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Failure Rate Analysis Paralysis

Failure Rate Analysis Paralysis

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…

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Competency and IEC61511

Competency and IEC61511

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…

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The Importance Of Considering Common Cause with Redundant Systems

The Importance Of Considering Common Cause with Redundant Systems

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…

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Machinery Hazards and Risk Assessment Techniques

Machinery Hazards and Risk Assessment Techniques

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…

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Measuring Performance – Why Are We Not Doing This?

Measuring Performance – Why Are We Not Doing This?

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…

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FAQ: More Failures with Actuated Valves than what published failure rates indicate?

FAQ: More Failures with Actuated Valves than what published failure rates indicate?

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…

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Can Checklists Prevent Human Error?

Can Checklists Prevent Human Error?

Learning From History So We Don’t Repeat It – New Tools

Learning From History So We Don’t Repeat It – New Tools

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…

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Why Sharing Components Between SIS & BPCS Is Not A Good Idea

Why Sharing Components Between SIS & BPCS Is Not A Good Idea

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)…

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Strong Safety Culture Translates to Lower Insurance Premiums

Strong Safety Culture Translates to Lower Insurance Premiums

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…

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The Dos and Don’t of SIS Application Programming

The Dos and Don’t of SIS Application Programming

It’s interesting that the majority of the time when people talk about functional safety, they are usually thinking about hardware: what sensors to use, which logic solver, what actuator, solenoid or valve to select; what voting architecture, etc.  What often gets overlooked, initially, is the application program.

Essentially, when…

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How the PHA and LOPA are going to affect your SIS

How the PHA and LOPA are going to affect your SIS

Both Process Safety Analysis (PHA) and Layer of Protection Analysis (LOPA) occur in the early stage of the Functional Safety Lifecycle, detailed in both IEC 61511 and IEC 61508. They both serve significant roles in the whole process safety management. Yet, as a facilitator…

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Share the Wealth (of Functional Safety Knowledge)

Share the Wealth (of Functional Safety Knowledge)

Experience is a good teacher.  But how do you get the experience?  

Formal classroom or online training is often available for more general skills, but on-the-job training usually provides a more in-depth path to gain such experience.  After doing a job for a while, working through difficulties with colleagues,…

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IEC 62061 Machine Safety: “It’s simply the right thing to do”

IEC 62061 Machine Safety: “It’s simply the right thing to do”

I can't begin to tell you how many of our customers share with us how lucky they have been to be incident-free at their plant.

Or, because they have not had an incident in over 10 years, it is hard to justify the cost of a Machine Hazard…

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Back to Basics: Failure Rates - λS

Back to Basics: Failure Rates - λS

The Greek symbol  λS represents safe or spurious failure rates in functional safety expressed in the unit of measurement of FITs which can be determined through FMEDAs. (FITs (λ) are failures per billion hours, expressed by 10-9 hours).

λS is the number of safe…

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