GUIDELINES FOR ENABLING CONDITIONS AND CONDITIONAL MODIFIERS IN LAYER OF PROTECTION ANALYSIS

Center for Chemical Process Safety

Chemical Industry Press

Brief Introduction

Layer of Protection Analysis (LOPA) is a tool for analyzing and assessing scenario risk. LOPA has grown in popularity in the time since the publication of the first CCPS/ AIChE guidebook on the subject (Layer of Protection Analysis: Simplified Process Risk Assessment; CCPS 2001). It uses estimates of cause frequency, independent protection layer failure probabilities and consequence severity, employing conservative rules for making and combining these estimates.

These Guidelines for Enabling conditions and Conditional modifiers contain information useful to the experienced analyst and accomplished practitioner.