When designing a Safety Instrumented Function (SIF), practitioners often encounter a complex scenario: multiple initiating events (independent causes) leading to the same hazardous consequence. While common industry practice is to design for the "worst-case" scenario in isolation, this approach contains a hidden danger. A groundbreaking whitepaper from exida reveals…
exida explains Blog
- by Alejandro Esparza, CFSE
- Wednesday, March 11, 2026
- Functional Safety
When “Worst-Case” Isn’t Good Enough: Why Your LOPA Might Be Underestimating Risk
- by Dr. Steve Gandy, CFSP
- Saturday, February 14, 2026
- Functional Safety
Defeating the Swiss Cheese Model: Managing Random and Systematic Failures Across the SIS Lifecycle
How often have you been at conferences where the presenters refer to the “Swiss Cheese Model”? The intent of the model is to convey what happens to the protection layers in Safety Instrumented Systems (SIS) when they are poorly designed, implemented and maintained. In this case, when any of…
- by Dr. Steve Gandy, CFSP
- Tuesday, November 04, 2025
- Functional Safety
How Does Mission Time, Proof Test Interval and Proof Test Coverage Impact PFDavg?
Oftentimes when this comes up during class it’s clear that there’s a misunderstanding as to how these three variables can impact the PFDavg calculations. Mission Time is defined as the period of time over which a set of Safety Instrumented Function (SIF) equipment is expected to operate without major…
- by Sarah O'Brien
- Thursday, October 23, 2025
- Software
From exSILentia® to SILstat™ – A Seamless Transition
Looking for a way to manage and maintain your operation and maintenance data, but don’t know where to start? Are you already using exSILentia® for your safety lifecycle task needs?
If so, SILstat™ offers a simple way to transfer exSILentia project data and build your database. SILstat is exida’s…
- by Sarah O'Brien
- Wednesday, October 15, 2025
- Software
Easy to Navigate – The Intuitive Data Structure of SILstat™
While using different safety system management platforms, it is essential to keep system and device data properly arranged between platforms to ensure efficient data management. This can be difficult, but not with SILstat™.
exida’s latest product launch, SILstat, is designed to provide users with a tool to…
- by Dr. Steve Gandy, CFSP
- Monday, September 08, 2025
- Functional Safety
How Does A SIF Achieve its SIL Target?
This is a question I’ve been asked many times, with some stating that as long as the PFDavg (or PFH) meets the target SIL then that’s fine. Whereas this statement is partially true, it is not the full answer. IEC61511 defines the criteria for meeting the requirements of an…
- by Sarah O'Brien
- Thursday, August 28, 2025
- Software
The Future of Safety Management: Embracing Digital O&M Data
In today’s world, having your Operation and Maintenance (O&M) data in a digital format allows for increased accessibility and traceability. Using more traditional recordings, such as on paper or with various Excel notebooks, increases the chances of error or loss of data. These methods also make it difficult to…
- by Hrishit Joshi
- Tuesday, August 26, 2025
- Industrial Cybersecurity
How IEC 62443 Can Help Achieve Compliance with the EU Cyber Resilience Act (CRA)
Introduction:
The European Union’s Cyber Resilience Act (CRA) is set to introduce mandatory cybersecurity requirements for “products with digital elements”, including those used in Industrial Control Systems (ICS) and Operational Technology (OT) environments. This regulation, slated for enforcement beginning December 2027, aims to enhance cybersecurity across supply chains by…
- by Alejandro Esparza, CFSE
- Friday, August 08, 2025
- Functional Safety
Más allá de la baja demanda: Entendiendo el verdadero modo de operación de tu SIF (Beyond Low Demand: Understanding Your SIF’s True Mode of Operation)
ESPANOL
¿Se calcula el SIL de una SIF de Demanda Baja igual que el de una SIF de Demanda Alta o Continua?
Es muy importante identificar el modo de operación que es asignado a la Función Instrumentada de Seguridad (SIF). En la industria de procesos lo más común es…
- by Hrishit Joshi
- Monday, July 28, 2025
- Industrial Cybersecurity
Understanding the EU Cyber Resilience Act (CRA)
Introduction:
The European Union Cyber Resilience Act (CRA) is a landmark regulation designed to enhance cybersecurity across hardware and software with digital elements that are offered for sale within the EU. As cyber threats continue to evolve, the CRA introduces mandatory security requirements for manufacturers to ensure that products…
- by Dr. Steve Gandy, CFSP
- Tuesday, July 08, 2025
- CertificationFunctional Safety
What Does IEC 61511 Mean by Competency?
When the latest edition of IEC61511 was published in 2016, one of the key changes was the emphasis on competency and some further guidance on what this means. The relevant clauses in the IEC61511:2016 are 5.2.2.1 to 5.2.2.3 under Clause 5.2.2: Organization and Resources. I am often asked what…
- by Valerie Motto
- Monday, June 16, 2025
- Functional Safety
A Component Reliability Data Source Must Include Useful Life
In exida’s Component Reliability Database (CRD), every component includes a Useful Life expressed in years and/or cycles.
Understanding Useful Life
This post, drawing from exida's whitepaper [1] on how environmental factors impact component reliability, shows how Useful Life, like failure rates, is affected by factors such as temperature…
- by Todd Stauffer
- Tuesday, June 10, 2025
- Functional Safety
Stress vs. Strength: The Foundation of Component Reliability in FMEDA
The So What:
Your product's safety and reliability depend on the constant battle between component stress and strength throughout its useful lifetime. This dynamic is influenced by everything from design and manufacturing to usage and environment. Crucially, without…
- by Sarah O'Brien
- Tuesday, May 20, 2025
- Software
Introduction to SILstat™
Earlier this year, exida announced major enhancements to the SILstat™ product.
SILstat completes the Safety Lifecycle by providing users with a tool to manage and maintain their operation and maintenance data for their installed safety systems and associated field devices.
SILstat is designed to easily…
- by Dr. Steve Gandy, CFSP
- Tuesday, April 08, 2025
- Functional Safety
What is Prior Use Justification & How To Achieve it?
This is a question I have often been asked in the past. Most people I have spoken with don’t have a good appreciation of what this means and the purpose. From the IEC61511 perspective, designers of Safety Instrumented Systems (SIS) are required to justify the selection…