Defining the Safety Integrity Level of Public Safety Monitoring System Based on the Optimized Three-dimension Risk Matrix

The functional safety is applied to the public safety monitoring system. Based on optimized three-dimension risk matrix, the safety integrity level (SIL) of public safety monitoring system is studied. The research indicates that other independent layers of protection, as a supplementary, can safeguard the public safety monitoring system lacking of protection. The number of people in a public place is not considered in the optimized three-dimension risk matrix which causes the SIL derived from the three-dimension risk matrix to be rather backward-looking. So the number of independent protection layers or (and) the SIL of a safety function safety monitoring system should be decreased accordingly and make the individual risk is properly below the acceptable individual risk of the public safety. It is suggested that the functional safety of the public safety monitoring systems should be researched specially.