exida explains Blog

  • by Dr. William Goble, CFSE
  • Tuesday, June 07, 2011
  • Certification

The Weakest Link

One of the objectives of new performance based standards like IEC 61508 is to allow performance metrics (like PFDavg for low demand systems) to identify the weak links in any proposed design.  Obviously, it is not necessary to put effort into design and spend money on areas…

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Industrial automation is in the cross hairs of the hacker

As the details of STUXNET’s design unfolded last fall, like many, I was truly impressed by the pin-point precision that the malware authors used to ensure that their target, and only their target, was impacted by the virus.  In this regard, STUXNET may be one of the…

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Keep Risk Personal

We are fortunate that Risk Analysts have developed a logical framework of quantitative and semi-quantitative analysis techniques that allow us to assess and optimally mediate risk. And we all know that this is part of the Safety Lifecycle, a series of engineering steps/procedures that represent best safety practices. These…

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When is a Variable Frequency Drive a SIS?

It used to be that a pump would operate at a single speed dictated by a motor, thus fixing the pump curve. As the discharge flow decreased due to a restriction downstream, the pump outlet pressure would increase reaching its deadhead pressure. If the downstream piping and vessels were…

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  • by Dr. William Goble, CFSE
  • Thursday, May 12, 2011
  • Certification

Buy Certified Equipment, Meet the Standard, Right? WRONG!

  • by John Yozallinas, CFSE
  • Thursday, April 28, 2011
  • Certification

What is So Important About Derating?

Some designs push their operating specifications right up to the limit of the components in the system or device.  (let’s not talk about the designs that try to spec a limit that is beyond the capability of one or more components… phooey on them!)  And if you make a…

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Lifecycle Analysis: It’s Worth the Effort

Functional Safety and Taxes: Are you an expert?

Today, April 15th, is tax-day in the US.  Ok, the Internal Revenue Service (IRS) has given us a few extra days this year (the tax filing deadline is not until April 18th).

There are a lot of similarities between how you do your taxes and how you handle…

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  • by John Yozallinas, CFSE
  • Thursday, April 14, 2011
  • Certification

Stepping stones to SIL 3

Imagine.  Marketing has just approached the engineering department and says your new safety product must have SIL 3 Capable certification instead of SIL 2 to be successful.  You are in the engineering group developing this new product.  Now what?

Let’s assume that the “change request” makes…

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Driving with Blinders

Imagine: An automobile that has only one window in the front.  No side windows. The driver can see to steer the auto forward and turn, but cannot see completely from side to side.  What happens when the driver reaches an intersection with no traffic lights? The driver cannot see…

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Certified to SIL 4 - Cycle Test Failure Data is Dangerous

I got a copy of the IEC 61508 certificate for a solenoid valve today from an engineer who thought something was wrong.  Although the certificate was from a well known certification company, the certificate gave a “Dangerous Failure Rate” of 1.7 FITS (1.7 * 10-9 failures per…

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What’s the Risk?

As safety professionals, it is our duty to attempt to educate and explain to the public.  Perhaps the biggest challenge is to explain the concept of risk.  Many times after an accident we have heard a politician say something like “We will do whatever it takes to make sure…

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A look into the control room of the Fukushima Dai-Ichi Unit 2 reactor!

I came across an interesting blog post the other day…

Talk about operating blind.  A great picture shows the status of the control room in the Fukushima Dai-Ichi Unit 2 reactor…Nothing is working (besides the lights)!

All of the computer monitors are blank. The clock…

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Rationalize Your Alarm Management Problems Away

Alarm Overload…Nuisance Alarms…Alarm Floods…Incorrectly Prioritized Alarms…. These alarm management problems are all too common in the modern Distributed Control System (DCS).

Why is this?  In the “olden” days (read panel boards and alarm lightboxes), there was considerable thought put into what alarms were necessary because there was limited real…

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The Real Impact of Stuxnet

Stuxnet has, rightly, generated a significant amount of discussion and concern with the industrial automation community.  Fortunately, unless you operate a uranium enrichment facility using Siemens S7 PLC’s and some very specific variable frequency drives (VFDs) you probably haven’t been directly impacted by the Stuxnet…

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