Industrial Must Modernise Safety Instrumented Systems

Industrial Must Modernise Safety Instrumented Systems

June 5, 2020

HIMA Vice President APAC Friedhelm Best says with factories, plants and major hazards installations re-opening in June, managers and owners need to consider not just COVID-19 safety and hygiene compliance, but for some, also increasingly the Singapore Safety Case Regime for major hazard installations.

By Friedhelm Best

Deep in a pandemic, every nation is trying its best to plan for a graceful exit strategy. It is as important to preserve a weakened economy and lives at the same time. Allowing workers back to the industrial workplace means both heightened hygiene, as well as conforming to safety, as recommended by the likes of the Singapore Safety Case Regime for major hazard installations (MHI).

There are many challenges down the road, and especially with companies seeking both modernization in a post-COVID-19 world. One of such challenges has to do with Safety Instrumented Systems (SIS) which manage operational safety of machinery and installations, and ensure that such operations never exceed safe limits, and if spikes occur in emergencies, provide emergency stop functions to preserve lives and facilities.

Conformity to standards

The first challenge for Safety Instrumented Systems is the conformity to standards, governed by the well-entrenched global standard for functional safety, the IEC61511 standard. There is a second edition since 2016 which contains updated and extended requirements, such as the need to do a security risk assessment as part of your safety life cycle.

In general, standards capture the state of the art of the technology and the procedures, and it is used as a reference for best practice. As technology and experiences are ever-changing, standards are also evolving. Legal requirements may also change.

In the event of an incident, an investigation will be made if pertinent laws and regulations have been observed during the planning, installation and the operation of an Safety Instrumented System. This highlights the importance of a periodical safety assessment.

An assessment and update of safety requirements can also trigger a modernization, such as when the current legal requirements are no longer met or if better technologies and procedures are available. Any kind of modernization is also a modification of the SIS, and may affect the operating license of the plant and its conformance to standards. There are existing guidance within the IEC61511 and the tightened NE126 to safeguard process control system safety equipment.

If there is proof that the Safety Instrumented Systems have been planned, installed, and operated in compliance with the regulations previously applied, this means that the availability of comprehensive safety requirements and documentation with the defined safety execution and maintenance strategy should be available. There must be a data recording and documentation of the operational experiences like functioning inspections or incident data.

A requirement is that the process risk and the legal conditions have not changed. Hence, there is no serious change of the plant or the boundary conditions under which the plant is operated.

Another requirement is that the safety function itself, named as ‘function plan’, has not changed to achieve the protection target with the same quality. If there is a change of equipment, the replacement equipment should provide equivalent or better safety specifications.

In the IEC61511, it also states that there are no compulsory changes due to new or changed standards. However, the user must be able to prove that a safety device is designed, maintained, inspected and operated according to the regulations, standards, and procedures that were valid prior to the release of the new standard. This is to define and prove that there is no need to renew examination due to modernization.

All these considerations are to ascertain if the risk level has changed because of conversion or device replacement. With new technologies, say for example a programmable safety system, new risks or new measures may take place. We must take care of automation security as well. Hence, the solution is to use a SIL3 certified system for the replacement and implement a systematic procedure according to IEC61511 which includes the specification and functional tests, of the changed areas or changed equipment.


The next challenge may mandate downtime for modernization. Downtimes should be shortened or avoided. However, as with large-scale industrial installations, the greater the conversion and technology leap, the longer the downtime may be expected. To avoid this, technology should be continuously up to date with the use of compatible system updates, upgrades or online conversion options. For example, at HIMA, we offer engineers tools or new versions of our operating systems, which can be implemented in the system online without stopping the process.

Always plan in the long term. Use compatible products or iterative shutdowns. If you have interconnected safety systems, you can replace them one after another and still, the old system can safely communicate with the new system.

Generally, updates also improve functional safety, automation security, and plant availability. This is because new versions always include bug fixes and enhancements which leads to a more robust installation.

Required expertise

Modernization demands expertise, which is a big challenge.

Starting with the status of Safety Instrumented Systems, do a periodical review of assets to know which devices are in use, how long they have been in use, and are there limiters to their lifespan?

Next, take care of ‘As-built’ documentation. Is the documentation up to date and does it really reflect the state of the installed systems? What are the critical needs and initial steps in modernization?

There will always be a need for expertise to bridge the existing systems with the news systems. Find experts who can help transition seamlessly with compatibility, little or no downtime. Some technologies and processes allow online troubleshooting and installation, which can help in downtime reduction.

When it comes to functional safety, stay on top of the current standards for the discussion and decision for the compliance and the impact on the operation license of your facilities and plants. Compile all the proof in hand, with the measure you need to consider during such modernization, and develop a concrete and compliant procedure and documentation to help your team complete the journey to modernization. The post-COVID-19 world will be a different one, and the most optimized, safest, most secure facility wins.

(Ed. HIMA Vice President APAC Friedhelm’s previous roles includes Sales Director for Europe and Africa at HIMA and Director of Global Key Account Management Industry, Eaton Corporation. Friedhelm says his career began as a Sales Engineer at HARTING in Germany and says he has Degrees in Precision Engineering from the University of Applied Sciences in Wilhelmshaven and in Industrial Engineering and Management. Friedhelm Best says he is a certified Functional Safety Engineer.)


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