Inherently Safer Design for Process Plant Piping and Equipment Exposed to Accidental Explosion Loads

Abstract

Recent statistics have indicate that it is not uncommon to have an accidental explosion on an offshore platform. The design and assessment of process piping systems against blast events are of importance and require advanced analysis capabilities. They are important because during an explosion rupture of a piping and vessel system leads to the leakage or release of hydrocarbons which will likely cause another explosion or fire, and can eventually leads to a disastrous event. On an offshore platform where availability of escape, shelter, and evacuation is limited, the consequences are worse because explosion escalation into severe scenarios can have more detrimental effects in addition to direct damages such as injuries, fatalities and asset losses. A safe design should be driven by the ultimate goal of no accidents, no harm to people, and no damage to the environment. In order to have such design for process piping systems, advanced nonlinear analysis is required to properly capture the dynamic response of the piping and vessels subjected to blast loadings. This type of analysis, in general, should take into account (1) Blast drag load and blast overpressure; (2) Nonlinear material properties, i.e. thermal and strain-rate dependence; (3) Effects of non-structural masses and adjacent piping systems; (4) Pipe supports; (5) Failure of flanges and piping detail; (6) Effects of operating temperature on material properties; (7) Blast direction/ignition location/attenuation sensitivity; (8) Shielding effect, e.g. pipes behind large objects such as vessels; and (9) Effects of pipe insulation, i.e. increased pipe diameters. This paper first discusses the methodology/techniques to account for such effects in nonlinear advanced analysis for a safe design. The paper then uses case studies to demonstrate the methodology we developed to show how advanced simulation techniques are applied as tools for piping blast response to minimize the risk of failure. These case studies involve a process piping system that is simulated from global to detailed modeling. The goal of the paper is to discuss how to achieve a safe design for process piping systems by using advanced analysis.