Most everyone has heard of the “80-20 rule”. It asserts that for many situations, roughly 80% of the effects (outcomes) come from 20% of the causes (inputs). This rule was first proposed in the early 1900s by Vilfredo Pareto, who was an Italian engineer, sociologist, economist, political scientist, philosopher,…
exida explains Blog
- by Todd Stauffer
- Monday, March 20, 2017
- Alarm Management
What do Nuisance Alarms, the 80-20 Rule, Mental Models, and More Have in Common?
- by John Yozallinas, CFSE
- Tuesday, March 07, 2017
- Functional Safety
Functional Safety Standards - IEC 61508 vs. IEC 61511
IEC 61508 is considered a basic or “umbrella” standard for functional safety. It is generic and sometimes even vague. IEC 61508 was intended that various industry sectors provide their own specific standards and guidelines as needed. Here we can see the relationship between 61508 and other standards, such as…
- by John Yozallinas, CFSE
- Thursday, February 16, 2017
- Functional Safety
So what does Interference-Free mean? And why do we care?
An Interference-Free component, either as an interface or a defined functional area, is a system component that is neither safety critical (C3) nor safety relevant (C2), but interfaces with such subsystems.
If a component has been shown to be interference free (C1), then it has been demonstrated that no…
- by Dr. William Goble, CFSE
- Thursday, February 09, 2017
- Functional Safety
Getting Good Proof Test Coverage Numbers
Several years ago we recognized that proof test coverage was an important variable that must be considered when doing PFDavg calculations. We ran some models and discovered that the difference between “perfect” proof test coverage (100%) and a very good 90% could mean a whole SIL…
- by Todd Stauffer
- Friday, February 03, 2017
- Alarm Management
Nuisance Alarms and “The Boy Who Cried Wolf”
The purpose of an alarm is pretty straightforward - to draw the operator’s attention to an abnormal situation that requires action in order to prevent an undesired consequence. Alarms that don’t meet this principle often become nuisance alarms. A nuisance alarm is defined as:
“an alarm that annunciates excessively,…
- by Dr. William Goble, CFSE
- Thursday, January 19, 2017
- Certification
High Demand Diagnostic Credit?
The IEC 61508 standard states that automatic diagnostics can only lower the dangerous undetected failure rate if those diagnostics execute 100 times faster than the expected demand rate. That requirement has always seemed excessive to many of us here at exida. As an accredited Certification Body we…
- by Kate Hildenbrandt
- Wednesday, January 18, 2017
- Software
Reducing Project Lifecycle Cost with exSILentia®
The international functional safety standard IEC 61511 provides the safety lifecycle as a steadfast guideline to assess and mitigate risk for manufacturing processes including refineries, chemical, petrochemical, pulp and paper, and power plants. To achieve a functionally safe system, it is essential to follow each…
- by John Yozallinas, CFSE
- Thursday, January 12, 2017
- Functional Safety
IF COMPUTERS RULED THE WORLD…
What if the best minds of the world got together to generate the optimum requirements specification for human co-habitation? And built it into one large decision matrix to run on the best super-computers?
Decisions would be made solely on objective criteria; no mental arbitration, no skipping steps, no checking…
- by Rick Smith
- Wednesday, January 04, 2017
- Functional Safety
Conceptual Design and SIL Verification’s Ultimate Resource
I was talking to a customer the other day regarding failure rate data and I brought up our Safety Equipment Reliability Handbook (SERH): 4th Edition. Through the years, along with our comprehensive safety lifecycle tool exSILentia, the book set has become one of exida's flagship products. If you…
- by Todd Stauffer
- Thursday, December 15, 2016
- Functional Safety
The Importance of Process Safety to the next Generation of Chemical Engineers
Significant progress in process safety has been made by many companies and engineers around the globe. This progress is often overshadowed when a process safety accident hits the news. In December of 2007, a runaway reaction led to an explosion at the T2 Laboratories in Jacksonville, FL.…
- by Ted Stewart, CFSP, exidaCSP
- Thursday, December 08, 2016
- Certification
The 3rd Party Effect (Part 1)
Have you even wondered, been involved, or WERE the little kid that didn’t listen to your parents, but always listened to a teacher? This is called the “Third party effect.” In business, it is well known that the power of persuasion can be the most effective by a third…
- by Todd Stauffer
- Thursday, December 01, 2016
- Alarm Management
How to become a world-class expert (the 10,000 hour rule)
In the book “Outliers”, Malcolm Gladwell popularized the notion that to become an expert in a field requires putting in 10,000 hours of practice.
The emerging picture from studies of expertise is that ten thousand hours of practice is required to reach the level of mastery associated with being…
- by Dr. William Goble, CFSE
- Thursday, November 17, 2016
- Functional Safety
Realistic Failure Rate Data – Necessary
Reliability engineers have known for decades that realistic data must ultimately come from one source, quality field failure data for devices operating in a similar application.
Perhaps that is why IEC 61511:2016, Clause 11.9.3 states
“The reliability data used when quantifying the effect of random failures shall…
- by John Yozallinas, CFSE
- Friday, November 04, 2016
- Functional Safety
Back to the Future?
At 7am, my personal robot (I call him ‘Jake’) turns on the bedroom lights to 50% brightness and waits for my body to recognize the onset of morning. If I take longer than 5 minutes, Jake will begin to play some soft music. This is usually enough to get…
- by Rick Smith
- Thursday, October 27, 2016
- Industrial Cybersecurity
Introduction to ICS Security - Pt. 4 - Control System Assessments
Over the last couple of blogs, I mapped out the importance of ISA/IEC-62443/ISA-99 based cybersecurity and how it applies to your work environment.
For part 1, I started from the beginning and outlined what exactly ICS cybersecurity is and why it is important.
For part 2, I explained the difference between…