SAFETY SPECIFICATIONS:
The principal concern of safety specification is to identify requirements that will minimize the probability that such system failures will occur. Safety requirements are primarily protection requirements and are not concerned with normal system operation. They may specify that the system should be shut down so that safety is maintained. In deriving safety requirements, you therefore need to find an acceptable balance between safety and functionality and avoid overprotection.
The activities in the general risk-based specification process, map onto the safety specification process as follows:
1. Risk identification: In safety specification, this is the hazard identification process that identifies hazards that may threaten the system.
2. Risk analysis: This is a process of hazard assessment to decide which hazards are the most dangerous and/or the most likely to occur. These should be prioritized when deriving safety requirements.
3. Risk decomposition: This process is concerned with discovering the events that can lead to the occurrence of a hazard. In safety specification, the process is known as hazard analysis.
4. Risk reduction: This process is based on the outcome of hazard analysis and leads to identification of safety requirements. These may be concerned with ensuring that a hazard does not arise or lead to an accident or that if an accident does occur, the associated damage is minimized.
