From an industrial point of view, Safety is protection of equipment, facilities and processes against hazards or threats to minimize risks in all encountered or foreseen operating conditions.
Hazards (or dangers) and threats, when associated (in contact) with some activity or situation constitute the Risks.
The notion of Safety is related to the more general one of Security, which includes in particular the protection of people (workers and public).
Eventually, Safety is linked with Quality.
Safety examines all dangers and threats from the point of view of Risks and possible Consequences on equipment and facilities, on environment and, finally, on people. Thus, safety aims for security, of which it forms part.
Hazards and threats to consider in the context of Safety are:
failures of equipment ensuring the operation of facilities;
aggressions from inside the installation (fire, flooding due to pipe or tank rupture, etc.);
aggressions from outside (river flood, earthquake, tsunami, aircraft crash, etc.).
Consequences to prevent are:
pollution of the environnement.
The general process of Safety applies to all activities which cannot a priori exclude environmental pollution or damage to persons, in particular:
all industrial activities;
Specific risks and their consequences depend on each activity (for instance, manufacture or use of sodium induces toxic risk due to sodium oxides and soda aerosols in case of fire).
These risks are managed under Regulations applicable to different activities, according to their location. In general, these regulations:
lay down steps and specific studies such as environmental impact study before granting authorization to pursue the corresponding activity;
prescribe specific measures to palliate certain risks, such as fire alarms.
To manage all the risks associated with a given activity, in accordance with all associated rules, it is essential to adopt a consistent approach.
The safety approach in nuclear industry is particularly well accomplished: in particular, it uses Defence in Depth.