Engineers and managers who work with safety equipment have likely seen a failure rate of some kind quoted for the equipment. Some equipment even comes with a safety certification stating the failure rate given certain assumptions about how the equipment will be used.
The numbers sometimes turn out to be…
I recently studied the design changes made on the T series of old British cars (a hobby) made by the MG Company in England from 1936-1955. Models progressed over that time period including the TA, TB, TC, TD, and TF. I noted a strange looking two position switch on the dash…
It’s an interesting fact that many end users and engineering companies that I’ve talked to have not or do not undertake Functional Safety Assessments (FSAs). Why is this? My view is that many do not realize and/or understand the true purpose of and benefit of performing FSAs. The IEC61511 standard identifies 5…
Realistic component failure rate data is critical to an effective Failure Modes, Effects, and Diagnostic Analysis (FMEDA). This failure rate data can eventually be obtained from component parts manufacturers, research and field failure data analysis. For example, exida’s Component Reliability Database (CRD) has been built from internet research, technical…
TL;DR Tools used in developing safety related automotive systems do not receive an ASIL. Some tools and the way they are used may not be suitable for the development of automotive safety electronics and this depends on the ASIL. When a tool vendor mentions an ASIL they might be…
Reliability Engineering experts know there are many variables that impact operational failure rates. These variables even include how operations and maintenance are done at a specific site. Sometimes it feels like there are so many variables that no realistic failure rate can ever be predicted without a few hundred hours of…
Many of you who follow exida’s blogs and webinars will know that we often talk about the requirement for competency. In fact, the 2016 edition of IEC61511 specifically addresses competency in more detail now than the 2003 version. The strong emphasis on competency is because the IEC61511 committee recognized that…
Common Cause is one of those variables that is not always considered important when it comes to SIL compliance. And yet, for redundant systems, it can have a significant impact on the PFDavg and Risk Reduction achieved (in Low Demand mode) or PFH (in high or continuous mode). Most of the…
Machinery related hazards continue to result in hundreds of deaths and thousands of serious injuries each year. In 2019, 2,963 deaths occurred in the construction, transportation and warehousing, agriculture, forestry, fishing and hunting, and manufacturing industries in the United States1. Additionally, serious injuries continue to pose a major challenge…
Part of the changes to the IEC61511 standard in 2016, some five (5) years ago now, was to emphasize the need to do a better job with regards to the Operations and Maintenance phase of the safety lifecycle. One of the key aspects of the Operation and Maintenance phase…
During a recent exida webinar we received the following question:
We tend to see more failures with actuated valves, than what manufacturers published failure rates would indicate! Any reason?
There are several reasons. Some manufacturers publish data based on field return data where they classify failures caused by customers…
In the book “The Checklist Manifesto: How to Get Things Right”, Atul Gawande, surgeon and best-selling author, tackles the problem of how to prevent human error in an age where 
professionals grapple with the increasing complexity of their responsibilities. Errors,…
According to numerous industry studies, significant improvement has been made over the last 20 -30 years in occupational safety, but not so much in operational safety (process safety). New process safety incidents continue to occur that bear a striking resemblance to previous incidents. This means we are not effectively learning…
This is a topic which comes up time and again, especially when reviewing legacy systems. Although IEC61511 doesn’t preclude the use of shared devices, it does however provide guidance under Clause 11 of what the constraints are. Even though the Safety Instrumented System (SIS) and Basic Process Control System (BPCS)…
Insurance Companies are hedging their bets through premiums while the Manufacturing Industry is placing their wagers on luck.
The worlds of gambling and insurance are similar in many ways. Both are built upon elements of probability, modeling and quantification of risk. Professional gamblers are well informed on the odds…