LOPA - Layer of Protection Analysis
The LOPA study provides a more consistent approach to Safety Integrity Level (SIL) Assessment. Independent Protection Layers are identified, that may provide risk reduction and can accurately define the performance requirements of the Safety Instrumented Function.
LOPA is a quantitative risk assessment process providing a Target Probability of Failure on Demand (PFD), which is associated with the Integrity Level requirements (SIL) as per IEC 61511.
In the process safety environment this activity is referred to as SIL Determination or SIL Assessment because the performance requirements of a safety function is expressed as a Safety Integrity Level (SIL) as per the requirements of IEC 61508 / IEC 61511.
EAC Consultants provide procedures and tools to facilitate SIL Study and offer expert advice on safety functions that are difficult to analyse. We deliver a comprehensive report detailing every aspect of the SIL determination workshop. Our experienced LOPA Facilitators have years of experience facilitating Deterministic SIL Workshops and our scribes are proficient in using popular Software packages such as PHA Pro, ExSILentia and TRAC to record LOPA Assessments.
LOPA is a quantitative risk assessment process providing a Target Probability of Failure on Demand (PFD), which is associated with the Integrity Level requirements (SIL) as per IEC 61511.

EAC Consultants provide procedures and tools to facilitate SIL Study and offer expert advice on safety functions that are difficult to analyse. We deliver a comprehensive report detailing every aspect of the SIL determination workshop. Our experienced LOPA Facilitators have years of experience facilitating Deterministic SIL Workshops and our scribes are proficient in using popular Software packages such as PHA Pro, ExSILentia and TRAC to record LOPA Assessments.
SIS Lifecycle Model
Standards
IEC 61508, IEC 61511, ISA 84.00.02
PHA/HAZOP
Hazard Scenarios
Risk Assessment
Level of Risk for each Scenario
SIL Detemination LOPA
SIF Performance Requirements
Safety Requirement Specification
General & Specific SIS/SIF Requirements
SIF Design Configuration
SIF Design
SIL Verification
SIF Performance Verification
Lifecycle Validation & Certification
Safety Validation & Certification