Evacuation i case of fire
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Transcript of Evacuation i case of fire
06.03.2013
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Fires in Buildings – evacuationSome basic theory with examples from real fires ..
March 2013
Phd-candidate Anders Arnhus, NTNU
Dept. of Civil and Transport Engineering
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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…
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Norwegian regulations – normative design density(VTEK10 §11-13 tabell 3):
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”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
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Reference:Copenhagen fire Brigade.Projektnummer : 00-01 Titel : Brand og brandsikkerhed i forsamlingslokaler – et fællesansvar.
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Norwegian regulations – design density(VTEK10 §11-13 tabell 3):
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Sales area, shops, shopping centres
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Assembly hall without seating, concerts
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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
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Calculating ASET in some objects e.g. in a shopping mall, convention centre etc., can be challenging
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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
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Tables and diagrams:• HO -3/2000 Temaveiledning for røykventilasjon
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Analysemetode Sonemodeller
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4,5
Distance to smokelayer
0,5
1
1,5
2
2,5
3
3,5
m
Distance to smokelayerT
S
T
a
V
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V
S
H T
U
emem
Smo,am
iam0 s
fm
i,a
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Output fromfrom CFD-modelFDS
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How do we calculate RSET?ASET
RSETRSET
Part 1 Part 2 Part 3
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Step-by-step for the 25 announced and 10 non-announced fire evacuation drills
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Procedures also include to search through restrooms
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Step-by-step for 25 announced and 10 non-announced fire evacuation drills in Norwegian shopping centres
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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
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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
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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.…
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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)
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RSET can now be calcultated
RSET = t1 + t2 + t3RSET = t1 + t2 + t3
+ Safety margin that has to be selected, individually for each separate project.
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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
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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
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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)
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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)
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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
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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
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Visibility before and after sprinkler releases
Kilde: http://www.boverket.se/Global/Om_Boverket/Dokument/diarium/Remisser/Brandskydd/3.%20Konsekvensutredning%20brandskydd.pdf
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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/
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Urtegata, rømningsveier
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Floorplans ofthe 1902 wing
Red circlesindicatewhere thewhere thevicitims werefound
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When the only escape is through ”safe” corridors What can we do to make them safer?
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..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
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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
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A tragedy can take place here too! Do you seesome more problems that may occur here?
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Introducing new risks in theinterest of the best intentions?
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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
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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.
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Be aware of;
• Actual HHR ?Actual HHR ?
• Calculation models for soot yield, temperature, smoke layer height?
• Persons individual reaction on fire effluents?
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Example, the Høyanger fire (shelteredhousing – ”omsorgsboliger”)
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Høyanger, sheltered housing for elderly people: - extensive spread of fire through the cold vented attics and corridors
Foto:Sogn Avis
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Two-zone model
(Høyanger, corridor level 2 andUrtegata corridor level 1)
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The most vulnerable group;elderly > 80 years
11 percent of the population are >
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70 years old, however they represent as manyas 1/3 of the victims in fires.
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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
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Gulskogen, fire escapes that were reported used
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Reference:Copenhagen fire Brigade.Projektnummer : 00-01 Titel : Brand og brandsikkerhed i forsamlingslokaler – et fælles ansvar.
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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
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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/
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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)
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Crowd management, not exactly as planned..?
..there was a new kid in town: