Layers of Protection Analysis - LOPA - is a risk assessment technique for all industrial-scale plants that store or process flammable, toxic or environmentally hazardous materials. Usually following on from a Process Hazard Analysis study like HAZOP, LOPA requires specialist support to correctly credit protection layers.
LOPA Frequently Asked Questions
LOPA - Layer Of Protection Analysis. LOPA is a risk study method first proposed by the AIChE (American Institute of Chemical Engineers) in the early 2000's to provide a simplified method for attributing risk reduction to protection layers.
End users in chemical, oil and gas, pharmaceuticals and others with major accident hazards.
No. LOPA gets done after hazards have been identified by other techniques such as HAZOP, What-If? or similar methods. A good guide is that Process Flow diagrams and P&ID's should be complete.
No. LOPA is applied in many different ways, so there is no standard (correct as of July 2021). This makes defining a LOPA procedure a critical step for companies to agree and approve.
Clear terms of reference (procedure) plus information about the scenarios to be assessed. Data usually comes from a process hazard analysis e.g. HAZOP, coupled with detailed P&ID drawings and a knowledge of the process. LOPA is a team study, and should be led by someone trained in the technique.
Yes and No.
Yes: Safety Integrity Level TARGETS can be derived directly from a LOPA study with appropriate procedures.
No: It is not possible to use LOPA to calculate if a Safety Instrumented Function (SIF) meets the SIL target.
LOPA Software Support
We can support projects with your preferred LOPA software if you have already selected one, or with template spreadsheets optimized for delivering LOPA documentation.
Our specialist software experience spans all the major specialist tools, including aeShield, exSILentia PHAx, HAZOP Leader, PHA-Pro, SafetyInsight and SISSuite.