AI Quick Summary

Compare consequence and QRA software by the decision you need to make—not a brand name. Learn where detailed modelling, screening tools and independent review fit.

QRA Software Tools: How to Choose the Right Modelling Approach

Quick answer: start with the decision. Use a detailed, documented consequence/QRA workflow for a safety report, site-layout or land-use decision; use a screening tool for training or a rapid planning estimate; and have a competent reviewer challenge scenarios, assumptions and outputs. Software supports engineering judgement—it does not make a weak basis defensible.

Choose the approach before choosing a tool

Decision Minimum capability Typical approach
Emergency drill or initial screening Transparent consequence estimate and stated limitations ALOHA or a comparable screening method
HAZOP follow-up or design comparison Repeatable release, dispersion, fire and explosion modelling Detailed consequence modelling with documented inputs
Formal QRA, site layout or land-use decision Scenario frequencies, consequence outputs, risk aggregation, review trail Full QRA workflow with independently reviewable assumptions
Complex congestion, confinement or geometry Model appropriate to the phenomenon and geometry Specialist analysis; do not extrapolate a simple model beyond its limits
Serious QRA work is not a spreadsheet exercise. It needs documented scenarios, credible frequencies, meteorology, model version, assumptions, sensitivity checks and an engineering review.
In this review we compare the main tools you will see in South Africa and abroad:
  • DNV PHAST/Safeti – industry standard and our primary tool.
  • Gexcon EFFECTS/RISKCURVES – strong European alternative.
  • ALOHA – free tool for quick checks, with clear limits.
  • Other tools – FRED, Canary, SuperChems.
    We also cover:
  • Why licences, versions and model capability must be confirmed with the supplier and project team.
  • How to build a reviewable basis for an MHI assessment.
  • How to choose the right tool for your project.
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    Free Resource: Need a fast breakdown to share with your team? Download our branded QRA Software Tools Comparison Guide.

1. DNV PHAST & Safeti (The Industry Standard)

Developer: DNV (Det Norske Veritas)
Status: The Global Market Leader
Website: dnv.com/software
If you walk into any major oil & gas company (Shell, BP, Sasol, Chevron), they are likely using PHAST (Process Hazard Analysis Software Tool) and Safeti.

What It Does

Module Function
PHAST Consequence modelling – discharge, dispersion, fire, explosion
Safeti QRA – combines PHAST results with frequency data to produce LSIR contours and F-N curves
Safeti Offshore Specialised for offshore platforms

Pros

  • Validation: The most extensively validated software in the world. Its Unified Dispersion Model (UDM) is accepted by virtually every regulator.
  • Comprehensive: Handles everything from pool fires to toxic infiltration into buildings. (See our guide on Consequence Modeling for details.)
  • Safeti Integration: Seamlessly calculates risk contours (LSIR) and F-N curves for full QRA.
  • Regulatory Acceptance: Accepted by the Department of Employment and Labour, SANAS-accredited AIAs, and international regulators.
  • Training & Support: DNV offers regular training courses in South Africa (Johannesburg, Cape Town).

Cons

  • Cost: Extremely expensive – annual licence fees can exceed R500 000 for a full Safeti suite.
  • Complexity: Requires a highly trained specialist to drive it. Garbage in, garbage out.
  • Hardware Requirements: Large QRA models can be computationally intensive.

Licensing and support

Software prices, modules, training and support arrangements change frequently. Obtain a current written quote from the supplier and define the required model capability before approving a project budget.

Who Uses It in South Africa?

  • Sasol (Secunda, Sasolburg)
  • Engen, Astron Energy, TotalEnergies (refineries)
  • AECI, Omnia (chemical manufacturing)
  • Anglo American, Sibanye-Stillwater (mining)
  • Major AIAs and consultancies (including MMRisk)
    When it fits: DNV describes Phast as a consequence-analysis tool for discharge, dispersion, fires, explosions and toxic effects; Safeti adds QRA capabilities such as individual-risk contours and societal-risk outputs. Confirm the required modules, model version and acceptance criteria with the project brief and reviewer.

2. Gexcon EFFECTS & RISKCURVES (The European Contender)

Developer: Gexcon (originally TNO Netherlands)
Status: Strong European Presence
Website: gexcon.com/software
Developed by the Dutch research organisation TNO, this software is scientifically rigorous and widely respected, particularly in Europe and increasingly in South Africa.

What It Does

Module Function
EFFECTS Consequence modelling – based on the famous "Yellow Book" (CPR 14E) models
RISKCURVES QRA – calculates LSIR contours, F-N curves, societal risk

Pros

  • User Interface: Generally considered more modern and user-friendly than PHAST.
  • The "Yellow Book": Built directly on the CPR 14E models, which are the bible of consequence modelling in Europe.
  • Visualisation: Excellent 3D mapping capabilities with Google Earth integration.
  • Cost: Typically 20–30% cheaper than DNV PHAST/Safeti.
  • Regulatory Acceptance: Accepted by European regulators (COMAH, Seveso) and increasingly by South African AIAs.

Cons

  • Market Share: Less common in the English-speaking oil & gas world than PHAST.
  • Training Availability: Fewer training courses available in South Africa compared to DNV.

Licensing and support

Ask the supplier for a current scope and support proposal. Budget should also include scenario development, input-data quality, specialist review and time to communicate results—not only the licence.

Who Uses It in South Africa?

  • Some AIAs and consultancies as a secondary tool.
  • European-owned facilities (e.g., some chemical plants).
  • Academic institutions for research.
    When it fits: EFFECTS and RISKCURVES can form part of a detailed consequence/QRA workflow. Confirm the model capability against the release physics, facility geometry and regulatory assessment requirements instead of selecting a tool on price alone.

3. ALOHA (The Free Option)

Developer: US EPA / NOAA
Status: Public Domain (Free)
Website: epa.gov/cameo/aloha-software
ALOHA (Areal Locations of Hazardous Atmospheres) is a free tool designed for emergency responders.

What It Does

  • Models toxic gas dispersion (Gaussian and heavy gas).
  • Models thermal radiation from fires (pool fire, BLEVE).
  • Models overpressure from explosions (VCE, BLEVE).
  • Integrates with CAMEO Chemicals database and MARPLOT mapping.

Pros

  • Free: Accessible to everyone – no licence cost.
  • Fast: Great for a quick "what if" check during a HAZOP study or emergency drill.
  • Easy to Learn: Minimal training required for basic use.
  • Chemical Database: Includes properties for 1 000+ chemicals.

Cons

  • Limited Physics: Uses simplified Gaussian / Heavy Gas models that break down in complex scenarios (e.g., near-field jet fires, two-phase releases).
  • No Risk Integration: Only does consequence (distance), not risk (frequency × consequence). You cannot generate risk contours with ALOHA alone.
  • Not for MHI Reports: Generally not accepted for formal MHI regulatory submissions in South Africa for complex sites.
  • No Multi-Scenario: Cannot combine multiple release scenarios into a cumulative risk picture.

When ALOHA is Appropriate

Use Case Appropriate?
Emergency response planning ✓ Yes
Quick screening during HAZOP ✓ Yes
Training and education ✓ Yes
Formal MHI QRA submission ✗ No
Land-use planning decisions ✗ No
Insurance or legal defence ✗ No
When it fits: EPA and NOAA position ALOHA for chemical-emergency planning and response. Treat its result as a screening estimate, record its limitations, and do not substitute it for a full QRA where the decision requires risk aggregation or complex release physics.

4. Other QRA Software Tools

Shell FRED

Developer: Shell Global Solutions
Status: Proprietary (Shell internal use)
FRED (Fire, Release, Explosion, and Dispersion) is Shell's in-house consequence modelling tool. It is not commercially available but is used extensively within Shell and by Shell contractors.

Quest Canary

Developer: Quest Consultants (USA)
Status: Commercial
Canary is a consequence modelling tool popular in the USA, particularly for LNG and petrochemical applications. Less common in South Africa.

ioMosaic SuperChems

Developer: ioMosaic Corporation (USA)
Status: Commercial
SuperChems is a comprehensive process safety software suite that includes consequence modelling, relief valve sizing, and reactive hazard analysis. Used by some multinational chemical companies.

BowTieXP

Developer: CGE Risk Management Solutions
Status: Commercial
BowTieXP is not a QRA tool per se, but a barrier management and risk visualisation tool. It is widely used in South Africa for Bow-Tie diagram development and integrates with QRA outputs.

5. Software Comparison Summary

Feature PHAST/Safeti EFFECTS/RISKCURVES ALOHA
Consequence Modelling ✓ Comprehensive ✓ Comprehensive ✓ Basic
Risk Contours (LSIR) ✓ Yes ✓ Yes ✗ No
F-N Curves ✓ Yes ✓ Yes ✗ No
Assessment fit Detailed consequence/QRA workflow Detailed consequence/QRA workflow Screening and emergency planning
Commercial model Supplier quote required Supplier quote required Free
Training Required High Medium Low
User Interface Dated Modern Simple
AI / Digital Twin Integration Moderate/Growing Moderate/Growing None
SA Support/Training ✓ Available Limited Self-service

6. Why Software Choice Matters

You might ask, "Why pay for a consultant using expensive software when I can download ALOHA for free?"
The answer is accuracy and defensibility.

Accuracy

Different software tools can produce significantly different results for the same scenario:

Scenario PHAST Result ALOHA Result Difference
Ammonia toxic cloud (IDLH distance) 850 m 1 200 m +41%
LPG pool fire (12.5 kW/m² radius) 45 m 38 m -16%
VCE overpressure (0.1 bar radius) 120 m 95 m -21%
Note: These are illustrative examples. Actual differences depend on scenario specifics.

Defensibility

In a legal dispute or regulator inquiry, the accuracy of your risk contour matters:

  • A contour that is 50 metres too wide could sterilise millions of Rands of land unnecessarily.
  • A contour that is 50 metres too small could put people in danger and expose you to liability.

Cost of Getting It Wrong

Consequence Potential Cost
Land sterilisation (false positive) R10 million – R100 million+ in lost development value
Incident in "safe" zone (false negative) Fatalities, prosecution, R100 million+ in damages
Regulatory rejection of MHI report R100 000 – R500 000 in rework, plus delays

7. How to Choose the Right Tool

For Formal MHI Assessments

Use: PHAST/Safeti or EFFECTS/RISKCURVES
Select a workflow with suitable consequence models, risk aggregation, documented assumptions and competent review. Confirm any AIA, client or regulator expectations before modelling; acceptance depends on the study basis and quality of the analysis, not the software name alone.

For Emergency Response Planning

Use: ALOHA (for quick estimates) or PHAST (for detailed planning)
ALOHA is sufficient for emergency drill planning and first-responder training. For detailed evacuation zone definition, use PHAST.

For HAZOP Support

Use: ALOHA (for quick "what if" checks) or PHAST (for detailed follow-up)
During a HAZOP, ALOHA can provide quick estimates of consequence distances. Detailed modelling should be done post-HAZOP with PHAST.

For Land-Use Planning

Use: PHAST/Safeti or EFFECTS/RISKCURVES
Municipal planning decisions require defensible risk contours. Only use industry-standard software.

Why MMRisk Uses Premium Software

MMRisk selects modelling tools and methods to suit the decision, the release physics, the facility and the required level of review. The key deliverable is a transparent, challengeable study—not a software screenshot.
Before commissioning a QRA, ask for the proposed model scope, software version, scenario register, frequency sources, weather data, sensitivity cases, quality-review process and how results will be communicated to operations and decision-makers.

Conclusion

The choice of QRA software directly affects the accuracy, defensibility, and regulatory acceptance of your risk assessment.
Key takeaways:

  • Match model complexity to the decision and the physical scenario.
  • Use screening tools for screening, and document their limitations.
  • Record software version, inputs, assumptions, sensitivity tests and independent review.
  • Connect the results to consequence modelling, VCE prevention and barrier controls—not just a contour map.

Ready for a Defensible QRA?

Ensure your MHI assessment is conducted using industry-validated software. Contact MMRisk for a study you can trust.
Request a Technical Capability Statement.

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