Note 1 to entry: In standardization, the safety of products, processes and services is generally considered with a view to achieve the optimum balance of a number of factors, including non-technical factors such as human behaviour, that will eliminate or reduce avoidable risks of harm to persons and goods to an acceptable degree.

Note 2 to entry: Risk that is not tolerable should be defined case by case.

Note 3 to entry: If no conditions that might lead to risk which is not tolerable can occur, then the EES system is in a safe state; otherwise, the EES system is in an unsafe state.