Auditory Hazard Assessment Algorithm for Humans (AHAAH)

Auditory Hazard Assessment Algorithm for Humans (AHAAH)

Modern weapons and a broad spectrum of industrial machinery produce intense acoustic impulses that can make them unsafe, limit their use, or restrict their design. Recent studies indicate that all current noise exposure standards and design guidelines for impulse generating weapons are seriously in error. To overcome these limitations, ARL's Human Research and Engineering Directorate (HRED) developed a mathematical model of the human auditory system that predicts the hazard from any free-field pressure and provides a visual display of the damage process as it is occurring. The model is a powerful design tool that shows the specific parts of the waveform that need to be addressed in machinery and weapon design. This unique model is the only method of assessing noise hazard for the entire range of impulses that are relevant to the Army. The model has the potential to serve as an international design standard for weapons and to provide damage or risk criteria for intense impulses of industrial origin.



  • Click here for the Web application version of the AHAAH model.
  • Click here for the ZIP (beta release W93e) of the AHAAH model.
  • Click here for the ZIP (v2.0) of the AHAAH model proposed for use with Military Standard 1474E: Design Criteria Standard - Noise Limits.

* The draft version of MIL-STD-1474E: Design Criteria Standard-- Noise Limits has not been approved for use and is subject to modification.
* An ARL Technical Report entitled: "Using the Auditory Hazard Assessment Algorithm for Humans (AHAAH) with Hearing Protection Software, Release MIL-STD-1474E" has been published.

Response to Technical Issues

Scientific Basis for the Model

Technical Reports

Support for Peer Review


Last Update / Reviewed: June 7, 2013