke Ts [deg C] (Value of maximum) *5 Exit sign operating time after a power failure (30 [min]) Evacuation time tescape [min] *5 *1 Evacuees cannot keep their eyes open in thicker irritant smoke over 0.5 [1/m] 1) *2 General evaluation criteria of Japan 2) *3 Pain from the application of heat to the skin occurs when the skin temperature at a depth 0.1 [mm] reaches 44.8 [deg C] 3) *4 Visibility distance of the exit sign (B-class) V=22.5/Cs (Reference Height = 2.4 [m]) 4) Figure 4.3. Relation between the visibility of the exit sign and extinction coefficient *5 Standard of Japan Luminaries Association(JIL55017) 36

39 Start During evacuation, evacuees are not exposed to the smoke YES Criteria: Smoke Layer height 1.8[m] NO The smoke condition does not affect to evacuees. Criteria of toxic: Cs [1/m] 0.5 [1/m] CO2 [%] 0.5 [%] Ts [deg C] 44.8 [deg C] Criteria of Visibility: V [m] L [m] 140 [deg C] Ts [deg C] 30 [min] tescape [min] YES NO Evaluation OK NG Figure 4.4. Flowchart of verification 37

40 4.3 Verification of Evacuation Safety Building equipment system for evacuation 1) Evacuation equipment Evacuation equipment planning is shown in Figure 4.5. We divide this plan into three zones, while preparing two places with stairs and refuge space within each zone. In this chapter, we focus on zone C for verification because zone C is largest of the three and has a dead end difficult to secure the safety of occupants. Zone B Zone A Zone C Vestibule Corridor Temporary refuge area Active smoke barrier Verification target Area Figure 4.5. Evacuation equipment planning 38

41 2) Exit sign planning The standard of exit sign defined by Fire Service Low of Japan is shown below. Garage: More than C-class Underground mall: A-class or B-class Specification of exit signs and exit route signs to be installed is to apply the standard of the underground mall. (Apply the A-class) Exit route sign is planned within 20 [m]. Table 4.1. Standard of specification of exit sign and exit route sign Class Vertical dimension of display H[m] Brightness of display [cd] Average luminance L[cd/m 2 ] Effective range [m] Exit sign A 0.4 H More than L < B 0.2 H < 0. 4 More than L < C 0.1 H < 0. 2 More than L < Exit route sign A 0.4 H More than L < B 0.2 H < 0. 4 More than L < C 0.1 H < 0. 2 More than L < Exit sign Exit route sign (within 20[m]) Figure 4.6. Exit sign planning 3) Illumination planning The luminosity of the car park is as generally planned in the 35 ~ 70 [lx]. Therefore, it plans 50 [lx] or more. 39

42 4.3.2 Design fire scenario We verify the six scenarios that assumed fire position, fire size, and operational reliability of the sprinkler system etc. Design fire scenarios that are assumed are shown in Table 4.2. The detail of the design fire is shown in Chapter 2 and 3. Table 4.2. Design fire scenario Scenario No. Fire origin Sprinkler system Success / Failure f1 Failure (1) s1 Success f2 Failure (2) s2 Success f3 Failure (3) s3 Success Method of evacuation analysis While zone C of this car park is an open room with a large area exceeding 5000 [sq. m], the ceiling height is 2.9 [m] that is not enough from point of accumulating smoke. There is a deadend space, which has only one evacuation route, between the baselines X13 and X18. Hence the following assumptions are considered: Occupants evacuate to the different exit of 5 in accordance with locations of each fire origin except a dead-end space. Occupants start to evacuate in different time in accordance with smoke flow. In this study, computer software to simulate the pedestrian movement named SimTread is adopted to calculate the evacuation time at each exit. Time to start the evacuation and destinations to evacuate can be provided as input factors to each occupant in this model. The feature of SimTread is described in Appendix (B). 40

43 Figure 4.7. Model of Sim Tread for Evacuation Analysis Input design factors Number of occupants Occupant load factor is adopted 0.05 [person/sq. m] in accordance with the Japanese guideline 5). Number of the occupant with disabilities is assumed from the rate of parking space for a person with wheelchair. Number of occupants at Zone C: 269 [persons] (5,370 [sq. m] x 0.05 [person/sq. m]) Number of the occupant with disabilities at Zone C: 1 [person] (included in 269 [persons]) Travel speed 78 [m/min] is used as the input data of the travel speed for this evacuation analysis using Sim Tread. Based on the assumption that persons with disabilities group and small children usually use this car park and get in their cars with persons who can assist them, the travel speed for these occupants also regards as 78 [m/min]. However, it should be noted that travel speed is reduced when the illuminance become lower than 3 [lx] as described below. In case of a fire at the underground car park, the illuminance is assumed to be lower than upper ground areas. The following travel speed reflected by the illuminance is proposed on the basis of the reference 6): 41

44 v = 1.3 v smoke = 1.56VA 0.12 ( E > 3.0) ( E 3.0) VA = γ (log 10 L +1.85) v : Travel speed [m/sec] v smoke : Travel speed in smoke[m/sec] E : Illuminance[lx] VA : Visual acuity γ : Age - related coefficient L : Luminance[cd/sq. m] Travel speed is reduced when the illuminance at the floor level is below 3.0 [lx]. For details, travel speed in smoke considering the illuminance is described in Appendix (C) Method of evacuation Time to start the evacuation This car park is located under the office or the residential building. It is assumed to be used by limited persons who are familiar with this building and recognize the evacuation route such as the location of staircases. Based on this, occupants start to evacuate when they are aware of fire or smoke. In this study the following configurations are considered: Zone C is divided into 12 grids, each of that is approximate 24 [m] x 24 [m] area. This grid size intends that the visibility to adjacent grids doesn t exceed around 30 [m]. Occupants in the grid of fire origin start to evacuate at the same time as fire occurs, that is in 0 [second]. Other occupants in each grid start to evacuate when smoke accumulates in an adjacent grid. Time that smoke starts to accumulate is calculated by CFD analysis. If smoke does not accumulate for 600 [seconds] in some grids, graphics of the smoke viewer simulated by CFD analysis is regarded as this time. The same amount of time to start the evacuation is provided for occupants in the same grid. 42

45 Figure 4.8. Definition of Time to Start the Evacuation in Scenario-f1 Time to prepare the evacuation for disabled persons Persons with disabilities need time to prepare for starting evacuation such as transferring from a car to a wheelchair. In this study 60 [seconds] is added to time to start the evacuation for the person in a wheelchair and his/her assistant. Directions to evacuate Occupants evacuate to the opposite directions from fire origin. Based on this human behavior, the following configurations are considered: Occupants who are aware of fire in their grid of fire origin evacuate to the nearest exit. Other occupants who are aware of smoke in their adjacent grid evacuate to the opposite directions from the fire origin and use the nearest exit. In case that the grid does not have exits at the opposite direction from fire origin, occupants in this grid evacuate to the nearest exit. Each direction is provided for each occupant even if they occupy in the same grid. 43

46 Evacuation time In this study RSET (Required Safety Egress Time) consists of the following total time: Time to start the evacuation on the basis from the time that smoke is accumulated in each grid, calculated by CFD analysis For the person in wheelchair and his/her assistant, additional 60 [seconds] as the time to prepare the evacuation Time that the occupant at the end of the queue reaches to each exit of Results and Evaluations of Evacuation Safety Results and summary Evacuation safety in 6 fire scenarios is evaluated and the results are summarized in the following table: Table 4.3. Summary of Evaluations of Evacuation Safety in 6 Scenarios Scenario No. Fire Origin Condition of Sprinkler Evaluation of Fire Safety Exit (Unavailable Condition before Completing the Evacuation) f1 (1) Failure NG Exit(3) s1 Success NG Exit(3) f2 (2) Failure OK - s2 Success OK - f3 (3) Failure NG Exit(3) s3 Success OK - It was confirmed that all occupants at Zone C of this car park could evacuate within available level in 3 scenarios-f2, s2 and s3. On the other hand, It was found that some criteria for evacuation safety were not be satisfied in other 3 scenarios-f1, s1 and f3. The following factors are indicated to be the cause of these results: In case of controlled fire with sprinkler, available levels for evacuation safety become better than uncontrolled fire for all of 3 fire origins. In this study, occupants start to evacuate when they are aware of fire or smoke. In accordance with this assumption, it takes long time to start the evacuation at some grids far from fire origin. In scenario-f1 and s1, occupants were delayed in starting the evacuation in more than 200 [seconds] in the area between baselines x13 to x18 in case of fire origin (1). In 3 scenarios-f1, s1 and f3, some criteria for evacuation safety were not be satisfied at Exit (3). Exit (3) is the only one evacuation route of the dead-end car park between the baselines X11 and X18. In other words, even if conditions of evacuation safety are not available at 44

47 this exit, persons who occupy between the baselines X11 and X18 cannot evacuate to opposite directions from the critical side. In all scenarios, the person in a wheelchair with his/her assistant could evacuate safety. These results and considerations intend that the following enhancement factors for evacuation safety: Fire extinguishing equipment such as sprinklers can control fire source and improves conditions including smoke layer level and visibility when occupants evacuate. Occupants far from fire origin might not be aware that fire occurs and smoke descends. This evacuation delay might cause these occupants to evacuate under unavailable conditions. Prompt assists by an emergency alarm/voice system and facility management play meaningful roles to start the evacuation without delay and to evacuate safety. Means of egress should be arranged in order to avoid dead ends in routes and keep other directions from fire origin to evacuate safety. Detail results and evaluations of fire safety for 6 fire scenarios are described in the next sections and graphics expressing time series conditions of evacuation, which are created by using Sim Tread, are shown in Appendix (D). 45

48 4.4.2 Scenario-f1_Unconrolled fire (1) The following drawing shows time to start the evacuation in each grid and time that smoke descends at 1.8 [m] height of each exit. Figure 4.9. Evacuation Plan 46

49 Evacuation safety of Scenario-f1 is evaluated and the results are shown in the following table: Table 4.4.: Evaluations of Evacuation Safety of Scenario-f1 (Fire Origin (1), Uncontrolled Fire by Sprinkler) Conditions at RSET Available Level Exit(1) Exit(2) Exit(3) Exit(4) Exit(5) RSET [sec] (Required Safe Egress Time) ) Smoke Level: Hs [m] Hs ) CO2 [%] CO ) Smoke Density: Cs Cs ) Visibility: V [m] V Illuminance: E [lx] * ) Smoke Temperature: Ts [degc] Ts ASET [sec] (Available Safe Egress Time) Time that Smoke Descends at 1.8 [m] Height of Exits ASET-RSET [sec] Evaluation OK OK NG OK OK (Evaluate Hs Hlim at first. In case of Hs<Hlim, evaluate 2)CO2, 3)Cs, 4)V and 5)Ts) CO2 Cs V Ts (NG) (NG) (NG) (NG) *: In this result of evacuation analysis that regards travel speed as 78 [m/min], the illuminance was below 3 [lx] at Exit (3). Though travel speed should be reduced when the illuminance is below [lx] as described in 4.3.4, all criteria such as CO2, Cs, V and Ts didn t satisfy each available level. Hence the further analysis that reduces travel speed is omitted. 47

50 4.4.3 Scenario-s1_Controlled fire (1) with sprinkler The following drawing shows time to start the evacuation in each grid and time that smoke descends at 1.8 [m] height of each exit. Figure Evacuation Plan 48

51 Evacuation safety of Scenario-s1 is evaluated and the results are shown in the following table: Table 4.5. Evaluations of Evacuation Safety of Scenario-s1 (Fire Origin (1), Controlled Fire by Sprinkler) Conditions at RSET Available Level Exit(1) Exit(2) Exit(3) Exit(4) Exit(5) RSET [sec] (Required Safe Egress Time) ) Smoke Level: Hs [m] Hs ) CO2 [%] CO ) Smoke Density: Cs Cs ) Visibility: V [m] V Illuminance: E [lx] ) Smoke Temperature: Ts [degc] Ts ASET [sec] (Available Safe Egress Time) Time that Smoke Descends at 1.8 [m] Height of Exits ASET-RSET [sec] Evaluation OK OK NG OK OK (Evaluate Hs Hlim at first. In case of Hs<Hlim, evaluate 2)CO2, 3)Cs, 4)V and 5)Ts) CO2 Cs V Ts (OK) (NG) (NG) (OK) 49

52 4.4.4 Scenario-f2_Unconrolled fire (2) The following drawing shows time to start the evacuation in each grid and time that smoke descends at 1.8 [m] height of each exit. Figure Evacuation Plan 50

53 Evacuation safety of Scenario-f2 is evaluated and the results are shown in the following table: Table 4.6. Evaluations of Evacuation Safety of Scenario-f2 (Fire Origin (2), Uncontrolled Fire by Sprinkler) Conditions at RSET Available Level Exit(1) Exit(2) Exit(3) Exit(4) Exit(5) RSET [sec] (Required Safe Egress Time) ) Smoke Level: Hs [m] Hs ) CO2 [%] CO ) Smoke Density: Cs Cs ) Visibility: V [m] V Illuminance: E [lx] ) Smoke Temperature: Ts [degc] Ts ASET [sec] (Available Safe Egress Time) Time that Smoke Descends at 1.8 [m] Height of Exits ASET-RSET [sec] Evaluation OK OK OK OK OK (Evaluate Hs Hlim at first. In case of Hs<Hlim, evaluate 2)CO2, 3)Cs, 4)V and 5)Ts) CO2 Cs V Ts (OK) (OK) (OK) (OK) 51

54 4.4.5 Scenario-s2_Controlled fire (2) with sprinkler The following drawing shows time to start the evacuation in each grid and time that smoke descends at 1.8 [m] height of each exit. Figure Evacuation Plan 52

55 Evacuation safety of Scenario-s2 is evaluated and the results are shown in the following table: Table 4.7. Evaluations of Evacuation Safety of Scenario-s2 (Fire Origin (2), Controlled Fire by Sprinkler) Conditions at RSET Available Level Exit(1) Exit(2) Exit(3) Exit(4) Exit(5) RSET [sec] (Required Safe Egress Time) ) Smoke Level: Hs [m] Hs ) CO2 [%] CO ) Smoke Density: Cs Cs ) Visibility: V [m] V Illuminance: E [lx] ) Smoke Temperature: Ts [degc] Ts ASET [sec] (Available Safe Egress Time) Time that Smoke Descends at 1.8 [m] Height of Exits ASET-RSET [sec] Evaluation OK OK OK OK OK (Evaluate Hs Hlim at first. In case of Hs<Hlim, evaluate 2)CO2, 3)Cs, 4)V and 5)Ts) CO2 Cs V Ts (OK) (OK) (OK) (OK) 53

56 4.4.4 Scenario-f3_Unconrolled fire (3) The following drawing shows time to start the evacuation in each grid and time that smoke descends at 1.8 [m] height of each exit. Figure Evacuation Plan 54

57 Evacuation safety of Scenario-f3 is evaluated and the results are shown in the following table: Table 4.8. Evaluations of Evacuation Safety of Scenario-f3 (Fire Origin (3), Uncontrolled Fire by Sprinkler) Conditions at RSET Available Level Exit(1) Exit(2) Exit(3) Exit(4) Exit(5) RSET [sec] (Required Safe Egress Time) ) Smoke Level: Hs [m] Hs ) CO2 [%] CO ) Smoke Density: Cs Cs ) Visibility: V [m] V Illuminance: E [lx] * ) Smoke Temperature: Ts [degc] Ts ASET [sec] (Available Safe Egress Time) Time that Smoke Descends at 1.8 [m] Height of Exits ASET-RSET [sec] Evaluation OK OK NG OK OK (Evaluate Hs Hlim at first. In case of Hs<Hlim, evaluate 2)CO2, 3)Cs, 4)V and 5)Ts) CO2 Cs V Ts (NG) (NG) (NG) (OK) *: In this result of evacuation analysis that regards travel speed as 78 [m/min], the illuminance was below 3 [lx] at Exit (3). Though travel speed should be reduced when the illuminance is below [lx] as described in 4.3.4, some criteria such as CO2, Cs and V didn t satisfy each available level. Hence the further analysis that reduces travel speed is omitted. 55

58 4.4.7 Scenario-s3_Controlled fire (3) with sprinkler The following drawing shows time to start the evacuation in each grid and time that smoke descends at 1.8 [m] height of each exit. Figure Evacuation Plan 56

59 Evacuation safety of Scenario-s3 is evaluated and the results are shown in the following table: Table 4.9. Evaluations of Evacuation Safety of Scenario-s3 (Fire Origin (3), Controlled Fire by Sprinkler)ure Conditions at RSET Available Level Exit(1) Exit(2) Exit(3) Exit(4) Exit(5) RSET [sec] (Required Safe Egress Time) ) Smoke Level: Hs [m] Hs ) CO2 [%] CO ) Smoke Density: Cs Cs ) Visibility: V [m] V Illuminance: E [lx] ) Smoke Temperature: Ts [degc] Ts ASET [sec] (Available Safe Egress Time) Time that Smoke Descends at 1.8 [m] Height of Exits ASET-RSET [sec] Evaluation OK OK OK OK OK (Evaluate Hs Hlim at grst. In case of Hs<Hlim, evaluate 2)CO2, 3)Cs, 4)V and 5)Ts) CO2 Cs V Ts (OK) (OK) (OK) (OK) 57

60 REFERENCES 1) The Society of Fire Protection Engineers (SFPE), Chapter 61 Visibility and Human Behavior in Fire Smoke, SFPE Handbook of Fire Protection Engineering 5 th Edition, p2190, (2015) 2) Architectural Institute of Japan, Chapter 3 Fire Safety of a Building, Bouka Zairyou Pamphlet (in Japanese) (Pamphlet of Fireproof materials),1993, p81 3) The Society of Fire Protection Engineers (SFPE), Chapter 63 Assessment of Hazards to Occupants from smoke, Toxic, Gases, and Heat, SFPE Handbook of Fire Protection Engineering 5 th Edition, p2376, (2015) 4) T. Yamada, K. Kubota, N. Abe and A. Iida, Visibility of Emergency Lights through Smoke,Proceedings of the 6 th Asia-Oceania Symposium of Fire Safety Science and Technology, International Association for Fire Safety Science, Daegu, 2004, pp ) Architectural Institute of Japan, Chapter 3 Fire Safety of a Building, Recommendations on Performance-Based Fire Safety Design for Buildings (in Japanese),2002, p35 6) The Society of Fire Protection Engineers (SFPE), Chapter 61 Visibility and Human Behavior in Fire Smoke, SFPE Handbook of Fire Protection Engineering 5 th Edition, pp ,(2015) 58

61 CHAPTER 5 EFFECTIVE FIREFIGHTING PLAN 5.1 Objective of Firefighting The main objective of firefighting at the fire site is to protect the life and property of occupants. Fire brigades operate their activities to rescue occupants at the fire site and to prevent the building from being damaged by fire Building performance requirements Performances required to buildings for safe and effective firefighting are: (1) Protection of a staging area for firefighting and rescue activity until the end of fire. (2) Safe and easy access to the location of fire origin and other places where firefighting and rescue activity are necessary General Planning and Firefighting Scenarios Facilities and equipment for firefighting Table 5.1 shows the facilities and equipment in the case study building, which meet the requirements described in section 5.1. Although a foam fire extinguishing system, which uses a mixture of fire-extinguishing agent (made mainly from harmless soap), water and air, is required in underground car park building by Fire Service Law in Japan, sprinkler system should be equipped in this car park according to the proposed building description in this scenario. 59

62 Table 5.1. Firefighting Facilities and Equipment in the Case Study Building Required Facilities and Performance Equipment Purpose Safety protection of firefighting staging area Vestibules connected to stairwells To provide staging areas for firefighting and rescue activity. Smoke control To exhaust smoke from the compartment of Safe & easy access to the location of fire origin system (vents) Automatic sprinkler system Fire stand pipe and piping system for fire brigade use Positive pressure ventilation Automatic fire alarm system fire origin through smoke shaft. To prevent fire spread from the compartment of fire origin to other compartments. To suppress fire to the degree that fire brigades can extinguish. To supply firefighting water from fire engine to higher floors. To send water to sprinkler system from fire engine. To protect firefighters from hot and dense smoke. To collect fire information swiftly. A control panel is equipped in the Emergency Control Center on ground floor Firefighting scenarios (1) Receiving a fire call. Fire brigades recognize a fire accident in the building by receiving a call from building occupants. (2) Arrival at fire site. The fire engines arrive at the fire site. We assumed the arrival time of the fire engines from a fire station to the fire site as 5 minutes or shorter referring to the rule of deployment of firefighting resources enacted by Tokyo Fire Department. (3) Access to the floor of fire origin. Fire engines halt near the entrance stairs to the underground car park. Firefighters approach the floor of fire origin via firefighting stairs. Table 5.2 shows the timetable of firefighting scenario from notification to arrival at fire origin. 60

63 Table 5.2. Timetable of Firefighting Scenario from Notification to Arrival at Fire Site Time elapsed after fire occurrence 1 Occupants identify a fire. 3 min *1 2 Occupants call the fire station. 4 min *2 3 Fire brigades recognize a fire 6 min *2 accident. 4 Fire brigades depart the fire 7 min *2 station. 5 Fire brigades arrive at the fire site. 11 min *2 6 Firefighters connect fire engine *2 13 min hose to fire stand pipe. 7 Firefighters arrive at the *2 Emergency Control Center on 16 min ground floor to make an effective firefighting plan 8 Firefighters arrive at the *2 vestibules on one floor above the 19 min fire origin (B1F when fire origin is B2F). 9 Firefighters arrive at the *2 vestibules on the floor of fire origin via stairwells and 20 min extinguish with water hoses. *1 Evacuation start time *2 The required time of mobilization of fire brigade from emergency call (in Japanese), Tokyo Fire Department, Case1: Fire Origin in Zone C on B2F Figure. 5.1 shows the approach routes when fire origin is within Zone C on B2F (Case1). Three out of six groups of firefighters approach Entrance-B2, C1 and C2 on the ground floor of the building and then approach the compartment of fire origin on B2F via Stairwell-B2, C1 and C2. Firefighters will use Entrance-B2, C1 and C2 as staging areas to allocate firefighting equipment and extend water hose. If there are some evacuees on B2F in the building at this moment, some of the firefighters play the role of rescue crews. When firefighters reach the vestibule in the compartment of fire origin on B2F, they open the fire door slightly to observe the condition inside the compartment in order to judge whether they can enter safely or not. Figure. 5.2 shows the firefighting operation when fire origin is on B2F. The rest of the groups of firefighters approach B1F via Stairwell-A1, A2 and B1 and search evacuees who failed to escape or lead them to the outdoor. 61

64 Entrance-B1 Stairwell-B1 Stairwe11-A1 Entrance-A1 Stairwell-B2 Ground floor of the Car Park Stairwell-A2 Entrance-A2 Entrance-B2 Entrance-C1 Stairwell-C1 Entrance-C2 Stairwell-C2 (1) Approach Route on Ground Floor Stairwe-B1 Zone B Stairwe-A1 Zone A Stairwe-B2 Stairwe-A2 Stairwe-C1 Zone C Stairwe-C2 (2) Approach Route on B2F Figure Approach Routes when Fire Origin Occurs in Zone C on B2F (Case1) 62

65 Entrance Car Park Rescue Crew B1 B2 Room of Fire Origin Vestibule Firefighters Stairwell Figure Firefighting Operation when Fire Origin Occurs on B2F Case2: Fire Origin in Zone A on B2F Three out of six groups of firefighters approach Entrance-A1, A2 and either B1 or B2 located on the ground floor of the building and then approach the compartment of fire origin on B2F via Stairwell-A1, A2 and either B1 or B2. Firefighters execute the successive operation in the same manner as Case 1. Case3: Fire Origin in Zone B on B2F Three out of six groups of firefighters approach Entrance-B1, B2 and either C1 or A2 on the ground floor of the building and then approach the compartment of fire origin on B2F via Stairwell-B1, B2 and either C1 or A2. Firefighters execute the successive operation in the same manner as Case 1. Fire Origin on B1F Three out of six groups of firefighters approach three of the entrances located on the ground floor of the building and then approach the compartment of fire origin on B1F via the three stairwells connected to the entrances which firefighter has approached. The rest of the groups of firefighters approach B2F via other stairwells and search evacuees who failed to escape or lead them to the outdoor. Firefighters execute the successive operation in the same manner as Case 1. (4) Suppression In case of malfunction of sprinkler, it is easily expected that firefighting cannot be operated safely because the compartment of fire origin will be fulfilled with hot and dense smoke. In reference to Chapter , temperature in the compartment of fire origin when the firefighters reach the vestibules on the floor of fire origin would be approximately 200 degree C without a sprinkler system. Therefore, this firefighting plan stands on the assumption that sprinkler system operates properly for firefighters to perform fire suppression. 63

66 5.3 Verification of Firefighting Plan Procedure of verification is described below. In this verification, firefighting safety is evaluated assuming that sprinkler system operates properly since firefighters could hardly enter the underground car park enclosed by walls if the sprinkler system failed to reduce the fire size Verification of safety in staging area (A) Smoke temperature Staging areas i.e. vestibules are protected from hot and dense smoke by the pressurized smoke control system. Maximum temperature at 1.93 m height from floor in the compartment of fire origin when the firefighters reach the vestibules on the floor of fire origin would be approximately 40 degree C. Therefore, smoke leak from the compartment of fire origin hardly affects firefighters in the staging area. Verification of smoke temperature in the staging area can be omitted. (B) Radiative heat flux Vestibules are separated by fire wall and fire door from the compartment of fire origin. Maximum temperature at 1.93 m height from floor in the compartment of fire origin when the firefighters reach the vestibules on the floor of fire origin would be approximately 40 degree C. Temperature in the vestibule is thought to be equal to the outdoor air due to pressurized smoke control system. Radiative heat flux from the vestibule side of fire wall and door surfaces hardly affects firefighters in the staging area. 64

67 5.3.2 Verification of safety in room of fire origin Indoor air temperature and carbon dioxide concentration in the compartment of fire origin would reach 40 degree C and 0.4 %, respectively, when firefighters arrive at the vestibules on the floor of fire origin 20 minutes after the fire has occurred. Refer to Chapter As the indoor air temperature and carbon dioxide concentration is relatively low, they would hardly affect the performance of firefighting. After water tank of the sprinkler system becomes empty, firefighters connect the hose of fire engine to the fire stand pipe, which interconnects to the sprinkler system. See Figure Referring to Chapter , the maximum value of extinction coefficient of smoke in the compartment of fire origin would become 2.0 L/m and visible distance would become less than 1 m when firefighters reach the vestibules on the floor of fire origin. Therefore, firefighters should spray water in a rough direction towards the fire origin through the opened door from the vestibule without entering the compartment of fire origin for safety of themselves. Water will be continuously sent to the sprinkler system from fire engine and simultaneously, firefighters will spray water to the fire origin until extinguishment. Fire Engine Fire stand pipe Hose Water Tank Car Park Sprinkler Head Room of Fire Origin Alarm Valve Stairwell Water Tank Sprinkler Pump Figure Connection of Fire Engine and Building Sprinkler System and Extinguishing Activity by Firefighters when Fire Origin Occurs on B2F 65

68 5.4 Conclusion of Firefighting plan Even if the sprinkler system is activated, the compartment of fire origin would be fulfilled with dense smoke hence the condition would become dangerous to perform the firefighting operations within the compartment. Results of this verification are summarized below. (1) The firefighters would arrive at the fire site 11 minutes after the fire has occurred. (2) Three out of six groups of firefighters approach the entrances located on the ground floor of the building and then approach the compartment of fire origin via stairwells. Firefighters will use entrances on the ground floor as staging areas to allocate firefighting equipment and extend water hose. (3) The rest of the groups of firefighters approach another floor via stairwells. These groups of firefighters will search evacuees who failed to escape, in order to rescue or lead them to the outdoor. (4) The firefighters would reach the vestibules on the floor of fire origin 20 minutes after the fire has occurred and the maximum value of extinction coefficient of smoke in the compartment of fire origin would become 2.0 L/m at that time. (5) Firefighters should spray water in a rough direction toward the fire origin through the opened door from the vestibules without entering the compartment of fire origin for safety of themselves. Water will be continuously sent to the sprinkler system from fire engine and simultaneously, firefighters will spray water to the fire origin until extinguishment. 66

69 CHAPTER 6 CONCLUSION In this case study, we focused on the characteristics of the fire behavior of car fire and found that power and the spreading speed of car fire is as small as fire can spread only to adjacent cars and not spread to the cars on the other side of drive way. Consequently, we installed least fire safety items such as compartmentalization with fire resistant wall and active smoke barriers and smoke exhaust system utilizing ramp and smoke shaft. As a verification result occupants can evacuate safely even though sprinkler system is not activated excluding the evacuation to the exit (3). Evacuation to the exit (3) could not be secured on account of density of smoke and visibility even though fire is controlled by the sprinkler if the strong fire occurred on the two level stacker. One of the reasons for this result is the fact that the starting time of evacuation is assumed to the time when evacuees find a smoke nearby. But, the main reason for this result is the dead end of the parking space beside the exit (3) and the occupants in this space could not be secured. The best solution to this problem is to install another stairs at the dead end. Smoke density and visibility are critical aspect of fire safety in this case because most of the combustibles in this car park is resin and gasoline that give out a lot of smoke and soot with fire. As a verification result of firefighting smoke and soot also prevent firefighters from being in risk during firefighting activity. 67

70 Appendix (A) Calculation Results of Smoke Analysise [Scenario f2] Temperature distribution at Z=1.8m, Sprinkler failed case 60s 240s 90s 300s 120s 420s 180s 600s Temp. [ o C] 68

71 [Scenario f2] Visibility distribution at Z=1.8m, Sprinkler failed case 60s 240s 90s 300s 120s 420s 180s 600s Vis_Soot. [m] 69

72 [Scenario s2] Temperature distribution at Z=1.8m, Sprinkler succeeded case 60s 240s 90s 300s 120s 420s 180s 600s Temp. [ o C] 70

73 [Scenario s2] Visibility distribution at Z=1.8m, Sprinkler succeeded case 60s 240s 90s 300s 120s 420s 180s 600s Vis_Soot. [m] 71

74 [Scenario f3] Temperature distribution at Z=1.8m, Sprinkler failed case 60s 240s 90s 300s 120s 420s 180s 600s Temp. [ o C] 72

75 [Scenario f3] Visibility distribution at Z=1.8m, Sprinkler failed case 60s 240s 90s 300s 120s 420s 180s 600s Vis_Soot. [m] 73

76 [Scenario s3] Temperature distribution at Z=1.8m, Sprinkler succeeded case 60s 240s 90s 300s 120s 420s 180s 600s Temp. [ o C] 74

77 [Scenario s3] Visibility distribution at Z=1.8m, Sprinkler succeeded case 60s 240s 90s 300s 120s 420s 180s 600s Vis_Soot. [m] 75

78 APPENDIX (B) Computer Evacuation Modelling B.1 Elements of the Model SimTread is a type of multi-agent model, where the characteristic of a crowd flow is made from movement of individual agents to which the same behavioral rule is given. Model elements of SimTread are as follows: Agent, a walker: position, direction, time to start and maximum speed, Space, building plan: obstacles such as walls and furniture, and Destination: target to which agents walk toward. Operation starts with drawing of a plan, then arrangement of agents and destinations follows next; those are prepared on a CAD drawing software. Figure B.1 illustrates it using a simple plan. Destination Obstacle Agent - Position - Direction - Maximum speed Figure B.1 An Example of Making a Model on a CAD 76

79 B.2 Process of the Simulation B.2.1 Time Processing Simulation runs on every t, 0.2 seconds. At first, position at the next t is given temporarily to every agent according to its speed and direction at the current time. Next follows determination of whether any agent conflicts with other agents and/or obstacles. If any conflict is found, the temporal position will be recalculated, repeating until all the conflicts dispel. This process will be described later. All of the agents are moved to the next position. Above procedure is repeated until they arrive at the last destination. Start t 0 n 0 Calculation of Temporal Position according to current direction and speed for all agents. l l 0 : θ θ 0 Move all agents to temporal positions according to their current speed and direction to a target. No Conflict? yes no Re-calculation of temporal position rotating by 12 degrees. Conflict Avoided? no yes n n +1 n < 25 no yes Agents having conflict do not move. Decision of position and speed at next Δt t t +Δt All agents arrived to a destination? yes no End Figure B.2 Flow Diagram of SimTread θ 0 : Direction of target l 0 : Maximum walking distance θ : Movement direction l : Walking distance t : Time n : Count of re-calculation 77

80 W A D A Conflict Determine Area Direction of Agent Agent D B =250 mm W B =420 mm Figure B.3 Configuration of Agent and Determined Area of Conflict Temporal Position of Agent A Agent B is going to invade the conflict determine area of Agent A Temporal Position of Agent B The first temporal position Re-calculated position The resulted position at the next t Figure B.4 Deciding Process of Next Position by Re-calculation B.2.2 Potential Map A grid is set on the plan at regular intervals; 100 mm is adopted in this study. A value is apportioned on each grid point according to the distance from destinations, where a potential map is formed to be used for deciding direction of agents. 78

81 APPENDIX (C) Travel Speed in Smoke and Visibility C.1 Travel Speed in Smoke Considering Illuminance In case of a fire at the underground car park, the illuminance is assumed to be lower than upper ground areas. The following travel speed reflected by the illuminance is proposed on the basis of the reference 1): v = 1.3 ( E > 3.0) 0.12 vsmoke = 1.56VA ( E 3.0) VA = γ (log 10 L +1.85) v : Travel speed [m/sec] v smoke : Travel speed in smoke[m/sec] E : Illuminance[lx] VA : Visual acuity γ : Age - related coefficient Coefficient γ is related to the age and becomes higher figure for the young. For safer side, here γ uses 0.17 which is for elders. L : Luminance[cd/sq. m] The illuminance (E [lx]) at the floor levelis calculated with the luminance (L (cd/sq.m]). Eρ L = π ρ : Reflection rate ρ uses 0.3 as the reflection rate of the concrete. 79

82 Travel speed is greatly reduced when the illuminance at the floor level is below 3.0 [lx] as shown in Figure C.1: Figure C.1 Travel Speed Affected by Illuminance 1) C.2 Reduction of Visibility Considering Smoke Density On the other hand, when smoke accumulates, smoke covers light fixtures and emergency signs. Then the distance of the visibility become short. Considered that the illuminance become low with smoke flow, the reduction of the luminance is calculated by the following formula 1) : 1 L Cs = Loge D L0 (1 ζ ) ζ = η Csdt = Cst L = e CsD 2 2 ( C t) L s 0 Cs :Smoke density [1/m] D : Light path length [m] L0: Initial luminance[cd/sq. m] L0 is provided as the spec.of lighting fixtures. L : Luminancein smoke[cd/sq. m] ζ :Smoke adresion [-] In this study fire is assumed to occur from a car. ζ uses when fire origin is made from flaming kerosene and polyurethane. References 1) The Society of Fire Protection Engineers (SFPE), Chapter 61 Visibility and Human Behavior in Fire Smoke, SFPE Handbook of Fire Protection Engineering 5 th Edition, pp ,(2015) 80

83 APPENDIX (D) Calculation Results of Evacuation Analysis using Sim Tread D.1 Scenario-f1 Uncontrolled Fire (1) 0 [sec] 18 [sec] : Evacuation time to Exit(2) 50 [sec] 71 [sec] : Evacuation time to Exit(4) 90 [sec] : Evacuation time to Exit(5) 100 [sec] 81

84 119 [sec] : Evacuation time to Exit(1) 150 [sec] 200 [sec] 250 [sec] 300 [sec] 310 [sec] : Evacuation time to Exit(3) END 82

85 D.2 Scenario-s1 Controlled Fire (1) with Sprinkler 0 [sec] 18 [sec] : Evacuation time to Exit(2) 50 [sec] 71 [sec] : Evacuation time to Exit(4) 92 [sec] : Evacuation time to Exit(5) 100 [sec] 83

86 118 [sec] : Evacuation time to Exit(1) 150 [sec] 200 [sec] 250 [sec] 300 [sec] 350 [sec] 84

87 375 [sec] : Evacuation time to Exit(3) END 85

88 D.3 Scenario-f2 Uncontrolled Fire (2) 0 [sec] 50 [sec] 100 [sec] 116 [sec] : Evacuation time to Exit(3) 150 [sec] 200 [sec] 86

89 201 [sec] : Evacuation time to Exit(5) 205 [sec] : Evacuation time to Exit(2) 210 [sec] : Evacuation time to Exit(1) 237 [sec] : Evacuation time to Exit(4) END 87

90 D.4 Scenario-s2 Controlled Fire (2) with Sprinkler 0 [sec] 50 [sec] 100 [sec] 116 [sec] : Evacuation time to Exit(3) 150 [sec] 200 [sec] 88

91 208 [sec] : Evacuation time to Exit(1) 250 [sec] 269 [sec] : Evacuation time to Exit(2) 278 [sec] : Evacuation time to Exit(5) 300 [sec] 349 [sec] : Evacuation time to Exit(4) END 89

92 D.5 Scenario-f3 Uncontrolled Fire (3) 0 [sec] 50 [sec] 67 [sec] : Evacuation time to Exit(1) 94 [sec] : Evacuation time to Exit(2) and Exit(4) 100 [sec] 104 [sec] : Evacuation time to Exit(5) 90

93 150 [sec] 200 [sec] 250 [sec] 274 [sec] : Evacuation time to Exit(3) END 91

94 D.6 Scenario-s3 Controlled Fire (3) with Sprinkler 0 [sec] 50 [sec] 66 [sec] : Evacuation time to Exit(1) 94 [sec] : Evacuation time to Exit(2) and Exit(4) 100 [sec] 103 [sec] : Evacuation time to Exit(5) 92