Houston: To protect against major fires on oil and gas platforms, the detailed design of safety systems can now be carried out using a new optimisation method developed by DNV. Critical safety systems, such as flares and passive fire protection, are optimised using a detailed fire risk analysis and computational fluid dynamics fire simulations.

Traditional standard design heat assuming a constant heat load for a certain duration – such as 250 kW/m2 for 15 minutes – are general and, in most cases, far too conservative. This may mean that structures and pipes are protected using too much passive fire protection, which can lead to increased corrosion, cost and weight.
Asmund Huser, DNV Energy’s expert in this field, explains that the new method developed by DNV is more detailed than traditional methods.

“For particular fires, the fire loads may also be more severe than the traditional standard heat loads. These variations from smaller to higher heat loads are captured in the analysis, ensuring that the total safety level is increased compared to traditional methods in a cost-effective manner,” he points out.

“Owners can now choose where measures should be implemented in order to achieve the best possible safety for their investments.”

Results from the analysis also show the design accidental loads for fires, as well as escalation probabilities.
The complex, dynamic behaviour of fires has posed special challenges when establishing the method. This has now been thoroughly studied, using detailed computational fluid dynamics calculations on several platforms in a development project started in collaboration with Statoil in 2001.

The optimisation service is offered using two computer programs developed by DNV: DNV ExpressFire and DNV PFPro.