evacuation i case of fire

27
06.03.2013 1 1 Fires in Buildings – evacuation Some basic theory with examples from real fires .. March 2013 Phd-candidate Anders Arnhus, NTNU Dept. of Civil and Transport Engineering 2 VTEK10 chap. 11-13.4 Required width in escape routes Requires an available escape access on 1 cm/person Total width should be calculated based on the sum of the two adjacent floors that gives the largest number of persons in sum An arena with 25 000 spectators should therefore have at least 250 meters width in the emergency exits…

Upload: pajsersmoc

Post on 19-Dec-2015

18 views

Category:

Documents


2 download

DESCRIPTION

Evacuation in case of fire. Lectures about evacuations from Norwegian NTNU in Trondheim, class of Fire Technology. Good lectures and short reminders about evacuation of people and factors that determinate it.

TRANSCRIPT

Page 1: Evacuation i case of fire

06.03.2013

1

1

Fires in Buildings – evacuationSome basic theory with examples from real fires ..

March 2013

Phd-candidate Anders Arnhus, NTNU

Dept. of Civil and Transport Engineering

2

VTEK10 chap. 11-13.4 Required width in escape routes

• Requires an available escape access on 1 cm/person

• Total width should be calculated based on the sum ofthe two adjacent floors that gives the largest numberof persons in sum

– An arena with 25 000 spectators should therefore have at least250 meters width in the emergency exits…

Page 2: Evacuation i case of fire

06.03.2013

2

3

Norwegian regulations – normative design density(VTEK10 §11-13 tabell 3):

4

”One size fits all”- regulationsdoes not always fit into reality

• Obviously there is sometimes a need to see if it is possible to reduce the number of doors and escapeexits– For example in shopping malls, 30 000 sqm requiers 150 metres of

exit witdth, about 125 doors á 1,2 m free opening width

• Solution: you can use simulations based on

ASET > RSET + safety margin + see if the normative design person density is relevant for your project

Page 3: Evacuation i case of fire

06.03.2013

3

5

Reference:Copenhagen fire Brigade.Projektnummer : 00-01 Titel : Brand og brandsikkerhed i forsamlingslokaler – et fællesansvar.

6

Norwegian regulations – design density(VTEK10 §11-13 tabell 3):

Page 4: Evacuation i case of fire

06.03.2013

4

7

Sales area, shops, shopping centres

8

Assembly hall without seating, concerts

Page 5: Evacuation i case of fire

06.03.2013

5

9

TEK10/VTEK10 chap. 11-11

• TEK10 Introduces a general requirement for safeTEK10 Introduces a general requirement for safe evacuation:

Available Safe Escape Time (ASET) > Required Safe Escape Time (RSET) + a safety margin

10

Calculating ASET in some objects e.g. in a shopping mall, convention centre etc., can be challenging

Page 6: Evacuation i case of fire

06.03.2013

6

11

How to calculate ASET?• Use tabels and handbooks ( HO-3/2000 can be useful in

some situations and is refered to in VTEK10)http://byggeregler.dibk.no/cms/content/uploads/2000HO-3-Roykventilasjon.pdf

• Through simple hand calculation (Drysdale)

• Two-zone computer models :– ARGOS (30 days free trial version http://en.dbi-net.dk/download_argos.asp

– CFAST (free version at NIST.GOV http://www nist gov/el/fire research/cfast cfmhttp://www.nist.gov/el/fire_research/cfast.cfm

• CFD models (e.g FDS is a free CFD computer program which is used by a number of fire safety engineers and consultants http://fire.nist.gov/fds/index.html

12

Tables and diagrams:• HO -3/2000 Temaveiledning for røykventilasjon

Page 7: Evacuation i case of fire

06.03.2013

7

13

Analysemetode Sonemodeller

4

4,5

Distance to smokelayer

0,5

1

1,5

2

2,5

3

3,5

m

Distance to smokelayerT

S

T

a

V

S

V

S

H T

U

emem

Smo,am

iam0 s

fm

i,a

14

Output fromfrom CFD-modelFDS

Page 8: Evacuation i case of fire

06.03.2013

8

15

How do we calculate RSET?ASET

RSETRSET

Part 1 Part 2 Part 3

16

Step-by-step for the 25 announced and 10 non-announced fire evacuation drills

Page 9: Evacuation i case of fire

06.03.2013

9

17

Procedures also include to search through restrooms

18

Step-by-step for 25 announced and 10 non-announced fire evacuation drills in Norwegian shopping centres

Page 10: Evacuation i case of fire

06.03.2013

10

19

RSET part 1”Deteksjonstid” = t1• The time elapsed from the fire starts to it is detected,The time elapsed from the fire starts to it is detected,

either manually or by technical means

– Depends on fire size and what item(s) burning (e.g soot fraction, how materials are stacked, amount of energy consumed in the first phase of the fire (glowing – free burning?)…)

– Area and height of the room where the fire starts

Draught and ventilation in the room of origin– Draught and ventilation in the room of origin

– If there are people present in the room of origin or not

– If there is installed a fire alarm system, and what kind of smoke or temperature detection system it is equipped with

20

How to determinet1 ”deteksjonstid” and t2 ”reaksjonstid”

t1: You can find some help in tabels in HO-3/2000 table 7.3

There is also a possibility to use computer models

t2: Use tables from reliable sources, e.g:Veiledning til NS 3901 tabell 6

t1– Veiledning til NS 3901 tabell 6

– BSI – standards, NFPA,

– Research reports

Page 11: Evacuation i case of fire

06.03.2013

11

21

RSET part 2”Reaksjonstid” = t2

Th ti t i t t th l i l th ti t• The time to interpret the alarm signal + the time to decide where to go and actually start moving

– Depends on the quality of the alarm signal (bells vs voice alarms = spoken message)

– Depends on builing category and use (homes, offices, hospital, cinemas e.t.c) – people do not react in the same manner in unfamiliar venues as they do in places they are accustomed tounfamiliar venues as they do in places they are accustomed to

– Depends on the quality of, and the degree of training and fire drills that have been carried out

– If people are awake, sleeping, intoxicated etc.…

22

RSET part 3 ”Forflytningstid” = t3Some links to evacuation modelling software:

• FDS + Evachttp://www.youtube.com/watch?v=agxCpRmPnOw&feature=results_video&playnext=1&list=PL442C0252111F4849

• EXODUS http://www.youtube.com/watch?v=eqpNL9XcGno

• STEPS http://www.youtube.com/watch?v=3Bo0tTUPL-M

• SIMULEX http://www.youtube.com/watch?v=KIySsKECpbE

– Free version of SIMULEX http://www.brand.lth.se/software/

(You need Autocad to prepare and adapt underlaying drawings)

Page 12: Evacuation i case of fire

06.03.2013

12

23

RSET can now be calcultated

RSET = t1 + t2 + t3RSET = t1 + t2 + t3

+ Safety margin that has to be selected, individually for each separate project.

24

To be able to calculate ASET, RSET and to select a proper Safety margin, some assumptions may have to be taken:

• Assumptions introduces uncertainty in your conclutions

• Assumtions we take have to be communicated with theowner and the users of the building. It is crucial in order to maintain the prescribed safety level in theb ildi th t th ti li d ithbuilding that these assumtions are complied withthroughout the buildings lifetime

Page 13: Evacuation i case of fire

06.03.2013

13

25

How to decide on a proper safety margin ?

• ? ASET – RSET = safety margin ?? ASET RSET safety margin ?

• No! You have to decide about the size of your safetymargin before you calculate ASET and RSET.

• You have to take the uncertainties in yourcalculations and models into consideration whendeciding about the size of your safety margindeciding about the size of your safety margin

26

Some rules of thump, evacuation and mowement calculations

• Determine the number of people:Determine the number of people:– You can use the prescribed regulations’ figures (VTEK §11-13 table 3)

Page 14: Evacuation i case of fire

06.03.2013

14

27

Some rules of thump, evacuation and mowement calculations

• Measure the traveling distance, normal walking speed (LR) is between 1,0 -1,3 m/s

• Walking speed down stairs are usually meassured as verticalspeed VR = 0,2 m/s if the stairs have an ideal design withtreadboard (inntrinn) T = 28 cm and a riser (opptrinn) R = 18 cm

• The capacity through openings and doors can roughly be set to 1 person/second pr metre width in the opening (B)

28

Example;

• 30 persons have 50 metres from their desks to thefire escape door

Th t t l idth (W) f th d i 1 2 t (B) i• The total width (W) of the door is 1,2 metres, (B) is set to be 1 person/second pr metre,

- Calculate the movment time (t3) for 30 persons to walk from their desks and pass through the door?

Walk to door L= 50 /1,3 to 50/1,0 = 38 – 50 sec

Through door F = 30 / (1,0 * 1,2) = 25 sec

Total movement time t3 = 63 – 75 sec

Page 15: Evacuation i case of fire

06.03.2013

15

29

Fires, sprinklers and theirimpact on evacuation: • Station Nightclub Fire:g

– Fra brannen: http://www.youtube.com/watch?v=Xd1F2VSvMNk&feature=related

– Uten sprinkling: http://www.youtube.com/watch?v=z6rP2m28itU&feature=related

– Med sprinkling: http://www.youtube.com/watch?v=XEdAx2sC9Qg&feature=relathttp://www.youtube.com/watch?v XEdAx2sC9Qg&feature related

– Evakueringssimulering:http://www.youtube.com/watch?v=gmPOIriMiyU&feature=related

30

Visibility before and after sprinkler releases

Kilde: http://www.boverket.se/Global/Om_Boverket/Dokument/diarium/Remisser/Brandskydd/3.%20Konsekvensutredning%20brandskydd.pdf

Page 16: Evacuation i case of fire

06.03.2013

16

31

Godt lesestoff for deg som vil vite mer om evakueringsberegninger:

• Gode eksempler på evakueringsanalyser rapport i NBL A09107 Analyse g y yav rømning fra kirkegalleri, kan lastes ned hos; http://nbl.sintef.no/publication/lists/listeB3.html

• En god bok for håndbergninger av RSET: Bjarne Chr Hagen, Brannteknisk rømningsanalyse, kan kjøpes hos; http://butikk.tapirforlag.no/node/1140

• Godt datagrunnlag for analyser av RSET: Håkan Frantzich: En modell för dimensionering av förbindelser för utrymning utifrånfunktionsbaserade krav, kan lastes ned hos; , ;www.brand.lth.se/publications/#3

• Boverket i Sverige har utarbeidet en nyttig rapport som gir anvisningerfor beregning av RSET, kan lastes ned hos: http://www.boverket.se/Om-Boverket/Webbokhandel/Publikationer/2006/Utrymningsdimensionering/

32

Urtegata, rømningsveier

Page 17: Evacuation i case of fire

06.03.2013

17

33

Floorplans ofthe 1902 wing

Red circlesindicatewhere thewhere thevicitims werefound

34

When the only escape is through ”safe” corridors What can we do to make them safer?

Page 18: Evacuation i case of fire

06.03.2013

18

35

..The Gothenburg fire which claimed over 60 lives waslit in chairs that was stowed in the alternative fire escape stairwell, leaving this ”main entrance door” as the only exit for 400 persons... Enligt

räddningspersonal var detta den enda väg de 400 ungdomarna hadeatt försöka ta sig ut igenom. Panik uppstodoch folk blev liggandepå varandra.

Se også denne lenken

Kilde:Kilde: http://wwwc.aftonbladet.se/nyheter/9810/30/brandbilder.html

36

Page 19: Evacuation i case of fire

06.03.2013

19

37

About 3000 plastic chairs, they were going to be remowed one of the next days.. This is actually a fire esacpe corridor form thestands in a sports arena

38

A tragedy can take place here too! Do you seesome more problems that may occur here?

Page 20: Evacuation i case of fire

06.03.2013

20

39

Introducing new risks in theinterest of the best intentions?

40

The most common Fire effluents

Narcotic gases:

• CO

• CO2

• O2

• HCN (Hydrocyanic acid)

Irritants:

• Acrolein (from burning of fat, glycerols etc)

• Hydrocloric acid - HCL (from burning PVC)

• + ”thousands” of chemical compounds

Page 21: Evacuation i case of fire

06.03.2013

21

41

One example of a set of acceptance criteria for maximum smoke and heat exposure

Reference:Copenhagen fire Brigade.Projektnummer : 00-01 Titel : Brand og brandsikkerhed i forsamlingslokaler – et fælles ansvar.

42

Be aware of;

• Actual HHR ?Actual HHR ?

• Calculation models for soot yield, temperature, smoke layer height?

• Persons individual reaction on fire effluents?

Page 22: Evacuation i case of fire

06.03.2013

22

43

Example, the Høyanger fire (shelteredhousing – ”omsorgsboliger”)

44

Høyanger, sheltered housing for elderly people: - extensive spread of fire through the cold vented attics and corridors

Foto:Sogn Avis

Page 23: Evacuation i case of fire

06.03.2013

23

45

Two-zone model

(Høyanger, corridor level 2 andUrtegata corridor level 1)

45

46

The most vulnerable group;elderly > 80 years

11 percent of the population are >

46

70 years old, however they represent as manyas 1/3 of the victims in fires.

Page 24: Evacuation i case of fire

06.03.2013

24

47

Frequency by age, fatalities in domestic fires 1996–2009(fatalities pr 1000 inhabitants/year distributed on gender and age)

0,12000

0,02000

0,04000

0,06000

0,08000

0,10000

Menn

Kvinner

0,000000-9 år 10-19 år 20-29 år 30-39 år 40-49 år 50-59 år 60-69 år 70-79 år 80-89 år 90 år og

eldre

Kilde: dsb

48

Gulskogen, fire escapes that were reported used

Page 25: Evacuation i case of fire

06.03.2013

25

49

Reference:Copenhagen fire Brigade.Projektnummer : 00-01 Titel : Brand og brandsikkerhed i forsamlingslokaler – et fælles ansvar.

50

Use of ladder is time consuming and not an effectivenot an effective alternative for the entire building

Foto. Bovärket. Rapport- Brandskyddstekniska alternativ till stegutrymningMichael Strömgren

Page 26: Evacuation i case of fire

06.03.2013

26

51

Crowds and crowd dynamics

Req ire speciali ed kno ledge to plan and• Require specialized knowledge to plan and to handle

• At large sports venues, concerts inside/outside

• Can be more complex and situations can escalate in an unforeseen mannerescalate in an unforeseen manner

• Good reading in: http://www.dsb.no/en/toppmeny/Publikasjoner/2010/Tema/Veileder-for-sikkerhet-ved-store-arrangementer/

52

Page 27: Evacuation i case of fire

06.03.2013

27

53

The Love Parade-disaster was not caused by panic, but from a “mass turbulence” - phenomenon

Folkemengden i området der trengselen oppsto, noen timer førselve katastrofen under Love Parade. Det var ikke mengdenspanikk, men fysikkens lover som førte til de tragiske dødsfallene, mener forskerne. (Foto: Arne Müseler/Wikimedia Creative Commons)

54

Crowd management, not exactly as planned..?

..there was a new kid in town: