Increasing safety concerns on offshore Oil and Gas facilities have been greatly influenced by several critical accidents over the past 15 to 20 years. As a consequence of the Piper Alpha disaster and other less major incidents, design approvals of fire and loss protection systems are receiving much stricter attention than in the past. Several design approaches are available based on simplified codes such as British standard BS5950–8, using load ratios and strength reduction factors or more advanced methods that utilize non-linear finite element analysis. Alternatively standard model experimental tests can be conducted in accordance with ASTM E119. For structural design against explosion two approaches are also available based on a single-degree-of-freedom (SDOF) model or non-linear finite element analysis. As in the case for fire design, more comprehensive material data relating to dynamic response in the elastic and plastic regime other than simple yield strength ratios is required. For other high strain rate loading events such as earthquakes the analysis must consider the nonlinearities in material modeling and geometry, such as local buckling and global instabilities. The paper discusses the application of these models for fires, explosions and earthquakes with the subsequent effect on quantitative risk assessment (QRA), fire protection design and actual structural performance for materials in offshore installations. In conclusion, some of the research issues and needs are detailed with respect to current challenges that require experimental testing to calibrate the complex analytical models.
The North Sea Piper Alpha platform incident in 1988 changed the HSE culture of offshore installations forever. This tragic accident claimed the lives of 167 people through a cascading effect that showed how an accidental release of a liquid or gaseous hydrocarbon could lead to the catastrophic failure of a major installation.
