Implementing PSM in the 21st Century

This paper introduces a practical approach to determine the design blast overpressure in the actual plant engineering. Process plants, such as petrochemical plants and refinery plants, handle flammable materials that can and have produced accidental explosions. Occupational buildings in process plants need to be designed to withstand explosion effect in order to protect the people inside, so-called blast resistant design, based on predicted blast loads assuming vapor cloud explosion (VCE). In general, two types of blast load prediction methodology can be applied to the actual process plant engineering. One is blast curve methods and the other is Computational Fluid Dynamics (CFD) modeling. The blast curve methods are based on VCE-specific blast curves developed using one-dimensional numerical calculations. There are two predominant sets of blast curves referred to as Baker-Strehlow-Tang (BST) method and TNO Multi-Energy method. These blast curve methods are simple methodology for VCE and are in widespread use in process industry. However, it is known that these blast curve methods provide conservative blast loads. On the other hand, the CFD modeling is based on the fundamental equations governing turbulent and reacting flows and is capable of providing more detailed description of explosion relative to the blast curve methods. Besides more accurate method for predicting blast overpressure, it requires longer time than empirical and phenomenological explosion models (i.e. blast curve methods) to develop a simulation model, and thus, the CFD modeling is not always reasonable prediction methodology for EPC contract for plant construction. Authors have been conducted blast studies using blast curve methods for several process plants to evaluate the blast resistance of occupied buildings, and developed application procedures of blast curve methods to the actual process plant engineering. This paper introduces those experiences on the application of blast curve methods to the actual process plant engineering, and examines the validity of them. The paper also shows a comparison of blast overpressure estimated by blast curve methods and CFD modeling for discussion.