exida explains Blog

Are All Field Devices Type A?

Are All Field Devices Type A?

I was told by an end user engineer that he considers all field devices to be simple Type A devices.  In IEC 61508, Type A is defined as a device with well-defined failure modes, well known failure rates, and behavior under fault conditions that can be completely determined.  Type…

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  • by Iwan van Beurden, CFSE
  • Monday, May 23, 2016
  • Software

PRODUCT SPOTLIGHT: exSILentia® – PHA / PHAx™

Each month at exida, we strive to spotlight one of our products that makes the job easier for today's industry professional.  In this blog, I wanted to talk about the PHAx module as part of our exSIlentia Safety Lifecycle Suite.

Process Hazards Analysis (PHA)

Process…

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Are You Ready For What’s Coming?

Are You Ready For What’s Coming?

If you’re like me then you’ve been waiting for the new draft of IEC 61511 to be officially issued since its release has been delayed for some time.  However, a draft has been released and can help in preparing end users for what’s to come.  The question…

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What Good is a Safety Manual?

What Good is a Safety Manual?

Many products have options and features that are valuable to users.  But not all these features should be permitted while the product is performing a safety function.  For example, HART communications should not be permitted to write data to a transmitter while it’s performing the safety function.  If you…

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The Road to More Secure Products

The Road to More Secure Products

As the incidence of cybersecurity threats in industry continue to rise, the automation world continues to grapple with how to address these issues.  There are many good practices available to end users such as creating demilitarized zones between the business network and the industrial network, banning the use of…

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New Version of ISA-18.2 Alarm Management Standard Is Released (2016)

New Version of ISA-18.2 Alarm Management Standard Is Released (2016)

The new and updated version of the ISA-18.2 standard (ANSI/ISA-18.2-2016, Management of Alarm Systems for the Process Industries) has now been officially released. This supersedes the original edition (2009). The new version incorporates feedback from 6+ years in the "field" and includes some updates based on the IEC 62682…

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PRODUCT SPOTLIGHT: Safety Equipment Reliability Handbook, 4th edition

Each month at exida, we strive to spotlight one of our products that makes the job easier for today's industry professional.  In this blog, I wanted to talk about our latest edtion of the SERH (Safety Equipment Realiability Handbook)

The SERH provides a collection of failure rate data…

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Site Safety Index™ (SSI) – A Simple Model for Site Variations in Safety
  • by Dr. William Goble, CFSE
  • Monday, April 11, 2016
  • Certification

Site Safety Index™ (SSI) – A Simple Model for Site Variations in Safety

In several of our technical papers over the years, we have noticed that failure rates for the manufacturer, model number are different at different sites, even when the processes were quite similar.  When I have mentioned this to end users and manufacturers, often the response is “Yes, I have…

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Is Your Team Ready for the Big Game?

Is Your Team Ready for the Big Game?

How does a team get to play in the NCAA tournament?  They don’t just buy plane tickets and arrive at the arena ready to play whoever else shows up.  In fact, there is a rather rigorous process to determine who gets to play and what seed they are, which…

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  • by Todd Stauffer
  • Tuesday, March 15, 2016
  • Software

PRODUCT SPOTLIGHT: SILAlarm V2.10 - Alarm Flood Suppression


The ISA-18.2 and IEC 62682 alarm management standards provide recommended targets for average alarm rate and for alarm floods - a condition during which the alarm rate is greater than the operator can effectively manage (e.g., more than 10 alarm per 10 mins)…

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Claiming alarms as an independent protection layer (IPL)

Claiming alarms as an independent protection layer (IPL)

An interesting question arose recently when creating an FSM plan:

Does the ISA-18.2 standard on alarm management address the claiming of the operator’s response to alarms as a layer of protection?

Not specifically, however the ISA-18.2 standard does require that alarms are rationalized, and that alarm system performance…

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Site Safety Index IMPACT on Failure Rates and PFDavg

Site Safety Index IMPACT on Failure Rates and PFDavg

Performing site audits for numerous customers can be very telling.  All sites have their own unique layout, procedures, documentation, and people.  Did you know that failure rates differ from site to site?  Are you surprised?  According to our recent webinar results, the majority of people aren’t, and in fact…

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A Year in Review: Functional Safety and Cybersecurity in 2015
  • by Dr. William Goble, CFSE
  • Tuesday, January 26, 2016
  • Certification

A Year in Review: Functional Safety and Cybersecurity in 2015

Good things happened in the fields of functional safety and control system cybersecurity in 2015.  I am not going to include the exciting new Star Wars movie as an event in the list as it does not really fit into the topic. But keeping focused, my highlights is 2015…

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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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