exida explains Blog

Alarm Response Procedures: More than Just a Good Idea

Alarm Response Procedures: More than Just a Good Idea

From an operations point of view, one of the significant parts of the ISA-18.2 and IEC 62682 alarm management standards is the endorsement of alarm response procedures. An alarm response procedure, otherwise known as “Alarm Help” or “Alarm Response Manual”, is defined as guidance for response to an alarm (e.g., operator…

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Back to Basics 20 – Safe Failure Fraction, SFF

Back to Basics 20 – Safe Failure Fraction, SFF

Safe Failure Fraction (SFF) is defined as the ratio of the average rate of safe failures plus dangerous detected failures of the subsystem to the total average failure rate of the subsystem. It is defined for a single channel (no redundancy, 1oo1).

It is a measurement of the likelihood of…

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Getting the Best IEC 62443 Cybersecurity Certification?
  • by Dr. William Goble, CFSE
  • Thursday, January 09, 2020
  • Certification

Getting the Best IEC 62443 Cybersecurity Certification?

After careful planning and development of your system, the last thing you want to worry about is the credibility of your certification. Although it may seem like a given for your certification to be well accepted by your customers, it is never a bad idea to dig a little…

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Back to Basics 19 – Route 2H

Back to Basics 19 – Route 2H

Route 2H is one of two Architectural constraints options made available in the standards IEC 61508-2 and IEC 61511. Route 1H . Both Route 1H and Route 2H are limitations that impose the hardware selected to implement a safety-instrumented function, regardless of the performance calculated for a subsystem. 

What exactly is Route 2H

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CSB Cites Lack of Alarm Management as Contributing Factors to Blowout in Oklahoma

CSB Cites Lack of Alarm Management as Contributing Factors to Blowout in Oklahoma

Back to Basics 18 – Route 1H

Back to Basics 18 – Route 1H

Route 1H is one of two Architectural constraints options made available in the standards IEC 61508-2 and IEC 61511. Route 1H . Both Route 1H and Route 2H are limitations that impose the hardware selected to implement a safety-instrumented function, regardless of the performance calculated for a subsystem. 

Route 1H  is…

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exida’s Safety Reliability Analysis (SRA) and How It May Help You

exida’s Safety Reliability Analysis (SRA) and How It May Help You

We all know that an FMEDA is only as good as the assumptions made regarding typical design engineering practices and the database used for the failure rates.  Here is the catch, not all products are designed and manufactured per the same rules!  Many manufacturers boast that their…

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Delivering Situation Awareness During an Alarm Flood: Throw Your Operators a Lifeline

Delivering Situation Awareness During an Alarm Flood: Throw Your Operators a Lifeline

Alarm floods are periods of alarm activity during which the alarm rate is greater than the operator can effectively manage (e.g., when the operator receives ≥10 alarms in 10 minutes). During a flood situation awareness is compromised and alarms are likely to be missed. In the eleven minutes prior to the explosion…

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The Site Safety Challenge – Do You Follow Good Site Practices?

The Site Safety Challenge – Do You Follow Good Site Practices?

The question of whether companies follow good site safety practices is an interesting one. Firstly, what do we mean by good site safety practices?  I think most companies believe they follow good site safety practices but do they really? Are they really measuring and tracking this?

The basis of having good site…

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The Benefits of exida’s Site Safety Index (SSI)

The Benefits of exida’s Site Safety Index (SSI)

New reports out now are claiming that an aging, failed elbow pipe appears to be the initial cause of a June 21 fire and subsequent explosions that injured five people at the largest oil refinery on the East Coast, federal investigators said.

The U.S. Chemical Safety and Hazard Investigation…

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Back to Basics 17 - PFH (Probability of Failure on Demand per Hour)

Back to Basics 17 - PFH (Probability of Failure on Demand per Hour)

PFH (The Probability of Failure on Demand per Hour)  is the probability that a system will fail dangerously, and not be able to perform its safety function when required. PFH can be determined as a probability or maximum probability over a time period of an hour. IEC…

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Evaluating Alarm System Performance in a Multi-Operator Control Room

Evaluating Alarm System Performance in a Multi-Operator Control Room

Situation: There are three operator consoles (positions) in the same control room. There is one general alarm horn that goes off whenever a new alarm comes in from any one of the three consoles. The horn draws the attention of each of the three operators.

Question: How are the…

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How Cars Relate to exida’s Site Safety Index (SSI)

How Cars Relate to exida’s Site Safety Index (SSI)

I got a new car.  The process was a bit disturbing. It took over an hour to go through the “set-up” menu. And it was suggested that I return for a second training session after spending time studying the manual and testing different settings.  I was thinking how different things…

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Guest Blog: Thar’s Gold in Them Thar Failure Data

Guest Blog: Thar’s Gold in Them Thar Failure Data

Failure data collection can seem tedious, time consuming and expensive.  Just figuring out what data to collect can be challenging.  Failure data analysis can be overwhelming with a sense of “I don’t even know where to begin.”  So it is not surprising that these useful, vital activities are often neglected especially when…

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Back to Basics 16 - PFDavg

Back to Basics 16 - PFDavg

PFDavg (the average Probability of Failure on Demand) is the probability that a system will fail dangerously, and not be able to perform its safety function when required. PFDavg can be determined as an average probability or maximum probability over a time period. IEC 61508 and IEC…

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