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John Yozallinas, CFSE

If There Was ONE THING You Need to Know About Using PIU

Tuesday, August 05, 2014 | Functional Safety Certification | Feed


If There Was ONE THING You Need to Know About Using PIU

Have a formal process for tracking, recording, and classifying field shipments and failure returns.

If your product was designed well in the first place, even if strict adherence to IEC 61508 was not followed, your field failure rate should be pretty low.

Using Proven-In-Use (PIU) methodology will allow an assessor to waive some requirements regarding systematic capability.  These are process related issues.  The theory goes that if the actual failure rate is below the predicted failure rate (determined with a detailed FMEDA), then sufficient measures were probably in place to meet the intention of IEC 61508 requirements.  But…

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Steve Gandy, CFSP

How Does Culture Affect Safety?

Tuesday, July 29, 2014 | Functional Safety Certification | Feed


How Does Culture Affect Safety?

I was reading an incident report on the Chemical Safety Board (CSB) website the other day, where it was the conclusion of the reviewing team that the incident (which sadly resulted in a loss of life) was the direct result of a poor safety culture across the organization.  If you consider the term “culture” it actually refers to a set of beliefs, values, and norms that a company adopts in relation to its day-to-day business transactions.  Culture should be endemic in an organization and should exist at all levels, starting at the top.

For the hazardous process industries, it is imperative that a company has the right…

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Iwan van Beurden, CFSE

The exida Certificate Explained

Monday, July 14, 2014 | Functional Safety Certification | Feed


The exida Certificate Explained

A manufacturer whose product passes the exida IEC 61508 Assessment Scheme will receive a certificate based on IEC 61508 and perhaps other functional safety standards. There is a significant amount of information on a certificate that may not be always trivial for a novice. This document explains how one should use and interpret an exida certificate.

It is important that a user understands that a certificate does not stand by itself. The certificate is supported by a detailed assessment report. For each product that is certified by exida (and for which the certification is still valid), exida posts both the certificate and the assessment report on the Safety Automation Element…

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Steve Gandy, CFSP

How Good Is Your Functional Safety Management?

Wednesday, July 02, 2014 | Functional Safety Certification | Feed


Functional Safety Management

Those operating in the process world should be familiar with the concept of Functional Safety Management (FSM) and the need to have well defined processes and procedures in place.  Otherwise, how else will they be able to ensure that their Safety Instrumented System (SIS) and plant are operating safely?

Functional Safety Management is really no different from normal management, which is to assess, plan, execute, monitor, and/or revise.  Or is it?  The key difference is that in the world of safety, getting something wrong can have disastrous consequences, in terms of the potential for loss of life, destruction of assets/property, environmental impacts, financial loss, and detrimental company image.

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Griff Francis

Functional Safety And Electromagnetic Interference: What’s the Connection?

Thursday, June 26, 2014 | Functional Safety Certification | Feed


Functional Safety And Electromagnetic Interference: What's the Connection?

Functional Safety and Electromagnetic Interference (EMI) may not often be used in the same sentence. But EMI is just one of the environmental stresses that can stop a system from performing its safety function. It is important for a functional safety system to be immune from the EMI levels that are likely to present.

Unlike other environmental stresses like temperature and vibration, EMI is more difficult to sense and it more likely to be transitory. Still the effects can be catastrophic.

EMI can take many forms: motor switching, lightning strikes and use of handheld radios. The standards for EMI use terms like surge, transient, and…

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John Yozallinas, CFSE

Stress vs. Strength… In My Process?

Thursday, June 19, 2014 | Functional Safety Certification | Feed


Stress vs. Strength… In My Process?


I consistently find that with companies who are new to functional safety development, the SW process is not as structured or mature as the HW process.  SW development is often more informal, and subject to the interpretation of one or more SW developers.  But when project delays occur, it’s usually due to SW and chaos can result without a well-defined SW process.  One key is to adopt and follow an overall lifecycle process that outlines the development phases and expected deliverables of each phase.  However, even then it can be difficult to get the entire team on board. There’s a principle in reliability engineering called…

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Iwan van Beurden, CFSE

World Cup Fever & Failure Rates

Monday, June 16, 2014 | Functional Safety Certification | Feed


World Cup Fever & Failure Rates

Do you have World Cup Fever? Well I do. Especially after the Netherlands (Holland) beat Spain 5-1 on Friday. I wished that was the score last time they played. So what does this have to do with failure rates? Sometimes my mind works in odd ways. While driving home from work Friday afternoon I was listening to an interview with the Dutch coach on Dutch radio (where would we be without internet radio?). The first thing being discussed was the penalty that was awarded to Spain. The Dutch opinion was very clear: that was a gift, there was no foul. I bet that the Spanish opinion was that…

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Steve Gandy, CFSP

How Secure Are Your SIS, BPCS, and/or SCADA Systems?

Thursday, June 05, 2014 | Cybersecurity | Feed


How Secure Are Your SIS, BPCS, and/or SCADA Systems?

As an end-user, do you know how reliable and safe your Safety Instrumented Systems (SIS) and Basic Process Control Systems (BPCS) are from potential cyber issues?  Do you rely on your vendor statements regarding the robustness of their products?  If the answer to these questions is “don’t know” or “yes” then maybe you should be considering using an independent 3rd party to perform a cybersecurity vulnerability assessment (for existing installations) and/or performing a cyber-risk assessment (as part of a HAZOP) for new installations.  This is especially true for legacy systems that are still in operation using products from the mid-1990s.  Although most software…

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John Yozallinas, CFSE

You Need a Checklist!

Tuesday, May 20, 2014 | Functional Safety Certification | Feed


You Need a Checklist

At least I do.  Sometimes I wonder how I could forget certain things.  Maybe it’s age? Maybe it’s information overload?  It’s always apparent when I get ready to go on vacation.  You’ve probably been in the same situation… arriving at your destination only to find that the one thing you really meant to bring with you is nowhere to be found, and then you remember exactly where you left it.  Most times, you can find a suitable replacement and it’s only a slight, although possibly costly, inconvenience.  At other times, not so easy.

Now, what was I talking about?  Oh yeah… checklists.

I’ve made and used vacation checklists for a…

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Dr. William Goble, CFSE

Random vs. Systematic?

Wednesday, May 07, 2014 | Functional Safety Certification | Feed


Random vs. Systematic

Most of you know that exida gathers field failure data from many sources including manufacturers’ warranty return data and end user maintenance/failure records.  At this point we have nearly 100 billion unit operating hours of data.  This is probably the largest process industry data set in the world.  And we use this data to calibrate the exida Failure Modes Effects and Diagnostic Analysis (FMEDA) component database which predicts future failure rates of new instruments.  We also use the data in combination with a collection of FMEDA data sets to establish exida’s Predictive Analytic Benchmarks which we use to establish generic instrument failure rates for our exSILentia toolset. The…

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Steve Gandy, CFSP

Still Using Excel to do PFD Calculations?

Monday, April 28, 2014 | Software | Feed


Still Using Excel to do PFD Calculations?

It’s very interesting to me to find that people are still using excel to do PFD calculations.  Whereas this is probably okay for simple single element architectures (i.e. single sensor, single logic solver and single final element), it becomes extremely complicated when dealing with redundant architectures.  Moreover, for performing SIL verification, it’s not just a simple case of calculating PFD (for continuous applications) or PFDavg (for demand applications) because compliance with IEC 61511 requires the end user to account for systematic capability as well as architectural constraints, when considering the Safety Integrity Level (SIL) of a Safety Instrumented Function (SIF).  When referring to…

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Dr. William Goble, CFSE

Most Failures are Systematic - NOT!

Wednesday, April 16, 2014 | Functional Safety Certification | Feed


Most Failures are Systematic - NOT!

We have studied hundreds of sets of field failure data from various sources here at exida.  Some of these data sets have indicated differences in failure rates by over an order of magnitude for the same product type.  After tracing through the data collection process for many of these field failure data sets, it is becoming clear that one significant variable is the question “What is a random failure?”

Very few failures are recorded in some data studies.  It was discovered in one study that many of the “possible failures” were classified as “systematic” and therefore not counted in the random failure rate.  In a January 2014…

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John Yozallinas, CFSE

Are You Building a Safer World?

Monday, April 14, 2014 | Functional Safety Certification | Feed


Are You Building a Safer World?

Every man takes care that his neighbor shall not cheat him. But a day comes when he begins to care that he does not cheat his neighbor. Then all goes well.”  - Ralph Waldo Emerson

I like to think about functional safety in a similar way.  We all want to be safe; it’s one of humanity’s primary needs.  But are we taking care to make our neighbor safe?

Functional safety standards IEC 61508 and IEC 61511 serve as a set of principles, techniques, best practices, and requirements to help us build a safer world.  Risks are analyzed, hazards are identified, and mitigation measures are developed.  Practitioners…

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John Yozallinas, CFSE

I Know My Requirements. Now What?

Monday, March 31, 2014 | Functional Safety Certification | Feed


I Know My Requirements. Now What?

If you’ve written your new product requirements, you probably understand exactly what they mean.  But will the other people on your project team?  You also probably understand that some unwritten requirements must also be met. They’re just common sense and everyone knows what they are. 

What about that new software developer who is a whiz at the computer stuff, but not so savvy about pressure transmitters? Requirements can be subject to interpretation and confusion.  Different parts of the organization speak different languages, literally or figuratively.  Marketing may know what the customer wants but engineering has to translate this information into a design.  A test engineer may have…

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Loren Stewart

Cycle Testing for Static Applications? NO!

Wednesday, March 12, 2014 | Functional Safety Certification | Feed


Cycle Testing for Static Applications? NO!

The failure rates of certain mechanical components used in solenoid valves, actuators, and valves vary substantially depending on operation. Seals such as O-rings, for example have fundamentally different failure modes when used in applications with frequent movement (dynamic) versus applications with infrequent movement (static). 

Static is generally defined as “stationary or fixed.”  We at exida define a mechanically static application as a low demand mode operation. Dynamic is generally defined as “energetic, capable of action and/or change, or forceful.”  exida defines a mechanically dynamic application as a high or continuous mode operation. 

Mechanical failure data can be found by four main sources:

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