A Look into Cumulative Risk Assessment: Past, Present and Future

S. Zohra Halim, Yogesh Koirala and M. Sam Mannan

Mary Kay O’Connor Process Safety Center

Artie McFerrin Department of Chemical Engineering

Texas A&M University

College Station, Texas 77843-3122, USA

zohrahalim@tamu.edu; +1 (979) 676-7504

The effort towards carrying out quantitative risk analysis in today’s sizeable facilities has mostly been focused on considering technical safety systems with little emphasis given to human errors. The consequences from the cumulative effect of a number of deviations that arise from equipment, procedure or a person not doing an assigned work properly can become catastrophic. In order to assess the total risk, we need to consider technical, operational, human and organizational factors together. This paper provides a comprehensive review of past attempts and progresses made at bringing all of these factors together into one risk assessment framework based on leading articles published in various journals. A comparative study has been carried out in an attempt to distinguish between the approaches based on whether they are qualitative, semi quantitative or quantitative and if they address the complexity and size of the systems, temporal aspects and dependencies of components and uncertainties of parameter estimation. The paper aims at providing a direction for future research towards better assessment of cumulative risk in today’s chemical plants.