With significant improvements to rainout and dispersion modelling and new capabilities for explosion risk and occupied building analysis

We are pleased to announce that Phast v6.6 is now released and available for download from the Safeti Support web-site. This is the most comprehensive upgrade to Phast and Phast Risk since v6.2 and includes many improvements for those interested in consequence modelling and risk analysis.

Improvements to Phast
This release brings to the market the combined benefits of many years R & D in the areas of droplet and rainout modelling, pool vapourisation modelling and dispersion from pools and improved modelling of the behaviour of Carbon Dioxide.

Over the last few years we have managed a number of Joint Industry Projects to improve the modelling of rainout. The most recent of these, on flashing and sub-cooled liquid releases, has provided improved correlations to characterise droplet size and size distribution. This new correlation is a major advance in Phast v6.6. In addition, we have made some significant improvements to the dispersion modelling. The new UDM, available in Phast v6.6, improves the modelling of droplets inside the cloud and the evaporation of vapour into the dispersing cloud following rainout. It also gives greater control over the time-steps at which dispersion results are reported and includes improved modelling of Carbon Dioxide to take account of post expansion solid effects.

Other improvements in Phast include:

• Long Pipeline Model - Compressibility effects are now considered; at very large pressures this may significantly increase the mass of material released
• Time Varying Discharge - The robustness of the thermodynamic calculations has been improved and the calculations now include the ability to model systems containing vacuum relief valves
• Export Results to Excel - This new feature allows you to export a wide range of consequence results to Excel and can be useful for exporting results for multiple concentrations of interest to a spreadsheet for graphing and results comparison
• Excel Import and Export - All new objects and several previously unhandled objects can be exported to and imported from Excel
• Convert Case List to Model - You can convert case lists to equivalent models using this new feature which can prove extremely useful when re-structuring studies or using spreadsheet import/export

Improvements to Phast Risk
Phast Risk users can now purchase an extension providing advanced capabilities for assessing risks from vapour cloud explosions in obstructed regions. This new 3D modelling takes account of the confinement and congestion due to process equipment into which a flammable release disperses. The Multi-Energy Method and Baker-Strehlow-Tang Model have been implemented within the extension, both of which are widely accepted for calculating effects from gas explosions. Using this extension provides increased accuracy and transparency when calculating risks from vapour cloud explosions. Account is taken of the interaction between the dispersing cloud and regions of congestion and confinement, providing estimates of the overpressure and impulse generated if the cloud is ignited within an obstructed region. More information is provided in the Phast Risk - 3D Congested Explosion - Technical Sheet.

The risk calculations also take into account buildings and occupant vulnerability. You can define multiple sets of vulnerability parameters, representing the relationship between effect level and fatality-probability for different groups of people. More information on the new building definition capabilities is provided in the Phast Risk - For Occupied Buildings and Land Use Planning - Technical Sheet.

Typical Static Pressure Exceedande Curves

Typical Exceedance Contours for 2 building types and effect levels

Phast Risk v6.6 with the Extended Explosion modelling is able to provide much more accurate prediction of the probable explosion damage and resulting lethality.

Phast Risk v6.6 also includes a new reporting module which provides powerful graphing and data drill-down capabilities for detailed analysis of risk results.

This gives much more transparency and a number of new reports including:

• Drill-down on FN Curve to identify key contributors to risk within each fatalaity range
• Report a range of risk metrics including FAR, N, RI values by area and population category

In addition, if you have licensed the Extended Explosion Modelling you can also:

• Filter and group all results by building type
• Produce Exceedance Curves for Overpressures or impulse at ranking points
• Contour risk to any effect level or combination of effects, so-called exceedance contours