numerical simulation of warehousesfire suppression

Numerical Simulation of Warehouses Fire Suppression

Essam Eldine Mouguib M.Sc, Mech. Power Dept.

Faculty of Engineering, Cairo University Giza, Egypt

[email protected]

Mahmoud Ahmed Fouad Professor, Mech. Power Dept.

Faculty of Engineering, Cairo University Giza, Egypt

[email protected]

Abstract— A CFD simulation has been conducted to study

the rack storage fires and suppression means in a pharmaceutical

warehouse. Simulations have been carried out for different fire

locations and rack storage geometries, to predict fire growth rate

and spread. Also, the activation time periods of in-rack and

ESFR sprinklers, fire growth control and fire suppression have

been simulated. The use of the foam-water sprinkler system has

been also considered. Simulations results showed that, the in-

rack sprinkler would actuate faster than the ESFR ceiling

mounted sprinklers. The successive operation of the adjacent

nearby in-rack sprinklers has a great effect on the control on the

fire growth. Also, the in-rack sprinklers have extinguished the

fire faster than ESFR sprinklers, due to the fast control of fire

growth. The foam-water sprinkler system has controlled the fire

growth in such time slightly more than the in-rack sprinklers and

considerably more than the ESFR sprinklers. The foam-water

sprinkler system has the fastest suppression, compared to other

cases, due to the great effect of the foam solution on the fire

spread. Also, the foam-water sprinkler system does not destroy

product, due to the lower water content. They have limited smoke

damage, and because of the detergent properties of the foaming

agent, they provide a self-cleaning effect. When studying the

effect of the rack storage geometry, it is found that the narrow

vertical and horizontal flues have a great effect on the fire

growth, as they do not allow the fire spread to adjacent surfaces,

which facilitate the sprinklers job to control the fire. Also, the

narrow vertical and horizontal flues have a great effect on the

fire suppression. The storage height has a strong impact on the

sprinkler activation. Upon the obtained results, the best sprinkler

activation was dedicated to the in-rack sprinklers. The best

suppression period was dedicated to the foam-water sprinkler

system. To get a better suppression performance for high bay

warehouses fires, in-rack sprinklers can be used along with foam-

water sprinkler system. But this configuration has a remarkable

impact on the economic-wise criteria. So, in order to have a

reasonable optimal configuration, in-rack sprinklers can be

installed along with ESFR ceiling sprinklers.

Keywords-component; in-rack sprinklers; ESFR sprinklers;

foam-water sprinkler system; activation time; fire growth

control; fire suppression.

I. INTRODUCTION Among the most challenging occupancies from a property

loss control viewpoint are warehouses, distribution centers and large retail businesses referred to as ―big box‖ establishments.

Warehouses represent a unique fire challenge to both fixed fire suppression systems and the manual firefighting forces that are called upon to deal with a fire. Modern warehouses and storage occupancies are especially subject to rapidly developing fires of great intensity, because complex configuration of storage and building layout are usually conducive to fire spread, presenting numerous obstacles to manual fire suppression efforts. The only proven method of controlling a warehouse fire is within properly designed and maintained automatic sprinkler systems. If sprinkler protection is not provided, the likelihood of controlling a fire in a warehouse is minimal. Some critical elements must be considered when developing a comprehensive risk mitigation strategy to protect various facilities. These elements include commodity classification, common storage configurations, various protection schemes, hazards associated with some of the common types of warehouses and loss prevention guidelines for minimizing the frequency and severity of a loss. Warehouses can range from several hundred to more than a million square feet and can include among other occupancies storage garages, refrigerated storage facilities, isolated storage buildings, underground storage locations, and air-supported structures. A variety of commodities is displayed and stored within these facilities, including soft goods, clothes, furnishings of all types, bedding materials, paints, home repair and building materials, chemicals, and plastics. Moreover, big box retail spaces often have ceiling or roof heights in excess of 16 feet and, in many cases, as high as 35 to 40 feet. Using rack storage configurations, these types of retail stores will typically display products at lower elevations and use the higher elevations for product storage.

NOMENCLATURE A area of the plume at a given height b width of the storage boxes. Cb non-dimensional constant and it can be taken as 3.4 according to

Heskestad [12] CD drag coefficient of the droplets Cp specific heat CT non-dimensional constant and it can be taken as 0.12 according to

Heskestad [12] Cu non-dimensional constant and it can be taken as 9.1 according to

Heskestad [12] d plume diameter Ds drag of the spray

Essam Eldine Mouguib et al. / (IJAEST) INTERNATIONAL JOURNAL OF ADVANCED ENGINEERING SCIENCES AND TECHNOLOGIES Vol No. 5, Issue No. 2, 212 - 228

ISSN: 2230-7818 @ 2011 http://www.ijaest.iserp.org. All rights Reserved. Page 212

IJAEST

mailto:[email protected]

g acceleration of gravity h height of the horizontal flue Hc heat of combustion per unit mass of fuel Kd diameter constant, ranges from 0.25 to 0.5 l longitudinal length of the rack Lfi mean flame height mi mass flow rate of air at the ith tier mn mass flow rate of air at the highest tier me total mass-entrainment rate of air below the level of the flame tip mf fuel flow rate Mp plume momentum n total number of drops in the spray Pn,a static pressure at the top of the rack storage Q total heat release rate from the burner Qc convective heat energy released from the burner Qci,a released convective energy at the top of the ith box

Qci,b released convective energy at the base of the ith box Qmax max heat release rate r plume radius RTI response time index of sprinkler s height of the boxes. t time in sec tg fire growth time to reach 1055 kW (1000 btu/sec) tc ramp-up time from ignition associated with the transport of hot air

from fire to the sprinkler location tv virtual time T gas temperature Tmax max gas temperature Ti,a air temperature at the top of the box i Ti,b air temperature at the base of the box i

T air ambient temperature

T average hot air temperature at the sprinkler location Tr temperature rating of the sprinkler Ti,b gas temperature at the base of each box Ti,l bulk temperature To centerline excess gas temperature

u average hot air velocity at the sprinkler location

v velocity of the plume

dv velocity of the droplets

w width of the vertical flue z height from floor level z0 height of virtual origin fire growth rate = [1055/tg2] Descending rate of HRR. Sprinkler location index

air density at ambient air

p density of the plume

o sprinkler actuation time

IRS In-rack sprinkler CS Ceiling sprinkler

II. MATHEMATICAL MODELING

2.1 Introduction The present work has used the FLUENT model version

6.3.26, to built-up the numerical CFD models describing the various case studies discussed in this work. The GAMBIT preprocessor geometry builder version 2.2.30, developed by Fluent, was used to built-up the models geometry and mesh generating.

2.2 Descriptions of Warehouse Geometrical Configuration The warehouse layout consists of one level building of

total floor area of 3700 m2 and total floor to ceiling height of 13.7 m. Fig.1 describes the warehouse plan layout. The commodity is stored in single and double rows racks with slatted shelves. The rack height is of 1.5 m and has an area of 2.8 m x 1.2 m. The flue space was 0.2 m and the aisle width was 1.2 m. The commodity stored in the warehouse is composed of pharmaceutical commodities and chemical materials. According to NFPA code, these commodities are classified as Class IV commodity. They can include pills, powders, and chemicals, put in glass or plastic bottles placed in corrugated carton boxes. The carton sheets which used to form the boxes have a thickness of 10 mm with the following thermal data: heat conductivity 0.12 W/m oC, specific heat 800 J/kg and density 700-800 kg/m3

2.3 Model Description The model, as shown in fig.2, consists of a two-

dimensional model of 13.7 m height and 6.4 m width. The commodity is arranged in 18 boxes, each have a height of 1.5 m and a surface area of 2.4 m x 1.2 m. The maximum storage height is 10.8 m. There are four air outlets placed on both sides of the model, each of 1.5 m height and are located at altitude of 2.02 m and 7.48 m respectively. The probability of fire hazard is considered in four locations inside the model, as shown in fig.2 and the fire pool has a surface area of 1.4 m2. The sprinkler system consists of seven in-rack sprinklers located on two levels and two ceiling sprinklers and it is distributed according to NFPA requirements.

ق 1

ق2

ق 3

ق4

Elec

Elec

w.c

water water

w.c

water

w.c

w.c

w.c

water

water

w.c

w.c

water

w.c

w.c

water

water

water

water

حذيقت

هبني الحركت .طفاء وا

خساى الوياة

الوكتب العلوي

هىالداث السىالر

شترلى

ا

يتخل

ال

يتال

لغا

اءرب

كه ال

فتر

غ

هناولت الهىاء

دةعيا

والت

بعط

لوا

هبني الوضاد الحيىي

هبني الوخازى الجذيذة

حذيقت هنطقت الىزى بالوخازىهبني الوخازى القذيوت

المست

ألت ا

طقهن

هكاتب الوخازى

صالفىاررا

ألقا

السىائل

العقيوت

هل الوعا

هبني تغيير

الوالبس

هبني الوطعن

اءرب

كه ال

ثال

حىه

9.30

11.7

0

2.20

47.6

5

24.90

48.8

5

55.65

Fig.1 Warehouse Plan Layout


ISSN: 2230-7818 @ 2011 http://www.ijaest.iserp.org. All rights Reserved. 13

IJAEST

Fig. 2 Model Description

2.4 Fire Modeling The ignition in a warehouse initially occurs at certain

location and then grows up at a rate depending on several factors such as the type of fuel, oxygen access, type of commodity and the configuration of storage. Subsequently, the developed fire transitions to the flashover period, which is a rapid transition from the growth period to a fully developed fire period, leading the total surface of the combustible materials to be involved in the fire. At the fully developed fire stage, the heat release rate (HRR) and average temperature reach their peaks while the fire is rapidly spreading to other locations through various paths. If the initial fire in the initial location is not discovered and suppressed in the first place, it will eventually spread to the whole warehouse. It is assumed that all buildings have approximately the same fire-development process which consists of five stages: ignition, flashover, full-development, collapse and extinguishment.

Fig.3, illustrates the fire growth behavior and the development of air temperature and heat release rate, where t1 is the time from ignition to flashover, t2, time from flashover to full-development, t3, time from full-development to collapse and t4, time from collapse to extinguishment. Fires can be

t ime

HRR

t 4t 3t 2t 1

Q=( t ) ² Q=( t - t 4) ²

Q=Qma x

Fig. 3 Develop Curve of HRR of a Building Fire

characterized by their rate of heat release, measured in terms of the number of kW (Btu/sec) of heat liberated. Previous researches have shown that most fires grow exponentially and can be expressed by what is termed the ―power law of fire growth model,‖ which follows:

ptQ (1) where: p equals 2.

In fire protection, fuel packages are often described as having a growth time (tg). It is the time necessary after the ignition with a stable flame for the fuel package to attain a heat release rate of 1055 kW (1000 Btu/sec). The following equations describe the growth of design fires: 2

2

1055 tt

Qg

for SI units (2)

Equation (3.2) can be generally expressed as: 2tQ (3)

2.4.1 Fire Plume Generation Four ignition sources were mounted at several locations,

as shown in fig.2. Each ignition source consisted of a square burner nozzle (25cm x 25cm) located at the floor area, where the gas fuel is injected. The fire plume is created when the fuel (methane) injected from the burner burns in the presence of oxygen, high temperature and minimum concentration of the reactants. A single-step irreversible chemical reaction is assumed: CH4 + 2O2 CO2 + 2H2O (4)

The combustion reaction and airflow can be described by the conservation equations of mass, momentum, energy and species along with the sub-models describing the turbulence and combustion. The standard K- model is used to estimate the turbulence characteristics of the gas phase flow, by solving the equations of turbulence kinetic energy and the dissipation rate, so as to calculate the turbulent effective diffusion coefficient.

2.5 Governing Equations The theoretical model is used to calculate the fire

parameters in a two-dimensional rack storage configuration. The model predicts the air temperature and velocity and the flame diameter in the flues. Gas temperature and velocity are

F # Fire hazard probability

A # Air outlet window



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represented by a mean value across the cross-section of the flue. The input parameters used in the model are: The longitudinal length of the rack (l). The height (s) and the width (b) of the boxes. The width of the vertical flue (w) The height of the horizontal flue (h). The convective heat energy released from the burner (Qc)

2.5.1 Continuity Equation By using the continuity equation, we can find that: 0,01 2mm . iii mmm ,01 2

(5)

nnnn mmm ,1 2

where i = 1, ………, n (n = 6)

2.5.2 Conservation of Energy When the mass flow rate in the vertical flue of each tier is

known, while the mass flow rate is constant between the base and the top of each box, the temperature at the corresponding height can be calculated using the following expressions:

)( ,, TTcmQ aipiaci

)( ,, TTcmQ aipiaci (6) Accordingly, the temperatures at the corresponding

locations can be calculated as shown in the following section. Also, by using the relationship for the mass flow rate:

uwlm (7) and the ideal gas law :

TT (8) where the influences of pressure changes and gas composition are neglected, the velocity at the top and the base of each tier can be calculated as shown in the following section.

2.6 In-Rack Temperature and Velocity Turbulent buoyant axi-symmetric fire plumes with a large

density defect or temperature rise relative to the surrounding are known as strong plumes, while plumes with a small density defect or temperature rise are known as weak plumes. Above axi-symmetric buoyant turbulent diffusion flames, the centerline values of excess temperature and velocity and the plume radius obey the following relationships:

3/50

3/23/1

2220 1

zzQ

TgcC

TT c

pT

(9)

3/10

3/13/1

0 zzQ

TcgCu c

pu

(10)

0

2/10 zz

TT

Cb bT

(11)

2.7 Plume Width and Flame Height As a plume rises, it entrains air and widens. Generally the

total plume diameter and height can be estimated as: zkd d (12) 5/2343.073.3 QwL f (13)

2.8 Modeling of Water Spraying To a better understanding of the fire suppression, it is

useful to consider the reaction of the flame and fire plume to the droplet spray and to consider this situation as a competition between the downward momentum of the spray and the upward momentum of the fire plume. If the downward spray is strong enough to balance or overpower the upward momentum of the fire plume, the structure of the fire plume changes. The momentum of the fire plume, Mp, is used to characterize the fire size. However, to characterize the strength of the spray, the drag of the spray, Ds, is used since this is the physical mechanism of the interaction between the droplets and the gas of the plume. Thus, a spray that has a very large effect on a fire plume does so by creating a large drag on the fire plume. The ratio of the drag of the spray to the momentum of the plume, Ds/Mp, is a non-dimensional parameter that characterizes the effect of the spray on the dynamics of the fire. To calculate this parameter, the drag of the spray, Ds, can be expressed as:

dddDps vvvvACnD )(21

(14)

The drag coefficient for the droplet, CD, depends primarily on the Reynolds number based on the droplet slip velocity:

dVU Re (15)

The plume momentum can be calculated from the plume velocity profile and width as

A

p dArvM )( 2 (16)

2.8.1 Calculation of the Sprinkler Actuation Time The heat flow into a sprinkler heat sensing element occurs

over a period of time. The thermal response coefficient is needed to accurately predict the heat sensing element response. A measure of the speed with which heat transfer occurs is currently called the detector time constant (0). The time constant is a measure of the sensitivity of the sprinkler sensing element. Upon calculating the air temperature and velocity at the sprinkler location, the sprinkler actuation time (0), can be obtained using the following equation:

c

ro t

TTTT

u

RTI

ln (17)



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2.9 Matrix of Experiments The conducted CFD calculations have been classified

according to the following criteria: 1. The consideration of four probabilities of fire

hazards, as shown in fig.2. 2. The operation of the following systems to suppress

each of these fire hazards: In-rack and standard ceiling sprinklers. Early-Suppression-Fast-Response (ESFR)

sprinklers. Foam-Water Sprinkler system.

3. The effect of rack storage geometrical configuration on fire suppression

TABLE 1. MATRIX OF EXPERIMENTS

Cas

e St

udy

Nam

e

Rack Storage Geometrical

Configuration

Nam

e of

Fire

Pro

babi

lity Suppression System Used

Vert

ical

Flu

e Sp

ace

Hor

izon

tal F

lue

Spac

e

With

out

Supp

ress

ion

In-R

ack

and

Stan

dard

C

eilin

g Sp

rink

lers

ESFR

Sp

rink

lers

Foam

-Wat

er

Spri

nkle

r Sy

stem

Sub-Case Study Name

A

v (cm)

h (cm)

fire 1 A1-1 A1-2 A1-3 A1-4 fire 2 A2-1 A2-2 A2-3

20 32 fire 3 A3-1 A3-2 A3-3 fire 4 A4-1 A4-3

B v

(cm) h

(cm) fire 1 B1-1 B1-2 fire 2 B2-1 B2-2

30 32 fire 3 B3-1 B3-2

C v

(cm) h

(cm) fire 1 C1-1 C1-2 fire 2 C2-1 C2-2

40 32 fire 3 C3-1 C3-2

D

v (cm)

h (cm)

fire 1 D1-1 D1-2 fire 2 D2-1 D2-2

20 48 fire 3 D3-1 D3-2 fire 4 D4-1 D4-2

E

v (cm)

h (cm)

fire 1 E1-1 E1-2 fire 2 E2-1 E2-2

20 64 fire 3 E3-1 E3-2 fire 4 E4-1 E4-2

III. CFD SIMULATION

The CFD simulations and case studies performed to predict the activation times of in-rack sprinklers with ceiling sprinklers and the ESFR sprinkler system as well as the Foam-Water sprinkler system and the suppression efficiencies of such systems are presented herein after. The activation times will be simulated by using a deterministic fire-water interaction model. The model illustrates the behavior of four cases of fire hazard probabilities in the warehouse compartment. Each case is subjected to different suppression systems including the use of the different suppression systems illustrated above.

3.1 Fire Simulation At the beginning, the fire is growing exponentially with

time and the heat release rate (HRR) takes a "t squared" shape profile. The phenomena of air temperature growing with time have been developed by using user-defined functions written in C++ code. When exporting these user-defined functions into the model, we can get a prediction of the behavior of the unsteady temperature rise with time. Figures 4.a, 4.b, 4.c and 4.d show the simulation results for the contours of the total temperature, obtained after several times, along the symmetrical axis of the flame (fire hazard vertical center line) for the four fire hazard probabilities studied for case study A. The fire reaches the fully-developed stage, where the heat release rate and air temperature reach its maximum values. Fig.4.e shows the contours of total temperature of the fully-developed fire obtained along the symmetrical axis of the flame. 3.1.2 Effect of Rack Storage Geometrical Configuration on

Fire Growth

Cases B1-1, B2-1 and B3-1 represent the three fire hazard probabilities studied for case study B with the vertical flue width equals to 30 cm. Fig.5 represents the simulation results of total temperature for case study B3-1.

Cases C1-1, C2-1 and C3-1 represent the three fire hazard probabilities studied for case study C with the vertical flue width equals to 40 cm. Fig.6 represents the simulation results of total temperature for case study C3-1. Cases D1-1, D2-1 and D3-1 represent the three fire hazard probabilities studied for case study D with the horizontal flue width equals to 48 cm.

60 sec 360 sec 480 sec Fig. 4.a Simulation Results of Total Temperature for Case A1-1

60 sec 360 sec 540 sec Fig. 4.b Simulation Results of Total Temperature for Case A2-1



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60 sec 90 sec 510 sec Fig. 4.c Simulation Results of Total Temperature for Case A3-1

60 sec 180 sec 360 sec

Fig. 4.d Simulation Results of Total Temperature for Case A4-1

Fig.7 represents the simulation results of total temperature for case study D3-1.

Cases E1-1, E2-1 and E3-1 represent the three fire hazard

Case A1-1 Case A2-1

13.5 min 16 min Case A3-1 Case A4-1

13.5 min 10.5 min Fig. 4.e Simulation Results of Total Temperature for Fully-Developed Fire

60 sec 90 sec

360 sec 660 sec

Fig. 5 Simulation Results of Total Temperature for Case B3-1

probabilities studied for case study E with the horizontal flue width equals to 64 cm. Fig.8 represents the simulation results of total temperature for case study E3-1.

Cases A4-1, D4-1 and E4-1, represent the three fire hazard probabilities to study the effect of rack storage height of 10.8m, 11.60m and 12.4m respectively

60 sec 180 sec

600 sec 780 sec

Fig.6 Simulation Results of Total Temperature for Case C3-1



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60 sec 180 sec

360 sec 540 sec

Fig.7 Simulation Results of Total Temperature for Case D3-1

60 sec 180 sec

360 sec 570 sec

Fig.8 Simulation Results of Total Temperature for Case E3-1 Fig.10a shows the contours of total temperature of the fully-developed fire obtained along the symmetrical axis of the flame. 3.2. Fire Suppression by Water Sprinkler Systems

3.2.1 In-Rack Sprinklers with Standard Ceiling Sprinklers

For case A3-2, as shown in fig.11, the first in-rack

60 sec 180 sec

240 sec 320 sec

Fig.9 Simulation Results of Total Temperature for Case D4-1

60 sec 180 sec

240 sec 290 sec

Fig.10 Simulation Results of Total Temperature for Case E4-1 sprinkler (IRS-14) will actuate at t = 59 sec. The second in-rack sprinkler (IRS-13) will actuate at t = 62 sec. The third in-rack sprinkler (IRS-15) will actuate at t = 64 sec. The sprinklers totally control the fire after 170 sec. The total suppression of the fire will occur after approximately 4.75 min.



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Case B3-1 Case C3-1 Case D3-1

18 min 23 min 14 min Case E3-1 Case D4-1 Case E4-1

16 min 10 min 8.5 min

Fig. 10.a Simulation Results of Total Temperature for Fully-Developed Fire

3.2.2 Early-Suppression-Fast-Response (ESFR) Sprinklers

For case A3-3, as shown in fig.12, the first ESFR sprinkler will actuate at t = 140 sec. The second ESFR sprinkler will actuate at t = 142 sec. The sprinklers totally control the fire after 305 sec. The total suppression of the fire will occur after approximately 7.4 min.

3.3 Foam/Water Sprinkler Systems

For case A1-4, as shown in fig.13, the first sprinkler will actuate at t = 135 sec. The second sprinkler will actuate at t = 140 sec. The sprinklers totally control the fire after 255 sec. The total suppression of the fire will occur after approximately 5 min.

3.4. Effect of Rack Storage Geometrical Configuration on Fire

Suppression

For case B3-2, as shown in fig. 14, the first sprinkler (IRS-14) will actuate at t = 68 sec. The second sprinkler (IRS-15) will actuate at t = 72 sec. The third sprinkler (IRS-13) will actuate at t = 78 sec. The sprinklers totally control the fire after 170 sec. The total suppression of the fire will occur after approximately 4.5 min

For case C3-2, as shown in fig.15, the first sprinkler (IRS-14) will actuate at t = 72 sec. The second sprinkler (IRS-13) will actuate at t = 79 sec. The third sprinkler (IRS-15) will actuate at t = 83 sec. The sprinklers totally control the fire after 170 sec. The total suppression of the fire will occur after


170 sec 4.75 min

Fig.11 Total Temperature Contours for Case A3-2

140 sec 142 sec 305 sec

360 sec 7.4 min


approximately 5 min. For case D3-2, as shown in fig.16, the first sprinkler (IRS-14) will actuate at t = 68 sec. The second sprinkler (IRS-13) will actuate at t = 74 sec. The third sprinkler (IRS-15) will actuate at t = 82 sec. The sprinklers will totally control the fire after 180 sec The total suppression of the fire will occur after approximately 6.5 min



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135 sec 140 sec 255 sec

270 sec 300 sec



170 sec 270 sec

Fig.14 Total Temperature Contours for Case B3-2

For case E3-2, as shown in fig.17, the first sprinkler (IRS-14) will actuate at t = 69 sec. The second sprinkler (IRS-13) will actuate at t = 76 sec. The third sprinkler (IRS-15) will actuate at t = 85 sec. The sprinklers totally control the fire after 190 sec. The total suppression of the fire will occur after approximately 7.5 min.


170 sec 300 sec

Fig.15 Total Temperature Contours for Case C3-2


180 sec 390 sec

Fig.16 Total Temperature Contours for Case D3-2

C.1 Effect of Rack Storage Height on Fire Suppression

For case A4-3, as shown in fig.18, the first ESFR sprinkler (CS-1) will actuate at t = 30 sec. The sprinkler totally controls the fire after 90 sec. The total suppression of the fire will occur after approximately 2.5 min.



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190 sec 450 sec

Fig.17 Total Temperature Contours for Case E3-2


120 sec 150 sec


For case D4-2, as shown in fig.19, the first sprinkler

(CS-1) will actuate at t = 26 sec. The sprinkler totally controls the fire after 85 sec. The total suppression of the fire will occur after approximately 3.5 min.


180 sec 210 sec

Fig.19 Total Temperature Contours for Case D4-2


81 sec 180 sec

Fig.20 Total Temperature Contours for Case E4-2

For case E4-2, as shown in fig.20, the first sprinkler

(CS-1) will actuate at t = 22 sec. The sprinkler totally controls the fire after 81 sec. The total suppression of the fire will occur after approximately 3 min.



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IV. RESULTS AND DISCUSSIONS

4.1. Results for Fire Simulation

At the beginning of ignition, the fire simulation showed an exponentially fire growing with time and the Heat Release Rate (HRR) takes a "t squared" shape profile. For sub-case A1-1, as shown in fig.4, the intensity and speed at which the vertical spread accelerates in the vertical flue space, allows the flames to reach the top of storage within 68 sec from ignition. The fire will continue to grow in intensity, involving new burning surfaces of the rack storage and releasing higher heat rates, until reaching the flashover at approximately 8 min from ignition. Results of the simulations are shown in fig.21, 22 and 23, where the excess in air temperature, flame vertical velocity and heat release rate (HRR) are plotted against time. As shown in fig.21, the excess in air temperature increases with time, for all cases. Based on the temperature profiles presented in section 4, the width of the thermal plume can be determined. The results are plotted in fig.24, where the thermal plume width, bT, is plotted against time. If no suppression happens, the fire will spread to the nearby stock and additional stock is consumed and the fire is getting out of control and the rack storage collapses, spreading the fire over large areas of the warehouse. The fire will be on his way to develop to encompass the whole warehouse building. At this stage, the temperature and HRR of the building reach their peaks, Tmax and HRRmax, at approximately 13.5 min from ignition and the fire has a strongest ability to spread outside the warehouse building. Then the fire exhibits an approximately fully-developed behavior, as shown in fig.21 and fig.22. Once the fire duration reaches the fire proof limit of the structural materials, the building is able to collapse. After collapse, the rack storage is totally consumed and with the decline of fire intensity, the ability of fire out-spreading gradually declines.

0

200

400

600

800

1,000

1,200

1,400

1,600

0 200 400 600 800 1000

t (sec)

T (oK)

Fig. 21 Variation of Gas Temperature with Time for Case Study A1-1

0

2

4

6

8

10

12

14

0 200 400 600 800 1000

t (sec)

Flame

vertical

velocity (m/s)

Fig. 22 Variation of flame vertical velocity with Time for Case Study A1-1

0

500

1,000

1,500

2,000

2,500

3,000

0 200 400 600 800 1000

t (sec)

Q (KW)

Fig. 23 Variation of Heat Release Rate (HRR) with Time for Case Study A1-1

4.1.2 Effect of Rack Storage Geometry

Fig.25 shows the temperature distributions along the vertical axis of the flame for sub-cases A1-1, A2-1, A3-1, B1-1, B2-1, B3-1, C1-1, C2-1 and C3-1 respectively. As the vertical flue width varies, the air entrainment into the rack behaves differently and consequently, the flame pattern is greatly influenced. As the vertical flue width increases, the air entrainment inside the flame increases, leading to more rapid fire development. On the other hand, as the vertical flue width decreases, there will be less entrained air inside the flame, leading to higher flame heights.



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0.00

0.05

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0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0 200 400 600 800 1000

t (sec)

b T (m)

Fig.24 Variation of Thermal Plume Width with Time for Case Study A3-1

Figure 26, also, shows the temperature distributions along

the vertical axis of the flame for sub-cases A1-1, A2-1, A3-1, D1-1, D2-1, D3-1, E1-1, E2-1 and E3-1 respectively. As the horizontal flue width increases, more air is entraining inside the flame increases, leading to more unsymmetrical flame and rapid fire development in the horizontal direction and consequently, incorporating of horizontal flues can have a reverse effect on the stability and the symmetry of the flames.

As the vertical and horizontal flue become larger and larger, the flame height will become more similar to open fire plumes, which can lead to even more rapid fire growth. This being the most common known cause of fire outbreak for the storage of bulk materials.

0

200

400

600

800

1,000

1,200

1,400

0 5 10 15

Vertical Position (m)

Temperature

(oC)

A1-1

A2-1

A3-1

B1-1

B2-1

B3-1

C1-1

C2-1

C3-1

Fig. 25 Comparison of the Gas Temperature along the vertical

Centerline of flame for different vertical Flue width

4.2 Results for Fire Suppression Simulation

4.2.1 In-rack Sprinklers vs. ESFR Sprinklers

The results obtained from the CFD simulations indicated that, for case A1-2, two sprinklers have been actuated, the first sprinkler (IRS-11) actuated at 55 sec, and the second sprinkler (IRS-12) actuated at 60 sec. For case A2-2, three sprinklers have been actuated, the first sprinkler (IRS-12) actuated at 75 sec, the second sprinkler (IRS-13) actuated at 80 sec and the third in-rack sprinkler (IRS-14) actuated at 83 sec. For case A3-2, three sprinklers have been actuated, the first sprinkler (IRS-14) actuated at 59 sec, the second sprinkler (IRS-13) actuated at 62 sec and the third sprinkler (IRS-15) actuated at 64 sec.

The results obtained from the CFD simulations indicated that, for case A1-3, the ESFR sprinkler (CS-1) actuated at 130 sec. For case A2-3, the first ESFR sprinkler (CS-1) will actuate at 150 sec. The second ESFR sprinkler (CS-2) actuated at 156 sec. For case A3-3, the first ESFR sprinkler (CS-1) will actuate at 140 sec. The second ESFR sprinkler (CS-2) actuated at 142 sec. For case A4-3, the ESFR sprinkler (CS-1) actuated at 30 sec. The sprinkler totally controls the fire after 90 sec. The total suppression of the fire will occur after approximately 2.5 min.

When comparing the simulation results of the ESFR sprinklers to those obtained for the in-rack sprinklers, it can be noticed that, the activation time for the in-rack sprinklers is much less than for the ESFR sprinklers. The in-rack sprinklers are somehow near to the flame tips and consequently are being faster thermally influenced.

0.00

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0.80

1.00

1.20

0 30 60 90 120 150 180

Activation Time (sec)

Sprinkler

Location Index

(

Case A1-2, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A2-2, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A3-2, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A1-3, ESFR Sprinkler, v = 20 cm, h = 32 cmCase A2-3, ESFR Sprinkler, v = 20 cm, h = 32 cmCase A3-3, ESFR Sprinkler, v = 20 cm, h = 32 cmFoam Sprinkler, v = 20 cm, h = 32 cm

IRS-11

IRS-12

IRS-14

IRS-13

IRS-12

IRS-15

IRS-13

IRS-14

CS-1 CS-1

CS-2

CS-1

CS-2

CS-1

CS-2

IRS … In-Rack SprinklerCS …. Ceiling Sprinkler

Fig.26 Activation Time for In-Rack and ESFR Sprinklers for Case studies A



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0.60

0 100 200 300 400 500

Time (sec)

Sprinkler

Location Index

(

Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cm Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cm

Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cm Case A, ESFR Sprinkler, v = 20 cm, h = 32 cm

Case A, ESFR Sprinkler, v = 20 cm, h = 32 cm Case A, ESFR Sprinkler, v = 20 cm, h = 32 cm

Case A1-4, Foam Sprinkler, v = 20 cm, h = 32 cm

Fig.27 Fire Control Growth For In-Rack And ESFR

Regarding the control of the fire growth and the fire extinguishment, the in-rack sprinklers control the fire growth in someway faster than the ESFR sprinklers. This can be due to the successive operation of the adjacent nearby in-rack sprinklers which has a remarkable effect on the fire growth control.

0.00

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0 5 10 15

Time (min)

Sprinkler

Location Index

(

Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cm Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cmCases A, In-Rack Sprinkler, v = 20 cm, h = 32 cm Case A, ESFR Sprinkler, v = 20 cm, h = 32 cmCase A, ESFR Sprinkler, v = 20 cm, h = 32 cm Case A, ESFR Sprinkler, v = 20 cm, h = 32 cmCase A1-4, Foam Sprinkler, v = 20 cm, h = 32 cm

Fig.28 Fire Suppression for In-Rack and ESFR Sprinklers for Case studies A

4.2.2 Effect of Vertical Flue Space

The results obtained from the CFD simulations indicated that, for case B1-2, two sprinklers have been actuated, the first in-rack sprinkler (IRS-1) actuated at 71 sec. The second in-rack sprinkler (IRS-2) actuated at 76 sec. The two operating sprinklers fight the fire growth and succeed to control the fire growth after 165 sec. The total suppression of the fire will occur after approximately 6 min For case B2-2, three sprinklers have been actuated, the first in-rack sprinkler (IRS-12) actuated at 78 sec. The second in-rack sprinkler (IRS-13) actuated at 84 sec. The third in-rack sprinkler (IRS-14) actuated at 89 sec. The sprinklers totally control the fire after 170 sec. Total suppression of the fire will occur after approximately 4.5 min. For case B3-2, three sprinklers have been actuated, the first sprinkler (IRS-14) actuated at 68 sec. The second sprinkler (IRS-15) actuated at 72 sec. The third sprinkler (IRS-13) actuated at 78 sec. The sprinklers totally control the fire after 170 sec. The total suppression of the fire will occur after approximately 4.5 min.

For case C1-2, two sprinklers have been actuated, the first in-rack sprinkler (IRS-1) actuated at 75 sec. The second in-rack sprinkler (IRS-2) actuated at 81 sec. The sprinklers totally control the fire after 165 sec. Total suppression of the fire will occur after approximately 6.5 min. For case C2-2, three sprinklers have been actuated, the first in-rack sprinkler (IRS-12) actuate at 75 sec. The second in-rack sprinkler (IRS-13) actuated at 80 sec. The third in-rack sprinkler (IRS-14) actuated at 86 sec. The sprinklers totally control the fire after 155 sec. Total suppression of the fire will occur after approximately 6 min.

For case C3-2, three sprinklers have been actuated, the first sprinkler (IRS-14) actuate at 72 sec.

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0 40 80 120 160 200 240

Time (sec)

Sprinkler

Location Index

(

Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A, ESFR Sprinkler, v = 20 cm, h = 32 cmCase A1-4, Foam Sprinkler, v = 20 cm, h = 32 cmCases B, In-Rack Sprinkler, v = 30 cm, h = 32 cmCases C, In-Rack Sprinkler, v = 40 cm, h = 32 cmCases D, In-Rack Sprinkler, v = 20 cm, h = 48 cmCases E, In-Rack Sprinkler, v = 20 cm, h = 64 cm

Fig.29 Sprinklers Activation for Different Rack Storage Geometries



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0 30 60 90 120 150 180


Sprinkler

Location Index

(

Case A1-2, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A2-2, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A3-2, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase B1-2, In-Rack Sprinkler, v = 30 cm, h = 32 cmCase B2-2, In-Rack Sprinkler, v = 30 cm, h = 32 cmCase B3-2, In-Rack Sprinkler, v = 30 cm, h = 32 cmCase C1-2, In-Rack Sprinkler, v = 40 cm, h = 32 cmCase C2-2, In-Rack Sprinkler, v = 40 cm, h = 32 cmCase C3-2, In-Rack Sprinkler, v = 40 cm, h = 32 cmCase D1-2, In-Rack Sprinkler, v = 20 cm, h = 48 cmCase D2-2, In-Rack Sprinkler, v = 20 cm, h = 48 cmCase D3-2, In-Rack Sprinkler, v = 20 cm, h = 48 cmCase E1-2, In-Rack Sprinkler, v = 20 cm, h = 64 cmCase E2-2, In-Rack Sprinkler, v = 20 cm, h = 64 cmCase E3-2, In-Rack Sprinkler, v = 20 cm, h = 64 cm

Fig.30 Fire Growth Control for Different Rack Storage Geometries

The second sprinkler (IRS-13) actuated at 79 sec. The third sprinkler (IRS-15) actuated at 83 sec. The sprinklers totally control the fire after 170 sec. Total suppression of the fire will occur after approximately 5 min

When analyzing the above results, it can be noticed the remarkable effect of the vertical flue width on the activation time of sprinklers. As the vertical flue width increases, the vertical flame spread is slowed down, which make some retardation on the sprinklers activation. Regarding the control of the fire growth and the fire extinguishment, the effect of the vertical flue width is very remarkable on the fire growth control and fire extinguishment. As the vertical flue width increases, more air is entrained inside the flame, leading to more rapid fire development and consequently, imposing more difficulty for the sprinklers to fight the fire growth.

4.2.3 Effect of Horizontal Flue Space

The results obtained from the CFD simulations indicated that, for case D1-2, two sprinklers have been actuated, the first in-rack sprinkler (IRS-11) actuated at 65 sec. The second in-rack sprinkler (IRS-12) actuated at 74 sec. The two operating sprinklers fight the fire growth and succeed to control the fire growth after 185 sec. Total suppression of the fire will occur after approximately 6.5 min. For case D2-2, three sprinklers have been actuated, the first in-rack sprinkler (IRS-12) actuated at 82 sec. The second in-rack sprinkler (IRS-11) actuated at 89 sec. The third in-rack sprinkler (IRS-13) actuated at 95 sec. The sprinklers totally control the fire after 170 sec.

0.00

0.20

0.40

0.60

0 5 10 15

Time (sec)

Sprinkler

Location Index

(

Cases A, In-Rack Sprinkler, v = 20 cm, h = 32 cmCase A, ESFR Sprinkler, v = 20 cm, h = 32 cmCase A1-4, Foam Sprinkler, v = 20 cm, h = 32 cmCases B, In-Rack Sprinkler, v = 30 cm, h = 32 cmCases C, In-Rack Sprinkler, v = 40 cm, h = 32 cmCases D, In-Rack Sprinkler, v = 20 cm, h = 48 cmCases E, In-Rack Sprinkler, v = 20 cm, h = 64 cm

Fig.31 Fire Suppression for Different Rack Storage Geometries

Total suppression of the fire will occur after approximately 6 min. For case D3-2, three sprinklers have been actuated, the first sprinkler (IRS-14) actuated at 68 sec. The second sprinkler (IRS-13) actuated at 74 sec. The third sprinkler (IRS-15) actuated at 82 sec. The sprinklers totally control the fire after 180 sec. Total suppression of the fire will occur after approximately 6.5 min.For case E1-2, two sprinklers have been actuated, the first in-rack sprinkler (IRS-11) actuated at 66 sec. The second in-rack sprinkler (IRS-12) actuated at 77 sec. The sprinklers totally control the fire after 180 sec. Total suppression of the fire will occur after approximately 6 min. For case E2-2, three sprinklers have been actuated, the first in-rack sprinkler (IRS-12) actuated at 82 sec. The second in-rack sprinkler (IRS-13) actuated at 90 sec. The third in-rack sprinkler (IRS-11) actuated at 98 sec. The sprinklers totally control the fire after 185 sec. Total suppression of the fire will occur after approximately 6 min. For case E3-2, three sprinklers have been actuated, the first sprinkler (IRS-14) actuated at 69 sec. The second sprinkler (IRS-13) actuated at 76 sec. The third sprinkler (IRS-15) actuated at 85 sec. The sprinklers totally control the fire after 190 sec. Total suppression of the fire will occur after approximately 7.5 min.

When analyzing the above results, it can be noticed the small effect of the horizontal flue height on the activation time of sprinklers. As the horizontal flue height increases, some flame are spread in the horizontal flue space to other adjacent surfaces, which impedes the vertical flame spread in the vertical flue space, yielding to somehow slower activation.



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0 50 100 150 200

Time (sec)

Sprinkler

Location Index

(

Sprinkler Activation, Case A4-3, ESFR Sprinkler, v = 20 cm, h = 32 cm

Sprinkler Activation, Case D4-2, ESFR Sprinkler, v = 20 cm, h = 48 cm

Sprinkler Activation, Case E4-2, ESFR Sprinkler, v = 20 cm, h = 64 cm

Fire Growth Control, Case A4-3, ESFR Sprinkler, v = 20 cm, h = 32 cm

Fire Growth Control, Case D4-2, ESFR Sprinkler, v = 20 cm, h = 48 cm

Fire Growth Control, Case E4-2, ESFR Sprinkler, v = 20 cm, h = 64 cm

Fire Suppression, A4-3, ESFR Sprinkler, v = 20 cm, h = 32 cm

Fire Suppression, Case D4-2, ESFR Sprinkler, v = 20 cm, h = 48 cm

Fire Suppression, Case E4-2, ESFR Sprinkler, v = 20 cm, h = 64 cm

Fig.32 Sprinklers Activation, Fire Growth Control and Fire Suppression for

Different Rack Storage Heights

4.2.4 Effect of Storage Height

The results obtained from the CFD simulations indicated that, for case D4-2, the sprinkler (CS-1) has been actuated at 26 sec. The operating sprinkler fights the fire growth and succeeds to control the fire growth after 26 sec. Total suppression of the fire will occur after approximately 3.5 min. For case E4-2, the sprinkler (CS-1) has been actuated at 22 sec. The sprinkler totally controls the fire after 81 sec. Total suppression of the fire will occur after approximately 3 min. Comparing these results with the results obtained for case A4-3, it is clear that the storage height has a strong impact on the sprinkler activation. As the rack storage increases, the activation will be faster. Regarding the control of the fire growth and the fire extinguishment and comparing these results with the results obtained for case A4-3, the improvement of the fire growth control and the fire extinguishment due to the increase of the rack storage, can be noticed.

4.2.5 Foam-Water Sprinkler System

The results obtained from the CFD simulations indicated that, for case A1-4, two sprinklers have been actuated, the first sprinkler actuated at 135 sec. The second sprinkler actuated at 140 sec. The two operating sprinklers fight the fire growth and succeed to control the fire growth after 255 sec. Total suppression of the fire will occur after approximately 5 min.

Comparing these results with the results obtained for the cases A1-2 and A1-3, in which in-rack sprinklers and ESFR sprinklers are used respectively, it is noticed that the activation

of the foam-water sprinkler system is slightly more than close to the ESFR sprinklers activation.

Regarding the control of the fire growth and comparing these results with the results obtained for the cases A1-2 and A1-3, it is noticed that the foam-water sprinkler system controls the fire growth in such time slightly more than the in-rack sprinklers and reasonably more than the ESFR sprinklers.

Also, regarding the fire extinguishment and comparing these results with the results obtained for the cases A1-2 and A1-3, it is noticed that the foam-water sprinkler system extinguishes the fire in such time slightly less than the in-rack sprinklers and reasonably less than the ESFR sprinklers.

4.3 Calculated Activation Time

The activation time of sprinklers can be calculated using the equation 17, knowing the air temperature and velocity around each sprinkler:

cr

o tTTTT

u

RTI

ln

Fig.33, exhibits the calculated values of sprinkler activation times compared to the simulated ones, for case studies A.

V. CONCLUSIONS

5.1 Conclusions for Fire Simulation

The fire simulation showed an exponentially fire growing with time and the Heat Release Rate (HRR) takes a "t squared" shape profile. The intensity and speed at which the vertical spread accelerates in the vertical flue space, allows a fast reaching of the flames to the top of storage. The fire will continue to grow in intensity, involving new burning surfaces of the rack storage and releasing higher heat rates, until reaching the flashover phase. The fire will spread to the nearby stock and additional stock is consumed and the fire is getting out of control and the rack storage collapses, spreading the fire over large areas of the warehouse. The fire will be on his way to develop to encompass the whole warehouse building. When considering the rack storage geometry, the narrow vertical flue width entrains less air inside the flame, leading to higher flame heights. The wider vertical flue width entrains more air inside the flame, leading to more rapid fire development. In the same way, the longer horizontal flue height will have a reverse effect on the stability and the symmetry of the flames. As the vertical and horizontal flue become larger and larger, the flame height will become more similar to open fire plumes, which can lead to a very rapid fire growth.

5.2 Conclusions for Fire Suppression Simulation

5.2.1 Conclusions for Sprinkler Activation Time

Although some trends have discussed the economical use of the in-rack sprinklers in such fire suppression and the use of ESFR ceiling mounted sprinklers in warehouses in place of in-rack fire sprinkler systems, the simulation results showed that



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0 30 60 90 120 150 180


Sprinkler

Location Index

(

Case A1-2, In-Rack Sprinkler, v = 20 cm, h = 32 cm



Case A1-3, ESFR Sprinkler, v = 20 cm, h = 32 cm



Calculated Sprinkler Activation,Case A1-2, In-RackSprinkler, v = 20 cm, h = 32 cmCalculated Sprinkler Activation, Case A2-2, In-RackSprinkler, v = 20 cm, h = 32 cmCalculated Sprinkler Activation, Case A3-2, In-RackSprinkler, v = 20 cm, h = 32 cmCalculated Sprinkler Activation, Case A1-3, ESFRSprinkler, v = 20 cm, h = 32 cmCalculated Sprinkler Activation, Case A2-3, ESFRSprinkler, v = 20 cm, h = 32 cmCalculated Sprinkler Activation, Case A3-3, ESFRSprinkler, v = 20 cm, h = 32 cm

Fig. 33 Calculated Values of Sprinkler Activation Times Compared to

Simulated Ones, for Case Studies A the in-rack sprinkler will actuate faster than the ESFR ceiling mounted sprinklers. When the flames start somewhere in the rack storage, the in-rack sprinklers are somehow near to the flame tips and consequently are being faster thermally influenced and actuated. The earlier actuation of the in-rack sprinklers may have a great effect on the fire growth control. Although the expensive installation of in-rack sprinklers and their problems arising from the operational problems, which might prevent layout improvements from being made, in-rack sprinklers still might be recommended for fire fighting of the extra-hazards occupancies and class IV commodities rack storage. In the present study, the in-rack sprinklers orientation was according to NFPA13, where only two rows of in-rack sprinklers are placed in the rack storage as described in chapter 3, so as to eliminate the installation cost and the operational problems as much as possible. Regarding the rack storage geometry, the narrow vertical flue width has a very remarkable effect on the activation time of sprinklers. Meanwhile, the narrow horizontal flue height can improve the sprinklers activation. The storage height has a strong impact on the sprinkler activation.

5.2.2 Conclusions for the Control of Fire Growth

By observing the above results, it is found that many adjacent nearby in-rack sprinklers have been actuated in a successive manner, which allowing more control on the fire growth. Furthermore, the narrow vertical and horizontal flues have a great effect on the fire growth, as they do not allow the fire spread to adjacent surfaces, which facilitate the sprinklers

job to control the fire. Regarding the control of the fire growth for the foam-water sprinkler system, it is noticed that these systems control the fire growth in such time slightly more than the in-rack sprinklers and considerably more than the ESFR sprinklers.

5.2.3 Conclusions for Fire Suppression

As the same way discussed above, the in-rack sprinklers have extinguished the fire faster than ESFR sprinklers, due to the fast control of fire growth, due to the successive actuation of the adjacent nearby in-rack sprinklers. Also, the narrow vertical and horizontal flues have a great effect on the fire suppression. The foam-water sprinkler system has the fastest suppression, compared to other cases, due to the great effect of the foam solution on the fire spread. Also, the foam-water sprinkler system does not destroy product, due to the lower water content. They have limited smoke damage, and because of the detergent properties of the foaming agent, they provide a self-cleaning effect.

5.3 Best Results Obtained:

The best sprinkler activation was dedicated to the in-rack sprinklers. The best suppression period was dedicated to the foam-water sprinkler system. To get a better suppression performance for high bay warehouses fires, in-rack sprinklers can be used along with foam-water sprinkler system. But this configuration has a remarkable impact on the economic-wise criteria. So, in order to have a reasonable optimal configuration, in-rack sprinklers can be installed along with ESFR ceiling sprinklers.

5.4 Recommendations for Future Work

Many research points seem to be essential as an extension to the present work for the rack storage fire suppression. The study of the effect of using fire-resistant materials, or fire-proof materials on the rack storage fire spread is essential. Also, a fully developed rack storage model (engineering models and/or CFD models) dedicated to predict the competition between the downward momentum of the water spray and the upward momentum of the fire plume may be of a great importance. Also, the use of Glycerin as an antifreeze for weatherproofing residential and commercial fire sprinkler systems can be studied by CFD models. The Glycerin, have many advantages due to its low toxicity and its low ability to corrode the plastic pipes and fittings.

REFERENCES [1] Beard Alan N., "Flashover and Boundary Properties", Fire Safety

Journal, Vol. 45 (2010), pp 116–121. [2] Beard Alan N, "Dependence of Flashover on Assumed Value of the

Discharge Coefficient", Fire Safety Journal, Vol. 36 (2001), pp 25-36.

[3] Chen Tao, Hongyong Yuan, Guofeng Su, Weicheng Fan, "An Automatic Fire Searching and Suppression System for Large Spaces", Fire Safety Journal, Vol. 39 (2004), pp 297–307.

[4] Cooper Leonard Y., "The Interaction of an Isolated Sprinkler Spray and a Two-layer Compartment Fire Environment Phenomena and Model Simulations", Fire Safety Journal, 15 (1995), pp 89-107.



IJAEST

[5] Delichatsiosa M.A., Liub X., Brescianinib C., "Propagation of Axisymmetric Ceiling Jet Front Produced by Power Law Time Growing Fires", Fire Safety Journal, Vol. 38 (2003), pp 535–551.

[6] Foley M., Drysdale D. D., "Heat Transfer From Flames Between Vertical Parallel Walls", Fire Safety Journal, Vol. 24 (1995), pp 53-73.

[7] Grosskopfa K.R., Kalbererb Jennifer, "Potential Impacts of Ultra-High-Pressure (UHP) Technology on NFPA Standard 403", Fire Safety Journal, Vol. 43(2008), pp 308–315.

[8] Hamins Anthony, Johnsson Erik, Donnelly Michelle, Maranghides Alexander, "Energy Balance in a Large Compartment Fire", Fire Safety Journal, Vol. 43 (2008), pp 180–188.

[9] Hansell G.O., "Heat And Mass Transfer Processes Affecting Smoke Control In Atrium Buildings", Ph.D. thesis. South Bank University, London, 1993.

[10] Hasofer Abraham M. & Beck Vaughan R., "A Stochastic Model for Compartment Fires", Fire Safety Journal, Vol. 28 (1997), pp 207-225.

[11] Hauptmanns U., Marx M. , Grunbeck S., "Availability analysis for a fixed wet sprinkler system", Fire Safety Journal 43 (2008) 468– 476

[12] Heskestad Gunnar, "Scaling The Interaction of Water Sprays and Flames", Fire Safety Journal, Vol. 37 (2002), pp 535–548.

[13] Holborna P.G., Nolana P.F., Goltb J., "An Analysis of fire Sizes, fire Growth Rates And Times Between Events Using Data From fire Investigations", Fire Safety Journal, Vol. 39 (2004), pp 481–524.

[14] Ingason Hauker & de Ris John, "Flame Heat Transfer in Storage Geometries", Fire Safety Journal, Vol. 31 (1998), pp 39-60.

[17] Ingason H., "Modeling of a Two-Dimensional Rack Storage Fire", Fire Safety Journal, Vol. 30 (1998), pp 47-69.

[18] Ingason H., "Plume Flow in High Rack Storages", Fire Safety Journal, Vol. 36 (2001), pp 437-457.

[19] Ingason H., "Investigation of Thermal Response of Glass Bulb Sprinklers Using Plunge and Ramp Tests", Fire Safety Journal, Vol. 30 (1998), pp 71-93.

[20] Jayaweera T.M., Yu H.-Z., "Water Absorption in Horizontal Corrugated Boards under Water Sprays", Fire Safety Journal, Vol. 41 (2006), pp 335–342.

[21] Kellera A., Loepfeb M., Nebikerb P., Pleischb R., Burtschera H.,"On-Line Determination of The Optical Properties of Particles Produced by Test Fires", Fire Safety Journal, Vol. 41 (2006), pp 266–273.

[22] Lattimera Brian Y., Christopher P. Hanauskaa, Joseph L. Scheffeya, Frederick W. Williams, "The Use of Small-Scale Test Data to Characterize Some Aspects of Fire Fighting Foam for Suppression Modeling", Fire Safety Journal, Vol. 38 (2003), pp 117–146.

[23] Lattimer Brian Y., Trelles Javier, "Foam Spread Over a Liquid Pool", Fire Safety Journal, Vol. 42 (2007), pp 249–264.

[24] "Lessons Learned from Understanding Warehouse Fires", Fire Protection Engineering, Winter 2006.

[25] Magrabi S.A., Dlugogorski B.Z., Jameson G.J., "A Comparative Study of Drainage Characteristics in AFFF and FFFP Compressed-Air Fire-Fighting Foams", Fire Safety Journal, Vol. 37 (2002), pp 21–52

[26] Magnusson S. E., "A Proposal for a Model Curriculum in Fire Safety Engineering", Fire Safety Journal Vol. 25 (1995), pp 1-88.

[27] Marbach Giuseppe, Loepfe Markus, Brupbacher Thomas, "An Image Processing Technique for Fire Detection in Video Images", Fire Safety Journal, Vol. 41 (2006), pp 285–289.

[28] Miles S. D., Cox G., "Prediction of Fire Hazards Associated with Chemical Warehouses", Fire Safety Journal, Vol. 27 (1996), pp 265-287.

[29] NFPA code 2002 Edition [30] Novozhilov V., Harvie D. J. E. & Kent J. H., "A Computational

Fluid Dynamics Study of Wood Fire Extinguishment by Water Sprinkler", Fire Safety Journal, vol. 29 (1997), pp 259 282.

[31] P&G Fire Protection Standard, "Sprinkler Protection Design for High Bay Warehouses", No. 618, March 1, 2007, pp 1-9.

[32] Peacock Richard D., Reneke Paul A., Forney C. Lynn & Kostreva Michael M., "Issues in Evaluation of Complex Fire Models", Fire Safety Journal, Vol. 30 (1998), pp 103–136.

[33] Persson B., Lonnermark A., Persson H., Mulligan D., Lancia A. and Demichela M., "Large-Scale Foam Application—Modelling of Foam Spread And Extinguishment", Swedish National Testing and Research Institute, 2001, ISBN 91-7848-856-7

[34] Poreh Michael, Garrad Gordon, "A Study Of Wall And Corner Fire Plumes", Fire Safety Journal, Vol. 34 (2000), pp 81-98.

[35] Rho J.S., Ryou H.S., "A Numerical Study of Atrium Fires Using Deterministic Models", Fire Safety Journal, Vol. 33 (1999), 213-229.

[36] Robert G. Zalosh, "Industrial Fire Protection Engineering", Wiley, New York, 2003, pp. 387, ISBN 0-471-49677-4

[37] Rufino Paolo, diMarzo Marino, "The Simulation of Fire Sprinklers Thermal Response in Presence of Water Droplets", Fire Safety Journal, Vol. 39 (2004), pp 721–736.

[38] Rusch D., Blum L., Moser A., Roesgen T., "Turbulence Model Validation for Fire Simulation by CFD and Experimental Investigation of a Hot Jet in Crossflow", Fire Safety Journal, Vol. 43 (2008), pp 429–441.

[39] Schwille John A., Lueptow Richard M., "The Reaction of a Fire Plume to a Droplet Spray", Fire Safety Journal, Vol. 41 (2006), pp 390–398.

[40] Seattle Fire Department, "High-Piled Combustible Storage", October 2007, Fire Dept., City of Seattle

[41] Sherman C.P. Cheunga, Richard K.K. Yuena, G.H. Yeohb, S.M., "Low Sensitivity Study on Three Different SN Order Schemes of the Discrete Ordinates Method for Two-Compartment Enclosure Fire", Fire Safety Journal, Vol. 40 (2005), pp 736–744.

[42] Sjolin Vilhelm, Evans David D., and Jason Nora H., "First International Conference On Fire Suppression Research", United States Department of Commerce, National Institute of Standards and Technology, May 2004.

[43] Soonil Nam, "Actuation of Sprinklers at High Ceiling Clearance Facilities", Fire Safety Journal, Vol. 39 (2004), pp 619–642.

[44] Soonil Nam, "Development of a Computational Model Simulating the Interaction Between a Fire Plume and a Sprinkler Spray", Fire Safety Journal, Vol. 26 (1996), pp 1-33.

[45] Underwriters Laboratories Inc., "Report of In Rack Sprinkler Comparison Fire Tests", Conducted for HSB industrial risk insures, NC1838 97NK31099, May 1998

[46] United States Fire Administration, "Sprinklers Control Arson Fires in Rack-Storage Warehouse Mt. Prospect, Illinois", Technical Report Series, Federal Emergency Management Agency, United States Fire Administration, National Fire Data Center, Nov 2001.

[47] Vytenis Babrauskasa, Richard D. Peacockb, Paul A. Renekeb, "Defining Flashover for fire hazard calculations: Part II", Fire Safety Journal, Vol. 38 (2003), pp 613–622.

[48] "Warehouse Sprinkler Design Configurations Not Covered by NFPA 13", Fire Protection Engneering, Winter 2006.

[49] White D., Beyler C. L., Fulper C. & Leonard J., "Flame Spread on Aviation Fuels", Fire Safety Journal, Vol. 215 (1997), pp 1-31.

[50] Widmann John F., Jason Duchez, "The Effect of Water Sprays on Fire Fighter Thermal Imagers", Fire Safety Journal, Vol. 39 (2004), pp 217–238.

[51] Widmann John F., "Phase Doppler Interferometry Measurements in Water Sprays Produced by Residential Fire Sprinklers", Fire Safety Journal, Vol. 36 (2001), pp 545–567.

[52] William D. Walton, Nelson Bryner and Nora H. Jason, Editors, "Building and Fire Research Laboratory", National Institute of Standards and Technology Gaithersburg, MD 20899-8644, July 2000 Fire Research Needs Workshop Proceedings Emmitsburg, Maryland, October 20, 1999.



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