HazId

HazId studies in the industrial sector are used to assess, in a semi-quantitative way (risk matrix), the major risks related to a site or to a single plant.

Eidos experience in Refinery field suggests that HazId is too coarse method to be used extensively alone. HazId works better as a preliminary screening method mated with other more exhaustive methods (HazOp, API RP581, Case histories, Random rupture, etc.) to rightfully evaluate the residual risks. When time or resource constraints command just HazId analysis, Eidos suggests a hybrid method that joins the HazId top-events identification with a full quantitative risk quantification (fault trees – event trees – consequences calculation – risk evaluation and mitigation).

Eidos suggests the use of HazId in refinery field during the following phases:

• the screening phase of a refinery safety assessment to identify the units to be investigated with HazOp analysis (this is an alternative approach to DOW index or derivative)
• the preliminary verification, required by Management of Change system, that a proposed modification will not impact on the “no-increase of risk” policy. For further details please refer to Plant Safety
• the feasibility phase of a new project to help the customer assessing the safety before committing the engineering.
• the screening phase of a refinery domino effect risk analysis to identify major source accidents when a complete site safety review is not requested by the customer.