Guidelines for Initiating Events and Independent Protection Layers in Layer of Protection Analysis

This book will address how the fields of Human Reliability Analysis, Fault Tree Analysis, Inherent Safety, Audits and Assessments, Maintenance, and Emergency Response relate to LOPA and SIS.

The book will separate IPL’s into categories such as the following:

1. Inherent Safety
   • eliminates a scenario or fundamentally reduces a hazard
2. Preventive/Proactive
   • prevents initiating event from occurring such as enhanced maintenance
3. Preventive/Active
   • stops chain of events after initiating event occurs but before an incident has occurred such as high level in a tank shutting off the pump.
4. Mitigation (active or passive)
   • minimizes impact once an incident has occurred such as closing block valves once LEL is detected in the dike (active) or the dike preventing contamination of groundwater (passive).