Working with ALOHA

Note: Only the CAMEO 365betÓéÀÖ desktop program can share information with the ALOHAAreal Locations of Hazardous Atmospheres (ALOHA) is a computer model that predicts the area potentially affected by a toxic gas release, fire, or explosion; ALOHA is a component of the CAMEO software suite. Find out more about ALOHA on the NOAA OR&R site (response.restoration.noaa.gov/aloha).® desktop program.

About ALOHA

Use the ALOHA program to estimate threat zones associated with hazardous chemical releases, including toxicPoisonous; can injure or kill people or other organisms. gas clouds, fires, and explosions.

Once you enter a description of a chemical release into the model, ALOHA makes a hazard prediction based on the characteristics of the released chemical, atmospheric conditions, and the circumstances of the release. ALOHA displays a threat zone estimate (like the one shown at left below) showing one or more areas where a hazard—toxicity, flammabilityA substance's tendency to ignite or take flame. Flammability is closely related to the volatility of a substance (and is not its relative ability to burn in the presence of oxygen with the evolution of heat)., thermal radiation (heat), or damaging overpressure (explosionA chemical or physical process in which the rate at which energy is being generated exceeds its ability to escape to its surrounding environment. The hazards of an explosion can include a shock wave (especially near the point of explosion) and projectiles generated by the shock wave. blast force)—may exceed key Levels of Concern and pose a threat to people and property. The threat zone pictures in ALOHA are always shown on a grid with the downwind direction to the right. It is not an indication of the cardinal wind directions (for example, if the threat zone is going to the right, it is not necessarily an indication that the wind is coming from the West).

You can also plot ALOHA threat zones on a map in MARPLOTMapping Application for Response, Planning, and Local Operational Tasks (MARPLOT) is the mapping program for the CAMEO software suite. Find out more about MARPLOT on the NOAA OR&R site (response.restoration.noaa.gov/marplot).® (like the one shown below), where you might want to check to see if any vulnerable locations (such as hospitals and schools) fall within the predicted threat zone and might be affected by a chemical release. In MARPLOT, the threat zone will be drawn based on the cardinal wind direction (for example, shifted based on a wind coming from the Southwest as shown). MARPLOT maps are always oriented with the top of the map being North, so the right side of the map is always East in MARPLOT.

At left, sample threat zone estimate for a toxic chemical release, shown in ALOHA. The worst hazard area (in red) is predicted to extend about 75 yards downwind of the release point; however, milder effects may be experienced in areas more than 500 yards downwind. At right, the same sample ALOHA threat zone, but in this case it is displayed on a MARPLOT map and adjusted based on the cardinal wind direction.

To learn more about ALOHA, External link. on the OR&RNOAA's Office of Response and Restoration (response.restoration.noaa.gov). OR&R co-develops the CAMEO suite with the Environmental Protection Agency's Office of Emergency Management (www.epa.gov/aboutepa/about-office-land-and-emergency-management#oem). site and the help topics that come with ALOHA.

Using ALOHA with CAMEO 365betÓéÀÖ

In the CAMEO 365betÓéÀÖ desktop program, you can use the ALOHA Sharing buttons to:

  • Go to ALOHA: Start (or launch) the ALOHA program. If ALOHA is already running, this will bring the program forward. The ALOHA button (marked in the image below) is always shown on the toolbar; however, you must download and install the ALOHA program separately before you can use it with CAMEO 365betÓéÀÖ.
  • Select this Chemical in ALOHA: If the CAS numberOr CAS #. Chemical Abstracts Service Registry number. This chemical identification number, in the format XXX-XX-X, is assigned by the American Chemical Society (www.cas.org/support/documentation/chemical-substances/faqs). on a chemical datasheet has an ALOHA icon next to it, then it may be possible to model that chemical in ALOHA to assess a hazardous chemical release. In those cases, you will see a Select in ALOHA button on the top of the chemical datasheet (as shown below). Use this Sharing feature to begin setting up an ALOHA scenario with this chemical.

The 'Launch ALOHA' button is always shown in the fourth position on the toolbar. The 'Select in ALOHA' button is shown on chemical datasheets if they may be selectable in ALOHA.

What chemicals are selectable in ALOHA?

While CAMEO 365betÓéÀÖ has thousands of chemical datasheets, only some of those chemicals meet air dispersionThe movement of molecules or finely divided particles through a gaseous or liquid medium (such as the distribution of a toxic chemical cloud in the atmosphere). hazard criteria and can be modeled in ALOHA.

On the chemical datasheets, an ALOHA icon next to a CAS numberOr CAS #. Chemical Abstracts Service Registry number. This chemical identification number, in the format XXX-XX-X, is assigned by the American Chemical Society (www.cas.org/support/documentation/chemical-substances/faqs). is an indicator that there is a chemical record in ALOHA with that CAS number. (Hover your mouse cursor over the icon to see the corresponding name in the ALOHA chemical library.) In most cases, the ALOHA chemical name will be the same or very similar to the name shown on the chemical datasheet in CAMEO 365betÓéÀÖ. However, in some cases, the connection will be less straightforward, especially with:

  • Mixtures: ALOHA does not model the release of multiple chemicals simultaneously, so it can't model mixtures. However, as shown in the picture below, you will find mixtures in CAMEO 365betÓéÀÖ with ALOHA icons next to one or more CAS numbers. In this example, the icons are indicating that ALOHA can model each mixture component individually. (If you try to select this chemical in ALOHA from the CAMEO 365betÓéÀÖ desktop program, the program will alert you to this situation.)
  • Solutions: ALOHA does model a small number of solutions, but its chemical library is primarily pure substances. Because the ALOHA connection uses the CAS number, the CAMEO 365betÓéÀÖ datasheets for solutions may seem to indicate that the chemical is selectable in ALOHA. However, you should be cautious with solutions, because they will link to the pure substance in ALOHA.

When you mouseover an ALOHA icon, the name of the chemical that you can model in ALOHA appears.

Note: The ALOHA indicators appear after CAS numbers in all CAMEO 365betÓéÀÖ formats; however, only the desktop format offers you the ability to use the Select in ALOHA button to interact with the ALOHA program. If you're using one of the other CAMEO 365betÓéÀÖ formats and you want to model the chemical in ALOHA, you will need to (a) open the ALOHA program and then (b) manually lookup the chemical in ALOHA using the name provided in the mouseover in CAMEO 365betÓéÀÖ.

From the ALOHA program, you can use the Sharing menu to go to the CAMEO 365betÓéÀÖ desktop program or to view the chemical datasheet in CAMEO 365betÓéÀÖ for the chemical in the ALOHA release scenario.