ALOHA 5.4.7 (September 2016)

• Updated chemical library, including new DIPPR chemical data and new Levels of Concern (PACs and ERPGs).
• Made minor update to the RAILCAR source strength model for pressurized liquid tanks where a stationary cloud or "mist pool" is predicted to form.
• Revised helps.
• Made additional minor changes and bug fixes.

ALOHA 5.4.6 (February 2016)

• Updated chemical library with new Levels of Concern (AEGLs, ERPGs, and PACs).
• Added CAS number (a chemical identification number) to the Text Summary screen.
• Fixed a typo in the source code for the Chamberlain equation, where the "CR" should be a multiplier in the final term of the equation (not an exponent). This could have an impact on some jet fire scenarios.
• Revised helps.
• Made additional minor changes and bug fixes.

ALOHA 5.4.5 (July 2015)

• Updated chemical library, including new DIPPR chemical data and new Levels of Concern (AEGLs and ERPGs).
• Added new RAILCAR source strength model for pressurized liquid tanks where a stationary cloud or "mist pool" is predicted to form. When RAILCAR predicts a mist pool will form, you have the option of running the RAILCAR model or the traditional ALOHA tank model to estimate the source strength values (i.e., release rate, duration, and amount). No additional inputs are required to run the portion of the RAILCAR model that is available in ALOHA. The RAILCAR model was developed by the Navy, based on the results of field tests that were performed to better estimate how ammonia and chlorine escape from transportation tanks that have been damaged.
• Revised helps.
• Made additional minor changes and bug fixes.

ALOHA 5.4.4 (August 2013)

• Updated chemical library, including new DIPPR chemical data and new Levels of Concern (AEGLs and ERPGs).
• Added wind arrow to threat zone pictures.
• Added additional tick marks to x-axis on the Threat at Point and Source Strength pictures.
• Resolved problem with ALOHA-MARPLOT sharing that occurred when the ALOHA folder did not have write permissions.
• Revised helps.
• Made additional minor changes and bug fixes.

ALOHA 5.4.3 (March 2012)

• Updated chemical library with new AEGLs and PACs. (The PACs dataset is a hierarchy-based system of the three common public exposure guideline systems: AEGLs, ERPGs, and TEELs. The latest PACs dataset is a major update: it includes the latest AEGLs and a significant update to the TEELs based on recommendations from an outside review committee. The TEEL developers have significantly modified the methodology for developing TEELs, which has resulted in one or more TEEL values changing for approximately 80 percent of the chemicals in the PACs dataset.)
• Minor changes and bug fixes.

ALOHA 5.4.2 (December 2011)

• Updated chemical library with new DIPPR data, AEGLs, ERPGs, and PACs. Note that interim AEGLs are now included in ALOHA and that PACs have replaced TEELs in the chemical library.
• Added export threat zones feature. Users can save the threat zones as a .KML file for use in Google Maps or Google Earth. Additionally, Esri users can save the threat zones .PAS file to a specific location (to be used with the ALOHA ArcMap Import Tool).
• Added support for Lion OS for Mac users.
• Revised the helps significantly.
• Changed default wind speed unit to miles per hour.
• Increased the allowable inputs for some fields.
• Minor changes and bug fixes.

ALOHA 5.4.1.2 (April 2009)

• Fixed nitric acid solution bug.
• Updated reactivity and carcinogenic warnings.
• Changed code so that the Windows version can now accept and process SAM transmissions while in the background or minimized.

ALOHA 5.4.1.1 (March 2009)

• Updated chemical library, including new DIPPR data, AEGLs, ERPGs, and TEELs.
• Minor bug fixes.

ALOHA 5.4.1 (March 2007)

• Updated chemical library with AEGLs, ERPGs, and TEELs.
• Minor changes and bug fixes.

ALOHA 5.4 (February 2006)

• Added fires and explosions capabilities to ALOHA. In addition to toxic vapor clouds, ALOHA now models pool fires, jet fires, vapor cloud explosions, and BLEVEs.
• Added ability to evaluate multiple types of hazard (depending on the release scenario) in addition to toxicity: flammability, thermal radiation, and overpressure.
• Added ability to model atmospheric dispersion over water.
• Added ability to model evaporation of liquid spills into water.
• Updated chemical library with AEGLs, ERPGs, and TEELs.
• Removed ALOHA's dose calculations.
• Updated and extensively revised ALOHA's on-screen helps, alerts and dialog boxes, and manual.
• Exchanged the term footprint for the term threat zone.
• Minor changes and bug fixes.

ALOHA 5.3.1 (Summer 2004)

• Updated AEGLs to match those in CAMEOfm.
• Removed interim AEGLs from ALOHA.
• Updated DIPPR chemical information.
• Minor changes and bug fixes.

ALOHA 5.3 (Spring 2004)

• Added ability to display up to three overlaid footprints when you enter up to three different Levels of Concern.
• Added five solutions to ALOHA's chemical library. ALOHA can estimate source strength from an evaporating puddle containing any of these solutions.
• Updated Windows version of ALOHA to a 32-bit application.
• Updated evaporating puddle algorithm. New ground heat algorithm provides smooth transition from cryogenic to non-cryogenic cases; the algorithm now uses 10-second time steps.
• Discontinued AlohaSpy companion program that allowed users to take a screen capture of ALOHA to refer to at a later time. (Opening ALOHA save files in planning mode replaced and improved on this functionality.)
• Removed options to manually update program windows and to update only the front window.
• Minor changes and bug fixes.

ALOHA 5.2.3 (Summer 1999)

• Improved Direct Source. Now ALOHA allows you to more easily model venting of an indoor puddle (by allowing you to enter release rate of an evaporating vapor at ambient pressure in volume units).
• Improved pipeline predictions. ALOHA now predicts the magnitude of the initial drop in release rate from ruptured pipes connected to large reservoirs.
• Developed cross-platform ALOHA save files (files saved on a Macintosh can be used in Windows and vice versa).
• Created a Fat Binary version for Macintosh users; there is no longer a math coprocessor version.
• Eliminated ChemManager; changes to the chemical library now can be made from within ALOHA.
• Removed DIPPR physical property values from view, by request from DIPPR developers.
• Minor changes and bug fixes.

ALOHA 5.2.2 (Fall 1997)

• Corrected a problem in ALOHA 5.2.1 that prevented ALOHA from receiving SAM data.
• Minor changes and bug fixes.

ALOHA 5.2.1 (Winter 1996)

• Refined algorithm for predicting two-phase flow from a tank.
• Corrected an erroneous value used in ALOHA 5.2 for the surface tension of ammonia. (The error caused overestimation of the rate of release of ammonia from a pressurized tank.)
• Minor changes and bug fixes.

ALOHA 5.2 (Fall 1995)

• Revised ALOHA's heavy gas module so that the heavy gas footprint is always ALOHA's best guess, rather than an overestimate. Previous versions overestimated heavy gas footprints for pressurized and/or short-duration releases.
• Refined some of ALOHA's computations as a result of testing. In particular, the equations used to predict puddle evaporation, two-phase flow, and heavy gas dispersion were modified.
• Modified ALOHA to require the wind speed measurement height, and to adjust its computations accordingly. Previous versions expected wind speed to have been measured at a height of about 3 meters (about 10 feet).
• Modified ALOHA to automatically pick a stability class, once you have entered values for wind speed, cloud cover, and time of day.
• Modified Direct Source to allow you to choose the duration of a continuous release, if it lasts for more than 1 minute and less than 1 hour.
• Updated and extensively revised ALOHA's on-screen helps, alerts and dialog boxes, and manual.
• Replaced BitPlot with MARPLOT for Windows.
• Minor changes and bug fixes.

ALOHA 5.1 (Fall 1992)

• Released first Windows version of ALOHA.
• Moved complex mapping functions out of ALOHA into the new mapping program, MARPLOT.
• Included AlohaSpy, a companion program that allows you to archive ALOHA results.
• Added carcinogen warnings to the chemical library.
• Revised ALOHA's equation describing subsonic flow of pure gas from a ruptured tank.
• Refined ALOHA's checks for inappropriate combinations of wind speed, cloud cover, and stability class.
• Modified the Conc & Dose dialog box to allow you to specify a location in either wind-relative or absolute coordinates.
• Updated ALOHA's on-screen helps, alerts and dialog boxes, and manual.
• Minor changes and bug fixes.

ALOHA 5.05 (Fall 1991)

• Corrected ALOHA to allow it to receive data transmitted from Weatherpak portable meteorological stations.
• Minor changes and bug fixes.

ALOHA 5.0 (Fall 1990)

• Rewrote ALOHA in C.
• Added time-dependent Gaussian and heavy gas dispersion algorithms.
• Added source strength algorithms to predict releases from leaking tanks and ruptured gas pipelines.
• Enhanced pool evaporation algorithms.
• Upgraded ALOHA to predict infiltration of pollutant gases into buildings.
• Minor changes and bug fixes.

ALOHA 4.x and Earlier Versions

ALOHA was first written in Basic for the Apple II+ in the early 1980s as a passive gas plume model for in-house use by NOAA during emergency responses. It was rewritten in FORTRAN for the Apple Macintosh in the mid-1980s. A chemical property library, meteorological station serial port interface, and base-mapping were added at that time, and an energy-balance pool evaporation algorithm was added in the late 1980s.

Go to the ALOHA overview page.