exida explains Blog

Safety Requirements Specifications (SRS):  The Good and the Bad

Safety Requirements Specifications (SRS):  The Good and the Bad

The IEC 61511 Standard requires the user to create a Safety Requirements Specification (SRS) for a Safety Instrumented System (SIS) that incorporates all the analysis done during the Risk Assessment, HAZOP/PHA and LOPA reviews.  The SRS falls into two types: an initial conceptual SRS, often referred to as the…

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WHY are Failures Occurring at a Different Rate from Our Other Site?

WHY are Failures Occurring at a Different Rate from Our Other Site?

Site audits have shown many differences in how things are done from site to site. This impacts many variables in a safety instrumented system!

A key metric for process industry designs is called average Probability of Failure on Demand (PFDavg).  After several studies of many field failure and proof…

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  • by Chris O'Brien, CFSE
  • Thursday, January 07, 2016
  • Certification

Best Practices in Achieving Functional Safety in Turbine Applications - Part 3

The adoption of the functional safety standards continues to gain momentum in turbine applications. Both industrial and power turbine sites are now requiring compliance to IEC 61511. This blog will review both technical requirements and market trends related to functional safety system design. Market trends will cover which standards…

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SILSafe Data Website

SILSafe Data Website

exida has launched the web site www.silsafedata.com. SILSafe Data is a web site listing a number of product categories used in process control and the expected range of failure rates for process industry applications. The use of realistic and application appropriate failure rate data has a significant…

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Are We Done Yet?

Are We Done Yet?

We all know when we’re finished with the product development cycle; it’s printed in a little box on the project schedule Gantt chart.  The end of July… right there on the schedule, and it’s been there since the project inception.  So what happens when you reach 31-July and your…

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Is your Car Smarter than a Fifth Grader?

Is your Car Smarter than a Fifth Grader?

While channel surfing the TV this weekend, I happened to stop on an old show called “My Mother The Car.”  (Ok, I’m dating myself, but it was filmed in color, as opposed to some other favorite old shows still in black-and-white).  The fictional car, a 1928 Porter built for…

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Best Practices in Achieving Functional Safety in Turbine Applications - Part 2

The adoption of the functional safety standards continues to gain momentum in turbine applications. Both industrial and power turbine sites are now requiring compliance to IEC 61511. This blog will review both technical requirements and market trends related to functional safety system design. Market trends will cover which standards…

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Best Practices in Achieving Functional Safety in Turbine Applications - Part 1

The adoption of the functional safety standards continues to gain momentum in turbine applications. Both industrial and power turbine sites are now requiring compliance to IEC 61511. This blog will review both technical requirements and market trends related to functional safety system design. Market trends will cover which standards…

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Train Wrecks Waiting to Happen?

Train Wrecks Waiting to Happen?

Hacking public transportation systems is always depicted on TV and movies.  And they make it seem so easy… it only takes seconds for these fictional experts.  Is it a reality?

Well, the Amtrak train derailment that occurred earlier this year in Philadelphia got me thinking about “hacking” as a…

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Say What?
  • by John Yozallinas, CFSE
  • Thursday, October 01, 2015
  • Certification

Say What?

The “see something, say something” mantra is being used as a countermeasure for terrorism and crime, but it can also be effective to improve functional safety in development teams and plant sites.  It could be useful in general process improvement as well.

This can be especially evident during training…

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How can I improve my SIL?

How can I improve my SIL?

Click here to read the first entry in this blog series (What is SIL compliance?)

Click here to read the second entry in this blog series (How is SIL Used?)

As we now know, a Safety Integrity Level (SIL) can only be given to a…

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How is SIL Used?
  • by Loren Stewart, CFSP
  • Tuesday, September 22, 2015
  • Certification

How is SIL Used?

Click here to read the first entry in this blog series 

Once the Safety Integrety Level (SIL) of a product is found, it will be used FOUR ways:

  1. To establish risk reduction requirements
  2. Probabilistic limits for hardware random failure
  3. Architectural constraints 
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What is SIL compliance?

What is SIL compliance?

The Safety Integrety Level (SIL) of a product is determined by three things:

  1. The Systematic Capability Rating
  2. The  Architectural Constraints for the element
  3. The PFDavg Calculation for the product

The Systematic Capability Rating

Systematic Capability is established by having your quality management system audited per IEC 61508.…

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Return to the “Just Do It” Approach
  • by John Yozallinas, CFSE
  • Tuesday, September 15, 2015
  • Software

Return to the “Just Do It” Approach

*The “Just Do It” approach was previously referenced in the blog entry Seat-of-your-Pants Software?

If used early in the development lifecycle, a “just do it” approach could help marketing determine the look-and-feel of an application program with a complex user interface.  Early software prototyping on a PC…

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What’s Your Biggest Fear?
  • by John Yozallinas, CFSE
  • Friday, September 11, 2015
  • Certification

What’s Your Biggest Fear?

Plane crash?

Earthquake?

Ebola outbreak?

Shark attack?

There are probably lots more things to add to that list.  What could we do to prevent them?  Not too much for some… a little more for others.  But would those mitigations be practical?  What tolerable risk can we accept for these…

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