LOPA
Bridge the gap between qualitative HAZOP findings and quantitative safeguarding decisions.
Layer of Protection Analysis to quantify risk reduction required and credit independent protection layers consistently.
Request a ConsultationWhat is LOPA?
Layer of Protection Analysis (LOPA) is a semi-quantitative risk assessment methodology that builds on HAZOP findings to evaluate whether independent protection layers (IPLs) provide sufficient risk reduction for a given hazard scenario, comparing calculated mitigated frequency against a defined risk tolerance criterion.
Why It Matters
- ●Provides defensible, semi-quantitative justification for safeguarding adequacy
- ●Directly feeds SIL determination for safety instrumented functions
- ●Avoids both under-protection and the cost of unnecessary, redundant safeguards
- ●Creates a consistent, auditable risk decision trail across a facility's HAZOP scenarios
Our Methodology
- 1Scenario selection from HAZOP register based on consequence severity screening
- 2Initiating event frequency assignment using recognised data sources
- 3Independent Protection Layer (IPL) identification and credit assignment
- 4Mitigated event frequency calculation and comparison to risk tolerance criteria
- 5Gap closure recommendations including SIL targets where instrumented layers are required
Deliverables
Industries We Serve
FAQ
LOPA Frequently Asked Questions
What is LOPA?
LOPA (Layer of Protection Analysis) is a semi-quantitative technique that evaluates the adequacy of independent protection layers against a hazard scenario by comparing the mitigated event frequency to a risk tolerance criterion.
What is the difference between LOPA and QRA?
LOPA is a scenario-based, order-of-magnitude technique typically applied per HAZOP finding, using simplified frequency data. QRA is fully quantitative, models consequences (dispersion, fire, explosion) with software, and aggregates risk across an entire facility, often producing societal and individual risk contours.
What counts as an Independent Protection Layer (IPL)?
An IPL must be independent of the initiating event and other IPLs, capable of detecting and responding to the hazard, and auditable/testable. Examples include relief valves, SIFs, and physical containment — but BPCS alarms only count under specific independence conditions.