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Blog Entry: The Undetected Detective; PVST
Have you ever wondered why some dangerous failures are classified as undetected and others are classified as detective? Aren’t dangerous failures all dangerous? Why do we classify them differently? Let's say we have a plant that is running in normal operation mode and the system needs to trip. The safety…
Parker Hannifin Manufacturing SRL - Solenoid Valves types F, V, X and N
IEC 61508 in the Safety Automation Equipment List
White Paper: The Meaning of Diagnostic Test Interval and It’s Impact on the Performance of SIFs
This paper explains what a diagnostic test interval (DTI) is, how it is measured, and how it impacts the safety performance of a safety instrumented function (SIF). In applications where a dangerous condition occurs infrequently, the DTI has an insignificant impact on PFDavg. For example if a dangerous condition occurs…
News Item: New White Paper: Safety Instrumented Function Verification: The Three Barriers
Safety Instrumented Function Verification: The Three Barriers The three constraints (systematic capability constraint, architectural constraint, and probabilistic performance metric constraint) that are implied by requirements per international safety standards IEC 61511 [1] and IEC 61508 [2] to determine the safety integrity level (SIL) of a safety instrumented function (SIF) are…
News Item: exida Announces the Addition of Jonathan Moore to Support Automotive and Robotics Solutions
exida is pleased to announce the addition of Jonathan Moore to our North American team. Jonathan joins exida as the Director of Advanced Systems and has over 20 years of automotive and robotics experience in systems engineering, failure mode avoidance, and standards based software development. He joins from Autonomous Solutions…
News Item: Emerson Collaborates with exida to Reduce Complexity and Time Required for Safety System Setup
AUSTIN, TEXAS – Emerson and exida announce the release of the DeltaV™ safety instrumented system 〈SIS〉 configurator , an exida exSILentia® tool that automatically generates DeltaV SIS configurations. By pairing built-in DeltaV functionality with exida’s comprehensive software tools for functional safety, users can develop safety logic configurations much faster and…
News Item: Article in SCSC Newsletter: Conforming to IEC6511: Operations and Maintenance Requirements
An article authored by exida's Steve Gandy entitled: Conforming to IEC 6511: Operations and Maintenance Requirements has been published in the Safety-Critical Systems Club newsletter . It is hard to believe that the IEC 61511 standard has been in existence since 2003 and most companies operating in the process, chemical,…
White Paper: Safety Instrumented Function Verification: The Three Barriers
The three constraints (systematic capability constraint, architectural constraint, and probabilistic performance metric constraint) that are implied by requirements per international safety standards IEC 61511 [1] and IEC 61508 [2] to determine the safety integrity level (SIL) of a safety instrumented function (SIF) are described and discussed. Examples of their applications…
Recorded Webinars: What is Safety Culture?
A look at safety culture, how it effects SIFs and the Site Safety Index!
Numerous field failure studies have shown that the failure rate for a specific device (same Manufacturer and Model number) will vary from site to site. Research has concluded that random failures can be divided in to two categories: product specific and site specific. The difference in failure rates could be any range from 1.2X – 2X based on data received to date. The Site Safety Index (SSI) was created to account for these failure rates differences as well as other variables. exida has written the Site Safety Index (SSI) information in the FMEDA reports, to provide an overview of the Site Safety Index (SSI) model used by exida to compensate for site variables including device failure rates.
This webinar will provide an overview of the impact of SSI on random failure rates, realistic PFDAVG calculations, and the impact of a good safety culture on lifecycle cost, along with reviewing the changes in the exida FMEDA report which captures this information.
News Item: exida Presenting and Exhibiting at the 2017 Rockwell Automation Fair
exida will be presenting and exhibiting at the 2017 ROCKWELL AUTOMATION FAIR. The fair will be held at the George R. Brown Convention Center in Houston, Texas 15-16 November 2017. Stop by Booth 1717 and say hello. The 2017 Automation Fair® event will feature in-depth industry training and showcase Rockwell's…
Training Course: IEC 62443 Cybersecurity for Industrial Automation Control Systems (IACS) for Employees & Contractors
This course addresses the quality and understanding employees and contractors need to have on the topic of Cyber Security for the IACS space. The access granted to IACS networks is often the same for employees and contractors. The seriousness of access must be established with a joint work process similar…
White Paper: Plug the Holes in the Swiss Cheese Model
Stop using operator error as an excuse. Apply human factors considerations to improve your alarm system and help operators respond to alarms effectively. Alarms play a significant role in maintaining plant safety by notifying operators of an equipment malfunction, process deviation, or abnormal conditions that requires a timely response .…
Blog Entry: Human Factors in Alarm Management
Question: Which one of these layers of protection (operator response to alarm, relief valves, dikes, and safety instrumented systems) is not like the other? Answer: Operator response to alarm (Operator Intervention), because of the “Human” factor. It is very difficult to calculate the probability of failure on demand (or the…
News Item: New exida Academy Online, Self-Paced Functional Safety Courses
exida Academy is excited to announce the launch of a new Online, Self-Paced model of learning for our Courses. This new platform of learning will provide many benefits to customers. Students who cannot invest several consecutive days away from work will now be able to get the training they need…
ASCO, L.P. - Series 362 3-Way & 562
IEC 61508 in the Safety Automation Equipment List
Blog Entry: What do you need to know about traceability for IEC 61508?
Traceability is about connecting the dots to determine that the web of activities for a functional safety project have followed the proper paths. Think of it like cheating at hide-n-seek; it provides a shortcut to find all those requirements and design parts that are hidden in your specification documents. If…
Woodward Industrial Controls - SonicFlo Gas Fuel Control Valve
IEC 61508 in the Safety Automation Equipment List
News Item: exida Presenting and Exhibiting at the 2017 ISA Process Control and Safety Symposium and Exhibition
exida will be presenting and exhibiting at the 2017 ISA Process Control and Safety Symposium and Exhibition . The Symposium will be held at the Houston Marriott Westchase 6-9 November 2017. Stop by Booth 308 and say hello. Sponsored by the Process Measurement and Control, Safety and Security, Chemical and…
Recorded Webinars: How Proof Test Coverage Affects PFDavg for a SIF
It’s a common problem that some end users assume a perfect proof test is possible, whereby all dangerous failures can be detected, removed and the SIF restored, thereby negating the effects of “mission time”. Another misconception surrounds Proof Testing and what this means. Some consider Proof Testing to be a means of ensuring the SIF is operational and works, however, in reality, the purpose of the Proof Test is to be able to find dangerous faults that the automatic diagnostics are not able to find.
Since there is no such thing as a “perfect Proof Test”, we have to consider the effectiveness in terms of the percentage of dangerous faults we can find during a Proof Test (i.e. 80% coverage means we can find 80% of potential dangerous faults, leaving 20% we can’t find). The webinar will explain and demonstrate the impact of imperfect Proof Testing on the PFDavg for Low Demand SIFs and how assuming 100% coverage can lead to a significant overestimation of the SIL capability of the SIF.
This is important for all SIS designers and End Users to understand since they could be fooling themselves into thinking they have more protection than they actually have.
Blog Entry: Random versus Systematic Faults: What’s the difference?
I saw and responded to a LinkedIn discussion on this very issue, where someone had asked “if I have a misaligned limit switch that fails dangerously, then is it random or systematic? “. This is an intriguing question because many view human error as being systematic and, whereas, this is…