WIT Press

Safety status: an innovative concept for maintaining the safety integrity level of operational safety systems


Free (open access)


Volume 8 (2018), Issue 1



Page Range

139 - 149

Paper DOI



WIT Press




The safety of industrial sites or large research facilities such as CERN (European Organization for Nuclear Research) is obtained by the combined actions of physical security, cyber-security and functional safety that jointly contribute to risk reduction. To deal with functional safety, the IEC 61508-61511-61513 standards are used for regulating design, development and maintenance of the Safety Instrumented Systems (SIS) that implement Safety Instrumented Functions. The SIF’s performance is characterized by its Safety Integrity Level (SIL) determined through a risk analysis and conditioned by parameters related to the design, the staff’s skills involved in its development, operation and maintenance or the compliance with repairing times. Heads of facility and SIS responsible persons have to continuously master the SIL performance. This is a responsible act to guarantee the risks reduction barriers efficiencies, considering criteria such as periodic testing, spare parts availability, components obsolescence, by-passes, changes control, system real-time status, physical and cyber protections. The Safety Status software imagined jointly by CERN and ASSYSTEM inherits both the CERN experience on the specification and operation of safety systems adapted to the specific risks of particle accelerators and experiments and the know-how developed by ASSYSTEM as a major player in the engineering of nuclear installations, particularly in the field of design and maintenance of critical security and control systems. Safety Status establishes a functional safety dashboard of each system updated automatically or manually with data coming from relevant sources such as maintenance management, document management or the SIS itself. Through a friendly interface, it displays an overview of all the useful information that illustrates the health of the SIS and the integrity of its safety functions. After intro- ducing the concept, the paper presents the methodology, the main features of the software, and the experience feedback gained by its implementation on the CERN MEDICIS facility


safety system engineering, security global approach, SIS operation & maintenance.