HAZard & OPerability(HAZOP)& Quantitative Risk Assessment(QRA) Study for Digboi Terminal

Indian Oil Corporation Limited proposed to conduct the Hazard and operability study (HAZOP) and Quantitative Risk Assessment(QRA) Studies for methanol blending facility and vapour Recovery unit at Digboi Terminal.


A Hazard and Operability (HAZOP) study is a structured and systematic examination of a process or operation to identify and evaluate problems that may represent risks to personnel or equipment, or environment. The Scope of HAZOP includes all process and utility P&IDs forming the scope of the project, all interface P&IDs, Operating and control philosophy, vendor data. It is conducted to examine the overall process design, searching for operating deviations and process interactions that can lead to hazardous situations or operability problems. This can be useful to bring about safety improvements at the Design stage itself in particular and also is effective in ensuring that the plant modifications do not ignore safety aspects.

QRA Study

QRA study determines the risks to personnel working in the facility. The study comprises of a number of distinct tasks as follows:

Collection of data and review of project documents
Identifying potential hazards through HAZID reports
Developing QRA methodology and assumptions report
Assessment of consequences including development of incident scenarios using Event Tree Analysis (ETA)
Failure frequency analysis
Risk evaluation and integration
ALARP demonstration
Provision of Risk Reduction Measures (RRMs)
Preparation of QRA report for project scope