Functionalsafety

Importance of functional safety in the process industry

The objective of Functional Safety is to ensure the safety of people, the environment, machines, devices and systems. This is done primarily by identifying possible sources of danger and the resulting risk minimization.

Functional safety is an important component of systems used in the process industry as, among other things, automated processes take place here that can pose risks to people, the environment and the plant. Systems in the process industry must be safe and reliable. A malfunction can have serious consequences.

If the functional safety is not fulfilled, this can result in health hazards for people or environmental disasters in the worst case.

IEC 61511: Standard for functional safety in the process industry

In the future, more and more automated plants and systems will be used, which must always be tested for safety. Various standards have already been set to increase the safety-relevant systems:

The international standard IEC 61511 provides the standard for safety instrumented systems (SIS) in the process industry. It describes methods and procedures for how these systems must be planned, designed, implemented, operated and maintained in order to minimize risks and ensure safety.

In addition to the IEC 61511 standard, there are other norms and standards that are also used and important for machines in the process industry, for example. Here, too, the aim of these standards is to minimize risks by achieving a high level of safety for machines, devices and systems. These include, for example:

1. IEC 61508: This international standard specifies the requirements for the functional safety of safety-related electrical/electronic/programmable electronic (E/E/PE) systems.
2. VDI/VDE 2180: National standard for "Functional safety in the process industry". This guideline is based on DIN EN 61511 (VDE 0810) and applies to plants in the process industry, for example in the chemical and petrochemical industries. It represents a proven way of implementing the requirements of the 12th BImSchV (Hazardous Incident Ordinance) for PCE equipment with safety function.
   
3. DIN EN IEC 62061: This standard specifies the requirements for the safety of machinery - Functional safety of safety-related control systems.
4. DIN EN ISO 13849: This European standard "Safety of machinery - Safety-related parts of control systems" specifies the requirements for safe operation.

Safety Integrity Level (SIL) in Functional Safety

Safety Integrity Level, abbreviated SIL, is a measure in functional safety that describes the probability of failure due to a fault or the risk reduction of a system or a safety-relevant function.

A safety integrity level (SIL) is determined by the combination of various factors such as:

1. the probability of occurrence of a hazardous event
2. the severity of the damage caused by such an event
3. the probability that the safety system or safety-related function will prevent the dangerous event from occurring
4. the likelihood that the system or function will operate properly when needed.

There are 4 SIL levels: SIL 1, SIL 2, SIL 3 and SIL 4.

The higher the SIL level, the higher the level of protection against the effects of dangerous events in a plant.

As a general rule, the Safety Integrity Level is used in Functional Safety to define and classify the requirements for the safety of equipment or systems.