exida explains Blog

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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Most engineers who design and verify safety instrumented functions (SIFs) understand how hard it is to design a manual proof test with high effectiveness (also called high proof test coverage). Those folks who understand that a proof test is not likely to detect all failures never use simplified equations…

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exida has traditionally been involved in industries such as oil and gas, chemicals, power generation and automotive.  While these are a diverse set of industries, many of the techniques that we use such as FMEDA (Failure Modes Effects and Diagnostic Analysis), Risk Assessment, Threat Modelling, etc.…

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At exida we have studied hundreds of sets of field failure data from various sources.  Some of these data sets have indicated differences in failure rates by two orders of magnitude for the same product type!  After tracing through the data collection process for many of these field failure data sets,…

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When we first invented the FMEDA technique in the late 1980s the biggest problem was the component failure rate and failure mode data.  Still is.  I picked up a well-known standard for component failure rates and saw a date of 2010.  The technology world has gone through an order of…

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Recently I witnessed something I never thought I would in the engineering profession: I was told by a system designer that even though they knew the safety reliability data for one device was too optimistic, they were going to use it because it meant they didn’t need to…

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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…

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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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exida has launched the web site www.silsafedata.com. SILSafe Data is a web site listing a number of product categories used in process control and the expected range of failure rates for process industry applications. The use of realistic and application appropriate failure rate data has a significant…

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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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In this blog, I will talk about the FMEDA method and how it can generate realistically accurate failure rate data.

The first question we have to ask is “why do you need failure rate data ?”

One of the fundamental concepts in today’s functional safety standard, IEC 61508 and…

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www.SILSafeData.com is a complimentary resource that contains the upper and lower bounds failure rates for many categories of automation equipment, as well as the methodology used by exida to derive the numbers.  

Many of you have asked how to…

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In the 1980’s, there was a raging debate in the functional safety committee about redundancy versus diagnostics. Some said functional safety could only be achieved with redundant systems. This was strongly supported by Triple Modular Redundant (2oo3) safety PLC vendors. 

Others argued that diagnostics would be an equal or…

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If you find yourself faced with this question you might be wondering why it is that having successfully used risk assessments without FMEDA your team are suddenly faced with the complexity of executing FMEDAs.

Maybe us safety people answer with a follow…

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With the drive for digitalization and the Internet of Things the expression “Content is King”, coined by Bill Gates, has now been replaced by “Data is King”. This is especially TRUE in functional safety where the safety and reliability predictions generated from a Failure Modes, Effects & Diagnostics Analysis…

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