SIL Verification

What is SIL verification?

Industrial facilities and equipment commonly use automatic safety functions to control risks. These functions are often known as Safety Instrumented Functions (SIFs) or Instrumented Protective Functions (IPFs). Their purpose is to monitor specific parameters such as the temperature of a reactor, position of a moving part, speed of a motor, or the presence of a person or object using a sensor. When specified conditions occur, such as a temperature exceeding a limit, the function takes action to prevent harm.

During the plant’s design phase, the instrument engineers should confirm that the proposed SIF design is sufficiently reliable. This task, known as SIL verification, is a requirement of international standards such as IEC 61508 and IEC 61511, and includes two aspects:

• a calculation of the SIF’s probability of random hardware failure
• an assessment of the required level of hardware fault tolerance (redundancy)

SILability helps the engineer to execute these tasks correctly and efficiently, and generates a detailed report automatically.