Consulting Engineer's Office EDOH

Functional Safety

Functional safety is a very versatile and complex discipline. Functional safety is related to medical engineering, aeronautic, automation, automotive and rail industry.

The international standard IEC 61508 is the basic standard with respect to functional safety. Out of IEC 61508 many product or area specific standards were derived. Some specific standards are ISO 13849, ISO 26262, IEC 62061, IEC 61511, EN 50126, EN 50128, EN 50129, EN 50159. These standards are related to automation, vehicles, machinery, process control and rail.

The decision about suitable solutions will be done on basis of the system behaviour in case of faults. There are three main reliability groups:

Fail Safe:   
In case of a fault the system falls into a safe state by itself or by external measures and remains in the safe state.

Fail Functional:
In case of a fault the system falls into a degraded mode with limited functionality for a specified time before entering the safe state. The system can be operated for a limited time in case of failure.

Fail Operational:
In case of a fault the system can be operated without degradation for a specified time period before the system must be repaired. It's possible to repair the system while operating. The system has to be repaired in the specified time period.

Depending on the above described reliability groups the fault tolerance shall be specified for safety reasons. Any decision about a wrong architecture can have impact to life of people or to the environment. A safety concept has to be developed depending on the related safety standards.

In all phases of the life cycle there is the need for using analytical methods to get evidence about safety. Measures shall be used to reduce the risk to an acceptable level.

Details about services of the Consulting Engineer's Office EDOH related to functional safety: