Hazard and Risk Analysis Methods: How HAZOP, What-If, LOPA, Risk Graph, FTA, ETA, and Bowtie Fit Together
A practitioner's orientation to the methods that make up an IEC 61511 hazard and risk assessment — HAZOP, What-If, LOPA, risk graph, FTA, ETA, and bowtie — and how they…
Layer of Protection Analysis (LOPA): The Engineer’s Guide to SIL Selection
LOPA — layer of protection analysis — is the most widely used method for SIL selection in the process industry. This guide covers how it works, where it fits in…
Hazard and Risk Assessment (H&RA): The Foundation of Functional Safety
A hazard and risk assessment (H&RA) is the foundation of every IEC 61511 safety case. This guide covers what it is, how it works, the methodologies used to conduct one,…
Functional Safety for the Process Industry: 10 Core Concepts Every Engineer Should Know
Functional safety in the process industry is more than calculations—it's a lifecycle approach to reducing risk. This guide explains IEC 61511, SIS, SIL, LOPA, and how safety systems actually work…
Failure Rates in Functional Safety: A Practical Guide for Working Engineers
Failure rates are central to SIL verification, device selection, diagnostics, and proof testing. This guide explains λDU, λDD, λSU, and λSD, where the values come from, and how functional safety…
How to Apply the Beta Factor: A Practical Guide to Common Cause Failures in SIL Verification
Learn how to apply the beta factor (β) in SIL verification and understand its link to common cause failures. This guide walks through where β values come from, how they…
Spurious Trip Rate Explained: 6 Facts Every Functional Safety Engineer Should Know
Spurious Trip Rate (STR) is often overlooked in functional safety. Learn what STR is, how it’s calculated, and why balancing STR with PFDavg matters.
How to Use Proof Test Coverage (Cpt) to Improve PFDavg
Proof test coverage (Cpt) plays a major role in determining whether a SIF meets its target SIL. This article explains what Cpt is, how it affects PFDavg, and how even…
How MTTR Affects Your SIL Calculations: A Beginner’s Guide to Mean Time to Restore
Learn how MTTR (Mean Time to Restore) fits into PFDavg and STR in IEC 61511 compliance. A clear, beginner-friendly guide for functional safety.
