exida explains Blog

Over the course of several blogs , I will talk about getting realistic failure rate data, where this failure data comes from, and how different methods of failure data analysis compare. I think if you understand this, you will begin to get a very good feel of what it…

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Over the course of several blogs , I will talk about getting realistic failure rate data, where this failure data comes from, and how different methods of failure data analysis compare. I think if you understand this, you will begin to get a very good feel of what it…

Read More...

Over the course of several blogs , I talked about getting realistic failure rate data, where this failure data comes from, and how different methods of failure data analysis compare. I think if you understand this, you will begin to get a very good feel of what it takes…

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Industry Benchmark Survey on Alarms as Safeguards and Independent Protection Layers (IPLs)

exida recently conducted an industry benchmark survey on the practices for the use of alarms as safeguards and IPLs. With over 200 safety practitioners from around the world providing responses, you can use the survey findings to…

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This is a question I’ve been asked many times, with some stating that as long as the PFDavg (or PFH) meets the target SIL then that’s fine.  Whereas this statement is partially true, it is not the full answer.  IEC61511 defines the criteria for meeting the requirements of an…

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Oftentimes when this comes up during class it’s clear that there’s a misunderstanding as to how these three variables can impact the PFDavg calculations.  Mission Time is defined as the period of time over which a set of Safety Instrumented Function (SIF) equipment is expected to operate without major…

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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…

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Both Process Safety Analysis (PHA) and Layer of Protection Analysis (LOPA) occur in the early stage of the Functional Safety Lifecycle, detailed in both IEC 61511 and IEC 61508. They both serve significant roles in the whole process safety management. Yet, as a facilitator…

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It is tough to receive an email with this message from a prospective CFSE candidate.  I know that when I have failed exams, I want to understand what was wrong so I can study those areas of knowledge more deeply and try again. Given the recognition and prestige…

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I am often asked whether extending proof test intervals will be a problem. 

This is a tricky question. The design and engineering SIL calculations for the Safety Instrumented Functions (SIFs) are taking credit for a specific proof test interval with a defined level of coverage, as defined within the…

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IEC 61508 and IEC 61511 are known as “performance” based standards.  Specific design rules, as found in “prescriptive” standards, are not included, allowing for innovation and new technology, as well as creativity and advancement.  However, it does imply that a certain level of competency is required.

Others would strongly…

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Part of the changes to the IEC61511 standard in 2016, some five (5) years ago now, was to emphasize the need to do a better job with regards to the Operations and Maintenance phase of the safety lifecycle.  One of the key aspects of the Operation and Maintenance phase…

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How often do Managers see training budgets being cut, or personnel becoming blasé about training in general?  Isn’t it the norm that annual performance reviews involve reviewing training requirements?  Realistically, how often do these training requirements get ignored and/or forgotten about during the year?  The answer, I’m afraid, is…

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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 exida publication  Practical SIL Target Selection - Risk Analysis per the IEC 61511 Safety Lifecycle which is based on numerous…

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Reliability engineers have known for decades that realistic data must ultimately come from one source, quality field failure data for devices operating in a similar application. 

Perhaps that is why IEC 61511:2016, Clause 11.9.3 states

“The reliability data used when quantifying the effect of random failures shall…

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The international functional safety standard IEC 61511 provides the safety lifecycle as a steadfast guideline to assess and mitigate risk for manufacturing processes including refineries, chemical, petrochemical, pulp and paper, and power plants. To achieve a functionally safe system, it is essential to follow each…

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I just read a great article in the May issue of IEEE Spectrum magazine called “Managing Risk and Responsibility During a Crisis.”  The author Robert N. Charette says “If the American people desire the federal government to be their risk manager of first resort, then an open and…

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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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Experience is a good teacher.  But how do you get the experience?  

Formal classroom or online training is often available for more general skills, but on-the-job training usually provides a more in-depth path to gain such experience.  After doing a job for a while, working through difficulties with colleagues,…

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