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 Although they are essentially conservative in approach, Ian Curtis, Process Safety Consultant, Siemens Automation & Drives, urges the guardians of safety control systems in process environments to embrace technological innovation, aimed at making their lives easier.
There can be no compromise on safety within an industrial environment. A simple and stark statement, but one that presents many challenges to those working everyday in a process control environment with many potentially hazardous processes. Process accidents can have disastrous consequences for individuals and companies alike, ranging from loss of life, damage to the environment, litigation, destroying corporate reputations, and the potential for extremely expensive financial penalties.
Experience of working with the IEC61508 &IEC61511 safety standards varies widely. Many companies will have ‘tried and tested’ safety management systems that undergo constant review and refinement whilst other companies will have less experience because their exposure to safety instrumented system (SIS) deployment experience is often infrequent. Add in factors such as the potential for lack of safety competent manpower in smaller firms, and the continual thirst for education and knowledge around safety system standards - increasingly performance based and not prescriptive - and it is clear that implementation and operation of safety systems continues to present challenges to process companies, both large and small.
Within such a dynamic overall safety environment what are the current technological trends that are helping set the safety system agenda? I believe they fall into three main technology driven categories:
Safety Lifecycle Tools. As international standards such as IEC 61511 place emphasis on a Safety Life Cycle (SLC) approach, we are starting to see a move towards the development of supportive safety lifecycle tools. The traditional Cause & Effect Matrix (CEM) approach for documenting and defining safety logic is well established, but a move toward additional system lifecycle tools to aid the engineering community should prove beneficial. Such planning tools allow the engineer to document the CEM logic required for a SIS in a form that will be familiar to them but with the subsequent automatic creation of associated code in the SIS and testing and commissioning using the same CEM format for visualisation. This approach can remove the possibility of human error and misinterpretation, and will inherently reduce systematic errors. The enhanced functionality of such tools not only creates the logic in the system controller but also generates the operator interface along with the mechanisms for implementing overrides and bypasses in a controlled manner.
Another exciting development is the possibility of even automatically generating cause and effects from SIL verification tools based on SIF architectures.
Closer Integration with Control Systems. The recognized safety standards call for separation of process control and process safety. This has traditionally been achieved by a combination of physical separation and diverse systems, often from separate suppliers. Increasingly companies are seeking the benefits of a more integrated approach. The potential benefits, such as a reduction in spare parts, reduced training, simplified engineering and a more consistent, single window operator view on the process, offered by a single source integrated approach are compelling. Systems such as Siemens PCS7 have an integrated safety capability but retain the necessary functional separation between control & safety to satisfy the intent of the standards regardless of whether the control and safety code resides in the same controller or, most likely, in separate but identical controllers.
Increased focus on overall safety. End users have already discovered the benefits of fieldbus solutions within process systems. And the move towards enjoying similar benefits with safety instrumented systems (SIS) is well underway. The big benefit of fieldbus solutions lie not in upfront installation, but in ongoing operations and maintenance savings made available through advanced diagnostics and asset management tools. Using digital platforms, users will be able to continuously assess information in intelligent SIS components and enable analysis of safety performance, as well as enabling access to data and diagnostic information that will be essential for all testing, whether automatic or planned. Information advantages and reduced installation, maintenance and testing costs will ensure this technology moves onwards toward general acceptance replicating the standardisation seen with non-safety fieldbus solutions.
Process accidents can have terrible consequences. People lose their lives or suffer horrible injuries. Families and communities are devastated. Adopting and maintaining best practice in safety management, implementing a strong safety culture and conforming with current process safety standards is a major challenge for industry. Technology trends outlined above are seeking to make this challenge easier to meet and are set to become the safety system norm, and not the exception, in the years to come.
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