What is DRIFT?

DRIFT (Dispersion of Releases Involving Flammables or Toxics) is an advanced gas dispersion model for modelling the extent of accidental releases of hazardous fluids.  DRIFT has been developed in association with the UK Health and Safety Executive (UK HSE) who use it to carry out major accident hazard (MAH) gas dispersion assessments.

DRIFT 3 incorporates a considerable number of modelling enhancements following the recommendations in HSE Research Report RR629 over DRIFT 2.

DRIFT is capable of modelling:

  • Dense Gas Dispersion
  • Buoyant lift-off and rise
  • Momentum jets (including crosswind effects)
  • Instantaneous (Catastrophic) Releases
  • Low Momentum Area Sources (e.g. vaporising pool surfaces)
  • Continuous (steady state), finite duration and time-varying releases
  • Thermodynamics of multi-component mixtures
  • Complex behaviour of Hydrogen Fluoride dispersion

DRIFT 3 also incorporates an interface to ESR Technology’s pool vaporisation model GASP.




Why choose DRIFT?

  • Developed for the UK HSE, the model has undergone extensive verification and validation testing.
  • DRIFT 3 is coded for speed and efficiency, producing reliable results in seconds.
  • Features both a comprehensive graphical user interface and a Component Object Model (COM) interface to allow the model to be batch run directly from Excel spreadsheets.
  • Highly customisable input and outputs. Includes support for user defined fluids, consequence levels, result tables and graphs.
  • Obtain results at a user chosen time of interest, receiver height and for persons indoors and outdoors.


Who uses DRIFT?

We have licensed DRIFT to a wide variety of organisations since its initial release in the 1990s.  Typical users include:

  • Safety and Risk Consultants
  • Regulators
  • Operators
  • Academic Institutions


Model Validation

DRIFT has been validated against a range of experiments including URAHFREP (hydrogen fluoride) and Jack Rabbit II (Chlorine) - pictured below

Jack Rabit II 1100px 

A full list of published papers relating to DRIFT is available here, which includes the following: 


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