Software for consequence modelling

Report
PIPELINE QRA SEMINAR
PIPELINE RISK ASSESSMENT
SOFTWARE FOR CONSEQUENCE
MODELLING
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SOFTWARE FOR CONSEQUENCE MODELLING
What is consequence modelling?
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Effects from accident (e.g. release or explosion)
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Strict physical effect (e.g. overpressure from explosion,
flow from release and concentration at distance)
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Overall effect on human safety (e.g. injuries from
overpressure or injuries from toxic concentration)
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SOFTWARE FOR CONSEQUENCE MODELLING
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What is included in consequence modelling?
-Dispersion (gas)
-Vaporization and dispersion (liquid to gas)
-Release (flow – liquid and gas)
-Explosion (overpressure)
-Jet fire/pool fire (extent and thermal radiation)
-Toxicity (gas)
-Smoked and gas ingress (buildings)
-Structural integrity
-Domino effects (e.g. BLEVE)
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SOFTWARE FOR CONSEQUENCE MODELLING
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Specialized software (specific consequence model) versus
software packages (several consequence models)
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Somewhat a question of wanted level of detail (e.g. urban
area or rural area and topography)
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Method depending on the situation (e.g. complexity, stage of
project and time)
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Economical and technological aspects (e.g. costs for license
and knowledge of the software)
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No single best software to solve all problems
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SOFTWARE FOR CONSEQUENCE MODELLING
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Different methods and philosophy for consequence
modelling
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Empirical consequence models (based on experiments)
versus CFD models (advanced numerical calculations)
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SOFTWARE FOR CONSEQUENCE MODELLING
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Different methods and philosophy for consequence
modelling
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Software established by consultant companies,
authorities, companies (e.g. oil and gas industry and
process industry) and software companies
PHAST from DNVGL
Canary from QUEST
EFFECTS from TNO
TRACE from Safer Systems
FRED from Shell
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All of the software listed to the right is empirical
consequence models
ALOHA from EPA
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SOFTWARE: PHAST
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Software package from DNVGL
- Discharge and dispersion models
- Flammability models (e.g. radiation effects from jet fires,
pool fires and fireballs)
- Explosion models
- Models for the toxic hazards (e.g. indoor and outdoor
toxic dose)
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Continuously developed for over 30 years
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Used frequently in the oil- and gas industry (e.g. BP,
Total, Maersk and Shell)
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SOFTWARE: PHAST
Strengths of PHAST
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All-round
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Simple (i.e. easy to learn)
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Possibility to connect to SAFETI (QRA software)
Weaknesses of PHAST
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Limitations in congested areas
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Limitations in urban areas (i.e. obstacles and topography)
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SOFTWARE: PHAST
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EXAMPLE OF PHAST
Ringsted, Denmark
- 30’’ gas pipeline
- 80 bar
- shopping centre at 100 meters
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EXAMPLE OF PHAST
- Jetfire (blue - radiation 4 kw/m2 – injuries from short
exposure) – 130 meter
- Jetfire (green - radiation 12.5 kw/m2 – fatalities from
medium exposure) – 100 meter
- Jetfire (yellow - radiation 37.5 kw/m2 – fatalities from
short exposure) – 70 meter
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EXAMPLE OF PHAST
- Flashfire (green - LEL) – 100 meter
- Flashfire (blue - ½ LEL) – 230 meter
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SOFTWARE: ALOHA
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Software (free) from EPA in USA
-Discharge and dispersion models
-Flammability models (e.g. radiation effects from jet fires,
pool fires and fireballs)
-Explosion models
-Models for the toxic hazards (e.g. indoor and outdoor toxic
dose)
•
Part of the CAMEO software package (i.e. tools for
emergency planning)
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EXAMPLE OF ALOHA
- Jetfire (blue - radiation 4 kw/m2 – injuries from short
exposure) – 80 meter
- Jetfire (green - radiation 12.5 kw/m2 – fatalities from
medium exposure) – 40 meter
- Jetfire (yellow - radiation 37.5 kw/m2 – fatalities from
short exposure) – 30 meter
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EXAMPLE OF ALOHA
- Flashfire (green - LEL) – 340 meter
- Flashfire (blue – ½ LEL) – 500 meter
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SOFTWARE: CFD
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Short for: computational fluid dynamics
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Not a specific software (i.e. group of software)
-CFX CFD from ANSYS
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Uses numerical methods and algorithms to solve and
analyse problems that involve fluid/gas flows
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Could be applicable for wide range of problems
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SOFTWARE: CFD
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Could be applicable for wide range of problems
- Aerodynamics (e.g. aircrafts and cars)
- Hydrodynamics (e.g. ships)
- Power plants (e.g. combustion in gas turbines)
- Process equipment (e.g. flows and loads)
- Process equipment (e.g. heat transfer and cooling)
- Marine structures (e.g. loads)
- Environment (e.g. exhaust and dispersion)
- Hydrology (e.g. flows in rivers and flooding)
- Buildings (e.g. ventilation)
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SOFTWARE: CFD
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SOFTWARE: CFD
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SOFTWARE: CFD
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SOFTWARE: CFD
Strengths of CFD
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Applicable for complex situations (e.g. urban areas and
topography)
Weaknesses of CFD
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Resources (e.g. man-hours, knowledge and economy)
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COMPARISON OF CONSEQUENCE MODELLING
Method
Hand calculations
PHAST
ALOHA
Distance to LEL
130 meter (size of fireball)
100 meter
340 meter
Distance to ½ LEL
230 meter
500 meter
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COMPARISON OF CONSEQUENCE MODELLING
Method
Hand calculations
PHAST
ALOHA
Distance to 4 kW/m2
Distance to 12.5 kW/m2
130 meter
80 meter
100 meter
40 meter
Distance to 37.5 kW/m2
100 meter (size of flame)
70 meter
30 meter
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QUESTIONS?
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