Safety Instrumented System Design and Implementation: Impacts to the Engineering and Construction Work Process

摘要

The process industry in the United States is mandated to use the ANSI/ISA-84.01-1996 standard for the design and implementation of a safety instrumented system (SIS). The evolution of SIS requirements, however, continues with the acceptance of IEC-61511 and the anticipated move to this international standard in place of ANSI/IS A-84.01-1996 in the near future. Engineering and Construction (E&C) companies have substantial responsibility to design, engineer and construct process and industrial plants utilizing the safety instrumented systems consistent with the life-cycle requirements inherent in the current standards. This paper will discuss the work process currently followed by one E&C company from project development and execution through start-up and commissioning. The changes anticipated after full migration to IEC-61511 will also be covered, including timely design and analysis of SIS components, documentation, facilitation of owner/operator requirements, and conformance to standards. To an E&C company, the desirable goal is delivering a well-engineered SIS, in compliance with standards and codes with minimal engineering rework. It should include well-organized testing and final commissioning following the construction process, and a well-documented and maintainable system that meets customer expectations. The work process will also review the role of the manufacturer and systems integrator.