FLACS CFD Software
A Gexcon X Suite Product

Explosion & Dispersion Modelling Software

Our powerful industry-leading computational fluid dynamics (CFD) software simulates the dispersion of hazardous materials, fire, and explosion with results that you can trust.

Designed for ease of use and multiple environments, FLACS-CFD represents more than 40 years of extensive and unrivalled modelling and validation work based on real-life testing.

FLACS-CFD is a suite of 3D computational fluid dynamic tools with a series of standard modules and additional bolt-ons designed to meet specific requirements. These can be leased separately or as a package and are effective for a wide range of users including facility operators who require quick answers to engineering questions through to consultants who need to perform large in-depth risk studies. All licence holders receive full training on how to use the software.

With continuous development and investment, FLACS-CFD helps raise the true level of safety for complex industrial environments.

FLACS-CFD 20 is now live

FLACS-CFD 20 is now available and has been re-written from the ground up to offer better integration and digitalisation capabilities, improved workflows, and greater flexibility than ever before.



New key features and benefits

Wider field of application
Models flammable and toxic release scenarios for approximately 1,800 chemical components based on the DIPPR database.

Improved 3D visualisations
Improved aesthetics and functionality of geometry modelling and now more than 10 CAD import formats.

Quicker results
Simulations are now up to 20 times faster using the new steady-state solver and porosity calculator.


Detailed functionality

  • Efficient set-up of scenarios/simulations
  • Features all environmental conditions
  • Includes effects of real geometries
  • Includes various mitigation measures
  • Comprehensive user guidelines based on extensive validation against experiments
  • Available for both Windows and Linux
  • Dedicated FLACS-CFD 20 training and help desk


Book a webinar

We are currently hosting a programme of webinars to show FLACS-CFD 20 in action. For webinar dates visit our Events page.

The webinars will demonstrate how the software can be used for a wide variety of  tasks including:

  • Offshore and onshore
    explosion studies
  • Design Load Calculations
  • Siting studies
  • Gas detector optimisation
  • Toxic dispersion calculations
  • Dust explosions
  • Jet and pool fire modelling
  • High explosive blast modelling
  • Quantitative Risk Assessment
  • Accident/incident investigation

High performance graphical user interfaces for setting up scenarios, CASD, and post-processing the results, FLOWVIS, makes FLACS significantly faster than other CFD tools. Users can easily import CAD from a large range of formats and view results in a high-quality 3D output.

FLACS-GasEx and FLACS-Dispersion
These modules form the core of FLACS-CFD and are used extensively to understand the consequences of an explosion in complex and large scale industrial environments. They allow the user to model the release and dispersion of a gas/vapour and model an explosion to support risk assessment and design processes.

FLACS-Hydrogen allows the simulation of hydrogen dispersion and explosions.

It is a valuable tool to evaluate the risk connected with the use of hydrogen as an energy carrier.

As a limited version that only allows the simulation of hydrogen dispersion and explosions, FLACS-Hydrogen has a lower price entry point to users from those industries.

FLACS-Hydrogen models:

  • Flame propagation and pressure build-up due to hydrogen explosion
  • Propagation of blast waves
  • The release and subsequent dispersion of hydrogen

FLACS-DustEx allows the simulation of industrial dust explosions.

This is a valuable tool for engineers designing facilities, especially when optimising mitigating measures such as venting devices, suppression systems or explosion barriers.

It remains the only CFD tool able to model industrial dust explosions.

FLACS-DustEx models:

  • Flame propagation and pressure build-up due to organic dust explosions.
  • Pressure-piling in interconnected vessel systems
  • Can include effect of various mitigation measures (e.g. explosion venting devices)
  • External blast waves
  • Dust lifting by flow or shock waves and secondary explosions
  • Dispersion of dust in system

The FLACS-Fire module adds jet and pool fire modelling.

The tool is used both to evaluate the risk associated with industrial fires and to provide input into design, such as the design of passive fire protection.

FLACS-Fire is highly regarded due to its ease of use and integration into the wider fire-explosion assessment through the other FLACS-CFD modules.

FLACS-Fire models:

  • Accurate and efficient transient modelling of combustion and heat radiation in complex geometries
  • Full 3D CFD and radiation ray-tracing model
  • High and low momentum flow jet-fires
  • Pool fires
  • Includes “solid flame” model for quick screening simulations

FLACS-Blast is a special variant of FLACS that simulates the propagation of blast waves arising from the detonation of condensed-phase explosives.

The tool, previously known as FLACS-Explo, is currently being used by clients for security applications.

FLACS-Blast can also be used to consider events such as ammonium nitrate explosions.

FLACS-Blast models:

  • Propagation of blast waves arising from the detonation of condensed-phase explosives
  • Modelling of TNT sources
  • Modelling of RDX sources

Resulting blast wave from ammonia nitrate explosion (336 tonnes TNT equivalent).


FLACS-Risk allows efficient 3D CFD risk modelling and visualisation.

The tool provides an efficient interface to perform both risk-based and non-risk-based parametric studies.

FLACS-Risk models:
  • Parametric set up for ventilation, dispersion, fire and explosion modelling
  • 3D visualisation of risk to efficiently communicate and improve risk-owners understanding of safety issues
  • UKOAA ignition model for fire
  • OLF time dependent ignition model for explosions

FLACS-Cloud/HPC provide users with access to a High-Performance Compute facility in partnership with the EPCC.

It allows users to perform high volumes of simulations without having to invest in local computing power.

FLACS-Cloud/HPC offers:

  • Simple easy to use solution driven by a Graphical User Interface (GUI).
  • Provides command line/expert access.

The FLACS User Group (FLUG) is a discussion forum for global enterprise leaders, experts and industry scholars.

It usually meet twice a year and topics include information about new software developments, user presentations and general discussions about safety-related topics.

Details about the next meeting of FLUG can be found in our events calendar.


FLACS I Course

Dispersion, Fire and Explosion Modelling Tool


Trusted, powerful and comprehensive industrial safety simulation

FLACS-CFD Technical Requirements

FLACS-CFD is delivered for Microsoft Windows and for Linux

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