phoenics conference 2004 phoenics in safety analysis of offshore and underground constructions dr...
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Phoenics Conference 2004
Phoenics in Safety Analysis ofPhoenics in Safety Analysis of
Offshore and Underground Offshore and Underground ConstructionsConstructions
Dr Terje Toften, Dr Bård Venås
Background - Objective
Phoenics in Safety Analysis > 15 years.Most important application area today.Review using versions from 1.4 to 3.5Purpose, Implementation, Advantage
Confined to Fire Safety Analysis
Offshore constructions
• Norway, North sea, Ekofisk, 1971.• Troll, concrete platform, 472m high.• Piper Alpha UK, fire 1988, 167 lives.• Sleipner A, sunk 1991, seismic event, 3.0 on Richter scale, Nothing but a pile of debris, of $700 mill
Wind tunnel -> CFD, 15 years ago
Underground constructions
• Mountains & Fjords - thousands of tunnels• Norwegian railway tunnels has taken no lives, yet.• Common safety elements People, size, fire load, technical outfit, access.• King’s Cross underground St. London 1987, took 31 lives.
Common safety regulations in EU
Safety Analysis
Murphy’s law:If anything can go wrong, it will.
Risk = Probability x Risk = Probability x ConsequenceConsequence
Safety analysis is part studiesin overall risk analysis of Health, Environment and Safety
Offshore Fire Safety
* F u e l* O xyg en* H e at
P ro b a b ility
* S cen a rio- H e at- S m o ke
F ire & E xp lo s ion
* P e rso n a l* P ro p e rty* V a lua b les* E n viro nm e nt
C o nse qu e nces
* T e ch n ica l- A c tive- P a ss ive* O rga n iza tio n a l
L o ss P re ven tion
F ire S a fe ty A n a lys is
Probability – Fuel
• Gas leakage• Oil spill• Dispersion• Scenarios• Barriers
Diffuse and Jet H2 gas leakage4% LEL after 1 and 30 seconds
Probability – Oxygen (Air)
• Natural wind Ventilation 12 ach, 95% of the time• Design of claddings• Ventilation Efficiency• Hazard areas, LEL-HEL• Gas detection systems
Ekofisk 2/4J, 1994
Fire Analysis
• Fire scenarios• Dispersion Heat/Smoke• Evacuation conditions• Escape route placing• Critical areas, life boats• Thermal load• Protection efficiency
Oil spill fire 400MW onboard Grane
Consequence Analysis
• Personal, death, injuries• Property, insurance loss• Valuables, irreplaceable, cultural• Environment, industry, community
Incapacity and lethal dose of smoke
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I n c a p a c i t a t i o n t i m e [ m i n ]
Conc
entra
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ss %
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d CO2
, CO
and O
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C o n s t a n t e x p o s u r e t i m e [ m i n ]
Conc
entra
tion C
O [vo
l %]
I n c a p a c i t a t i o n L e t h a l i t y 5 0 %
• Heat, T<60’C, Radiation• Smoke, poisoning• Oxygen, suffocation• Visibility, 10m escape routes
Loss Prevention
• Technical, Active & Passive Arrangements
• Organisational, Inspection, testing, education
Providing smokeless access with walls
Underground Fire Safety
• Tunnel length: 2,3km• Station LxWxH: 110x20x5m• Pressure shafts• Trains 3-6 17m carriages• 3 escape routes, 7min
Nydalen St. in Oslo - Smoke Ventilation
Phoenics Model
Entrance, escalator, east staircaseCa 250000 cells, 30s time stepSensitivity testing
Platform area and ducts – looking west
Fire Simulations
FIRE SCENARIO• Fire detected, train stopped• Shafts closed, ventilation started• Phoenics simulations start• Fire 20MW/0.9kg/s in 14min
Computed Temperatures and Velocities
VARIABLES• Ventilation system design• Ventilation capacity, minimum• Ceiling / Screen design• Evacuation conditions
Results and Analysis
ANIMATION• Surface plot• Smoke Concentration• Loss of visibility (5m)
Exhaust 300,000m3/h, 4 ducts, new ceiling
Underground Tunnels
Special Considerations• Tunnel construction, gradient• Fire dimension and development• Limited/Long evacuation• Natural wind and buoyancy• Tunnel fan efficiency and fragility
Simulation of tunnel fan response time
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Tid fra oppstart av vifter [minutter]
Trek
khas
tig
het
[m
/s]
Innløp av tunnel
Utløp av tunnel
Med brann (innløp)
Med brann (utløp)
Med trekk i mot (innløp)
Med trekk i mot (utløp)
Evacuation during aFire in a BM69 train
Verification full scale
Lindeberg train station• 110m platform• 240.000 m3/h• 10MW fire
Linderberg St. -Full scale test
Verification• Full scale test• Measurements• Visualisation
Tests and Measurements
National Theatre St. Smoke visualisation
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Hastighet Tunnel Øst [m/s]
Fre
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Natural wind and buoyancyTunnel measurements