exida explains Blog

Entries tagged with: FMEDA

  • by John Yozallinas, CFSE
  • Tuesday, December 17, 2013
  • Certification

12 Days of Christmas: Safety Edition

What’s on your Christmas list?  Instead of relying on Santa, here are some gifts you can expect from a SIL 3 compliant process:

Conceptual Design and SIL Verification’s Ultimate Resource

Conceptual Design and SIL Verification’s Ultimate Resource

Cycle Testing for Static Applications? NO!

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…

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Dare to Be Different

Dare to Be Different

Does Everyone Really Ignore Failure Rates?

Does Everyone Really Ignore Failure Rates?

While discussing functional safety certification of an integrated valve assembly with a manufacturer, exida stated that all devices (actuator, pneumatic parts, valve, etc.) must be IEC 61508 certified. The manufacturer said this was no problem, and provided a set of exida and TÜV certificates. 

Of…

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Field Data Validation with Predictive Analytics

Who cares about field failure data? Why are we even here?

IEC 61511 – Fundamental Concepts

The fundamental concepts from our functional safety standards are the probabilistic performance based design.  Many of you know that this was terribly controversial when this was first proposed. Even to this day, there…

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FMEDA Predictions
  • by Loren Stewart, CFSE
  • Thursday, September 01, 2016
  • Certification

FMEDA Predictions

The FMEDA technique is performed on a specific device (e.g., ball valve, pressure transmitter, temperature sensor, electronic module, etc.) specified down to the manufacturer and series/model. Based on the specifics of the design, the parts used to execute the design, the design margins, any automatic diagnostics, the…

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Getting Realistic Failure Rate Data - Part 4

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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Getting Realistic Failure Rate Data - Part 5

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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  • by Dr. William Goble, CFSE
  • Tuesday, August 04, 2015
  • Certification

Getting Realistic Failure Rate Data - Part 6

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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How to Calculate Proof Test Coverage
  • by Dr. William Goble, CFSE
  • Thursday, October 16, 2014
  • Certification

How to Calculate Proof Test Coverage

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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Most Failures are Systematic - NOT!
  • by Dr. William Goble, CFSE
  • Wednesday, April 16, 2014
  • Certification

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…

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Product Stewardship and Engineering Ethics

Product Stewardship and Engineering Ethics

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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Random vs. Systematic?
  • by Dr. William Goble, CFSE
  • Wednesday, May 07, 2014
  • Certification

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…

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Realistic Failure Rate Data – Necessary

Realistic Failure Rate Data – Necessary

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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SILSafe Data Website

SILSafe Data Website

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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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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The exida FMEDA Process - Accurate Failure Data for the Process Industries

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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Using SILSafeData to Check Your Failure Data Source
  • by Dr. William Goble, CFSE
  • Monday, October 29, 2018
  • Certification

Using SILSafeData to Check Your Failure Data Source

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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