We are in the process of completing our final acceptance testing of Phast v6.53, with many new features and enhancements.

This is the first Phast release to include multi-component dispersion capabilities, in addition to improved automation of
toxic concentration calculations. It will be available to all maintained customers by the end of May.

The lead article and editorial in the previous issue of DNV Software News described how Safeti has been adopted as the family brand for all our products and solutions in the process industries. In order to facilitate this alignment, Phast has been selected as the name for the product suite which previously included the Phast and Safeti products. Current
products in the Phast package are:

• Phast Risk (formerly Safeti)
• Phast Risk Micro
• Phast Professional
• Phast Micro and PhastFX

With Financial and Multi-Component extensions available for Phast Professional, Risk Micro and Risk.

Since releasing Phast 6.51 in April 2006 and Phast 6.52 for the Financial extensions to the products in June 2006, we have been developing the Phast application in two main areas. The first of these is multi-component modelling for much improved accuracy of discharge and dispersion of mixtures. The second is improved modelling of risk from explosions, using the TNO Multi-Energy model and the Baker Strehlow Tang model. In addition to these major enhancements of the program, we have been working on many minor enhancements. A number of these parallel development projects are nearing completion, although we will not finish the enhancements of the explosion modelling until early next year. This program of work was originally planned for release as Phast 6.6. However, in order to minimise the wait for the completed projects, we have decided to issue an interim release, Phast v6.53. This is due for completion imminently; the new features included are described in more detail below.

Multi-component modelling
The phased development of multi-component modelling continues with this new version of Phast. Following implementation of the new property system in the previous version, work has continued to introduce the capability of modelling multi-component discharge and dispersion. This will be restricted to cases that do not rain-out in this release, but development of this significant piece of work continues; updates on future developments will follow later this year. The first phase includes:

• Discharge calculations for leaks, line ruptures, relief valves, disk ruptures, catastrophic ruptures and vent from vapour space
• Dispersion of vapour, two-phase and liquid releases which do not rain-out. For two-phase and liquid releases, the new discharge modelling will predict component separation between liquid and vapour phases
• New reports of phase compositions after discharge and during dispersion.

Limitations:

• Does not currently model rain-out, so no pool modelling
• The time varying discharge, long pipeline, in-building and tank roof collapse scenarios, and the user-defined
  model are not yet supported.

Automated averaging time adjustment
We have added an option to select the exposure duration to be used as the averaging time without the need for user intervention. This allows toxic effects that are integrated over time to use the matching averaging time. It also better aligns with current guidelines provided in the regulations used in France. Using this option, the exposure time may simply match the release duration for non-quasi-instantaneous single-segment continuous releases. Alternatively, for instantaneous, multi-segment and quasiinstantaneous releases, the exposure times can vary with downwind distance and elevation. There are new parameters controlling the start and end of the exposure period, and new graphs and reports for exposure time. The adjusted concentrations are used to calculate toxic effects; these are used in any subsequent risk calculations. In addition to these two major enhancements in Phast, there are many others which are described in detail in the release notes.

Some of the more useful enhancements are:

• Improvements to fire modelling with the ability for users to define their own Surface Emissive Power for jet fires, use the ‘DNV Recommended’ models which will automatically select the most appropriate jet fire model for a given situation and define their own material properties and emissivity for pool fires
• Updates to the pool fire materials data to provide improved compatibility with latest literature
• Improvements to the route model with the ability to define routes using polylines, have multiple routes in a single study folder, and improved smart-run
• Addition of relative coordinates as an alternative way to define the location of objects in the risk version
• Improvements to spreadsheet features, with the ability to export to as well as import from spreadsheets and create multiple folder levels in spreadsheets
• New version of reports component with more flexible reports, including export to third-party applications and file formats, and much better copy-and-paste capabilities

A number of graphing improvements, including radiation against distance plots for linked flammable models in the risk versions, better facilities for setting graph defaults such as line thickness and style, ability to display areaunder cloud and maximum footprinton legend, rotation of maps, and more intelligent weather selection.

Author: Nic Cavanagh
Safeti Product Marketing Manager