The latest software version v13

What’s new in EFFECTS v13

EFFECTS v13 introduces substantial modelling enhancements that improve accuracy, broaden applicability, and support a more realistic representation of real-world scenarios. The update focuses on three pillars: indoor ventilation, dispersion and overpressure, enhanced long-pipeline release modelling, and a refined outdoor dispersion model, all designed to give safety and risk professionals stronger predictive capability and higher confidence in results.

1. Indoor Ventilation, Dispersion & Overpressure Modelling

A completely new model that enables simulation of gas leaks, accumulation, ventilation behaviour, and overpressure inside buildings.

What technical improvements does this bring?

• Predicts gas accumulation, layer formation, stratification, and mixing dynamics.

• Supports both natural ventilation (through vents and windows) and mechanical ventilation systems (HVAC), in accordance with ATEX 60079 requirements.

• Models gases across the full spectrum: buoyant, neutral, dense.

• Calculates indoor overpressure when ignition occurs.

• Links indoor scenarios directly to outdoor dispersion, enabling indoor–outdoor chains.

Practical applications

• Allows realistic assessment of indoor leak hazards, including accumulation risks in workshops, technical rooms, battery rooms, compressor buildings, control rooms, etc.

• Supports screening studies and rapid evaluation of many indoor cases to identify those that require CFD.

• Helps optimise ventilation design, leak management strategies, sensor placement, and emergency procedures.

• Provides validated predictions based on experimental datasets (e.g., CO₂ dispersion and hydrogen release experiments).

This is the most significant expansion of modelling capability in v13. For detailed information, see the validation report available for all EFFECTS users in our download centre.

2. Improved Two-Phase Releases from Long Pipelines

This update introduces an enhanced Liquefied Gas from Long Pipeline model, building on the existing capabilities of EFFECTS. The original model already included advanced features such as buried pipeline modelling with crater formation, heat transfer between the wall and the fluid, modelling beyond the CO₂ triple point, and support for both full and partial ruptures within a single configuration. The new improvement further increases the accuracy of results for small-hole leaks and full-bore ruptures, especially for high-pressure liquefied systems such as CO₂ and LPG.

What technical improvements does this bring?

• More accurate simulation of small leaks (<20% of pipe cross-sectional area (CSA)).

• Enhanced modelling of high-pressure effects for compressed liquids during full-bore rupture.

• Captures both:

  • Unchoked incompressible liquid outflow

  • Choked liquid flow regimes

• Enhances alignment with experimental datasets for full-bore failures.

Practical applications

• Provides more realistic predictions for pipeline QRA, including CO₂ transport, ammonia, LPG, and other two-phase pipelines.

• Reduces uncertainty in high-pressure release scenarios relevant to CCUS, midstream transport, and industrial transfer lines.

• Supports better planning of pipeline routing, isolation distances, and emergency response.

For detailed information, see the validation report available for all EFFECTS users in our download centre.

3. Improved Outdoor Dispersion Model

Version 13 also brings important enhancements to the Dispersion model, improving accuracy, consistency, and flexibility across a wide range of release and environmental conditions. All dispersion-related improvements are designed to work together so you can model realistic jet and cloud behaviour with fewer work-arounds and less conservatism.

What technical improvements does this bring?

• New “user-defined window” release type.

  • A versatile new release type enables seamless coupling between the new Indoor Ventilation, Dispersion and Overpressure model and the outdoor Dispersion model. This is particularly valuable for low-speed releases and building-wake simulations, where gas exits through openings such as windows or vents. Users can define window dimensions corresponding to the building’s cross-section to more accurately represent airflow and entrainment effects when gas moves from an indoor space to the outdoor environment.

• Refined coupling between the turbulent jet and the dispersion region. This results in:

  • Smoother, more consistent transitions across varying wind speeds and release conditions.

  • Effect distances, such as the Lower Flammable Limit (LFL), are calculated with higher precision and improved realism, generally leading to less conservative flammable cloud extents.

  • Enhanced treatment of ground-affected turbulent jets, further improving predictive accuracy for near-ground releases.

• Optimised vertical jet release.

  • Vertical releases of heavier-than-air gases, such as cold methane, now produce smoother and more physically accurate trajectories. These improvements ensure reliable results across all vertical jet scenarios, increasing the realism and credibility of vertical vent, relief, and stack discharge simulations.

Together, these enhancements provide a more robust dispersion framework, supporting both standalone outdoor releases and complex indoor–outdoor scenarios. For detailed validation information, see the validation report available for all EFFECTS users in our download centre.

How to access the update

Existing users can download the new software update and model documentation by clicking on the button below.

If you need any assistance, our customer support team is here to help all EFFECTS users.