smoke management in a medium sized sprinklered car park · presentation outline •introduction...

Friday, December 27, 2019

Smoke Management in a Medium Sized Sprinklered

Car Park

Dr. Dalia Essam Eldin Khalil ,and Prof.Dr. Essam E.Khalil,

Cairo University, Faculty of Engineering, Cairo, Egypt

1

Belgrade, December 2019


PRESENTATION OUTLINE

• Introduction

• Literature Review

• Methodology

• Case Study

• Results and Discussion

• Conclusions and Recommendations for Future Work

2


Why Sprinklers

Over the past few years, many national codes and standards

enforced the installation of sprinkler systems in enclosed

car parks.

للجراجاتالمصرىالكود•

ىتلقائرشاشاتنظامباستخدامحمايتهايتمالمغلقةالجراجاتحالةفى

الساللمفىرطبتلقائىنظامالىباالضافة

• NFPA 88A

6.4.3 Automatic sprinkler systems shall be installed in

enclosed parking structures located at or above grade, or

within or immediately below a building used for another

occupancy

3


Sprinklered Car Parks Statistics

A statistic on car park fires reported 3096 fires in car

parks in the UK between 1994 and 2005, only 162

incidents were in car parks provided by sprinklers,

➢16 (9.9%) operated and extinguished the fire,

➢84 (51.9%) operated and contained/controlled the fire,

➢1 (0.6%) operated but did not contain/control the fire

➢ 61 (37.6%) did not operate. (Noting that those that “did

not operate” are likely to be because the fire was too

small to activate the sprinklers)

4


Unsprinklered Fire Disaster

A massive fire tore through up to 1,400 vehicles in a car

park in central Liverpool, stranding many people after their

New Year's Eve celebrations.

“One thing is for certain – had the building been

sprinklered there is every chance that they would have

suppressed the fire sufficiently then for us to be able to go in

and extinguish the fire without it spreading in the way that it

did” , said the chief fire officer

5


Scope Of Work And Study Objectives

Scope Of Work

• Investigate the tenability criteria in an enclosed car

park provided with sprinklers and smoke

management system in case of ducted system and

impulse ventilation system.

• Study the interaction of water particles and their

downward movement with the smoke layer

• Study the effect of increasing the distance between

the sprinklers and smoke layer on the visibility

levels6


Scope Of Work And Study Objective

Scope Of Work

• Investigate the effect of increasing the

sprinkler operating pressure on the smoke

behaviour

• Calculating and implementing fire decay

equation after sprinkler activation.

• Parametric analysis for series Jet fan

configuration to study their effect on the smoke

layer disturbance

7


Objectives

This investigation aims to :

• Demonstrate the physical effect of the sprinklers

water spray on the smoke behavior and propagation.

• Recommend a modelling approach to correctly

simulate the fire in a sprinklered car park.

• Propose solution to enhance the evacuation process

and tenability criteria of occupants in a sprinklered

car park.

8


Literature Review Main Topics

Impulse ventilation system for smoke control in car parks

Sprinklers activation effect

9


K.Y. Li, R. Huo, J. Ji, B.B. Ren (2009),

The discharge rate of a horizontal smoke vent adjacent to a sprinkler spray

is experimentally investigated.

Experimental results have shown that :

• The efficiency of smoke venting is controlled by a combination of

smoke buoyancy and drag force of sprinkler spray.

• The CO concentration was found to increase after sprinkler was

operated as the smoke is constrained in the spray region with horizontal

momentum decreased.

• Negative pressure difference is caused at the vent when there is smoke

venting logging, which might practically bring the exterior fresh air into

the fire building.

12


Hugues Pretrel (2017)

This work deals with the interaction between water droplet flows and smoke in a

fire event in a confined and ventilated enclosure.

It was concluded that :

• The concentrations of species (oxygen and combustion products) are similar

near the ceiling and the ground. The water spray along with the smoke reach

the lower part of the room and thus reduces visibility and also the level of

oxygen near the seat of the fire.

• The energy released by the fire is mainly transferred to the walls and through

the ventilation network. If a water spray system is activated, a significant

share (up to 65%) of the energy is transferred to the droplet flow. The water

spray system is therefore a very efficient way to limit the spread of the fire

into the environment, the enclosure walls and the ventilation network.

Sketch of the facility with the location of the measurement

points and the fire room with the water spray system operating

14


Assessment & Validation

A selected test from experiments carried out by

Gutierrez-Montes et al to predict the behavior of

smoke in an atria fire in Centro Technologic del

Metal, Spain was used in the validation process of

FDS (Version 6.5.3)

15

Test facility layout and main dimension



16

Central section and top plane layout showing test apparatus used

(highlighted in red)

Heat release variation with time for each of

the three test cases as measured



• Two parameters were examined, plume and

exhaust smoke temperature.

• The variations of plume and smoke

temperature were compared with the

experimental results carried out by

Gutierrez-Montes et al.

17

FDS geometry used for validation case



18

0

50

100

150

200

250

0 200 400 600 800 1000

Tem

per

ature

(C

)

time

Sensor 24

Temp (EXP)

Temp (FDS)

Plume and smoke

temperature measurements

Sensors 24,28 and 60 experimental and FDS temperature distribution

with time

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90

0 200 400 600 800 1000T

emp

erat

ure

(C

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Sensor 28

Temp(EXP)

Temp(FDS)0

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80

0 200 400 600 800 1000

Tem

per

ature

(C

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time (s)

Sensor 60

Temp(EXP)

Temp(FDS)


Base Case Study

• Geometry

• Boundary Conditions & Input Data

• Grid sensitivity study

• Simulated Base Cases

• Results

• Discussion & Recommendations

• Proposed Design Options

19


Two car park outlets 8 m wide, 3 m

high on the south east side of the

building are available for cars exit.

One car park inlet 7 m wide, 3 m high

on the south west side of the building

is available for car entrance.

An enclosed car park 100 m long, 34 m wide, and 3 m high, is considered.

Geometry

20


• The model applies 1,285,200 uniform cubic grid cells. The

overall volume of the simulated net car park is 10200 m3.

• The domain is divided into 16 meshes to save

computational time by performing FDS_MPI version.

• All walls, columns and jet fan shrouds are specified as

inert surfaces that are non-reacting solid boundary fixed at

40°C.

• The dimensions of the computational domain are chosen to

achieve the optimum solution as recommended by FDS 6

manual.

Mesh Mesh 01-16

X xY x Z 12.5m x 17m x 3 m

Uniform cubic cell size 0.2

Average Nx 63

Average Ny 85

Average Nz 15

Ntot 80325

Boundary Conditions & Input Data

21


Supply Fresh Air

Fresh air is supplied in the car park by mechanical

supply system.

• The supply air/make-up air is introduced through

six supply fans at the right hand side of the car

park.

• The supply fans are simulated as three vent with

an area of 8 sq.m each (4 m wide and 2 m high)

and a flow rate of 6.14 m3/s each (65% of the total

exhaust air)

22

Friday, December 27, 2019 23

Exhaust System

Two systems are proposed for exhaust system namely:

• Impulse ventilation system: Five exhaust fans

located at the left side of the car park are used along

with eight jet fans. These exhaust fan stations are

simulated as vents with an area of as 3sqm. each (3 m

Wide and 1 m high) and 17 m3/s flow rate based on

assumption of 30 ach.

• Ducted system: 86 exhaust grill are located at ceiling

level extracting 86 m3/s based on 30 ACH

assumption. Each grill has a 0.16 m2 free area and

flow rate of 0.5 m3/s in case of normal mode and 1

m3/s in smoke mode


Jet Fans

• Eight jet fans are used with 50 N thrust force (2 m3/s volumetric flow).

• The upper shroud of each jet fan is located directly below the ceiling.

• Each fan is simulated with round cross section of 35 cm diameter and a

shroud length of 2.9 m.

• The flow rate is maintained for 180 s on the normal mode at 1 m3/s and

then the smoke mode 2m3/s is used till the end of the simulation time.

Car Fire

• The fire dimension is 4.4 m wide, 1.8 m long and 0.5 m high with a

heat release rate per unit area of 505 kw/m2.

• The car fire is simulated by flaming polyurethane as a burning fuel with

a soot yield of 0.1kg soot/kg fuel.

Parameter Value

Car fire heat release rate 4 MW

Fire type T-squared fire

Fire growthFast growing

fire

Car park size 100x34x3

Car park general

ventilation systemOn

Car park jet fans On

Ventilation rate 8 ach

Extraction rate 30 ach

24


Sprinklers Parameters Value

Operating pressure 1 bar

Flow rate 80 l/min

K-factor 5.6

Orifice diameter 0.5 inch

Particles diameter 1 mm

Water particles

distribution

Rosin-Rammler

lognormal

Particles flux 10000 per second

Activation temperature 68 Deg.C

Sprinkler density 0.15 gpm/ft2

Sprinklers

• The investigated car park was covered with sprinklers

with 4 m distance between every two consecutive

sprinklers

• The firefighting system used is wet pipe system

• Sprinkler type is standard upright

• Sprinklers operate between 0.5-12 bar

25


Grid Sensitivity Analysis

• Three different grid sizes were utilized to check the

results’grid independency and the effect of mesh

size on the CFD results with computational element

sizes of 0.1 m, 0.2 m and 0.4 m.

• Thermocouple temperature at point 1, 2, 3, 4 and 5

around car fire were investigated using the three

different mesh sizes.

• In each simulation the car fire heat release rate was

8 MW and the simulation time was 200 seconds.

26

Investigated car park and thermocouple locations



27

Simulation SIM.1 SIM.2 SIM.3

Cell volume, m3 0.001 0.008 0.064

Size of uniform Cubic Grid

Cell, m 0.1 0.2 0.4

Cells total number 11,870,208 1,483,776 185,472

Number of meshes 8 8 8

Computational mesh characteristics at different mesh sizes



28

0

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0 50 100 150 200 250

Temperature

Time

Temperature Profile for Thermocouple 1

SIM 1 SIM 2 SIM3

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0 50 100 150 200 250

Tem

per

ature

Time


SIM 1 SIM 2 SIM 3

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0 50 100 150 200 250

Tem

per

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SIM 1 SIM 2 SIM 3

0

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0 50 100 150 200 250

Tem

per

ature

Time


SIM 1 SIM 2 SIM 3


Simulated Base Cases

The purpose of the following simulations is to find the suitable smoke management system

configuration to provide occupants’ safe egress at all times through the fire event as well as

clear access for fire brigades after 20min from fire ignition with different fire scenarios.

This can be achieved when:

• The egress route to the car park outlets with visibility of 10 m is maintained at all times

• A distance of 10-15 m downward the fire seat is maintained clear of smoke for fire

brigades to easily reach the fire

29


InputS1a S1b S2a S2b

Impulse ventilation system Ducted system

Fire load Constant at 4MW

Exhaust Air 30 ACH

Make-up air 65% of exhaust air

Jet fans quantity 8 jet fans -

Jet fan thrust and flow rate 50 N & 2m3/s -

Ducting system - 86 exhaust grills with 1 m3/s flow rate

Sprinklers Sprinklered

Sprinklers physical effect Not modelled Modelled Not modelled Modelled


Visibility Contours At 1.8 m above FFL For Case S1a

31

Visibility

Contours

180s 240s

300s 360s

480s 600s


Visibility Contours At 1.8 m above FFL For Case S1b

32

Visibility

Contours

180s 240s

300s 360s

480s 600s


Visibility Contours At 1.8 m above FFL For Case S2a

33

Visibility

Contours

180s 240s

300s 360s

480s 600s


Visibility Contours At 1.8 m above FFL For Case S2b

34

Visibility

Contours

180s 240s

300s 360s

480s 600s


Discussion & Recommendations

From the above figures it is observed that

• Upon sprinkler activation, smoke logging occurs where smoke is dragged to occupants

level due to sprinklers downward motion.

• Due to the assumed constant heat release rate, the smoke rate of production remains

constant throughout the simulation time.

The above will lead to:

• Lower visibility levels due to smoke logging after only 3 min from fire event threatening

the safe egress of occupants.

• Fire brigades will have more difficulty in locating the fire source and consequently

extinguish it.

35


Therefore three different design options were proposed in

order to achieve the smoke management system objectives

• The first design option is to increase the distance between the

sprinklers and the smoke layer to maintain the sprinklers spray region

below the smoke layer. This can only be achieved either by decreasing

the level of sprinkler installation or by increasing the height of the car

park at early project design stages.

36


• The second design option is to increase the minimum threshold of

the sprinklers operating pressure to 4-6 bar and consequently the

water flow rate to help trap the fire induced smoke below the water

spray and decrease its spread.

• The third design option is to change the common 4MW steady fire

curve and use a transient fire curve with unsteady HRR by

implementing the ASHRAE decay equation.

37


Design Option #1

38

• The common adopted sprinklers system is wet pipe system in

which the sprinklers are located near ceiling level within the

smoke region in order to operate when subjected to high

smoke temperature.

• To install the sprinklers outside of the smoke region, the

sprinklers level must be below the smoke layer that is

usually attached to car park ceiling

• Sprinklers’ activation must rely on another mean than the

usual temperature detection.

• For this to be achieved, the deluge system is proposed.

Installation of the Sprinklers below the Smoke Layer


Design Option #1

Deluge system that operates upon smoke detector signal

A Deluge System is a fixed fire protection system in which

the pipe system is empty until a deluge valve operates

upon smoke detector activation to distribute pressurized

water from sprinklers.

39


Six deluge networks are used as shown in the

figure, where each system relies on three smoke

detectors located above the parked cars for the

activating signal.

Once smoke is detected at one of the three

signals, all sprinklers on the deluge network are

activated.

It was found that deluge #3 operates after 100 s

where deluge #4 and #2 operate after 150 s.

Proposed Deluge System

Proposed Deluge System networks


Series Jet fan performance study

Investigation of the effect of the intermediate distance between the different jet fans on the predicted

visibility and local temperature. The following cases were investigated:

41

• Four jet fans were located 20 m away from each other

• Three jet fans were located 30 m away from each other

• Two jet fans were located 40 m away from each other

The fans were of similar capacity and were located 8 m away from the source of fire. The smoke behavior

was examined and the study was conducted at time interval of 90 s after the onset of fire event to ensure

that the smoke has propagated and moved from the fire source till the last jet fan.


Visibility Contours In A Vertical Y- Plane With No Jet Fans

42


Visibility Contours In A Vertical Y- Plane At 20 M Jet Fans Longitudinal Distance

43



44



45


From the above figures it can be concluded that:

• Jet fans operation causes smoke spreading down 2 m from ceiling level which will make the

installation of sprinklers at ceiling level within the smoke layer very challenging.

• At the same time sprinklers cannot be installed below 2.2m from floor level which is the

minimum allowable height for any mechanical system installation in a car park as per the

Egyptian code.

• Therefore, Three cases were modelled to investigate the visibility level at different ceiling height ;

• Car park with clear height of 3 m with sprinklers installed at 2.2 m

• Car park with clear height of 3.6 m with sprinklers installed at 2.2 m

• Car park with clear height of 4 m with sprinklers installed at 2.2 m


Visibility Contours At 1.8 m above FFL at 300s with

impulse ventilation system at different ceiling heights

47

Visibility

Contours

(m)

@ Ceiling height 3m

@ Ceiling height 3.6m

@ Ceiling height 4m


Ducted system study

• When ducted smoke extraction system is installed at ceiling level, it can be observed that the smoke layer

extends down to 1.4-1.5 m from ceiling level making it also difficult to install the sprinklers at a height of 2.2 m.

• Therefore, it is recommended to increase the car park clear height to avoid the sprinkler spray interaction with

smoke layer.

• Three cases were modelled to investigate the visibility level at different ceiling heights;

• Car park with full height of 3 m

• Car park with full height of 3.2 m

• Car park with full height of 3.4 m

Smoke layer depth with ducted exhaust without sprinkler activation


Visibility Contours At 1.8 m above FFL at 300s with

ducted system at different ceiling heights

49

Visibility

Contours

(m)

@ Ceiling height 3m




Design Option 1

Results & Discussion

50

For impulse ventilation system:

• Jet fan operation on ventilation mode leads to intense mixing between

the smoke layer and the surrounding air

• Increasing the number of consecutive jet fans in a row increases the

mixing of smoke layer with the air below

• Due to this mixing, the smoke layer height can reach up to 2 m below

the ceiling

• Car park height is recommended to be more than 3.5 m high in

order to efficiently install the sprinklers along with jet fans so

that the interaction between smoke and water spray can be

avoided


For ducted system:

• Ducted system at ceiling level allows for more uniform smoke layer

• Nevertheless, the smoke layer extends down to 1.2 m from ceiling

level

• Minimal turbulence and mixing can be observed throughout the car

park compared to impulse ventilation system

• Car park height is recommended to be more than 3.2 m high in

order to efficiently install the sprinklers along with jet fans so

that the interaction between smoke and water spray can be

avoided


Design Option #2

52

Three different sprinkler operating pressure will be

examined to study the effect of pressure and hence the

flow rate on the smoke behavior.

As per NFPA 13, the minimum pressure for a sprinkler

to effectively operate is 0.5 bar and the maximum

pressure a sprinkler can withstand is 12 bar. Therefore,

the sprinkler system network pressure must be

maintained within these limits.

TrialsSprinkler

pressure

Sprinkler

Flow rateSprinkler k-factor

Trial 1 1 bar 80 L/min 80 L/(min.atm^0.5)



Design option 2 trials

Increasing the Sprinklers Operating Pressure


Design Option #2

53

Sprinkler performance is described by the following equation:

Q = K √(P)

Where;

Q: Sprinkler flow rate (L/min)

K: Sprinkler discharge coefficient (L/min.bar^0.5)

P: Sprinkler operating pressure (bar)

A hydraulic calculation study is usually performed to ensure that the most remote twelve sprinklers can

achieve the required pressure and density.


Visibility contours at 1.8m for different

sprinklers operating pressure after 600 s


Temperatures contours at 1.8m for different

sprinklers operating pressure after 600 s


Design Option 2


• Sprinkler operating pressure can greatly enhance the tenability conditions in car park.

• The spread of smoke can be limited by the increased water flow rate and water pressure, as the

smoke is trapped beneath the sprinkler.

• The number of sprinklers activated decreases with the operating pressure increase where 32

sprinklers operated in case of 1 bar , 28 sprinklers in case of 4 bar and 22 sprinklers in case of 6 bar

were activated.

• The increased water flow rate will lead to a slight increase in fire pump capacity and consequently

fire tank size.

• To ensure that the most remote sprinklers operate at high pressure, a pump with higher head might

be needed.

• More balancing and accurate hydraulic calculations is required for the sprinklers network to

ensure that all sprinklers operate at high pressure.


Design Option #3

Over the last decade, many experimental tests were conducted to investigate the heat release rate of burning cars. The curves

obtained from these experiments differ depending on the experiment setup, source of ignition, car year of production,

location of ignition and many other factors.

The below figure illustrates different experimental curves done over the last 40 years

Using Transient Fire Curve instead of common Steady Fire Curve

HRR curves comparison from various car fire

experiments between the years 1994-2000HRR curves for experimental sedan passenger car fire in 2009


Change the common 4 MW steady fire curve used in case of sprinklered car park and apply the decay equation on the fire curve:

𝑸 = 𝑸𝒂𝒄𝒕 𝒆−(𝒕−𝒕𝒂𝒄𝒕)/𝝉

Where;

Q = post sprinkler actuation HRR, Btu/s (kW),

𝑸𝒂𝒄𝒕 = HRR at sprinkler actuation, Btu/s (kW),

t = time from ignition, s,

𝒕𝒂𝒄𝒕 = time of sprinkler actuation, s

𝝉 = time constant for fire decay, s.

Using a time constant correlation as found by Evans:

𝝉 =𝑪𝝉

𝝎𝟏.𝟖𝟓

Where;

𝜔 = spray density, gpm/ft2 (mm/s);

𝐶𝜏 = 6.15 (3.0 for SI).

58

Design Option #3


Sequence of operation

This part aims to demonstrate the sequence of sprinkler operation and its effect on the fire curve An 8 MW fast

growing car fire will be simulated to get sprinklers activation time. The whole car park is covered by sprinklers

as shown in figure below, the required sprinklers density for ordinary hazard spaces is 0.15 gpm/ft2 .

Sprinklers distribution within car park

59


First sprinkler operation @103 s Second sprinkler operation @105s

Third sprinkler operation @108s Fourth sprinkler operation @110s

Sprinklers operation @120s Start of the decaying fire @180s

Sequence of sprinkler operation


• From the simulation and as illustrated in figure above, it was

found that first sprinkler is activated after 105 sec from fire

ignition and the fourth sprinkler is activated at 110 sec from

fire ignition.

• The decay equation will be only implemented after 3 min

from the fire event to be more conservative.

• The fire load will be kept to increase according to the used t2

function until it reaches a peak of 1.52 MW at 180 s, then it

will decay as per ASHRAE handbook of smoke control

engineering decay equation.

Heat Release Rate Decay Due To Sprinkler Activation

62

0

200

400

600

800

1000

1200

1400

1600

0 200 400 600 800 1000 1200 1400


Heat Release Rate Change With Time

• The following data will be implemented in FDS to

accurately study the effect of different HRR on

smoke logging and hence the evacuation and

tenability criteria.

• The graph shows the decay in HRR as a result of

sprinkler activation, the maximum obtained HRR

is 1520 kW which is only 18.75 % from the 8

MW used in car park fires and 37.5 % from the

common 4 MW design fire used in sprinklered

car parks.

63

t Q t Q t Q t Q

0 0 230 1191.266 460 389.2007 690 127.1564

10 4.689 240 1134.712 470 370.7237 700 121.1198

20 18.756 250 1080.842 480 353.1239 710 115.3697

30 42.201 260 1029.53 490 336.3596 720 109.8926

40 75.024 270 980.654 500 320.3912 730 104.6756

50 117.225 280 934.0982 510 305.1808 740 99.70616

60 168.804 290 889.7526 520 290.6926 750 94.97268

70 229.761 300 847.5122 530 276.8922 760 90.46393

80 300.096 310 807.2772 540 263.7469 770 86.16922

90 379.809 320 768.9523 550 251.2258 780 82.0784

100 468.9 330 732.4469 560 239.299 790 78.18179

110 567.369 340 697.6746 570 227.9385 800 74.47017

120 675.216 350 664.553 580 217.1173 810 70.93476

130 792.441 360 633.0038 590 206.8098 820 67.56718

140 919.044 370 602.9525 600 196.9916 830 64.35948

150 1055.025 380 574.3277 610 187.6396 840 61.30406

160 1200.384 390 547.062 620 178.7316 850 58.3937

170 1355.121 400 521.0906 630 170.2464 860 55.6215

180 1519.236 410 496.3522 640 162.1641 870 52.98091

190 1447.111 420 472.7883 650 154.4655 880 50.46568

200 1378.411 430 450.343 660 147.1323 890 48.06986

210 1312.972 440 428.9633 670 140.1474 900 45.78778

220 1250.64 450 408.5986 680 133.494


Visibility Contours At 1.8 m above FFL For Design Option # 3 in case of ducted system

64

Visibility

Contours

(m)

180s 240s

300s 360s

480s 600s


Visibility Contours Across Fire For Design Option # 3 in case of Jet fans

65

Visibility

Contours

(m)

180s 240s

300s 360s

480s 600s


• It is noticeable that the sprinkler activation causes low visibility levels and high-water velocity only

downstream and in the vicinity of the fire thus keeping clear egress path upstream the fire throughout

the whole simulation.

• The bed of fire can be easily accessed by fire brigades and within only 10-15 min the whole car park is

clear of smoke due to decaying fire and hence decaying smoke production rate.

• In case of IVS, it can be clearly noticed that sprinkler skipping occurs; the sprinklers away from the

fire activate instead of the sprinklers right above the fire

• It can be concluded that if the sprinkler effect on fire curve is taken into consideration, then the results

will be improved drastically.

• The smoke production rate is low due to the decreasing heat release rate, consequently the visibility

across car park is within the tenable conditions at all times.

Design Option 3



• When modelling a sprinklered car park, the sprinklers and their physical effect has to be modelled

• Installing the sprinklers directly below the ceiling within the smoke layer leads to smoke logging where

high-pressure water particles drags the smoke along.

• Sprinkler system located exactly at ceiling level leads to lesser visibility at occupants level compared to

sprinklers installed further away from ceiling due to the interaction of the water spray with the smoke layer

creeping on the ceiling.

• To install the sprinkler beneath the smoke layer, a deluge system has to be used where the sprinklers

activation depends on smoke detectors signal rather than temperature signal

• The use of Jet fans led to intensified mixing and consequently lower visibility at occupants level compared to

the conventional ducted system

67

Conclusions


• Ducted system has proven to be better in maintaining an undisturbed smoke layer compared to jet fan system

as demonstrated previously.

• For the IVS to work efficiently, a ceiling height of 3.5 m along with sprinklers installation level of 2.2 m is

recommended

• Sprinkler skipping occurs when IVS is used and this might lead to decreased sprinkler effectiveness

• For the ducted extraction system to work efficiently, a ceiling height of 3.2 m along with sprinklers

installation level of 2.2 m is recommended

• High sprinklers operating pressures trap the smoke underneath the activated sprinklers and limit its

horizontal spread

68


• Therefore it is recommended to use sprinkler operating pressures higher than 4 bar in car park applications

• The use of steady fires leads to constant smoke production rate throughout the simulation and consequently

oversized smoke extract system as the smoke rate highly depends on the value of the heat release rate

• The use of decaying fire curves can significantly enhance the tenability criteria within car parks

69


• Further investigations have to be made in order to reach the most feasible solution for eliminating

the smoke accumulation in the occupied zone in sprinklered car parks

• More experimental studies on the effect of sprinkler activation on fire curve and smoke

behavior in car parks have to be conducted

• Verify experimentally the possibility of increase the sprinkler network operating pressure to

a limit at which the smoke is trapped beneath the activated sprinklers and does not propagate into

the car park and hence affect the visibility.

70

Recommendations For Future Work


Questions

72

smoke management in a medium sized sprinklered car park · presentation outline •introduction...

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