Providing independent layers of protection with integrated safety systems

Modern automation systems incorporate (Safety Integrity Level) SIL certified Safety Instrumented Systems (SIS) as an inherent part of the system. Phrases such as “integrated but separate” are often used to illustrate the undiminished safety integrity of these fully integrated automation systems. This paper will cover how an Integrated Safety System (one that performs both basic process control in addition to safety protection) can still act as a completely independent layer of protection and enhance safe operation by addressing additional sources of risk The paper will describe industry requirements throughout the safety lifecycle, and the design requirements on the safety system to provide the most comprehensive platform for process safety management, including safety engineering tools, operation management tools including alarm management, management of change and maintenance. This paper will discuss the basic requirements of the standard for SIL–1, SIL–2, & SIL–3, which is more than just (Probability of Failure on Demand) PFD, and the potential end-user benefits enabled by a fully integrated system.