Safety Instrumented Systems (SIS) Management: Assess, Manage and Proof Test Instrumentation in Your Asset-Intensive Facility

In the energy industry, there’s no compromise to operational safety.

The annual accidental release (of regulated and/or extremely hazardous substances) report published by the U.S. Chemical Safety and Hazard Investigation Board (CSB) shows a worrying trend. In 2020, there were 39 cases. 2021 saw a 113% increase to 83 cases. 2022 and 2023 had 105 and 120 cases — an increase of 27% and 15% from the prior year.

Such upward trends urge end users to revisit their existing safety practices. A starting point? Using Safety Instrumented Systems (SIS) Management to effectively manage the reliability of critical processes and safety instrumentation onsite.

A SIS combines sensors, logic solvers, and final elements to serve multiple functions (i.e. SIF).  A SIF adds a protection layer when there are abnormal conditions in the plant. Each SIF is designed to ensure a safe state for a specific defined event (e.g. if a reading is higher than normal, there’s an automated action to shut down a valve). Furthermore, the SIF is mapped to specific SILs which indicate the severity of the risk. If the SIL is high (SIL 3 or 4), safety requirements need to be strengthened.

For process industries, there is a need to comply with international process safety management standards IEC 61508 and IEC 61511 that define SIL standards, instrument safeguards, safety lifecycle requirements, and more.

SIS management, part of GE Vernova’s Asset Performance Management (APM) Safety application, provides users the tools to assess, design, manage, and proof test their critical process and safety instrumentation. Key phases include:

• SIL Assessment: Supports multiple SIL methodologies, such as Risk Matrix, explicit quantitative Layer of Protection Analysis (LOPA), Process Hazards Analysis (PHA), as well as external SIL Assessment methods.
• SIL Verification: Helps users determine the probabilistic failure rate of a protective loop to determine if the protective loop will or will not meet the SIL requirements.
• SIL Validation: Allows users to define and conduct periodic proof tests to reveal undetected faults and integrate with APM where results can be re-used in the SIL Verification phase.

Having a robust SIS management tool promotes a better safety culture in the organization and helps eliminate hazards associated with industrial equipment and processes.

In addition to performing and tracking SIL analysis, a few unique functional capabilities in SIS Management include:

• Calculation of Probability of Failure on Demand (PFDavg) or Probability of Failure per Hour (PFH) to ensure SIF design meets integrity requirements.
• Generation of SIS trip reports which are records that store details on events such as trip alarms — cause of trip, cost of trip, etc..
• Review of performance metrics:

1. compare actual failure rates to design failure rates, work orders, and proof test trip reports.
2. identify and eliminate systematic failures.
3. evaluate demand rates based on incident reports and deviations. 
4. continuous monitoring of equipment condition.
5. recommendation tracking.

While most vendors focus on solutions at the design level, GE Vernova’s APM Safety application (part of the overall Asset Performance Management suite) is built at an operational level to seamlessly align with existing APM programs or frameworks developed by the organization.

In addition to the SIS management module, GE Vernova’s APM Safety application also includes:

• Hazard Analysis: A module that uses Hazard and Operability (HAZOP) analysis to identify and assess risks and acts as an input for SIS management.
• Management of Change (MOC): A module for creating and managing change projects, communicating changes to team members, and enforcing an approval system to provide accountability for the change.

All three modules allow users to follow a “closed loop” approach to safety and integrate safety lifecycle management initiatives with corporate asset hierarchy, Enterprise Asset Management (EAM), and APM programs.

Additionally, APM Safety can also integrate with other APM applications such as APM Health to monitor the health of SIFs, APM Reliability to investigate SIS and instrumentation failures, and APM Strategy to view HAZOP risks and optimize actions against other strategic actions. This helps in the standardization and replacement of multiple software solutions that may be prevalent in the current setup.

In addition to securing your facility from hidden safety issues, GE Vernova’s APM Safety allows users to lengthen proof test intervals for systems that are already installed. For each SIF, the dollar savings multiply significantly — which can positively impact your bottom line. From a compliance standpoint, insurance premiums can also be reduced by aligning to global standards such as IEC 61508 and IEC 61511.