ALOHA Development History

Over the years, ALOHA has changed and evolved. Here's a list of the most significant modifications to the program, starting with the most recent.

ALOHA 5.4.1 (Winter 2007)

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

ALOHA 5.4 (Winter 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 (Boiling Liquid Expanding Vapor Explosions).
  
• 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 CAMEO.
  
• Removed interim AEGLs from ALOHA.
  
• Updated DIPPR (Design Institute for Physical Properties) 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 (Station for Atmospheric Measurements) 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.