These European standards have been adopted as international standards IEC 62278, IEC 62279, IEC 62425, so they are also relevant for non-European railways. An Independent Safety Assessor (ISA) must always be approved by the National Safety Authority (NSA); this is done in the Nordic countries on a case by case basis (i.e. for each individual assignment) and the approval is communicated to the customer rather than to the assessor. For all projects where SINTEF is or has been ISA, the responsible national safety authority - including non- European countries such as Australia, India and Malaysia - has explicitly approved the identified employees from SINTEF.
Independent safety assessment is a third-party judgement that the safety requirements for a system and its development process are appropriate and adequate for the planned application and is fit for its intended use. A person who carries out independent safety assessment is known as an independent safety assessor or ISA.
Note: In some industry sectors the term 'Functional Safety Assessor' is used for 'Safety Assessor'.
Who uses Independent Safety Assessors?
Anyone who needs or wants an independent assessment of safety. This includes:
• To comply with a standard that requires an ISA
• To be assured that a contractor's product is safe
• To assure your customer that your product is safe
• To assure yourself that your product is safe
• To demonstrate to a regulator that your product is safe
Because the safety assessment provided by the ISA is independent of existing safety analysis and assessment, it can provide confidence that safety claims are justified and that any weaknesses that are identified have been dealt with appropriately.
In some situations, an ISA is mandatory. For instance, when carrying out work on safety critical systems for the railway industry.
In some other cases, use of an ISA is good practice. For instance, IEC 61508 represents best practice for safety-related electrical/electronic/programmable electronic systems (E/E/PES). It requires the use of independent safety assessment (called functional safety assessment in the standard) where the degree of independence depends on the Safety Integrity Level of the system.
As well as providing assurance of safety, using an ISA can help to focus safety planning and analyses. This can come about naturally by answering questions and providing safety information for the ISA. However, in addition, an ISA is often able to offer generic guidance that does not compromise independence, particularly in the early stages of a project.
• According to CENELEC standards DIN EN 5012x
• According to the Common Safety Method CSM (352/2009)
• According to functional safety IEC 61508
• According to national rules and regulations