Seediscussions,stats,andauthorprofilesforthispublicationat:https://www.researchgate.net/publication/264464035

Erratumto:TheoreticalandExperimentalStudyofCriticalVelocityforSmokeControlinaTunnelCross-Passage

DatainFireTechnology·August2014

DOI:10.1007/s10694-013-0347-4

CITATION

1

READS

47

3authors:

Someoftheauthorsofthispublicationarealsoworkingontheserelatedprojects:

AutomaticsprinklerintunnelsViewproject

TheMETROprojectViewproject

YingZhenLi

RISEResearchInstitutesofSweden

62PUBLICATIONS666CITATIONS

SEEPROFILE

BryanLei

BeijingUniversityofTechnology

28PUBLICATIONS313CITATIONS

SEEPROFILE

HaukurIngason

RISEResearchInstitutesofSweden

99PUBLICATIONS1,368CITATIONS

SEEPROFILE

AllcontentfollowingthispagewasuploadedbyYingZhenLion05August2014.

Theuserhasrequestedenhancementofthedownloadedfile.

Theoretical and Experimental Studyof Critical Velocity for Smoke Controlin a Tunnel Cross-Passage

Ying Zhen Li and Bo Lei, Department of HVAC Engineering, School ofMechanical Engineering, Southwest Jiaotong University, Chengdu 610031Sichuan, People’s Republic of China

Haukur Ingason*, Fire Technology, SP Technical Research Institute of Sweden,Box 857, 50115 Boras, Sweden

Received: 7 December 2009/Accepted: 13 July 2010

Abstract. Theoretical analyses and model-scale experiments have been conducted toinvestigate the critical velocity in a tunnel cross-passage which is defined as the mini-mum ventilation velocity through the fireproof door to prevent smoke from flowing

into a cross-passage. The effect of the fireproof door geometry, heat release rate, ven-tilation velocity and fire source location were taken into account. The critical velocityin a tunnel cross-passage varies approximately as 3/2 power of the fireproof door

height, as one-third power of the heat release rate and as exponential law of the ven-tilation velocity, almost independent of the fireproof door width. The critical FroudeNumber mainly ranges from 5 to 10 and consequently as it is not a constant value it

is not very suitable to predict the critical velocity in a tunnel cross-passage. A dimen-sionless correlation that can correlate well with the experimental data was proposed.

Keywords: Tunnel fire, Cross-passage, Smoke control, Critical velocity

Nomenclature

A Area (m2)

Cd Coefficient defined in Equation 14

cp Heat capacity of air (kJ/kg K)

Frcc Critical Froude Number

g Gravitational acceleration (m/s2)

H Height (m)

l Length (m)

m Mass flow rate (kg/s)

Q Total heat release rate (kW)

Qc Convective heat release rate (kW)

T Temperature (K)

V Ventilation velocity (m/s)

Vcc Critical velocity in a tunnel cross-passage (m/s)

* Correspondence should be addressed to: Haukur Ingason, E-mail: haukur.ingason@sp.se

Fire Technology, 49, 435–449, 2013

� 2010 Springer Science+Business Media, LLC. Manufactured in The United States

DOI: 10.1007/s10694-010-0170-012

Greek symbols

q Density (kg/s)

Sup and Subscripts

a Cross-section no

b Cross-section no

c Cross-section no

d Fireproof door in a cross-passage

f Smoke flow

r Full scale

o Ambient

m Small scale

t Tunnel

* Dimensionless

1. Introduction

Fires in tunnels have attracted special attention in recent years due to catastrophicfires, such as the Funicular tunnel fire in Australia on November 11, 2000, causing155 deaths [1]. At the same time, more and more road and railway tunnels havebeen designed and constructed to develop new transportation networks throughmountainous districts and underground urban space.

Control of smoke flow in tunnel fires is a topic that has been investigated bymany researchers in the past. For example, Kennedy et al. [2] proposed a simpleequation for critical velocities in tunnel fires. Wu and Bakar [3] proposed a dimen-sionless correlation to take variant tunnel cross-sections into account and all theexperimental results were correlated into a single form.

However, limited research has been performed on control of smoke flow in atunnel cross-passage. A tunnel cross-passage connects the main tunnel to a safeplace, and provides a safe route for evacuation and rescue operations. In the eventof a fire, enough fresh air should be supplied to keep the cross-passages free ofsmoke. The minimum ventilation velocity through an opened fireproof door thatcan prevent smoke from spreading into a cross-passage is called the critical veloc-ity for smoke control in a cross-passage.

Currently there is no consensus on the critical velocity for smoke control in across-passage. The French tunnel regulation refers to an airflow velocity of at least0.5 m/s being required through an open double-leaf door. The European Directive2004/54/EC just specifies that appropriate means, such as doors or overpressure,shall prevent the propagation of smoke or gases from one tube to the other [4].Kim and Park [5] performed experiments by use of buoyant smoke with the 1:48reduced scale models of a rescue station with many cross-passages, just for verifica-tion of the ventilation plan of the Sol-An Rail Tunnel in Korea. Tarada et al. [6]suggested a minimum flow velocity of 2 m/s should be generated through all theopen doors in the cross-passages of the Young Dong Rail Tunnel in Korea. Valuesmentioned above are arbitrary. In practice, the critical velocity for smoke controlin a cross-passage is influenced by heat release rate, tunnel ventilation velocity and

436 Fire Technology 2013

geometries of tunnel and cross-passage, etc. Tarada [7] proposed a performance-based method to calculate a specific critical velocity in a tunnel cross passage loca-ted downstream of the fire site, and considered the critical Froude Number equalto 4.5. Based on Tarada’s method, Li [8] proposed a specific formula and ascer-tained by aid of CFD simulations that the critical Froude Number for smoke con-trol in a cross-passage of a subway tunnel is about 2.46.

In the present study, theoretical analysis of the critical velocity in a cross-passage is given. A series of model-scale experiments were carried out and used tovalidate the results of theoretical analysis. The study does not necessarily considerthe practical measures to obtain this critical velocity in a cross passage, but pro-vides the necessary means, i.e. experimental data and correlation to determine thecritical velocity for smoke control in a cross-passage.

2. Theoretical Analysis

During a tunnel fire, smoke may spread from the accident tunnel into a cross-passage if the ventilation velocity is too low across the fireproof door, and a back-layering phenomenon, as shown in Figure 1, may occur. When the ventilationvelocity across the fireproof door gets higher, the back-layering in the cross-passage disappears.

Two methods are presented here to predict the critical velocity for smoke con-trol in a tunnel cross-passage. One is the critical Froude model and the other isthe dimensionless analysis method.

2.1. Critical Froude Model

Assume that there is a constant critical Froude for smoke control in a tunnelcross-passage, which can be defined as [7, 8]:

Frcc ¼gHdðqo � qf Þ

qoV 2cc

ð1Þ

smoke cross-passage

fireproof doortunnel

air flow

Figure 1. The schematic diagram of smoke ingress intothe cross-passage.

Theoretical and Experimental Study of Critical Velocity 437

Assume that the smoke flow will not spread into a cross-passage if the critical Froudedefined in Equation 1 is lower than a certain value. It is also assumed that the freshair and smoke flow are fully mixed near the fireproof door, as shown in Figure 2. Thefundamental equations for continuity and energy can be set up as follows:

Continuity:

ma þ mc ¼ mb ð2Þ

Energy:

ðmCpT Þa þ Qc þ ðmCpT Þc ¼ ðmCpT Þb ð3Þ

Equations 2 and 3 can be expressed in another form:Continuity:

qoVtAt þ qoVdAd ¼ qf Vf At ð4Þ

Energy:

qoVtAtcpTo þ Qc þ qoVdAdcpTo ¼ qf Vf AtcpTf ð5Þ

The ideal gas law gives:

qo

qf¼ Tf

Toð6Þ

Substituting Equations 4, 5 and 6 into Equation 1 gives:

Vcc ¼gHdQc

qoCpAdTfFrccV 2cc� At

AdVt ð7Þ

cross-passage

tunnel

air flow

a

a

b

b

c c

firesmoke flow

fireproof door

Figure 2. Schematic diagram of the model.

438 Fire Technology 2013

where

Tf ¼Qc

qoCpðVtAt þ VccAdÞþ To

We can calculate the critical velocity according to Equation 7 easily, if the criticalFroude Number for smoke control in a cross-passage, Frcc, is known a priori.However, there is no experimental data available that can be used to confirm thiscritical Froude Number.

If tunnel ventilation velocity approaches zero, Equation 7 is of the similar formwith the formulae proposed by Kennedy et al. [2] for predicting the critical veloc-ity in a longitudinally ventilated tunnel. This means that when the tunnel ventila-tion velocity approaches zero, we have a case with thermal power acting againstthe flow in the cross-passage.

2.2. Dimensional Analysis

The governing parameters for critical velocity for smoke control in a tunnel cross-passage can also be obtained by a dimensional analysis. The parameters toconsider are the fire heat release rate, longitudinally ventilation velocity, tunnelgeometry, air density, air temperature, heat capacity of air, gravity acceleration,door geometry and slope of the cross-passage. Tunnel height and fireproof doorheight are used as the characteristic lengths of longitudinal tunnel and cross-passage, respectively. In practice the cross-passages are always set at the horizon-tal level, consequently, slope of the cross-passage can be ignored. The function ofcritical velocity for smoke control in a tunnel cross-passage can be given:

Vcc ¼ f ðQ; Vt; qo; cp; To; g;Ht;HdÞ ð8Þ

Based on simple dimensional analysis, this function can be expressed as:

Vcc

Vt¼ f

Q

qocpTog1=2H5=2t

;gHt

V 2t;Hd

Ht

!ð9Þ

The dimensionless heat release rate, dimensionless tunnel ventilation velocity,dimensionless critical velocity for smoke control in a cross-passage, and dimen-sionless fireproof door height are respectively defined as:

Q�t ¼Q

qocpTog1=2H5=2t

; V �t ¼VtffiffiffiffiffiffiffiffigHtp ; V �cc ¼

VccffiffiffiffiffiffiffiffigHdp ;H�d ¼

Hd

Htð10Þ

Consequently, Equation 9 can be transformed into a more general form:

V �cc ¼ f ðQ�t ; V �t ;H�d Þ ð11Þ

Theoretical and Experimental Study of Critical Velocity 439

According to Equation 11, the critical velocity for smoke control in a cross-passage is related to the dimensionless heat release rate, the dimensionless tunnelventilation velocity and the dimensionless fireproof door height. Further, Coeffi-cients in Equation 11 should be determined from experimental data.

3. Experimental Procedure

The 1:20 small-scale test-rig consisted of a 12 m long model tunnel, a 5.25 m longair supply duct, a static pressure box and a cross-passage, as shown in Figure 3.The static pressure box, which is used to smooth the turbulence of the air flow, isa cuboid with 1 m length, 0.5 m width and 0.5 m height.

Figure 4 shows cross-sections of the model tunnel and the cross-passage. Themodel tunnel was made from stainless steel with a thickness of 1 mm covered by23 mm of concrete. The cross-passage was made from stainless steel with a thick-ness of 1 mm. A stainless-steel door was set up in the conjunction between themodel tunnel and the cross-passage, as shown in Figure 3. The stainless-steeldoors with various geometries, as shown in Figure 5, were used to analyze theeffect of the geometries of fireproof doors on the critical velocity for smoke con-trol in a cross-passage.

A fire source was set in Location 1 and Location 2, respectively, with an inter-val of 1.5 m. The purpose was to analyze the effect of fire source location on thecritical velocity in the cross-passage. The fire source was a 150 mm diameter por-ous bed burner with its top surface set at floor level. Propane was used as fuel,and its gas flow rate was metered by a rotameter with 1% accuracy. Tunnel venti-lation flow rate was metered by a vortex flow meter with a range of 30–540 m3/hand 1% accuracy. The tunnel ventilation velocity was calculated by dividing the

Figure 3. Schematic diagram of small-scale test bed (dimensionsin mm).

440 Fire Technology 2013

volumetric flow rate by the tunnel cross-sectional area. The ventilation flow rateof the cross-passage was metered by a vortex flow meters with a range of8–60 m3/h and 1% accuracy. The ventilation velocity across the fireproof door inthe cross-passage was calculated by dividing the volumetric flow rate by the door’scross-sectional area.

380 300

125 21

8

393

450

(a) model tunnel (b) cross-passage

Figure 4. Cross-sections of the model tunnel and cross-passage(dimensions in mm).

Figure 5. Cross-sections of doors set in the cross-passage(dimensions in mm). The shadow in Cross-section A correspondsto stainless steel and other blank corresponds to the open door.The shadows in other cross-sections are neglected.

Theoretical and Experimental Study of Critical Velocity 441

The volumetric flow rate was gradually adjusted from high to low, i.e. 0.5 m3/hevery time, until smoke ingress occurred. Gas was sampled inside fireproof doorto determine whether smoke ingress happened in the cross-passage by filter paper.

Froude modelling strategy has been widely used in model-scale experimentaltests concerning fires in tunnels [9–14]. Its main feature is that the Froude numberthat characterizes the ratio between inertia and buoyancy forces is preserved. TheReynolds number is not preserved but retains a sufficiently high value to ensure aturbulent flow inside the tunnel. According to the Froude modelling, the scalingof the heat release rate between model and full-scale is expressed:

Qm

Qr¼ lm

lr

� �5=2

ð12Þ

The scaling of ventilation velocity between model and full scale is expressed:

Vm

Vr¼ lm

lr

� �1=2

ð13Þ

4. Results and Discussion

4.1. Location of Fire Source

The fire source was set in two representative locations, Location 1 and Location2, respectively, as shown in Figure 1. Figure 6 shows the effect of the fire sourcelocation on critical velocity in a tunnel cross-passage. The results were gainedfrom the experiments with Door A set inside the cross-passage. It is clearly shown

Figure 6. Effect of fire source location on critical velocity in across-passage.

442 Fire Technology 2013

that the critical velocity in the cross-passage with fire source located in Location 1is larger than that in Location 2, for a given heat release rate of 7.1 kW and10.5 kW, respectively. The reason is that the thermodynamic pressure, i.e. the ver-tical temperature distribution, at the position where the fireproof door is located,dominates the smoke back-layering inside a cross-passage. The fire plume, in thecase of a longitudinal flow, will be leaning towards the tunnel floor surface and inthe flow direction. This leaning effect makes the vertical temperature with firesource positioned in Location 2 lower, compared with that positioned in Location1, which results in a lower thermodynamic pressure and consequently a lower crit-ical velocity in the cross-passage.

4.2. Heat Release Rate

Figure 7 shows the effect of heat release rate on critical velocity in a tunnel cross-passage. The results were gained from the experiments with Door A set inside thecross-passage for tunnel ventilation velocity of 0.1 m/s and 0.3 m/s, respectively. Itis shown that the critical velocity in a tunnel cross-passage increases with the heatrelease rate, and it varies as 1/3 power law of dimensionless heat release rate.Note that the critical velocity for smoke control in a longitudinally ventilated tun-nel varies as one-third power law of dimensionless heat release rate [3]. The reasonfor the similarity in these two cases is that the critical velocities relate to the ther-modynamic pressure generated near the fire plume, i.e. relate to the same govern-ing physical law.

4.3. Tunnel Ventilation Velocity

Figure 8 shows the effect of tunnel ventilation velocity on critical velocity in across-passage. The results were gained from the experiments with Door A set

Figure 7. Critical velocity in a cross-passage against heat releaserate.

Theoretical and Experimental Study of Critical Velocity 443

inside the cross-passage for heat release rates of 9.1 kW, 10.5 kW and 14.5 kW,respectively. It is clearly shown that the critical velocity decreases with tunnel ven-tilation velocity for the same heat release rates. This may result from the decreaseof smoke temperature as tunnel ventilation velocity increases. It can also beshown that experimental data can be correlated with a natural exponential func-tion of tunnel ventilation velocity.

4.4. Geometry of Fireproof Door

Table 1 gives the experimental data of critical velocity in a tunnel cross-passagewith different door widths. Clearly, it shows that, for a given heat release rate, the

Figure 8. Critical velocity in the cross-passage against tunnelventilation velocity.

Table 1Experimental Data of Critical Velocity in a Cross-Passage withDifferent Door Widths

Door height

(mm)

Heat release

rate (kW)

Door width

(mm) Door no.

Ventilation velocity (m/s)

0.5 0.3 0.2 0.1

112.5 10.5 170 A 0.179 0.190 – 0.191

100 C 0.170 0.191 – 0.205

13.5 170 A 0.185 0.190 – 0.211

100 C 0.190 0.206 – 0.204

125.0 7.5 170 H – 0.216 0.230 0.235

100 D – 0.194 0.239 0.239

10.5 170 H 0.184 0.229 – 0.251

100 D 0.178 0.217 – 0.222

137.5 12.5 170 E – 0.237 0.245 –

140 G – 0.246 0.252 –

444 Fire Technology 2013

critical velocities in the cross-passages with the same door height of 112.5 mm,125 mm, 137.5 mm, respectively, and different widths are almost of the samevalue. This means that the door width has little effect on the critical velocity inthe cross-passage. This can by explained by the fact that the door width is almostindependent of the vertical temperature distribution, i.e. thermodynamic pressure,at the position where the fireproof door was located.

Figure 9 shows the effect of the door height on the critical velocity in a cross-passage. The results were gained from the experiments with Door B to Door F setinside the cross-passage at heat release rates of 10.5 kW and different Tunnel ven-tilation velocity. Correction coefficients of 0.983, 0.994 and 0.984, respectively,were found for these 3/2 power lines. From Figure 9, it is seen that the criticalvelocity in the cross-passage increases with the door height, and the 3/2 power linecan correlate well with the experimental data. According to Equation 10, the ratioof dimensionless critical velocity to critical velocity varies as the -1/2 power lawof door height, consequently, the dimensionless critical velocity in a cross-passagevaries as 1st power law of the dimensionless fireproof door height.

4.5. The Critical Froude Number for Tunnel Cross-Passages

The critical Froude model established in Section 2.1 was based upon the criticalFroude Number, which is the most important parameter in this model. Figure 10gives the critical Froude Number for the tunnel cross-passages with differentdoors inside. It is clearly shown that the critical Froude varies with heat releaserate, tunnel ventilation velocity and geometry of the fireproof door in the cross-passage. The value of the critical Froude Number mainly varies between 5 and 10,not a constant. Consequently, the critical Froude model derived in Section 2.1may not be suitable to predict the critical velocity in a cross-passage, since thecritical Froude Number is not a constant.

Figure 9. Critical velocity in a cross-passage against door height(Q = 10.5 kW).

Theoretical and Experimental Study of Critical Velocity 445

The critical Froude Numbers for Door B to Door F are in a range of 8.0 to17.0, 7.0 to 13.5, 6.0 to 13, 5.0 to 9.0, and 4.0 to 8.0, respectively. The criticalFroude Number for Door E and G is basically at the same level, and so is thecritical Froude Number for Door D and Door H. Consequently, it can be con-cluded that the critical Froude Number decreases with height of the fireproofdoor, but almost independent of door width. The reason for this is that the criti-cal velocity for smoke control in a cross-passage increase with the door height,almost independent of door width.

The critical velocity decreases with increasing critical Froude Number, accord-ing to Equation 1. Although the critical Froude Number is not a obvious constantvalue, the predicted critical velocity, using a value of 5 as the critical Froude,should be high enough to prevent the smoke from flowing into the cross-passage.This value assumes that the dimensionless door height is in a range of 0.25 to 0.35and the dimensionless heat release rate is lower than 0.15.

4.6. Critical Velocity in the Tunnel Cross-Passage

Based on the above analysis on the influences of the individual parameters on thecritical velocity, the dimensionless critical velocity varies as 1/3 power law ofdimensionless heat release rate, 1st power law of the dimensionless fireproof doorheight, and natural exponential law of tunnel ventilation velocity. Then Equa-tion 11 can be transformed into:

V �cc ¼ CdðH �d ÞðQ�t Þ1=3 expð�V �t Þ ð14Þ

Due to the fact that coefficient Cd is still unknown, experimental data are neededto determine it. Figure 11 shows the results of critical velocity in the cross-passage

Figure 10. Critical Froude Number for various geometries of doors.

446 Fire Technology 2013

with various geometries of fireproof doors (Door A to Door H). All the experi-mental data correlate well with the following equation:

V �cc ¼ 1:65H�d Q�1=3 expð�V �t Þ ð15Þ

Correlation coefficient of 0.929 was found for Equation 15 and Cd is equal to1.65, compared Equation 14 with Equation 15. Further, the excellent agreementbetween the experimental data and the proposed correlation shows that the aboveanalysis of the effect of fire source location, heat release rate, tunnel ventilationvelocity and the geometry of fireproof door on critical velocity for smoke controlin a cross-passage is reasonable. The validity of Equation 15 outside the testeddistances has not been examined.

5. Conclusion

Theoretical analysis and a series of model-scale fire experiments were carried outto investigate the critical velocity in a tunnel cross-passage. This critical velocity isdefined as the minimum ventilation velocity through an opened fireproof doorthat can prevent smoke from spreading into a cross-passage. The critical Froudemodel for predicting the critical velocity in a tunnel cross-passage has been builtupon the critical Froude Number. Dimensional analysis of the critical velocity ina cross-passage was also conducted. The effect of the fireproof door geometry,heat release rate, ventilation velocity and the fire source location were taken intoaccount.

The critical velocity in a tunnel cross-passage increases with the height of thefireproof door and the heat release rate, and decreases with tunnel ventilation

Figure 11. Critical velocity in a tunnel cross-passage with variousgeometries of doors.

Theoretical and Experimental Study of Critical Velocity 447

velocity, and the critical velocity is larger when the fire source is located upstreamof the cross-passage than in front of the cross-passage. It is evident that the heightof the fireproof door is a very important parameter for preventing smoke fromspreading into the cross-passage. The critical velocity in a cross-passage variesapproximately as 3/2 power of the fireproof door height, as 1/3 power of the heatrelease rate and as natural exponential law of the ventilation velocity, and isalmost independent of width of the fireproof door. A dimensionless correlation forpredicting the critical velocity in a tunnel cross-passage was proposed.

The experimental data show that the critical Froude Number was not a con-stant value. Over 84% of the values varied between 5 and 10 and 16% variedbetween 10 and 17. Due to this fact, the critical Froude model may not be suit-able to predict the critical velocity in a tunnel cross-passage. However, the pro-posed dimensionless correlation correlates well with the experimental data withvarious fireproof door geometries, tunnel ventilation velocities, and heat releaserates.

Acknowledgements

This work was sponsored by the ministry of railway of the People’s Republic ofChina which is gratefully acknowledged. The authors would also like to thankadjunct Prof. Zhihao Xu and adjunct Prof. Zhihui Deng for their help in theseexperiments. Acknowledgement to SP Tunnel and Underground Safety Centre forthe support to the project.

References

1. Carvel RO, Marlair G (2005) A history of fire incidents in tunnels. In: Beard AN,Carvel RO (eds) The handbook of tunnel fire safety. Thomas Telford Publishing,London, pp 3–41

2. Kennedy WD, Parsons B (1996) Critical velocity: past, present and future. Seminar ofsmoke and critical velocity in tunnels. London, UK, pp 305–322

3. Wu Y, Bakar MZA (2000) Control of smoke flow in tunnel fires using longitudinal ven-

tilation systems—a study of the critical velocity. Fire Safety J 35:363–3904. Hall RC (2006) Ventilation during road tunnel emergencies. Published project report,

PPR140. TRL Limited, Berkshire

5. Kim DH, Park WH (2006) Experiment by using reduced scale models for the fire safetyof a rescue station in very long rail tunnel in Korea. Tunn Undergr Space Technol21:303

6. Tarada F, Bopp R, Nyfeler S (2000) Ventilation and risk control of the Young Dong

Rail Tunnel in Korea. 1st international conference on major tunnel and infrastructureprojects, Taiwan

7. Tarada F (2000) Critical velocities for smoke control in tunnel cross-passages. 1st inter-

national conference on major tunnel and infrastructure projects, Taiwan8. Li YZ, Lei B (2008) Model of critical velocity in a tunnel cross-passage. J Chin Rail

Soc Beijing 30(3):87–90

448 Fire Technology 2013

9. Quintiere JG (1989) Scaling application in fire research. Fire Safety J 15:3–2910. Heskestad G (1972) Modeling of enclosure fires. 14th symposium on combustion. The

Combustion Institute, University Park, PA, pp 1021–1030

11. Saito N, Yamada T, Sekizawa A, Yanai E, Watanabe Y, Miyazaki S (1995) Experimen-tal study on fire behavior in a wind tunnel with a reduced scale model. In: Second inter-national conference on safety in road and rail tunnels, Granada, Spain, April 1995,pp 303–310

12. Heskestad G (1975) Physical modeling of fire. J Fire Flamma 6:253–27313. Ingason H (2007) Model scale railcar fire tests. Fire Safety J 42:271–28214. Ingason H (2008) Model scale tunnel tests with water spray system. Fire Safety J

43:512–528

Theoretical and Experimental Study of Critical Velocity 449

View publication statsView publication stats