Developing hydrogen codes and standards is challenging because the relevant models and information span multiple science and engineering disciplines. The Hydrogen Risk Assessment Models (HyRAM) toolkit integrates state-of-the-art models and data for assessing hydrogen safety. HyRAM provides a common platform for stakeholders conducting quantitative risk assessment and consequence analysis for hydrogen systems.

The resulting information provides the scientific basis to ensure code requirements are consistent, logical, and defensible.
The HyRAM toolkit integrates deterministic and probabilistic models for quantifying accident scenarios, predicting physical effects, and characterizing hydrogen hazards’ impact on people and structures. HyRAM incorporates generic probabilities for equipment failures and probabilistic models for heat-flux impact on humans and structures, with computationally and experimentally validated models of hydrogen release and flame physics.

The HyRAM software is available under an open source license.




Downloads, source code, documentation, and more information:



  • Quantitative Risk Assessment (QRA) Mode
    • User-defined hydrogen system
      • Pipe sizes, pressures, components, fueling dispensers, facility occupants
    • Risk metrics
      • Overall risk metrics, scenario-specific metrics, cut sets, plots of heat flux on occupants
    • Save and reload different systems
  • Physics Mode
    • Unignited gas jet plume
      • Concentration map and contours
    • Accumulation/overpressure
      • Time-histories of accumulation of release in an enclosure
    • Jet flame
      • Temperature and heat flux maps
  • Engineering Toolkit
    • Temperature/pressure/density relationships
    • Tank mass/volume calculations
    • Steady and transient flowrate through an orifice
    • TNT mass equivalence


Sample HyRAM output:

Risk Metric Value Unit
Potential Loss of Life (PLL) 1.246E-005 Fatalities/system-year
Fatal Accident Rate (FAR) 1.580E-002 Fatalities in 10^8 person-hours
Average Individual Risk (AIR) 3.160E-007 Fatalities/year





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