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PART 7 - TOPIC 2 CONSEQUENCE 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: •  EPA’s Chemical Emergency Preparedness and Prevention Office

•  NOAA’s 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 ALOHA’s Output

9

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.

NOAA’s Office of Response & Restoration—Protecting our Coastal Environment

)RU�IXUWKHU�LQIRUPDWLRQ�DERXW�12$$’s Office of Response and Restoration, please call (301) 713-2989 or visit our website at

http://response.restoration.noaa.gov

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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.

NOAA’s Office of Response & Restoration—Protecting our Coastal Environment

)RU�IXUWKHU�LQIRUPDWLRQ�DERXW�12$$’s Office of Response and Restoration, please call (301) 713-2989 or visit our website at

http://response.restoration.noaa.gov

8�6��'HSDUWPHQW�RI�&RPPHUFH��1DWLRQDO�2FHDQLF�DQG�$WPRVSKHULF�$GPLQLVWUDWLRQ July 2015

Threat Zones Concentration at a point


GIS Compatible Output

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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 release—as 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, ALOHA’s calculations represent a compromise between accuracy and speed. Many of ALOHA’s features were developed to quickly assist the responder. For example, ALOHA:

x Minimizes data entry errors by cross-checking the input values and warning the user if the value is unlikely or not physically possible.

x 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 x Generates a variety of scenario-specific output,

including threat zone pictures, threats at specific locations, and source strength graphs.

x Calculates how quickly chemicals are escaping from tanks, puddles, and gas pipelines—and predicts how those release rates change over time.

x Models many release scenarios: toxic gas clouds, BLEVEs (Boiling Liquid Expanding Vapor Explosions), jet fires, vapor cloud explosions, and pool fires.

x Evaluates different types of hazard (depending on the release scenario): toxicity, flammability, thermal radiation, and overpressure.

x 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 ALOHA’s 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 ALOHA’s 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 ALOHA’s KML export feature—or in Esri’s ArcMap using the ALOHA ArcMap Import Tool available at http://response.restoration.noaa.gov/aloha_arcmap.


Fire and Explosion

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Pool Fire


Pool Fire


Jet Fire


BLEVE Fireball 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



§  Vapor cloud explosion major assumptions: (cont.) •  Congestion options

•  High – area blockage ratio > 40% •  Low – area blockage ratio < 10%


Example


Example: Facility Siting Case Study


Example: Facility Siting Case Study

§  Release through 3-inch relief valve leading to: •  Jet fire

•  Flash fire

•  Vapor cloud explosion

§  Failure of storage vessel engulfed in flames leading to: •  BLEVE fireball


Facility Siting Case Study – BLEVE & Fireball


Facility Siting Case Study – Jet Fire Results


Facility Siting Case Study – VCE Detonation


Facility Siting Case Study – VCE Deflagration


Facility Siting Case Study – Combined


ALOHA Scenario

§  In a transportation accident at km 182 of Southbound North-South Expressway in Nilai, a 9000 Gallon tank truck carrying ammonia overturns and shears off a flange whose diameter is 4 inches. The size of the tank is 24 feet long and 8 feet in diameter. The tank contains liquid, which is stored at ambient temperature. The fill density of the tank is 75% by volume. The sheared-off flange creates a circular opening of about 3 inches in diameter, and it is located at 30% of the way to the top of the tank.

§  At the time of the accident, the wind direction is NE (i.e. blowing from NE), the wind speed is 3 m/s, measured at 10 m height. The accident occurred on a highway near a small village. The weather is partly cloudy, 80% relative humidity, and the temperature is 32 degrees Celsius.


Mapping Aloha Threat Zones into Google Earth


Displaying Aloha Threat zones on Google Earth §  Step 1: Create any Threat Zone in ALOHA; for example you

could enter the following criteria as an example:

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SITE DATA:•  Location: STILLWATER, OKLAHOMA•  Building Air Exchanges Per Hour: 0.93

(unsheltered single storied)•  Time: December 19, 2011 1000 hours CST (using

computer's clock)

CHEMICAL DATA: Chemical Name: CHLORINE Molecular Weight: 70.91 g/mol•  AEGL-1 (60 min): 0.5 ppm AEGL-2 (60 min): 2

ppm AEGL-3 (60 min): 20 ppm •  IDLH: 10 ppm•  Ambient Boiling Point: -30.5° F•  Vapor Pressure at Ambient Temperature: greater

than 1 atm•  Ambient Saturation Concentration: 1,000,000

ppm or 100.0%

ATMOSPHERIC DATA: (MANUAL INPUT OF DATA) •  Wind: 10 miles/hour from n at 3 meters•  Ground Roughness: open country Cloud

Cover: 5 tenths•  Air Temperature: 66° F Stability Class: D•  No Inversion Height Relative Humidity:

50% SOURCE STRENGTH:•  Direct Source: 200 pounds/min Source

Height: 0•  Release Duration: 10 minutes•  Release Rate: 200 pounds/min•  Total Amount Released: 2,000 pounds•  Note: This chemical may flash boil and/or

result in two phase flow.


Displaying Aloha Threat zones on Google Earth §  Step 1: Select the Display / Threat Zone menu §  Step 3: Accept the Level of Concern values

§  ALOHA should now display the Threat Zone graph

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Displaying Aloha Threat zones on Google Earth

§  Step 4: To display this graph on Google Earth, you MUST know the specific Latitude / Longitude of the release point. If you don’t know the Lat / Long value, you can determine it by using MARPLOT, or Google Earth, a hand-held GPS unit, etc. •  For my example, I am using the following Lat / Long coordinates as

the release point: 34.726930°N 99.389449°W

§  Step 5: After you have determined the exact Lat / Long coordinates, return to ALOHA with the Threat Zone displayed

§  Step 6: Select the “File à Export Threat Zones” menu

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Displaying Aloha Threat zones on Google Earth

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Step 7: Choose “PAS” if exporting to ArcView using the ArcMap Import Tool or Choose “KML” if exporting to Google Earth


Displaying Aloha Threat zones on Google Earth §  Step 8: Enter the Lat / Long values

§  Step 9: Select OK

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Displaying Aloha Threat zones on Google Earth §  Step 10: Name the file and save to your computer desktop; in my

example, I have named the file ALOHA Chlorine Threat Zone.kml

§  Step 11: Save the file

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Displaying Aloha Threat zones on Google Earth §  Step 12: Go to your computer desktop §  Step 13: Find the saved KML file and double-click on it

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This should launch Google Earth and automatically zoom-in and display the Threat Zone at the specified Lat / Long position.


GROUP PROJECT

§  Carry out QRA on the scenario given §  Plot the individual risks on Google map/ Google earth

§  Prepare a written report (20-30 pages) §  Prepare for oral presentation

§  Oral presentation is expected in 3 weeks

§  Written report shall be due in 4 weeks

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End of Lecture

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