You can't have safety in a vacuum, and you can't have an effective safety instrumented system (SIS) in one either. Such was the theme of Mike Boudreaux's DeltaV SIS Roadmap session this week at the 2010 Emerson Global Users Exchange in San Antonio, Texas.
"It is all about risk management," Boudreaux said. "You have risk to personnel and risk of fines, lawsuits and insurability loss that you have to manage and mitigate. You have to manage the risk of unfavorable public perception too."
Among the trickiest risks to manage is that of unplanned shutdowns, he said. "Not only are they costly, but in most situations, it is during unplanned shutdowns that the highest incidence of abnormal situations occurs. And it is the response to abnormal situations that often produces a safety incident."
Effects also come into play from the economic situation, Boudreaux added. "We're doing more with less, doing it longer, and trying to cut expenses at the same time. When you add the ever increasing complexity of the process environment and the effects of an aging and less skillful workforce, pro-active safety measures are even more important."
It is essential to meet five key elements in order to use safety to increase return on investment (ROI). Those elements, Boudreaux said, are simplifying regulatory compliance, reducing engineering complexity, increasing visibility into the process, advancing flexibility to meet process needs, and optimizing the reliability of the process.
"We have put together a very deeply integrated safety lifecycle management system," Boudreaux said. This includes:
- Hazard analysis, layers of protection analysis (LOPA), and safety requirement specification from Meridium
- Document control, document repository, and management of change from Syncade
- The implementation step, where Meridium provides SIL verification and spares analysis, and Syncade continues to provide document control, repository and management-of-change services
- Device management, configuration, calibration and electronic loop testing from AMS
- Engineering tools, simulation and testing capabilities from DeltaV SIS, which rounds out management of change
- The operation step, where all the integrated services are brought together to serve the safety lifecycle process:
- Meridium provides reliability, production and performance analysis, calculates cost of unreliability and integrates with the ERP system.
- Syncade provides document management, proof tests workflow and reports
- AMS suite continues to provide device management, configuration, calibration and loop testing.
- DeltaV SIS provides SIF execution, event recording, bypassing and overrides, and management of change.
"Finally," Boudreaux said, "in the operations phase is when the benefits of using DeltaV Smart SIS field devices are found. Smart flow, temperature, level and pressure sensors provide not only the process variables, but they also provide diagnostics that can be used to predict the health of the safety instrumented system."
Boudreaux pointed out that there are, according to the ARC Advisory Group, three types of SIS. There is the traditional system, where the SIS and basic process control system (BPCS) are completely separated; sometimes these systems are interfaced through a gateway. The second type, exemplified by DeltaV SIS, is an integrated system, where the SIS and the BPCS are separate but are integrated at the information layer and use common design tools and interfaces. The third is the common system, where the SIS and BPCS use the same backplane.
"Security, especially the security of the safety system, has been a common topic in the last few weeks," Boudreaux said. "Emerson has created an integrated approach to safety system security, with a layers of protection analysis approach based very closely on safety methodologies. These layers include virus scanners, patch management, role-based access control, account management, secure architecture, the use of a DMZ (demilitarized zone), intrusion protection, firewalls, secure VPNs, policies and procedures, and management of change, and finally physical security."
Only DeltaV SIS provides a simple secure architecture, an integrated operations environment, separate control and safety hardware, and separate control and safety networks, according to Boudreaux. "Combined with the integrated safety lifecycle management system, DeltaV SIS optimizes process reliability, is flexible enough to meet your evolving needs, and gives you increased visibility into the process—all in a simplified engineering environment."