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Part 2.5
Dispersion Modeling Using ALOHA
1 www.utm.my innovative entrepreneurial global
Dr. Arshad Ahmad
Email: [email protected]

Software Commonly used for Risk Analysis
Software Application
SAFETI Onshore Risk Analysis.
SFU Offshore Risk Analysis.
CAFTAN Fault Tree Analysis.
ETRA Event Tree Analysis.
HAZSEC. HAZOP Study.
HAZTRAC. HAZOP Recommendation Tracking.
PHAST. Consequence Analysis.
WHAZAN Consequence Analysis.
EFFECTS. Consequence (Effects) Modeling.
DAMAGE Consequence (Damage) Modeling.
PC-FACTS. Failure & Accident Databank.
ASAP Event Tree Analysis.
FMECA Failure Mode Effects & Criticality Analysis.
ANEX Life Time Analysis & Failure Estimation.

Software Commonly used for Risk Analysis
Software Application
ALOHA Consequence Analysis
CLASS Hazardous Area Risk & Classifications
RISK CURVES TNO Individual & Group Risk computations
RISKA T Risk Analysis model of Health & Safety Executives, UK
E&P FORUM Hydrocarbon Leak & Ignition Database.
FACTS TNO Frequency Estimation Database
OREDA DNV Frequency Estimation Database
FRED Consequence Analysis software of Shell, UK
EAHAP Consequence modeling software of Energy Analysts Inc. US)

What is CAMEO?
CAMEO is computer software primarily used: For chemical emergency planning For chemical response; and For regulatory compliance
The overall CAMEO system is a suite of three separate, integrated software applications: CAMEO (Computer aided management of emergency operation) MARPLOT (Mapping application for response and planning of local
operational task) ALOHA (Areal locations of hazardous atmosphere)
Developed by: EPAs Chemical Emergency Preparedness and Prevention Office NOAAs Hazardous Materials Response and Assessment Division

CAMEO Answers Questions
What hazards are at this site? Where is the hazard located? What is the chemical? What specific hazard(s) does it present? How can the hazard be mitigated?

Toxic Release Inventory
Chemicals in Inventory/Transit Storage
Locations
Chemical Information Screening &
Scenarios
Incidents
Special Locations
Contacts
Routes
Resources
Census Data
Facilities
Cameo Module Relationships

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ALOHA

What is ALOHA
Air hazard modeling program Predicts how quickly chemical will escape from a tank,
puddle, gas pipeline etc
Model how gas travel downwind (include neutrally buoyant and heavy gas dispersion)
Model fire and explosion (pool, jet, flash, BLEVE, VCE) Produces threat zone estimate, showing area of hazards
(toxicity, thermal radiation)
Threat zones can me mapped into MARPLOT, Google maps, Google earth
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Example of ALOHAs Output
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Getting ALOHA To download ALOHA, go to http://www2.epa.gov/cameo/aloha-software.
ALOHA runs on both Windows and Macintosh computers.
ALOHA Contact Information For additional information: http://response.restoration.noaa.gov/aloha [email protected]
Sample ALOHA Output
Some sample ALOHA output. On the left, the circular thermal radiation threat zone estimates for a BLEVE. On the right, a threat point graph shows the toxic concentration hazard over time at a specific location; the horizontal lines show how the concentration compares to the chosen toxic levels of concern.
NOAAs Office of Response & RestorationProtecting our Coastal Environment
s Office of Response and Restoration, please call (301) 713-2989 or visit our website at
http://response.restoration.noaa.gov
July 2015
Getting ALOHA To download ALOHA, go to http://www2.epa.gov/cameo/aloha-software.
ALOHA runs on both Windows and Macintosh computers.
ALOHA Contact Information For additional information: http://response.restoration.noaa.gov/aloha [email protected]
Sample ALOHA Output
Some sample ALOHA output. On the left, the circular thermal radiation threat zone estimates for a BLEVE. On the right, a threat point graph shows the toxic concentration hazard over time at a specific location; the horizontal lines show how the concentration compares to the chosen toxic levels of concern.
NOAAs Office of Response & RestorationProtecting our Coastal Environment
s Office of Response and Restoration, please call (301) 713-2989 or visit our website at
http://response.restoration.noaa.gov
July 2015
Threat Zones Concentration at a point

GIS Compatible Output
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NOAA
ALOHA
A LOHA (Areal Locations of Hazardous Atmospheres) is a computer program designed to model chemical releases for emergency responders and planners. It can estimate how a toxic cloud might disperse after
a chemical releaseas well as several fires and explosions scenarios.
ALOHA is designed to produce reasonable results quickly enough to be of use to responders during a real emergency. Therefore, ALOHAs calculations represent a compromise between accuracy and speed. Many of ALOHAs features were developed to quickly assist the responder. For example, ALOHA:
Minimizes data entry errors by cross-checking the input values and warning the user if the value is unlikely or not physically possible.
Contains its own chemical library with physical properties for approximately 1,000 common hazardous chemicals so that users do not have to enter that data.
Key Program Features Generates a variety of scenario-specific output, including threat zone pictures, threats at specific locations, and source strength graphs.
Calculates how quickly chemicals are escaping from tanks, puddles, and gas pipelinesand predicts how those release rates change over time.
Models many release scenarios: toxic gas clouds, BLEVEs (Boiling Liquid Expanding Vapor Explosions), jet fires, vapor cloud explosions, and pool fires.
Evaluates different types of hazard (depending on the release scenario): toxicity, flammability, thermal radiation, and overpressure.
Models the atmospheric dispersion of chemical spills on water.
ALOHA is part of the CAMEO software suite, which is developed jointly by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Environmental Protection Agency (EPA).
How ALOHA Works ALOHA is designed to be easy to use so that responders can use it during high-pressure situations. A series of dialog boxes prompt users to enter information about the scenario (e.g., chemical, weather conditions, and the type of release). Detailed help is provided with each dialog box. The scenario information and calculation results are summarized in a printable, text-only window. Once ALOHAs calculations are complete, users can choose to display a variety of graphical outputs.
Threat Zone Estimates and Threat at a Point A threat zone is an area where a hazard (such as toxicity or thermal radiation) has exceeded a user-specified Level of Concern (LOC). ALOHA will display up to three threat zones overlaid on a single picture. The red threat zone represents the worst hazard.
The Threat at a Point feature displays specific information about hazards at locations of interest (such as a school).
GIS-Compatible Output ALOHAs threat zones can be displayed on maps in MARPLOT, another program in the CAMEO suite.
A sample ALOHA threat zone estimate shown on a MARPLOT map (key locations of concern were added in MARPLOT).
Threat zones can also be shown in Google Earth or Google Maps using ALOHAs KML export featureor in Esris ArcMap using the ALOHA ArcMap Import Tool available at http://response.restoration.noaa.gov/aloha_arcmap.

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Fire and Explosion

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Pool Fire

Pool Fire

Jet Fire

BLEVE Fireball Model

Flash Fire & Vapor Cloud Explosion Model

Flash Fire & Vapor Cloud Explosion Model
Vapor cloud explosion major assumptions: Uses Baker-Strehlow-Tang methodology Flammable mass (0.9LEL - UEL) Explosion efficiency
Detonation 100% Deflagration 20%
Ignition options Hard ~106 Joules Soft ~1 Joule

Flash Fi

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