Kenexis - Functional Safety Podcast

The SIS is built, tested, and waiting on the factory floor. Now comes installation and commissioning, where new problems can surface.

During the Factory Acceptance Testing (FAT), you're going to find issues.  You can’t fix them on the spot— you need to trace each one back to wherever it originated in the safety lifecycle and correct everything downstream from that point.

Factory Acceptance Testing is where Ed Marszal picks up in Clause 13, starting with an admission: the clause title may be wrong, since 13.2 is called Recommendations when every other point-two clause in the standard states requirements. Scope matters here FAT applies to the SIS logic solver, the engineered, customized subsystem, not off-the-shelf field devices like a pressure transmitter. Ed works...

Clause 12.5 closes out the software section with the meat of application program testing: verification planning tied back to Clause 7, an independent competent-person review, and nine bullet points covering conformance testing, exercising all parts of the program, representative data ranges, negative testing, timing and sequence checks, communication overload stress tests, and integration with the...

The best and safest way to write software is to break things down into tested reusable modules...

At the risk of saving you from hours of unnecessary work, in our latest episode, we tackle a surprisingly common habit: trying to do application program design and implementation at the exact same time. Tune in to hear why this happens, why it's a problem, and how to stop doing it! Grab your headphones and let's streamline your workflow!

Designing software comes before writing it. We're still inthe design phase and will be for a bit… Listen in to this episode as the discussion of this topic continues.

To clarify, the standard separates application program design from its actual implementation.  It feels like a bit much… Join us for our 50th episode as this is discussed in more detail!

The startup sequence of a Safety Instrumented System (SIS)represents a critical vulnerability phase, as it triggers initialization code that rarely executes during steady-state operation. Join us as this important topic is discussed in this episode.

The first technical safety standard ISA84 didn’t talk about programming in it at all.  So, we decided when we added it, wewould wildly over complicate the situation…

Do not incorporate human failure into your SIL verification calculations, it will actually lead you to do the wrong thing. In this episode, this important topic is covered by our industry expert as he discusses these sections and shares his vast knowledge and experience.

When it comes to SIL verification calculations, we look at Clause 11.9. It’s appropriately titled 'Quantification of Random Failures'…putting the focus on 'random' right there in the name.

A device should never remain in bypass indefinitely. Bypass duration must be time-limited, and appropriate compensating measures must be implemented.   Listen in for more information and thoughts on this important topic.

The design shall allow for testing of the SIS either end to end OR in segments meaning you could test one piece at a time, but when you do that, you have to be very careful… Tune in as this topic is explored in greater detail, covering Sections 11.8.1 to 11.8.3 in this episode.

Many users of generic, off-the-shelf PLC logic solvers for Safety Instrumented Systems are surprised to learn that maintenance and engineering interfaces are not permitted to be connected while the process is in operation. Join us as section 11.7.3 is discussed in more detail.

Bypasses and resets are two standard data elements routinelytransmitted from the BCPS to the SIS, and this communication must be done safely… Listen in for more information on this section.

You can transfer data to and from the Safety Integrated System (SIS), but your design must prevent an outside failure from causing an internal SIS failure. In this episode, we dive into the crucial world of secure data transfer for SIS.

Don't let the certificate distract you. Your role as an instrumentation and control engineer requires continued diligence. The work still needs to be done!

Did you know that you can install Programmable Logic Controllers (PLCs) based on prior use without being certified? Sounds easy, right? Think again! While they are exempt from formal certification, we reveal why achieving full compliance with installation and safety requirements is often an extremely difficult, if not impossible, hurdle for engineers. Tune in to learn why relying on prior use migh...

The devices you use in your safety instrumented systems DO NOT have to be certified! We're cutting through the noise to give you the facts on what truly matters for functional safety. In this episode we discuss the actual requirements—the principles, standards, and engineering practices—that dictate a device's suitability.

You achieve a given SIL target by running a calculation that verifies you achieved the proper probability of failure on demand, yet the standards committee doesn’t trust to do that properly….

How should the safety instrumented system respond to adetected failure?  Well, it will respond however you want it to respond…

Unscrupulous equipment vendors often bury critical safety information in a product's safety manual to get their products certified. Therefore, it's essential to read the manual thoroughly to uncover any potential hazards. Join us as Ed discusses this topic in more detail.

Energize to trip or de-energize to trip, that is the question… and the answer is… you can do whatever you want…

A device used by the SIS shall not be used by the BPS (unless that’s what you really want to do) …. Join Ed to hear his thoughts, experience and insights as he digs further into Clause 11.2.9 to 11.2.10.