What is a safety instrumented system? 

A safety instrumented system is often the last line of defense before a hazardous event occurs at a plant or operation. A SIS is composed of logic solvers, sensors, and final elements. These systems detect “out of control” process conditions that could lead to an unwanted incident, and then automatically return the process to a safe state. But it’s important to remember that safety instrumented systems (SIS) are different from process control systems.

Safety systems are applied across many industries. Emergency shutdown systems and fire and gas detection are among the most common applications. But there are other areas where a SIS can help protect workers and operations such as:

• Burner management
• Turbomachinery control and protection
• High integrity pressure protection