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Safety standards play catch up

April 26, 2021
Angela Summers of SIS-TECH charts the recent history of process safety, and details how standards can help digitalization evolve
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Even though COVID-19 and the Texas freeze's power outages are the latest, most visible forces impacting many process industries and safety efforts, digitalization has been steadily increasing for years, and safety standards are ramping up to help.

"Previously, transmitters installed in the 1980s could run for 30 years or more. However, as transmitters got smarter and added diagnostics, their lifecycles got shorter due to their onboard software," says Angela Summers, president at engineering consultant SIS-TECH. "We don't know how much shorter, but it could be 30-50%, depending on when and to what extent suppliers upgrade their products." Of course, such short lifecycles can be a problem for users responsible for thousands of devices, so Summers adds that there have been ongoing meetings by the subcommittees developing the IEC 61511/ISA 84 standard for safety instrumented systems (SIS). These efforts include the launch of the new ISA 84 Working Group 3 guidance on obsolescence strategy, which plans to release a review draft in May 2021.

"Because so much process equipment only gets replaced after running until it breaks, many users don't want to hear about replacing components simply because they're obsolete, rather than patching them and trying to keep them running," says Summers, who is also an ISA 84 member. "Managing all the devices in a process facility—and then planning to address those that are obsolete—isn't something many process engineers have been dealing with. However, after 50 years of their process applications remaining basically the same, many engineers are realizing they need a new path forward. They're learning they need to integrate digitalized systems and cybersecurity, so they can successfully migrate to a new operational world, while keeping the old one running."

Summers reports ISA 84 WG 3 will cover several topics, but will focus on how to assess obsolescence, and how to justify replacing obsolescent devices to managers. "Digitalization also ties into obsolescence. Old systems only provide a limited view of what can happen in a process because they only work with a few architectures and communication protocols, so users don't get access to the data beyond their plant floor and can't leverage outside resources to solve problems," she explains. "However, new systems can work with cloud-computing services, so you can see what hosts are running or what the trends look like, resolving problems faster. This is why a lot of hardware will go away, while those that remain provide repeatable, reliable and timely data."

Summers adds that managing obsolescence doesn't always involve a clear-cut migration from old hardware to new software, and that transitioning can get murky when hybrid systems of older hardware and next-generation hardware need to coexist. "Some devices are available for Ethernet networking and Internet of Things (IoT), and some are not, so the question is how does a user take advantage of the next generation when older devices don’t support it? Or, if a user is trying to simulate part of a production line, how can they do it if the data can't be delivered at the speed the simulation needs?" asks Summers. "This is a big challenge because most process plants have patchworks of applications and devices that were updated at different times, but IoT and the cloud is the way things are going to be."

Digitalization runs ahead 

"Process safety is usually upgraded after users migrate to new process monitoring and control technologies, but I don't think safety is going to slow down digital transformation. Digital transformation and its available data, visualization and simulation tools are going to pull process safety along with it," says Summers. "This is because software tools like hooking up models to digitalized clones of control systems allow users to simulate events, and see how their production and safety instrumented system (SIS) responds. This lets users optimize operations and safety, improve their interfaces, enable controls recovery from events, and produce data trends that can be compared to earlier estimates. These simulations also make future estimates more accurate, and reduce much of the usual guesswork in maintaining production and safety."

Summers reports the key to effectively simulating operations and safety systems is the data that's fed to the model, and how closely the simulation matches the actual process to tighten estimates. She adds that SIS-TECH has been working with Indiss Plus dynamic simulation software from Corys that uses chemistry first principles to model routine operations and infrequent events.

"We also understand that we can't chase every shiny penny software out there. Process safety practitioners are trained to be cautious and conscious of safety loops that don't run as often as processes that are running all the time," explains Summers. "We preach that SISs should adopt proven technologies, so operations needs to check them first, see how they impact production, find and address any gotchas, and gain sufficient experience before using them for process safety. This is good practice that still applies in the new, increasingly digitalized, and hopefully post-pandemic world. The need for severity and frequency evaluations in PHAs and LOPAs aren't changed by technology. They can still identify failure mechanisms, help users understand the frequency of safety issues, and help them reduce the potential for high-hazard events.

"I've been using remote conferencing and web-based tools for 25-30 years, but they weren't used to do PHAs because it wasn't considered good practice. They didn't enable the team dynamic that PHAs require, in which groups and members must be willing to say what their processes and facilities truly need to be safe. In the past year, of course, online meetings became essential, COVID-19 got us comfortable with remote work tools, and now we're doing PHAs and LOPAs via Zoom and Microsoft Teams. The good news is modern video and teleconferencing don't need the special setups and equipment of the past, they experience fewer disruptions, and can be done on anyone's laptop or tablet PC screen by downloading a software app and granting access to our PC's microphone and camera. Virtual meetings aren't always perfect, but we can interact in mostly real-time, and collaborate like we're in the same room."

About the author: Jim Montague
About the Author

Jim Montague | Executive Editor

Jim Montague is executive editor of Control. 

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