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

tion C

1 [ma

ss %

]Co

mbine

d CO2

, CO

and O

2

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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

Fire Simulation

• Surface, 3m visibility• Ventilation 3m/s• Fire 200MW

Tid = 16 min

Tid = 2 min

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

kve

ns

[%]

Natural wind and buoyancyTunnel measurements

Concluding Remarks

• The application of Phoenics in Safety Analysis is practically unlimited.• The reliability of its performance has been confirmed by verifications.• Phoenics is a natural safety analysis tool for construction engineers today.