Marplot and Aloha Exercises
ALOHA
This ALOHA exercise must be performed using the new ALOHA version 5.4.1.2.
ALOHA 5.4.1.2 has the capacity to produce footprints for 3 different LOC
simultaneously. This allows for many new options! The following exercise
demonstrates a method for using UEL and LEL to predict the potential ignition
area.
Open ALOHA and select Butane as your chemical.
Assume the following weather conditions:
Wind Speed
Wind Direction
Ground Roughness
Partly Cloudy
Temperature
Relative Humidity
10 mph
S
Open
5
50 degrees F
50%
Set the Source as: Direct / Instantaneous / 12,000 gallons / Liquid
Select Display / Threat Zone
Question 2: What are your choices for the threat Zone?
Select Toxic Area- What are the Choices?
Select TEEL
Go back and set the display Threat Zone to Flammable, note the information : Set
the ALOHA LOC values as:
Red Footprint:
60% LEL
Orange Footprint: LEL
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Yellow Footprint: 10% LEL
Display the resulting footprint on MARPLOT.
Open a new MARPLOT Layer; use the “polygon” tool to “draw” the LEL area
while excluding the UEL area. This ALOHA’s “predicted” potential ignition zone.
For safety purposes, you may elect to use 10% LEL instead.
Use the MARPLOT Layer List to “Hide” the ALOHA Footprints. Your drawn
“ignition zone” should be displayed.
Exercise 2
Use ALOHA to model a release based on the following parameters.
Location
use your own location
Chemical
ammonia (anhydrous)
Atmospheric
Wind speed
10 mph
Wind direction
N
Cloud cover
5
Temperature
70
Humidity
50%
Source
Direct / Instantaneous
8000 pounds
Display the Threat Zone using the Default ERPG values as your Level of Concern
(LOC).
Display this on your Marplot map using our location.
Draw outlines of the 3 Threat zones and save to a new layer called Ammonia Toxic
8000 lb. Also draw ERG protective zones.
Question 4: Use the CAMEO Chemical Library to determine the following Level
Of Concern values:
LEL
_____
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UEL
½ IDLH
_____
________
10% LEL
_____
Question 5: Run ALOHA plumes for all these LOC values. For LEL / UEL you
will need to convert % to ppm and use the ALOHA User Specified LOC boxes!
MARPLOT EXERCISES
Create and print a MARPLOT map displaying the ALOHA plumes for:
ERPG values
IDLH / TLV values
LEL / UEL values
Use your MARPLOT county map for this exercise.
1)
2)
3)
4)
Create a new map layer titled “VINYL ACETATE RELEASE” direct 5000 lbs.
Locate a spot for your fictitious release to occur.
Use the Sharing Menu to display the ERPG-1, 2, and 3 ALOHA footprints
“Copy and paste” your screen to a Word document; here is one way to do that
a. Use “Alt - Print Screen” keys to copy the screen;
b. open a Word document;
c. use “Control - V” keys, or “right-click – paste” to paste
5) Return to ALOHA and Display the LEL / UEL / 10% LEL Footprints (notice only the 10% LEL
footprint is large enough for ALOHA to display a footprint)
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ALOHA EXERCISES
Use ALOHA to model a direct release of 150 pounds of CARBON DISULFIDE. Weather conditions are:
Wind Speed:
7 mph
Wind Direction: SSE
Cloud Cover:
3
Temperature:
75 F
Inversion:
no
Relative Humidity:
50%
What is the Maximum Plume Distance when the LOC = IDLH
__________
ERPG-1 __________
ERPG-2 __________
ERPG-3 __________
LEL
__________
10% LEL
__________
What is the difference between measuring toxicity (ERPG) versus flammability (LEL)? How do you
interpret the difference between ERPG and LEL plume distance?
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MARPLOT EXERCISES
Create and print a MARPLOT map displaying both the “Toxic” and the “Flammable Range” ALOHA
plumes for CARBON DISULFIDE and the ERG suggested Immediate Isolation Area.
Use your MARPLOT county map for this exercise.
1)
2)
3)
4)
Locate a spot for your fictitious release to occur.
Use the “Sharing” menu to display the ALOHA “Toxic” plume.
Go to the “List” menu.
Select the “New” button
Open ALOHA and select Methylamine (1061) as your chemical.
Question 1: Review the Text Summary. What value(s) will ALOHA use for the
default Level of Concern?
Assume the following weather conditions:
Wind Speed
Wind Direction
Ground Roughness
Partly Cloudy
Temperature
Relative Humidity
10 mph
S
Open
5
50 degrees F
50%
Set the Source as: Tank
Horizontal; 14 x 40 feet; 46,061 gallons capacity
Tank contains Liquid at Ambient Temperature
85% full
Leak is 3 inch, broken valve
Leak location is halfway up the side of the tank
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Select Display / Footprint menu
Question 2: What is the “primary hazard” for Methylamine? Do the ERPG values
reflect that hazard? Are any of the ERPG values reflective of the UEL or LEL?
Question 3: Can you set the LOC values to UEL and LEL using the Display
menu?
Question 4: Set the ALOHA LOC values as:
Red Footprint:
UEL
Orange Footprint: LEL
Yellow Footprint: 10% LEL
Question 5: How many “footprints” are now displayed on your ALOHA screen?
Why?
ALOHA:
A local company keeps 55-gallon drums of a product named ETHYLENE
CHLOROHYDRIN. These are not pressurized containers. You have been asked
to determine if a spill of this product at the company loading dock (outside of the
building) could have any impact on a residential neighborhood that is .3 miles
north of the facility.
Assume the following weather conditions:
Wind Speed
Wind Direction
4 mph
S
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Ground Roughness
Partly Cloudy
Temperature
Relative Humidity
Open
5
90 degrees F
50%
First, use the Direct/Instantaneous Source option to create the “worst-case”
scenario for a 55-gallon release. Use the ALOHA default TEEL values for your
Level of Concern. Is there a problem?
Question 1: List the Maximum Footprint Distance for the TEEL values for the
Direct/Instantaneous Source:
TEEL-1
TEEL-2
TEEL-3
____________
____________
____________
Now use the “Puddle” source option for a 440 square foot puddle containing 55
gallons of this product.
Question 3: Using the Puddle Source information, what is your estimate of the
time necessary for a 55-gallon pool of this product to completely enter the
atmosphere?
Question 4: According to the ALOHA predictions, is it likely the product could
impact on the neighborhood 0.3 miles north of the facility:
For “Worst-Case” conditions?
Yes No
For “Puddle” conditions?
Yes No
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ALOHA
Use the Chemical ETHANOL.
Scenario: A 8,000 gallon semi-trailer placarded 1170 is stopped at a local
convenience store. The liquid product is gushing from a failed 2” valve located at
the bottom of the tank, rear end of the truck. 30 minutes have elapsed before you
are consulted. Responders at the scene estimate tank size as 25 feet by 8 feet. The
liquid runoff has been contained in the parking lot; no estimate of the pool/puddle
size is currently available.
Assume the following weather conditions:
Wind Speed
Wind Direction
Ground Roughness
Partly Cloudy
Temperature
Relative Humidity
10 mph
S
Open
5
65 degrees F
50%
Question 1: Is it possible to model this substance using ALOHA?
Question 2: With the information currently available, which ALOHA Source
Option(s) could be utilized?
Question 3: What value will you use for the Level of Concern? Explain why the
available LOC values are all the “same” number.
Question 4: Analyze the “footprint” information for a “Tank” Source release.
Explain why ALOHA does not “draw” the plume/footprint for a Tank Source, but
does “draw” a footprint for a “Direct/Instantaeous” source.
Question 5: What is the ALOHA estimate for the size of the puddle from the tank
release?
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******************************************************************
Question 1: Can you model a BORON TRIFLUORIDE release using ALOHA?
Question 2: In what physical state does ALOHA need BORON TRIDLUORIDE
to model a release at “ambient temperature”?
Question 3: Use ALOHA to model a release based on the following parameters.
Location
use your own location
Chemical
boron trifluoride
Atmospheric
Wind speed
10 mph
Wind direction
N
Cloud cover
5
Temperature
70
Humidity
50%
Source
Direct / Instantaneous
1000 pounds
Question 4: Display the footprint.
Use the CAMEO Chemical Library to determine the following Level Of Concern
values:
ERPG-1
ERPG-2
ERPG-3
Question 5: Run ALOHA plumes for all 3 available LOC values. Make sure to
change your units from ppm to mg/m3!
MARPLOT EXERCISES
Create and print a MARPLOT map displaying a radius for the 3 ALOHA plumes for BORON TRIFLUORIDE
from the above scenario.
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Use your MARPLOT county map for this exercise.
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
Create a new map layer titled “BORON TRIFLUORIDE RELEASE”
Locate a spot for your fictitious release to occur.
Use the Sharing Menu to display the ERPG-1 ALOHA footprint
Use the Polygon Tool to trace around the footprint; when finished, select “OK”
Name the new “object” “BT with ERPG = 2 mg/m3”
Make the object color “PINK” and select a “Fill Pattern”
Select “OK”.
Repeat steps 4 – 7 with these changes:
a. Change LOC to ERPG-2; display footprint on map
b. Object name is “BT with ERPG = 30 mg/m3”
c. Make the color BLUE and the fill pattern different
Repeat steps 4 – 7 with these changes:
a. Change LOC to ERPG-3 display footprint on map
b. Object name is “BT with ERPG = 100 mg/m3”
c. Make the color RED and the fill pattern different
Print the map.
Save it as a bitmap file to your desktop (use the “File” menu). Make sure to give it a name!
Minimize all screens until you can see your desktop. Use a “photo editor” program to open the
bitmap you just saved. You can now “edit” the picture using the photo editor functions. Edit
the photo and print it.
You should now be able to e-mail the picture. If you can, e-mail it to someone you know or
someone in your office, then print it again.
You may also “Export” the picture to other MARPLOT users as a “.mie” file. The other MARPLOT
users would “Import” the .mie file, and the picture will appear EXACTLY as it does on your
computer.
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