Consequence modelling of hazardous releases 

When evaluating the risks at an installation with toxic or flammable substances, it is necessary to estimate how far ranging the consequences of an accidental release would be.

COWI has the expertise and the tools to identify scenarios and to model the relevant sequences in the development of an accident:

• Release rate of gases, liquids and two-phase mixtures
• Dispersion of dense, neutral and buoyant gases, evaporation from spills, flash vaporization from a two phase release
• Ignition probability as a function of time and the activities in progress
• Jet fires, flash fires, vapour cloud explosions, BLEVEs
• Dangerous doses of heat radiation, smoke and toxic gas. The effects of explosion overpressure
• Vulnerability of persons, equipment and structures
• Prevention of escalation by fire walls, or explosion venting arrangements or other measures 
• Computerized fluid dynamics (CFD), modelling of gas or smoke concentration under special conditions

Software for modelling

In addition to the calculation models developed in-house, the software we use includes PHAST Professional, GReAT, HYSYS, FLOWmaster, WinVent, Star CD and Kameleon.

COWI has developed OffCalc, a system for standardized consequence modelling of hydrocarbon releases on offshore installations. OffCalc is used on each section of the process and estimates the ignition and explosion probabilities as well as the consequences of releases from large, medium and small holes.