For those of us who have an interest in Functional Safety but are not quite sure where it sits within the general Safety banner, this interesting little piece covers it quite well. But, for those in the area, is this a much too simple explanation?
In a similar manner to the way cyber-security has overtaken plain security as the current Big Issue (but distinguishes us from the guys who guard the gate), I can't help feel the functional tag is simply a means to distinguish us from the hi-viz jacket-wearing clip-board monitors (aka Health and Safety peeps) ;-)
Indeed, when I first gained the job title of Safety Manager, it didn't take long before I asked for the word Functional to be added...
Functional safety is a subset of system safety. Systems can produce many different types of hazards with different mitigation and risk control means. For example, a complex system may have to exhibit electrical safety (due to presence of dangerous voltages and currents), chemical safety (use and storage of hazardous materials), structural safety, biological safety (use and storage of hazardous lifeforms) and so on - as well as present occupational health and safety issues. That's why IEC 61508 has such a complex title - Functional Safety of E/E/PE Safety Related Systems - to show that it does not include these other aspects of system safety. Functional safety is about the need for active (as opposed to passive) risk control measures, generally (although not always) implemented by computer based or electronic systems. So it's not just a functional safety versus the clipboard and hi-vis jacket brigade occupational safety people.
You raise an interesting point, Ron... both IEC 61508 and its derivative ISO 26262 refer to Functional Safety of E/E/PE Safety Related Systems
While I agree with you that functional safety is a subset of system safety, the title of those standards implies that there is a functional safety aspect to non-E/E/PE (although probably not non-safety related?) systems, not that functional safety only applies to E/E/PE safety related systems.
Likewise, and despite my first rather blase reply) there will be some aspects of functional safety (and/or wider system safety) that overlap with the occupational safety sphere - notably in the operations area.
