Functional safety plays a key role in all process plants and the chemical industry has especially high requirements for the protection of people and the environment. Designing a standard-compliant safety circuit is no trivial matter. The best way to achieve this is with prudent design principles and reliable SIL data that can be used for calculations. We will be happy to provide you with the necessary data for your risk assessment and will support you during the implementation with our tried-and-tested components and redundant systems.
To ensure that a system does not become a danger to people and the environment in the event of an emergency, you must design it systematically for functional safety. The SIL specifications are therefore a key criterion for plant engineering and construction, especially in the chemical process industry.
SIL stands for safety integrity level. It is an international measurement used to classify the functional safety of a system. There are four such levels, from SIL1 to SIL4, which poses the highest risk and therefore requires the strictest measures. What this means is that you use the failure probabilities of the components to perform an accurate risk assessment, take measures to minimize residual risk,select suitable devices and finally ensure the correct compliance of the SIL functions in recurring tests.
The SIL classification is based on two international standards: IEC 61508 and IEC 61511.
IEC 61508 (“Functional Safety of Electrical/Electronic/Programmable Electronic Safety Systems”) is the basic standard. It describes how to assess risks and the measures required to design suitable safety functions. It therefore also includes the requirements for the individual components of the safety circuit. These include sensors such as pressure sensors, temperature sensors, and level gauges or the evaluation and output unit plus automated process valves.
IEC 61511 (“Functional Safety – Safety Instrumented Systems for the Process Industry Sector”) applies specifically to process automation. This mainly focuses on low-demand applications with lower requirements, which are standard practice. Among other things, IEC 61511 contains the selection criteria for sensors and actuators, for example in terms of operational reliability.