Functional Safety FAQ - What is Functional Safety
Functional Safety FAQ
What is the definition of Functional Safety?
Functional Safety is freedom from unacceptable risk due to hazards caused by malfunctioning behavior of electrical or electronic system
What is Functional Safety?
Functional Safety is the idea that electronic systems need to be developed in a way which minimizes the possibility that people will be injured when a malfunction occurs. All electronics have some potential to fail, perhaps because of reliability problems or bugs in the design, or unforeseen noise in the system. An electronic system has Functional Safety if it was developed with a methodology that reduces the possibility of design bugs, and increases the capability to self-detect when the electronics are operating in an unintended way and then transition to a state in which people are less likely to be injured.
Does Functional Safety mean that everything must be fully redundant?
No. Although redundancy is a great method of ensuring that when a failure occurs that the system keeps running as intended, Functional Safety says that it’s OK to not function as intended as long as people don't get hurt. Ex: if something is wrong with the airbag system in a car, it is OK if the car's engine is prevented from starting. It’s also OK to allow the engine to start but disable the airbag and tell the driver that the airbag is disabled.
Are there any Functional Safety standards that define what must be done to achieve Functional Safety?
Yes, there are many standards that customize the Functional Safety concepts and ideas for specific industries. IEC 61508 for industrial products was one of the first standards, after which many others were derived from it, such as ISO 26262 for automotive, ISO 25119 for agriculture equipment, and ISO 13849 for machinery. Not all Functional Safety standards are derived from IEC 61508, such as IEC 60335 for appliances and DO-178 and DO-254 for aerospace hardware and software.
Is there one standard that is a superset of all the Functional Safety standards, so that if compliant to the spec, a system would be compliant to all the Functional Safety specs?
No. Although there can be many similarities, each standard must be evaluated separately for compliance. However, some customers might accept compliance to a variety of standards. Ex: a medical company might be willing to accept compliance to an automotive Functional Safety standard.